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180 Multiprocess
Operating manual
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Welcome to a better way of welding.
This operating manual provides the basic knowledge required for
MIG/MAG, TIG and MMA welding, as well as highlighting important areas
of how to operate the Smootharc 180 Multiprocess machine.
With normal use and by following these recommended steps, your
Smootharc 180 Multiprocess machine can provide you with years of
trouble-free service. Smootharc equipment and technical support is
available through the national BOC Customer Service Centre or contact
your local Gas & Gearoutlet.
Please Note: This machine is to be used only by appropriately trained
operators in industrial applications.
Important Notice
This document has been prepared by BOC Limited ABN 95 000 029 729
(‘BOC’), as general information and does not contain and is not to be taken
as containing any specic recommendation. The document has been prepared
in good faith and is professional opinion only. Information in this document
has been derived from third parties, and though BOC believes it to be reliable
as at the time of printing, BOC makes no representation or warranty as to
the accuracy, reliability or completeness of information in this document and
does not assume any responsibility for updating any information or correcting
any error or omission which may become apparent after the document has
been issued. Neither BOC nor any of its agents has independently veried the
accuracy of the information contained in this document. The information in
this document is commercial in condence and is not to be reproduced. The
recipient acknowledges and agrees that it must make its own independent
investigation and should consider seeking appropriate professional
recommendation in reviewing and evaluating the information. This document
does not take into account the particular circumstances of the recipient and
the recipient should not rely on this document in making any decisions,
including but not limited to business, safety or other operations decisions.
Except insofar as liability under any statute cannot be excluded, BOC and its
aliates, directors, employees, contractors and consultants do not accept
any liability (whether arising in contract, tort or otherwise) for any error
or omission in this document or for any resulting loss or damage (whether
direct, indirect, consequential or otherwise) suered by the recipient of
this document or any other person relying on the information contained
herein. The recipient agrees that it shall not seek to sue or hold BOC or their
respective agents liable in any such respect for the provision of this document
or any other information.
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BOC Smootharc 180 Multiprocess operating manual
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Contents.
1.0 Recommended Safety Guidelines andPrecautions 4
1.1 Health Hazard Information 5
1.2 Personal Protection 5
1.3 Electrical shock 7
1.4 User Responsibility 7
2.0 MIG/MAG Operating Manual 8
2.1 Introduction to Metal Inert Gas(MIG) & Metal Active Gas (MAG) 8
2.2 Introduction to Flux Cored Arc Welding (FCAW) 8
2.3 Introduction to Metal Cored Arc Welding (MCAW) 10
2.4 Modes of metal transfer 11
2.5 Fundamentals of MIG/MAG, FCAW and MCAW 13
2.6 4T/2T Trigger Latch Selection 15
3.0 Gas tungsten arc welding (GTAW/TIG) 16
3.1 Introduction 16
3.2 Process 16
3.3 Process variables 17
3.4 Shielding gas selection 18
3.5 Welding wire selection 18
3.6 Tungsten electrode selection 19
3.7 Welding techniques 21
3.8 Torch movement during welding 21
3.9 Positioning torch tungsten for various weld joints 22
3.10 Joint preparation 23
4.0 Manual Metal Arc Welding Process (MMAW) 25
4.1 Process 25
4.2 Welding Machine 25
4.3 Welding Technique 26
4.4 Electrode Selection 26
4.5 Types of Joints 28
4.6 Fillet Welds 30
4.7 Typical Defects Due to FaultyTechnique 32
5.0 General Welding Information 34
5.1 Recommended Welding Parameters for MIG/MAG 34
6.0 Correct Application Techniques 35
7.0 Package Contents 37
8.0 Installation 38
8.1 Installation for MIG/MAG process 38
8.2 Installation for MIG/MAG set up with OPTIONAL spool gun 38
8.3 Installation for TIG setup 39
8.4 Installation for MMA process 39
9.0 Control panels 40
9.1 Polarity selection 40
10.0 Operation 41
10.1 Starting up 41
10.2 Operation instruction under MIG mode 41
10.3 Operation instruction under LIFT TIG mode. 43
10.4 Operation instruction under MMA mode. 43
10.5 Error display 44
11.0 Troubleshooting and Fault Finding 46
11.1 TIG/MMA functions 46
11.2 MIG/MAG functions 48
12.0 Periodic Maintenance 50
12.1 Power Source 50
13.0 Technical Specications 51
14.0 Warranty Information 52
14.1 Terms of Warranty 52
14.2 Limitations on Warranty 52
14.3 Warranty Period 52
14.4 Warranty Repairs 52
3BOC Smootharc 180 Multiprocess operating manual
Page 4
1.0 Recommended Safety Guidelines
andPrecautions
Some safety precautions BOC
recommends are as follows:
• Repair or replace defective cables immediately.
• Never watch the arc except through
lenses of the correct shade.
• In conned spaces, adequate ventilation
and constant observation are essential.
• Leads and cables should be kept clear
of passageways.
• Keep re extinguishing equipment at a handy location
in the workshop.
• Keep primary terminals and live parts eectively covered.
• Never strike an arc on any gas cylinder.
• Never use oxygen for venting containers.
Diagram and safety explanation
Electrical safety alert
Welding electrode causing electric shock
Fumes and gases coming from welding process
Welding arc rays
Read instruction manual
Become trained
Wear dry, insulated gloves
Insulate yourself from work and ground
Disconnect input power before working on equipment
Keep head out of fumes
Use forced ventilation or local exhaust to remove fumes
Use welding helmet with correct shade of lter
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BOC Smootharc 180 Multiprocess operating manual
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5BOC Smootharc 180 Multiprocess operating manual
1.1 Health Hazard Information
The actual process of welding is one that can cause a variety of hazards.
All appropriate safety equipment should be worn at all times, i.e.
headwear, hand and body protection. Electrical equipment should be
used in accordance with the manufacturer’s recommendations.
Eyes
The process produces ultra violet rays that can injure and cause
permanent damage. Fumes can cause irritation.
Skin
Arc rays are dangerous to uncovered skin.
Inhalation
Welding fumes and gases are dangerous to the health of the operator
and to those in close proximity. The aggravation of pre-existing
respiratory or allergic conditions may occur in some workers. Excessive
exposure may cause conditions such as nausea, dizziness, dryness and
irritation of eyes, nose and throat.
1.2 Personal Protection
Respiratory
Conned space welding should be carried out with the aid of a fume
respirator or air supplied respirator as per AS/NZS 1715 and AS/NZS
1716 Standards.
• You must always have enough ventilation in conned spaces. Be alert
to this at all times.
• Keep your head out of the fumes rising from the arc.
• Fumes from the welding of some metals could have an adverse eect
on your health. Don’t breathe them in. If you are welding on material
such as stainless steel, nickel, nickel alloys or galvanised steel,
further precautions are necessary.
• Wear a respirator when natural or forced ventilation is insucient.
Eye protection
A welding helmet with the appropriate welding lter lens for the
operation must be worn at all times in the work environment. The
welding arc and the reecting arc ash gives out ultraviolet and infrared
rays. Protective welding screen and goggles should be provided for
others working in the same area.
Recommended lter shades for arc welding
Less than 150 amps Shade 10*
150 to 250 amps Shade 11*
250 to 300 amps Shade 12
300 to 350 amps Shade 13
Over 350 amps Shade 14
*Use one shade darker for aluminium.
Clothing
Suitable clothing must be worn to prevent excessive exposure to UV
radiation and sparks. An adjustable helmet, ameproof loose-tting
cotton clothing buttoned to the neck, protective leather gloves, spats,
apron and steel capped safety boots are highly recommended.
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BOC Smootharc 180 Multiprocess operating manual
Cylinder safety diagram
1 Cylinder valve hand-wheel
2 Back-plug
3 Bursting disc
Ten points about cylinder safety
1 Read labels and Material Safety Data Sheet (MSDS) before use
2 Store upright and use in well ventilated, secure areas away
from pedestrian or vehicle thoroughfare
3 Guard cylinders against being knocked violently or being
allowed to fall
4 Wear safety shoes, glasses and gloves when handling and
connecting cylinders
5 Always move cylinders securely with an appropriate trolley.
Take care not to turn the valve on when moving a cylinder
6 Keep in a cool, well ventilated area, away from heat sources,
sources of ignition and combustible materials, especially
ammable gases
7 Keep full and empty cylinders separate
8 Keep ammonia-based leak detection solutions, oil and grease
away from cylinders and valves
9 Never use force when opening or closing valves
10 Don’t repaint or disguise markings and damage. If damaged,
return cylinders to BOC immediately
Cylinder valve safety
When working with cylinders or operating cylinder valves, ensure
that you wear appropriate protective clothing – gloves, boots and
safetyglasses.
When moving cylinders, ensure that the valve is not accidentally opened
in transit.
Before operating a cylinder valve
Ensure that the system you are connecting the cylinder into is suitable
for the gas and pressureinvolved.
Ensure that any accessories (such as hoses attached to the cylinder
valve, or the system being connected to) are securely connected. Ahose,
for example, can potentially ail around dangerously if it is accidentally
pressurised when not restrained at both ends.
Stand to the side of the cylinder so that neither you nor anyone else is
in line with the back of the cylinder valve. This is in case a back-plug
is loose or a bursting disc vents. The correct stance is shown in the
diagramabove.
When operating the cylinder valve
Open it by hand by turning the valve hand-wheel anti-clockwise. Use
only reasonable force.
Ensure that no gas is leaking from the cylinder valve connection or
the system to which the cylinder is connected. DO NOT use ammonia-
based leak detection uid as this can damage the valve. Approved leak
detection uid, can be obtained from a BOC Gas & Gear centre.
When nished with the cylinder, close the cylinder valve by hand
by turning the valve hand-wheel in a clockwise direction. Use only
reasonable force.
Remember NEVER tamper with the valve.
If you suspect the valve is damaged, DONOT use it. Report the issue to
BOC and arrange for the cylinder to be returned to BOC.
Back view of typical cylinder valve.
1
2
3
Operator wearing personal
protective equipment (PPE)
in safe position.
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7BOC Smootharc 180 Multiprocess operating manual
1.3 Electrical shock
• Never touch ‘live’ electrical parts.
• Always repair or replace worn or damagedparts.
• Disconnect power source before performingany maintenance
orservice.
• Earth all work materials.
• Never work in moist or damp areas.
Avoid electric shock by:
• Wearing dry insulated boots.
• Wearing dry leather gloves.
• Working on a dry insulated oor where possible.
1.4 User Responsibility
• Read the Operating Manual prior to installation of this machine.
• Unauthorised repairs to this equipment may endanger the technician
and operator and will void your warranty. Only qualied personnel
approved by BOC should perform repairs.
• Always disconnect mains power before investigating
equipmentmalfunctions.
• Parts that are broken, damaged, missing or worn should be
replacedimmediately.
• Equipment should be cleaned periodically.
BOC stock a huge range of personal protective equipment. This combined
with BOC’s extensive Gas and Gear network ensures fast, reliable service
throughout the South Pacic.
STOP
PLEASE NOTE that under no circumstances should any
equipment or parts be altered or changed in any way from the
standard specication without written permission given by
BOC. To do so, will void the EquipmentWarranty.
Further information can be obtained from Welding Institute of Australia
(WTIA) Technical Note No.7.
Health and Safety Welding
Published by WTIA,
PO Box 6165 Silverwater NSW 2128
Phone (02) 9748 4443
Page 8
2.0 MIG/MAG Operating Manual
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BOC Smootharc 180 Multiprocess operating manual
2.1 Introduction to Metal Inert Gas(MIG)
& Metal Active Gas (MAG)
MIG/MAG welding embraces a group of arc welding processes in which
a continuous electrode (the wire) is fed by powered feed rolls (wire
feeder) into the weld pool. An electric arc is created between the tip of
the wire and the weld pool. The wire is progressively melted at the same
speed at which it is being fed and forms part of the weld pool. Both the
arc and the weld pool are protected from atmospheric contamination by
a shield of inert (non-reactive) gas, which is delivered through a nozzle
that is concentric with the welding wire guide tube.
Operation
MIG/MAG welding is usually carried out with a handheld torch as a semiautomatic process. The MIG/MAG process can be suited to a variety of
job requirements by choosing the correct shielding gas, electrode (wire)
size and welding parameters. Welding parameters include the voltage,
travel speed, arc (stick-out) length and wire feed rate. The arc voltage
and wire feed rate will determine the ller metal transfer method.
This application combines the advantages of continuity, speed,
comparative freedom from distortion and the reliability of automatic
welding with the versatility and control of manual welding. The process
is also suitable for mechanised set-ups, and its use in this respect
isincreasing.
MIG/MAG welding can be carried out using solid wire, ux cored, or a
copper-coated solid wire electrode. The shielding gas or gas mixture may
consist of the following:
• Argon (MIG)
• Carbon dioxide (MAG)
• Argon and carbon dioxide mixtures (MAG)
• Argon with oxygen mixtures (MAG)
• Argon with helium mixtures (MIG)
Each gas or gas mixture has specic advantages and limitations. Other
forms of MIG/MAG welding include using a ux-cored continuous
electrode and carbon dioxide shielding gas, or using self-shielding ux-
cored wire, requiring no shielding.
2.2 Introduction to Flux Cored
Arc Welding (FCAW)
How it Works
Flux-cored arc welding (FCAW) uses the heat generated by a DC electric
arc to fuse the metal in the joint area, the arc being struck between a
continuously fed consumable ller wire and the workpiece, melting both
the ller wire and the workpiece in the immediate vicinity. The entire arc
area is covered by a shielding gas, which protects the molten weld pool
from the atmosphere.
FCAW is a variant of the MIG/MAG process and while there are many
common features between the two processes, there are also several
fundamental dierences.
As with MIG/MAG, direct current power sources with constant voltage
output characteristics are normally employed to supply the welding
current. With ux-cored wires the terminal that the ller wire is
connected to depends on the specic product being used, some wires
running electrode positive, others running electrode negative. The work
return is then connected to the opposite terminal. It has also been found
that the output characteristics of the power source can have an eect on
the quality of the welds produced.
Typical MIG/MAG set up
Torch trigger
Welding wire
Weld
Weld pool
Torch
Shroud
Gas diuser
Contact tip
Shielding
Droplets
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9BOC Smootharc 180 Multiprocess operating manual
The wire feed unit takes the ller wire from a spool, and feeds it
through the welding torch, to the arc at a predetermined and accurately
controlled speed. Normally, special knurled feed rolls are used with ux-
cored wires to assist feeding and to prevent crushing the consumable.
Unlike MIG/MAG, which uses a solid consumable ller wire, the
consumable used in FCAW is of tubular construction, an outer metal
sheath being lled with uxing agents plus metal powder. The ux ll is
also used to provide alloying, arc stability, slag cover, de-oxidation, and,
with some wires, gas shielding.
In terms of gas shielding, there are two dierent ways in which this may
be achieved with the FCAW process.
• Additional gas-shielding supplied from an external source, such as a
gas cylinder
• Production of a shielding gas by decomposition of uxing agents
within the wire, self-shielding
Gas shielded wires are available with either a basic or rutile ux ll,
while self-shielded wires have a broadly basic-type ux ll. The ux
ll dictates the way the wire performs, the properties obtainable, and
suitable applications.
Gas-shielded Operation
Many cored wire consumables require an auxiliary gas shield in the same
way that solid wire MIG/MAG consumables do. These types of wire are
generally referred to as ‘gas-shielded’.
Using an auxiliary gas shield enables the wire designer to concentrate
on the performance characteristics, process tolerance, positional
capabilities, and mechanical properties of the products.
In a ux cored wire the metal sheath is generally thinner than that of
a self-shielded wire. The area of this metal sheath surrounding the ux
cored wire is much smaller than that of a solid MIG/MAG wire. This
means that the electrical resistance within the ux cored wire is higher
than with solid MIG/MAG wires and it is this higher electrical resistance
that gives this type of wire some of its novel operating properties.
One often quoted property of uxed cored wires are their higher
deposition rates than solid MIG/MAG wires. What is often not explained
is how they deliver these higher values and whether these can be
utilised. For example, if a solid MIG/MAG wire is used at 250 amps,
then exchanged for a ux cored wire of the same diameter, and welding
power source controls are left unchanged, then the current reading
would be much less than 250 amps, perhaps as low as 220 amps. This
is because of Ohms Law that states that as the electrical resistance
increases if the voltage remains stable then the current must fall.
To bring the welding current back to 250 amps it is necessary to
increase the wire feed speed, eectively increasing the amount of
wire being pushed into the weld pool to make the weld. It is this aect
that produces the ‘higher deposition rates’ that the ux cored wire
manufacturers claim for this type of product. Unfortunately in many
instances the welder has diculty in utilising this higher wire feed speed
and must either increase the welding speed or increase the size of the
weld. Often in manual applications neither of these changes can be
implemented and the welder simply reduces the wire feed speed back
to where it was and the advantages are lost. However, if the process
is automated in some way then the process can show improvements in
productivity.
It is also common to use longer contact tip to workplace distances with
ux cored arc welding than with solid wire MIG/MAG welding and this
also has the eect of increasing the resistive heating on the wire further
accentuating the drop in welding current. Research has also shown
that increasing this distance can lead to an increase in the ingress of
Extended self shielded ux cored wire nozzle
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BOC Smootharc 180 Multiprocess operating manual
nitrogen and hydrogen into the weld pool, which can aect the quality
of the weld.
Flux cored arc welding has a lower eciency than solid wire MIG/MAG
welding because part of the wire ll contains slag forming agents.
Although the eciency varies diers by wire type and manufacturer it is
typically between 75–85%.
Flux cored arc welding does, however, have the same drawback as solid
wire MIG/MAG in terms of gas disruption by wind, and screening is
always necessary for site work. It also incurs the extra cost of shielding
gas, but this is often outweighed by gains in productivity.
Self-shielded Operation
There are also self-shielded consumables designed to operate without
an additional gas shield. In this type of product, arc shielding is provided
by gases generated by decomposition of some constituents within the
ux ll. These types of wire are referred to as ‘self-shielded’.
If no external gas shield is required, then the ux ll must provide
sucient gas to protect the molten pool and to provide de-oxidisers and
nitride formers to cope with atmospheric contamination. This leaves less
scope to address performance, arc stabilisation, and process tolerance,
so these tend to suer when compared with gas shielded types.
Wire eciencies are also lower, at about 65%, in this mode of operation
than with gas-shielded wires. However, the wires do have a distinct
advantage when it comes to site work in terms of wind tolerance, as
there is no external gas shield to be disrupted.
When using self-shielded wires, external gas supply is not required and,
therefore, the gas shroud is not necessary. However, an extension nozzle
is often used to support and direct the long electrode extensions that
are needed to obtain high deposition rates.
2.3 Introduction to Metal Cored
Arc Welding (MCAW)
How it Works
Metal-cored arc welding (MCAW) uses the heat generated by a DC
electric arc to fuse metal in the joint area, the arc being struck between
a continuously fed consumable ller wire and the workpiece, melting
both the ller wire and the workpiece in the immediate vicinity. The
entire arc area is covered by a shielding gas, which protects the molten
weld pool from the atmosphere.
As MCAW is a variant of the MIG/MAG welding process there are many
common features between the two processes, but there are also several
fundamental dierences.
As with MIG/MAG, direct current power sources with constant voltage
output characteristics are normally employed to supply the welding
current. With metal-cored wires the terminal the ller wire is connected
to depends on the specic product being used, some wires designed
to run on electrode positive, others preferring electrode negative, and
some which will run on either. The work return lead is then connected
to the opposite terminal. Electrode negative operation will usually give
better positional welding characteristics. The output characteristics
of the power source can have an eect on the quality of the welds
produced.
The wire feed unit takes the ller wire from a spool or bulk pack, and
feeds it through the welding torch, to the arc at a predetermined and
accurately controlled speed. Normally, special knurled feed rolls are used
with metal-cored wires to assist feeding and to prevent crushing the
consumable.
Gas hose
Gas cylinder
Power source
Return cable
Continuous wire
Wire feed unit
Power cable
Torch conduit
Welding torch
Workpiece
Arc
Earth clamp
Process Schematic Diagram for MIG/MAG, FCAW and MCAW
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11BOC Smootharc 180 Multiprocess operating manual
Unlike MIG/MAG, which uses a solid consumable ller wire, the
consumable used in MCAW is of tubular construction, an outer metal
sheath being lled entirely with metal powder except for a small amount
of non-metallic compounds. These are added to provide some arc
stability and de-oxidation.
MCAW consumables always require an auxiliary gas shield in the
same way that solid MIG/MAG wires do. Wires are normally designed
to operate in argon-carbon dioxide or argon-carbon dioxide-oxygen
mixtures or carbon dioxide. Argon rich mixtures tend to produce lower
fume levels than carbon dioxide.
As with MIG/MAG, the consumable ller wire and the shielding gas are
directed into the arc area by the welding torch. In the head of the torch,
the welding current is transferred to the wire by means of a copper alloy
contact tip, and a gas diuser distributes the shielding gas evenly around
a shroud which then allows the gas to ow over the weld area. The
position of the contact tip relative to the gas shroud may be adjusted to
limit the minimum electrode extension.
Modes of metal transfer with MCAW are very similar to those obtained
in MIG/MAG welding, the process being operable in both ‘dip transfer’
and ‘spray transfer’ modes. Metal-cored wires may also be used in
pulse transfer mode at low mean currents, but this has not been widely
exploited.
2.4 Modes of metal transfer
The mode or type of metal transfer in MIG/MAG and MCAW welding
depends upon the current, arc voltage, electrode diameter and type of
shielding gas used. In general, there are four modes of metal transfer.
Modes of metal transfer with FCAW are similar to those obtained in MIG/
MAG welding, but here the mode of transfer is heavily dependent on the
composition of the ux ll, as well as on current and voltage.
The most common modes of transfer in FCAW are:
• Dip transfer
• Globular transfer
• Spray transfer
• Pulsed arc transfer operation has been applied to ux-cored wires
but, as yet, is not widely used because the other transfer modes are
giving users what they require, in most cases.
Dip Transfer
Also known as short-circuiting arc or short-arc, this is an all-positional
process, using low heat input. The use of relatively low current and arc
voltage settings cause the electrode to intermittently short-circuit with
the weld pool at a controlled frequency. Metal is transferred by the wire
tip actually dipping into the weld pool and the short-circuit current is
sucient to allow the arc to be re-established. This short-circuiting mode
of metal transfer eectively extends the range of MIG/MAG welding to
lower currents so thin sheet material can readily be welded. The low
heat input makes this technique well-suited to the positional welding
of root runs on thick plate, butt welds for bridging over large gaps and
for certain dicult materials where heat input is critical. Each shortcircuit causes the current to rise and the metal fuses o the end of the
electrode. A high short-circuiting frequency gives low heat input. Dip
transfer occurs between ±70-220A, 14–23 arc volts. It is achieved using
shielding gases based on carbon dioxide and argon.
Metal-cored wires transfer metal in dip mode at low currents just like
solid MIG/MAG wires. This transfer mode is used for all positional work
with these types of wire.
1 2 63 4 5
Time
Short circuit cycle Arcing cycle
Current (A)
Voltage (V)
1 Short circuit
2 Necking
3 Arc re-ignition
4 Arc established
5 Arc gap shortens
6 Short circuit
Schematic of Dip Transfer
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BOC Smootharc 180 Multiprocess operating manual
Globular Transfer
Metal transfer is controlled by slow ejection resulting in large,
irregularly-shaped ‘globs’ falling into the weld pool under the action
of gravity. Carbon dioxide gas drops are dispersed haphazardly. With
argon-based gases, the drops are not as large and are transferred in
a more axial direction. There is a lot of spatter, especially in carbon
dioxide, resulting in greater wire consumption, poor penetration and
poor appearance. Globular transfer occurs between the dip and spray
ranges. This mode of transfer is not recommended for normal welding
applications and may be corrected when encountered by either
decreasing the arc voltage or increasing the amperage. Globular transfer
can take place with any electrode diameter.
Basic ux-cored wires tend to operate in a globular mode or in a
globular-spray transfer mode where larger than normal spray droplets
are propelled across the arc, but they never achieve a true spray
transfer mode. This transfer mode is sometimes referred to as non-axial
globulartransfer.
Self-shielded ux-cored wires operate in a predominantly globular
transfer mode although at high currents the wire often ‘explodes’ across
the arc.
Spray Transfer
In spray transfer, metal is projected by an electromagnetic force from
the wire tip in the form of a continuous stream of discrete droplets
approximately the same size as the wire diameter. High deposition
rates are possible and weld appearance and reliability are good. Most
metals can be welded, but the technique is limited generally to plate
thicknesses greater than 6mm. Spray transfer, due to the tendency of
the large weld pool to spill over, cannot normally be used for positional
welding. The main exception is aluminium and its alloys where, primarily
because of its low density and high thermal conductivity, spray transfer
in position can be carried out.
The current ows continuously because of the high voltage maintaining
a long arc and short-circuiting cannot take place. It occurs best with
argon-based gases.
In solid wire MIG/MAG, as the current is increased, dip transfer passes
into spray transfer via a transitional globular transfer mode. With metalcored wires there is virtually a direct transition from dip transfer to spray
transfer as the current is increased.
For metal cored wire spray transfer occurs as the current density
increases and an arc is formed at the end of the ller wire, producing
a stream of small metal droplets. Often the outside sheath of the wire
will melt rst and the powder in the centre ows as a stream of smaller
droplet into the weld pool. This eect seems to give much better transfer
of alloying elements into the weld.
In spray transfer, as the current density increases, an arc is formed at
the end of the ller wire, producing a stream of small metal droplets. In
solid wire MIG/MAG this transfer mode occurs at higher currents. Fluxcored wires do not achieve a completely true spray transfer mode but a
transfer mode that is almost true spray may occur at higher currents and
can occur at relatively low currents depending on the composition of
theux.
Rutile ux-cored wires will operate in this almost-spray transfer mode, at
all practicable current levels. They are also able to operate in this mode
for positional welding too. Basic ux-cored and self-shielded ux-cored
wires do not operate in anything approaching true spray transfer mode.
Large droplet
Splatter
Workpiece
Gas shroud
Wire
Shielding gas
Droplets
Weld
Workpiece
Schematic of Globular Transfer Schematic of Spray Transfer
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13BOC Smootharc 180 Multiprocess operating manual
Typical Metal Transfer Mode
Process
Dip
Transfer
Globular
Transfer
Spray Transfer
Metal Inert Gas (MIG)
Metal Active Gas (MAG)
Flux Cored (Gas Shielded)
*
Flux Cored (Self Shielded)
Metal Cored
* Not True Spray
Pulsed Transfer
Pulsed arc welding is a controlled method of spray transfer, using
currents lower than those possible with the spray transfer technique,
thereby extending the applications of MIG/MAG welding into the range
of material thickness where dip transfer is not entirely suitable. The
pulsed arc equipment eectively combines two power sources into one
integrated unit. One side of the power source supplies a background
current which keeps the tip of the wire molten. The other side produces
pulses of a higher current that detach and accelerate the droplets of
metal into the weld pool. The transfer frequency of these droplets is
regulated primarily by the relationship between the two currents. Pulsed
arc welding occurs between ±50-220A, 23–35 arc volts and only with
argon and argon-based gases. It enables welding to be carried out in all
positions.
2.5 Fundamentals of MIG/MAG, FCAW and MCAW
Welding Technique
Successful welding depends on the following factors:
1 Selection of correct consumables
2 Selection of the correct power source
3 Selection of the correct polarity on the power source
4 Selection of the correct shielding gas
5 Selection of the correct application techniques
a Correct angle of electrode to work
b Correct electrical stickout
c Correct travel speed
6 Selection of the welding preparation
Selection of Correct Consumable
Chemical composition
As a general rule the selection of a wire is straightforward, in that it
is only a matter of selecting an electrode of similar composition to
the parent material. It will be found, however, that there are certain
applications that electrodes will be selected on the basis of its
mechanical properties or level of residual hydrogen in the weldmetal.
Solid MIG/MAG wires are all considered to be of the 'low Hydrogen type'
consumables.
The following table gives a general overview of the selection of some of
the BOC range of MIG/MAG wires for the most common materials.
Common Materials Welded with BOC MIG Wire
Material BOC MIG Wire
AS2074 C1,C2,C3,C4-1,C4-2,C5,C6 BOC Mild Steel MIG Wire
AS/NZS1163 C250 BOC Mild Steel MIG Wire
AS/NZS3678 200,250,300 BOC Mild Steel MIG Wire
ASTM A36,A106 BOC Mild Steel MIG Wire
Stainless Steel
Grade 304/L BOC Stainless Steel 308LSi
Grade 309 BOC Stainless Steel 309LSi
Grade 316/L BOC Stainless Steel 316LSi
Physical condition
Surface condition
The welding wire must be free from any surface contamination including
mechanical damage such as scratch marks.
A simple test for checking the surface condition is to run the wire
through a cloth that has been dampened with acetone for 20 secs. If a
Page 14
14
BOC Smootharc 180 Multiprocess operating manual
Cast
Helix
Cast – Diameter of the circle
Helix – Vertical height
Cast and Helix
black residue is found on the cloth the surface of the wire is not properly
cleaned.
Cast and Helix
The cast and helix of the wire has a major inuence on the feedability of
MIG/MAG wire.
If the cast is too large the wire will move in an upward direction from the
tip when welding and if too small the wire will dip down from the tip.
The result of this is excessive tip wear and increased wear in the liners.
If the helix is too large the wire will leave the tip with a corkscrew eect.
Selection of the Correct Power Source
Power sources for MIG/MAG welding is selected on a number of dierent
criteria, including:
1 Maximum output of the machine
2 Duty cycle
3 Output control (voltage selection, wire feed speed control)
4 Portability
The following table gives an indication of the operating amperage for
dierent size wires.
Wire Size Amperage Range (A)
0.8 mm 60–180
0.9 mm 70–250
1.0 mm 90–280
1.2 mm 120–340
Selection of the Correct Polarity on the Power Source
Many power sources are tted with an optional reverse polarity dinse
connector.
To achieve the optimum welding it is important to adhere to the
consumable manufacturer's instruction to select the polarity.
As a general rule all solid and metal cored wires are welded on electrode
positive. (Work return lead tted to the negative connector.)
Some grades of self shielded ux cored wires (i.e. E71T-11, E71T-GS etc)
needs to be welded on electrode negative. (Work return lead tted to
the positive connector.)
Selection of the Correct Shielding Gas
The selection of the shielding gas has a direct inuence on the
appearance and quality of the weldbead.
The thickness of the material to be welded will determine the type of
shielding gas that has to be selected. As a general rule the thicker the
material (C-Mn and Alloy steels) are the higher the percentage of CO
2
in
the shielding gas mixture.
Dierent grades of shielding are required for materials such as stainless
steel, aluminium and copper.
The following table gives an indication of the most common shielding
gases used for Carbon Manganese and alloy steel.
Material thickness Recommended shielding gas
1–8 mm Argoshield Light
5–12 mm Argoshield Universal
>12 mm Argoshield Heavy
Page 15
15BOC Smootharc 180 Multiprocess operating manual
More detailed selection charts, including recommendations for welding
parameters (voltage, amperage, electrical stickout, travelspeed and
gasow rate) can be found in the following pages.
2.6 4T/2T Trigger Latch Selection
On all MIG machines there is no current or wire feed until the trigger
on the torch is depressed. If a welder is doing a lot of welding then he
has to hold the trigger down for long periods of time and may cause
discomfort. This is can be similar to repetitive strain injury (RSI) that has
become a very popular topic for compensation by oce workers.
On all machines a special function called 2T and 4T is available. Also
referred to as trigger latching, this special feature allows the operator to
relax the trigger after rst depressing it, the gas shielding to start before
the welding commences. This feature is of particular importance as it
ensures that the weld will have adequate gas shielding to eliminate the
risk of oxidisation (contaminants) causing a defective weld. (Remember,
adefective weld may not be detected by a visual inspection.)
The 2T/4T function also allows for the shielding gas to continue after the
weld has nished and cooled. This eliminates the risk of oxidation while
the weld is still in its molten state. This is particularly important when
welding stainless steel materials.
Page 16
3.0 Gas tungsten arc welding (GTAW/TIG)
16
BOC Smootharc 180 Multiprocess operating manual
3.1 Introduction
The Tungsten Inert Gas, or TIG process, uses the heat generated by an
electric arc struck between a non-consumable tungsten electrode and
the workpiece to fuse metal in the joint area and produce a molten
weld pool. The arc area is shrouded in an inert or reducing gas shield to
protect the weld pool and the non-consumable electrode. The process
may be operated autogenously, that is, without ller, or ller may be
added by feeding a consumable wire or rod into the established weld
pool.
3.2 Process
Direct or alternating current power sources with constant current output
characteristics are normally employed to supply the welding current.
For DC operation the tungsten may be connected to either output
terminal, but is most often connected to the negative pole. The output
characteristics of the power source can have an eect on the quality of
the welds produced.
Shielding gas is directed into the arc area by the welding torch and a
gas lens within the torch distributes the shielding gas evenly over the
weld area. In the torch the welding current is transferred to the tungsten
electrode from the copper conductor. The arc is then initiated by one of
several methods between the tungsten and the workpiece.
Schematic of the TIG welding process
Tungsten electrode
Collet
Workpiece
Shielding gas
Arc
TIG ller rod
Weld pool
Page 17
3.3 Process variables
Process variable Explanation Usage
DCEN
Narrow bead,
deeppenetration
Nozzle
Ions Electrons
When direct-current electrode-negative (straight polarity)
is used:
• Electrons strike the part being welded at a highspeed
• Intense heat on the base metal is produced
• The base metal melts very quickly
• Ions from the inert gas are directed towards the
negative electrode at a relatively slow rate
• Direct current with straight polarity does not require
post-weld cleaning to remove metaloxides
For a given diameter of tungsten electrode, higher
amperage can be used with straight polarity. Straight
polarity is used mainly for welding:
• Carbon steels
• Stainless steels
• Copper alloys
The increased amperage provides:
• Deeper penetration
• Increased welding speed
• A narrower, deeper, weld bead
DCEP
Wide bead,
shallowpenetration
Nozzle
Ions Electrons
The DCEP (reverse polarity) are dierent from the DCEN in
followingways:
• High heat is produced on the electrode rather on the
base metal
• The heat melts the tungsten electrode tip
• The base metal remains relatively cool compared to sing
straight polarity
• Relatively shallow penetration is obtained
• An electrode whose diameter is too large will reduce
visibility and increase arc instability
• Intense heat means a larger diameter of electrode must
be used with DCEP
• Maximum welding amperage should be relatively low
(approximately six times lower than with DCEN)
17BOC Smootharc 180 Multiprocess operating manual
Page 18
3.4 Shielding gas selection
Material Shielding gas Benets
Brass Argon Stable arc
Low fume
Cobalt-based alloys Argon Stable and easy to control arc
Copper-nickel
(Monel)
Argon Stable and easy to control arc
Can be used for copper-nickel
to steel
Deoxised copper Helium Increased heat input
Stable arc
Good penetration
Helium(75%)
/Argon(25%)
Stable arc
Lower penetration
Nickel alloys
(Inconel)
Argon Stable arc
Manual operation
Helium High speed automated
welding
Steel Argon Stable arc
Good penetration
Helium High speed automatic welding
Deeper penetration
Small concentrated HAZ
Magnesium alloys Argon Used with continuous high
frequency AC
Good arc stability
Good cleaning action
Stainless steel Argon Good penetration
Good arc stability
Helium Deeper penetration
Titanium Argon Stable arc
Helium High speed welding
3.5 Welding wire selection
The following table includes the recommended welding consumable for
the most commonly weldedmaterials.
Base material BOC Consumable
C-Mn and low carbon steels BOC Mild steel TIG wire
Low Alloy steels
1.25Cr/0.5Mo Comweld CrMo1
2.5Cr/1Mo Comweld CrMo2
Stainless Steel
304/304L Proll 308
316/316L Proll 316
309/309-C-Mn Proll 309
321/Stabilised grades Proll 347
Filler rod diameter (mm) Thickness of metal (mm)
2 0.5 – 2
3 2 – 5
4 5 – 8
4 or 5 8 – 12
5 or 6 12 or more
18
BOC Smootharc 180 Multiprocess operating manual
Page 19
3.6 Tungsten electrode selection
Base metal type
Thickness
range Desired results
Welding
current Electrode type Shielding gas Tungsten performance characteristics
Copper alloys,
Cu-NI alloys and
Nickelalloys
All General purpose DCSP 2% Thoriated
(EW-Th2)
75% Argon/
25% Helium
Best stability at medium currents. Good arc
starts
Medium tendency to spit
Medium erosion rate
2% Ceriated
(EW-Ce2)
75% Argon/
25% Helium
Low erosion rate. Wide current range. AC or
DC. No spitting. Consistent arc starts
Good stability
Only thick
sections
Increase
penetration or
travel speed
DCSP 2% Ceriated
(EW-Ce2)
75% Argon/
25% Helium
Low erosion rate. Wide current range. AC or
DC. No spitting. Consistent arc starts
Good stability
Mild Steels,
Carbon Steels,
Alloy Steels,
StainlessSteels
and Titanium
alloys
All General purpose DCSP 2% Thoriated
(EW-Th2)
75% Argon/
25% Helium
Best stability at medium currents. Good arc
starts
Medium tendency to spit
Medium erosion rate
2% Ceriated
(EW-Ce2)
75% Argon/
25% Helium
Low erosion rate. Wide current range. AC or
DC. No spitting Consistent arc starts
Good stability
2% Lanthanated
(EWG-La2)
75% Argon/
25% Helium
Lowest erosion rate. Widest current range on
DC. No spitting. Best DC arc starts and stability
Only thick
sections
Increase
penetration or
travel speed
DCSP 2% Ceriated
(EW-Ce2)
75% Argon/
25% Helium
Low erosion rate. Wide current range. No
spitting. Consistent arc starts. Good stability
2% Lanthanated
(EWG-La2)
Helium Lowest erosion rate. Highest current range. No
spitting. Best DC arc starts and stability
19BOC Smootharc 180 Multiprocess operating manual
Page 20
Tungsten tip preparation
= Diameter
Taper length
2–3x Dia
Flat
1/4–1/2x Dia
DCSP (EN) or DCRP (EP)
Max. ball
1x Dia
ACHP General Purpose
Ball tip by arcing on clean metal at low current DCRP (EP) then slowly
increase current to form the desired ball diameter. Return setting to AC.
Tungsten grinding
Shape by grinding longitudinally (never
radially). Remove the sharp point to
leave a truncated point with a at
spot. Diameter of at spot determines
amperage capacity (See below). The
included angle determines weld bead
shape and size. Generally, as the
included angle increases, penetration
increases and bead width decreases.
Use a medium (60 grit or ner)
aluminium oxidewheel.
Tungsten extension
General
purpose
3x Dia
Standard Parts
General
purpose
3x Dia
Maximum
6x Dia
Gas Lens Parts
(in draft free areas)
Tungsten electrode tip shapes and current ranges
Thoriated, ceriated, and lanthanated tungsten electrodes do not ball
as readily as pure or zirconiated tungsten electrodes, and as such are
typically used for DCSP welding. These electrodes maintain a ground
tip shape much better than the pure tungsten electrodes. If used on
AC, thoriated and lanthanated electrodes often spit. Regardless of the
electrode tip geometry selected, it is important that a consistent tip
conguration be used once a welding procedure is established. Changes
in electrode geometry can have a signicant inuence not only on the
weld bead width, depth of penetration, and resultant quality, but also on
the electrical characteristics of the arc. Below is a guide for electrode tip
preparation for a range of sizes with recommended current ranges.
Electrode
diameter (mm)
Diameter arc
tip (mm)
Constant
included angle,
(degrees)
Current range
(A)
1.0 0.125 12 2 – 15
1.0 0.250 20 5 – 30
1.6 0.500 25 8 – 50
1.6 0.800 30 10 – 70
2.3 0.800 35 12 – 90
2.3 1.100 45 15 – 150
3.2 1.100 60 20 – 200
3.2 1.500 90 25 – 250
20
BOC Smootharc 180 Multiprocess operating manual
Page 21
3.7 Welding techniques
TIG Welding techniques
60–75°
15–30°
Nozzle
Direction of travel
Welding Rod
Shield gas
Vertical
Tungsten electrode
The suggested electrode and welding rod angles for welding a bead on
plate are shown above. The same angles are used when making a butt
weld. The torch is held 60–75° from the metal surface. This is the same
as holding the torch 15–30° from the vertical.
Take special note that the rod is in the shielding gas during the
weldingprocess.
3.8 Torch movement during welding
Tungsten Without Filler Rod Tungsten With Filler Rod
75°
Welding
direction
Form pool
75°
Welding
direction
Form pool
75°
Tilt torch
75°
Tilt torch
Move torch to front of pool. Repeat.
15°
Add ller metal
75°
75°
15°
Remove rod
75°
75°
15°
Move torch to front of pool. Repeat.
21BOC Smootharc 180 Multiprocess operating manual
Page 22
Butt Weld and Stringer bead
90°
20°
70°
90°
20°
70°
20°
70°
‘T’ Joint
90°
20°
70°
20°
10°
15°
75°
20°
70°
15°
75°
90°
20°
70°
20°
75°
Corner Joint
90°
15°
75°
90°
20°
70°
20°
10°
15°
75°
15°
75°
20°
70°
75°
90°
15°
75°
90°
20°
70°
20°
10°
15°
75°
Lap Joint
75°
90°
20-40°
15°
75°
90°
20°
70°
20°
10°
15°
75°
15°
75°
90°
20-40°
30°
15°
75°
90°
20°
70°
20°
10°
15°
75°
15°
75°
15°
75°
20°
70°
15°
75°
3.9 Positioning torch tungsten for various weld joints
22
BOC Smootharc 180 Multiprocess operating manual
Page 23
3.10 Joint preparation
r =
s
2
s
2
r =
s
2
s
2
3
r =
s
2
s
2
3
r =
s
2
s
2
3
0-
S
2
3
0-3
4
12
2
1
1.5-3
6-20
10°
~
~
0-3
4
12
2
1
1.5-3
6-20
10°
~
~
1
1.5-3
6-20
r =
s
2
s
2
3
0-
S
2
3
0-3
4
12
2
1
1.5-3
6-20
50°
2-3.5
1
3-20
10°
60°
2-3
5
5
16
10°
~
~
~
~
2
8-40
1.5-3
50°
0-3
4
12
2
1
1.5-3
6-20
10°
60°
2-3
5
5
16
10°
~
~
~
~
2
8-40
1.5-3
50°
1
1.5-3
6-20
2
8-40
1.5-3
50°
r =
s
2
s
2
3
0-
S
2
3
0-3
4
12
2
1
1.5-3
6-20
50°
2-3.5
1
3-20
10°
60°
2-3
5
5
16
10°
~
~
~
~
2
8-40
1.5-3
50°
50°
15-40
3
~
~
20°
6
~
~
3
15°
~
~
0-3
4
12
2
1
1.5-3
6-20
10°
60°
2-3
5
5
16
10°
~
~
~
~
2
8-40
1.5-3
50°
20°
6
~
~
3
15°
~
~
1
1.5-3
6-20
2
8-40
1.5-3
50°
15°
~
~
Roll direction
Oset
All measurements in mm
23BOC Smootharc 180 Multiprocess operating manual
Page 24
Condition Result
Undercut
Wide bead
prole
Porosity
Air Air
OxidesOxides
Long arc length
Acute angle
Loss of gas
coverage
Angular
mis-alignment
Unsymmetrical bead
prole
Mis-alignment
Incomplete
penetration
Filler rod removed
from gas shield
Tungsten inclusions
Tungsten inclusions
Electrode contact
with the weld pool
Rod
movement
Oxides
Air
24
BOC Smootharc 180 Multiprocess operating manual
Page 25
4.0 Manual Metal Arc Welding Process
(MMAW)
TIG Welding techniques
Weld Metal
Slag
Core Wire
Flux Covering
Arc
Weld Pool
Workpiece
4.1 Process
Manual Metal Arc welding is the process of joining metals where an
electric arc is struck between the metal to be welded (parent metal) and
a ux-coated ller wire (the electrode). Theheat of the arc melts the
parent metal and the electrode which mix together to form, on cooling, a
continuous solid mass.
Before arc welding can be carried out, a suitable power source is
required. Two types of power sources may be used for arc welding, direct
current (DC) or alternating current (AC).
The essential dierence between these two power sources is that, in the
case of DC, the current remains constant in magnitude and ows in the
same direction. Similarly, the voltage in the circuit remains constant in
magnitude and polarity (i.e. positive or negative).
In the case of AC however, the current ows rst in one direction and
then the other. Similarly, the voltage in the circuit changes from positive
to negative with changes in direction of current ow. This complete
reversal is called a ‘half cycle’ and repeats as long as the current
ows. The rate of change of direction of current ow is known as the
‘frequency’ of the supply and is measured by the number of cycles
completed per second. The standard frequency of the AC supply in
Australia is 50 Hz (Hertz).
4.2 Welding Machine
The most important consideration when contemplating the use of arc
welding for the rst time is the purchase of a suitable weldingmachine.
BOC supplies a popular range of arc welding machines. Machines
range from small portable welders that operate from standard 240
Volt household power to heavy-duty welders used by the largest steel
fabricators.
Basic Welding Machine and Cables
The choice of welding machine is based mostly on the following factors:
• primary voltage, e.g. 240 Volt or 380 Volt
• output amperage required, e.g. 140 amps
• output required, e.g. AC or DC +/-
• duty cycle required, e.g. 35% @ 140 amps
• method of cooling, e.g. air-cooled or oil-cooled method of output
amperage control, e.g. tapped secondary lugs
• or innitely variable control.
For example, the Smootharc 175 Multiprocess connects to 240 Volt
supply (15 amps Input), has an output of 175 amps DC @ 35% duty
cycle.
Having decided on a welding machine, appropriate accessories are
required. These are items such as welding cables, clamps, electrode
holder, chipping hammer, helmet, shaded and clear lenses, scull cap,
gloves and other personal protective equipment.
BOC stocks a huge range of personal protective equipment. This
combined with BOC’s extensive network ensures fast reliable service
throughout the South Pacic.
25BOC Smootharc 180 Multiprocess operating manual
Installation for MMA process
Page 26
4.3 Welding Technique
Successful welding depends on the followingfactors:
• selection of the correct electrode
• selection of the correct size of the electrodefor the job
• correct welding current
• correct arc length
• correct angle of electrode to work
• correct travel speed
• correct preparation of work to be welded.
4.4 Electrode Selection
As a general rule the selection of an electrode is straight forward, in that
it is only a matter of selecting an electrode of similar composition to the
parent metal. It will be found, however, that for some metals there is a
choice of several electrodes, each of which has particular properties to
suit specic classes of work. Often, one electrode in the group will be
more suitable for general applications due to its all round qualities.
The table (page27) shows just a few of the wide range of electrodes
available from BOC with their typical areas of application.
For example, the average welder will carry out most fabrication using
mild steel and for this material has a choice of various standard BOC
electrodes, each of which will have qualities suited to particular tasks.
For general mild steel work, however, BOC Smootharc 13 electrodes
will handle virtually all applications. BOC Smootharc 13 is suitable for
welding mild steel in all positions using AC or DC power sources. Its easy-
striking characteristics and the tolerance it has for work where t-up
and plate surfaces are not considered good, make it the most attractive
electrode of its class. Continuous development and improvement of
BOC Smootharc 13 has provided in-built operating qualities which
appeals to the beginner and experienced operator alike. For further
recommendations on the selection of electrodes for specic applications,
see table page27.
Electrodes and Typical Applications
Name AWS Class. Application
BOC Smootharc 13 E6013
A premium quality electrode for general
structural and sheet metal work in all
positions including vertical down using low
carbon steels
BOC Smootharc 24 E7024
An iron powder electrode for high speed
welding for H-V llets and at butt joints.
Medium to heavy structural applications in
low carbon steels
BOC Smootharc 18 E7018-1
A premium quality all positional hydrogen
controlled electrode for carbon steels in
pressure vessel applications and where high
integrity welding is required and for freemachining steels containing sulphur
BOC Smootharc S
308L E308L
Rutile basic coated low carbon electrodes for
welding austenitic stainless steel and dicult
to weld material
BOC Smootharc S
316L E316L
BOC Smootharc S
309L E309L
Rutile basic coated low carbon electrode
for welding mild steel to stainless steel and
dicult to weld material
Electrode Size
The size of the electrode is generally dependent on the thickness of the
section being welded, and the larger the section the larger the electrode
required. In the case of light sheet the electrode size used is generally
slightly larger than the work being welded. This means that if 1.5 mm
sheet is being welded, 2.0 mm diameter electrode is the recommended
26
BOC Smootharc 180 Multiprocess operating manual
Page 27
size. The following table gives the recommended maximum size of
electrodes that may be used for various thicknesses of section.
Recommended Electrode Sizes
Average Thickness of Plate or Section Max. Recommended Electrode Dia.
≤1.5 mm 2.0 mm
1.5–2.0 mm 2.5 mm
2.0–5.0 mm 3.15 mm
5.0–8.0 mm 4.0 mm
≤8.0 mm 5.0 mm
Welding Current
Correct current selection for a particular job is an important factor in arc
welding. With the current set too low, diculty is experienced in striking
and maintaining a stable arc. The electrode tends to stick to the work,
penetration is poor and beads with a distinct rounded prole will be
deposited.
Excessive current is accompanied by overheating of the electrode. It will
cause undercut, burning through of the material, and give excessive
spatter. Normal current for a particular job may be considered as the
maximum which can be used without burning through the work, overheating the electrode or producing a rough spattered surface, i.e. the
current in the middle of the range specied on the electrode package is
considered to be the optimum.
In the case of welding machines with separate terminals for dierent
size electrodes, ensure that the welding lead is connected to the correct
terminal for the size electrode being used. When using machines with
adjustable current, set on the current range specied.
The limits of this range should not normally be exceeded.
The following table shows the current ranges generally recommended
for BOC Smootharc13.
Generally Recommended Current Range for BOC Smootharc 13
Size of Electrode (mm) Current Range (Amp)
2.5 60–95
3.2 110–130
4.0 140–165
5.0 170–260
Arc Length
To start the arc, the electrode should be gently scraped on the work until
the arc is established. There is a simple rule for the proper arc length; it
should be the shortest arc that gives a good surface to the weld. An arc
too long reduces penetration, produces spatter and gives a rough surface
nish to the weld. An excessively short arc will cause sticking of the
electrode and rough deposits that are associated with slag inclusions.
For downhand welding, it will be found that an arc length not greater
than the diameter of the core wire will be most satisfactory. Overhead
welding requires a very short arc, so that a minimum of metal will be
lost. Certain BOC electrodes have been specially designed for ‘touch’
welding. These electrodes may be dragged along the work and a
perfectly sound weld isproduced.
Electrode Angle
The angle which the electrode makes with the work is important to
ensure a smooth, even transfer of metal. The recommended angles
for use in the various welding positions are covered later.
27BOC Smootharc 180 Multiprocess operating manual
Page 28
Butt Welding
WELD FACE
FACE REINFORCEMENT
ROOT FACE ROOT GAP
Correct Travel Speed
The electrode should be moved along in the direction of the joint being
welded at a speed that will give the size of run required. At the same
time the electrode is fed downwards to keep the correct arc length
at all times. As a guide for general applications the table below gives
recommended run lengths for the downhand position.
Correct travel speed for normal welding applications varies between
approximately 125–375 mm per minute, depending on electrode size,
size of run required and the amperage used.
Excessive travel speeds lead to poor fusion, lack of penetration, etc.
Whilst too slow a rate of travel will frequently lead to arc instability, slag
inclusions and poor mechanical properties.
Run Length per Electrode – BOC Smootharc 13
Electrode Size (mm) Electrode Length (mm)
Run Length (mm)
Min. to Max.
4.0 350 175 to 300
3.2 350 125 to 225
2.5 350 100 to 225
Correct Work Preparation
The method of preparation of components to be welded will depend on
equipment available and relative costs. Methods may include sawing,
punching, shearing, lathe cut-os, ame cutting and others. In all
cases edges should be prepared for the joints that suit the application.
The following section describes the various joint types and areas
ofapplication.
4.5 Types of Joints
Butt Welds
A butt weld is a weld made between two plates so as to give continuity
of section. Close attention must be paid to detail in a butt weld to ensure
that the maximum strength of the weld is developed. Failure to properly
prepare the edges may lead to the production of faulty welds, as correct
manipulation of the electrode is impeded.
Two terms relating to the preparation of butt welds require explanation
at this stage. They are:
• Root Face: the proportion of the prepared edge that has not been
bevelled.
• Root Gap: the separation between root
faces of the parts to be joined.
Various types of butt welds are in common use and their suitability for
dierent thickness of steel are described as follows:
Square Butt Weld
The edges are not prepared but
are separated slightly to allow fusion through the full thickness
of the steel. Suitable for plate up
to 6 mm in thickness.
Single ‘V’ Butt Weld
This is commonly used for plate up to 16 mm in thickness and on
metal of greater thickness where access
is available from only one side.
Double ‘V’ Butt Weld
Used on plate of 12 mm and over in thickness when welding
can be applied from both sides. It allows faster welding and
greater economy of electrodes than a single ‘V’ preparation on
the same thickness of steel and also has less of a tendency to
distortion as weld contraction can be equalised.
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BOC Smootharc 180 Multiprocess operating manual
Page 29
Welding Progression Angle
Weld Metal
Slag
Electrode
Arc
Weld Pool
Workpiece
70–85˚
Direction of Welding
Butt Weld with Backing Material
When square butt welds or single ‘V’ welds cannot be welded
from both sides it is desirable to use a backing bar to ensure
complete fusion.
Single ‘U’ Butt Weld
Used on thick plates an alternative to a single ‘V’ preparation.
It has advantages as regards speed of welding. It takes less
weld metal than a single ‘V’, there is less contraction and
therefore a lessened tendency to distortion. Preparation is
more expensive
than in the case of a ‘V’, as machining is required. The type of
joint is most suitable for material over 40 mm in thickness.
Double ‘U’ Butt Weld
For use on thick plate that is accessible for welding from both
sides. For a given thickness it is faster, needs less weld metal
and causes less distortion than a single ‘U’ preparation.
Horizontal Butt Weld
The lower member in this case is bevelled to approximately 15°
and the upper member 45°, making an included angle of 60°.
This preparation provides a ledge on
the lower member, which tends
to retain the molten metal.
General notes on Butt Welds
The rst run in a prepared butt weld should be deposited with an
electrode not larger than 4.0 mm. The angle of the electrode for the
various runs in a butt weld is shown.
It is necessary to maintain the root gap by tacking at intervals or by
other means, as it will tend to close during welding.
All single ‘V’, single ‘U’ and square butt welds should have a backing
run deposited on the underside of the joint; otherwise 50% may be
deducted from the permissible working stress of the joint.
Before proceeding with a run on the underside of a weld it is necessary
to remove any surplus metal or under penetration that is evident on that
side of the joint.
Butt welds should be overlled to a certain extent by building up
the weld until it is above the surface of the plate. Excessive build-up,
however, should be avoided.
In multi-run butt welds it is necessary to remove all slag, and surplus
weld metal before a start is made on additional runs; this is particularly
important with the rst run, which tends to form sharp corners that
cannot be penetrated with subsequent runs. Electrodes larger than 4.0
mm are not generally used for vertical or overhead butt welds.
The diagrams following indicate the correct procedure for welding thick
plate when using multiple runs.
Electrode Angle for 1st and 2nd Layers
WELD BEADS
LAYERS
ELECTRODE
Electrode Angle for Subsequent Layers
WELD BEADS
LAYERS
70˚ - 85˚
WELD BEADS
LAYERS
ELECTRODE
SLAG
WELD POOL
WELD METAL
ARC
DIRECTION OF WELDING
29BOC Smootharc 180 Multiprocess operating manual
Page 30
Convex Fillet Weld
ACTUAL THROAT
EFFECTIVE
THROAT
CONVEXITY
LEG
LENGH
THEORETICAL THROAT
CONCAVITY
ACTUAL THROAT
AND EFFECTIVE
THROAT
LEG
SIZE
SIZE LEG
THEORETICAL THROAT
Concave Fillet Weld
CONCAVITY
ACTUAL THROAT
AND EFFECTIVE
THROAT
LEG
SIZE
SIZE LEG
THEORETICAL THROAT
4.6 Fillet Welds
A llet weld is approximately triangular in section, joining two surfaces
not in the same plane and forming a lap joint, tee joint or corner joint.
Joints made with llet welds do not require extensive edge preparation,
as is the case with butt welded joints, since the weld does not
necessarily penetrate the full thickness of either member. It is important
that the parts to be joined be clean, close tting, and that all the edges
on which welding is to be carried out are square. On sheared plate it
is advisable to entirely remove any ‘false cut’ on the edges prior to
welding. Fillet welds are used in the following types of joints:
‘T’ Joints
A llet weld may be placed either on one or both
sides, depending on the requirements of the work.
The weld metal should fuse into or penetrate the
corner formed between the two members. Where
possible the joint should be placed in such a position
as to form a “Natural ‘V’ llet” since this is the easiest
and fastest method of llet welding.
Lap Joints
In this case, a llet weld may be placed either on one
or both sides of the joint, depending on accessibility
and the requirements of the joint. However, lap
joints, where only one weld is accessible, should be
avoided where possible and must never constitute
the joints of tanks or other fabrications where
corrosion is likely to occur behind the lapped plates.
In applying llet welds to lapped joints it is important
that the amount of overlap of the plates be not less
than ve times the thickness of the thinner part.
Where it is required to preserve the outside face or
contour of a structure, one plate may be joggled.
Corner Joints
The members are tted as shown, leaving a ‘V’shaped groove in which a llet weld is deposited.
Fusion should be complete for the full thickness
of the metal. In practice it is generally necessary
to have a gap or a slight overlap on the corner.
The use of a 1.0–2.5 mm gap has the advantage of
assisting penetration at the root, although setting
up is a problem. The provision of an overlap largely
overcomes the problem of setting up, but prevents
complete penetration at the root and should therefore
be kept to a minimum, i.e. 1.0–2.5 mm.
The following terms and denitions are important in specifying and
describing llet welds.
Leg Length
A fusion face of a llet weld, as shown below. All specications for llet
weld sizes are based on leg length.
Throat Thickness
A measurement taken through the centre of a weld from the root to the
face, along the line that bisects the angle formed by the members to
bejoined.
Eective throat thickness is a measurement on which the strength of a
weld is calculated. The eective throat thickness is based on a mitre llet
(concave Fillet Weld), which has a throat thickness equal to 70% of the
leg length. For example, in the case of a 20 mm llet, the eective throat
thickness will be 14 mm.
Convex Fillet Weld
A llet weld in which the contour of the weld metal lies outside a
straight line joining the toes of the weld. A convex llet weld of
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BOC Smootharc 180 Multiprocess operating manual
Page 31
specied leg length has a throat thickness in excess of the eective
measurement.
Concave Fillet Weld
A llet in which the contour of the weld is below a straight line joining
the toes of the weld. It should be noted that a concave llet weld of
a specied leg length has a throat thickness less than the eective
throat thickness for that size llet. This means that when a concave llet
weld is used, the throat thickness must not be less than theeective
measurement. This entails an increase in leg length beyond the
speciedmeasurement.
The size of a llet weld is aected by the electrode size, welding speed
or run length, welding current and electrode angle. Welding speed and
run length have an important eect on the size and shape of the llet,
and on the tendency to undercut.
Insucient speed causes the molten metal to pile up behind the arc
and eventually to collapse. Conversely, excessive speed will produce
a narrow irregular run having poor penetration, and where larger
electrodes and high currents are used, undercut is
likely to occur.
Fillet Weld Data
Nominal
Fillet Size (mm)
Minimum Throat
Thickness (mm)
Plate Thickness
(mm)
Electrode Size
(mm)
5.0 3.5 5.0–6.3 3.2
6.3 4.5 6.3–12 4.0
8.0 5.5 8.0–12 & over 4.0
10.0 7.0 10 & over 4.0
Selection of welding current is important. If it is too high the weld
surface will be attened, and undercut accompanied by excessive
spatter is likely to occur. Alternatively, a current which is too low will
produce a rounded narrow bead with poor penetration at the root.
The rst run in the corner of a joint requires a suitably high current
to achieve maximum penetration at the root. A short arc length is
recommended for llet welding. The maximum size llet which should
be attempted with one pass of a large electrode is 8.0 mm. Eorts to
obtain larger leg lengths usually result in collapse of the metal at the
vertical plate and serious undercutting. For large leg lengths multiple
run llets are necessary. These are built up as shown below. The angle
of the electrode for various runs in a downhand llet weld is shown
below.
Recommended Electrode Angles for Fillet Welds
1st Run 2nd Run
3rd Run Multi-run Fillet
Multi-run horizontal llets have each run made using the same run
lengths (run length per electrode table). Each run is made in the same
direction, and care should be taken with the shape of each, so that it
31BOC Smootharc 180 Multiprocess operating manual
Page 32
Recommended Angles for Overhead Fillet Welds
30˚
15˚
45˚
has equal leg lengths and the contour of the completed llet weld
is slightly convex with no hollows in the face.
Vertical llet welds can be carried out using the upwards or downwards
technique. The characteristics of each are: upwards – current used is low,
penetration is good, surface is slightly convex and irregular. For multiple
run llets large single pass weaving runs can be used. Downwards –
current used is medium, penetration is poor, each run is small, concave
and smooth (only BOC Smootharc 13 is suitable for this position).
The downwards method should be used for making welds on thin
material only. Electrodes larger than 4.0 mm are not recommended
for vertical down welding. All strength joints in vertical plates 10.0
mm thick or more should be welded using the upward technique. This
method is used because of its good penetration and weld metal quality.
The rst run of a vertical up llet weld should be a straight sealing run
made with 3.15 mm or 4.0 mm diameter electrode. Subsequent runs
for large llets may be either numerous straight runs or several wide
weaving runs.
Correct selection of electrodes is important for vertical welding.
In overhead llet welds, careful attention to technique is necessary to
obtain a sound weld of good prole. Medium current is required for
best results. High current will cause undercutting and bad shape of
the weld, while low current will cause slag inclusions. To produce a
weld having good penetration and of good prole, a short arc length is
necessary. Angle of electrode for overhead llets is illustrated above.
4.7 Typical Defects Due to FaultyTechnique
Manual metal arc welding, like other welding processes, has welding
procedure problems that may develop which can cause defects in the
weld. Some defects are caused by problems with the materials. Other
welding problems may not be foreseeable and may require immediate
corrective action. A poor welding technique and improper choice of
welding parameters can cause weld defects. Defects that can occur
when using the shielded metal arc welding process are slag inclusions,
wagon tracks, porosity, wormhole porosity, undercutting, lack of
fusion, overlapping, burn through, arc strikes, craters, and excessive
weld spatter. Many of these welding technique problems weaken the
weld and can cause cracking. Other problems that can occur which can
reduce the quality of the weld are arc blow, nger nailing, and improper
electrode coating moisture contents.
Defects caused by welding technique
Slag Inclusions
Slag inclusions occur when slag particles are trapped inside the weld
metal which produces a weaker weld. These can be caused by:
• erratic travel speed
• too wide a weaving motion
• slag left on the previous weld pass
• too large an electrode being used
• letting slag run ahead of the arc.
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BOC Smootharc 180 Multiprocess operating manual
Page 33
This defect can be prevented by:
• a uniform travel speed
• a tighter weaving motion
• complete slag removal before welding
• using a smaller electrode
• keeping the slag behind the arc which is done by shortening the arc,
increasing the travel speed, or changing the electrode angle.
Undercutting
Undercutting is a groove melted in the base metal next to the toe or
root of a weld that is not lled by the weld metal. Undercutting causes a
weaker joint and it can cause cracking. This defect is caused by:
• excessive welding current
• too long an arc length
• excessive weaving speed
• excessive travel speed.
On vertical and horizontal welds, it can also be caused by too large
an electrode size and incorrect electrode angles. This defect can be
prevented by:
• choosing the proper welding current for the type and size of electrode
and the welding position
• holding the arc as short as possible
• pausing at each side of the weld bead when a weaving technique
isused
• using a travel speed slow enough so that the weld metal can
completely ll all of the melted out areas of the base metal.
Lack of Fusion
Lack of fusion is when the weld metal is not fused to the base metal.
This can occur between the weld metal and the base metal or between
passes in a multiple pass weld. Causes of this defect can be:
• excessive travel speed
• electrode size too large
• welding current too low
• poor joint preparation
• letting the weld metal get ahead of the arc.
Lack of fusion can usually be prevented by:
• reducing the travel speed
• using a smaller diameter electrode
• increasing the welding current
• better joint preparation
• using a proper electrode angle.
33BOC Smootharc 180 Multiprocess operating manual
Page 34
5.0 General Welding Information
34
BOC Smootharc 180 Multiprocess operating manual
5.1 Recommended Welding Parameters for MIG/MAG
Argoshield Light
Indicative
WeldingParameters Dip Transfer
Spray
Transfer
Material thickness (mm) 1–1.6 2 3 4 3
Welding position Horizontal /
Vertical
Horizontal /
Vertical
Horizontal /
Vertical
Horizontal /
Vertical
Horizontal
Wire diameter (mm) 0.8–0.9 0.8–0.9 0.8–0.9 0.9–1.0 0.8
Current (amps) 45–80 60–100 80–120 80–150 160–180
Voltage (volts) 14–16 16–17 16–18 16–18 23–25
Wire feed speed (m/min) 3.5–5.0 4.0–7.0 4.0–7.0 4.0–7.0 7.5–9.0
Gas rate ow (L/min) 15 15 15 15 15
Travel speed (mm/min) 350–500 350–500 320–500 280–450 800–1000
Stainshield (Aus) or Stainshield Light (NZ)
Indicative
WeldingParameters Dip Transfer
Material thickness (mm) 4 6 8
Welding position
Horizontal /
Vertical
Horizontal /
Vertical
Horizontal /
Vertical
Wire diameter (mm)
0.9–1.0 0.9–1.0 0.9–1.0
Current (amps)
100–125 120–150 120–150
Voltage (volts)
17–19 18–20 18–20
Wire feed speed (m/min)
5.0–6.5 6.0–7.5 6.0–8.0
Gas rate ow (L/min)
15 15 18
Travel speed (mm/min)
400–600 280–500 280–450
Page 35
6.0 Correct Application Techniques
Electrical stickout
35BOC Smootharc 180 Multiprocess operating manual
Correct Application Techniques
Direction of welding.
MIG/MAG welding with solid wires takes place normally with a push
technique. The welding torch is tilted at an angle of 10° towards the
direction of welding. (Push technique)
10°
The inuence of changing the torch angle and the welding direction on
the weld bead prole can be seen below.
Torch perpendicular to workpiece narrow bead width with increased
reinforcement.
10°
Torch positioned at a drag angle of 10° narrow bead with excessive
reinforcement.
Flux cored welding with cored wires takes place normally with the drag
technique. The welding torch is tilted at an angle of 10° away from the
direction of welding. For all other applications the torch angle remains
the same.
90° 90°
0–15°
Torch position for butt welds
When welding butt welds the torch should be positioned within the
centre of the groove and tilted at an angle of ±15° from the vertical
plane. Welding is still performed in the push technique.
0–15°
45°
45°
C
Contact Tube Setback
S
Stando Distance
V
Visible Stickout
A
Arc length
E
Electrical Stickout
A
S
C
V
E
Contact Tube
Gas Nozzle
Consumable
Electrode
Workpiece
Page 36
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BOC Smootharc 180 Multiprocess operating manual
Torch position for llet welds
When welding llet welds the torch should be positioned at an angle of
45° from the bottom plate with the wire pointing into the llet corner.
Welding is still performed in the push technique.
Electrical stickout
The electrical stickout is the distance between the end of the contact
tip and the end of the wire. An increase in the electrical stickout results
in an increase in the electrical resistance. The resultant increase in
temperature has a positive inuence in the melt-o rate of the wire that
will have an inuence on the weldbead prole.
Inuence of the change in electrical stickout length on the weldbead
prole.
The travel speed will have an inuence on the weldbead prole and the
reinforcement height.
If the travel speed is too slow a wide weldbead with excessive rollover
will result. Contrary if the travel speed is too high a narrow weldbead
with excessive reinforcement will result.
Electrical stickout
Short Normal Long
Travel speed
Slow Normal Fast
Page 37
7.0 Package Contents
Package consists of the following:
• Power source
• Work return lead
• Electrode holder with cable
• Lift-TIG 26 torch
• Binzel MB15AK MIG/MAG torch
• Regulator
• Gas hose
• Spare feed rolls
• Operating manual
Optional:
• Spool gun not part of this package. Purchased separately.
37BOC Smootharc 180 Multiprocess operating manual
10 Euro output connection
11 Positive terminal
+
12 Short mechanical connector
14 Negative terminal
–
13 Control connector
Page 38
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BOC Smootharc 180 Multiprocess operating manual
Installation for MIG/MAG process Installation for MIG/MAG set up with OPTIONAL spool gun
8.1 Installation for MIG/MAG process
1 Connect the gas cylinder to the regulator. Select correct shielding gas
for the application.
2 Fit the wire spool to the machine. Select correct welding wire for
application.
3 Select the appropriate feed roller to suit the wire being used
- This machine comes complete with two types of wire feed rollers
- V groove for use with solid carbon manganese and stainless steels
- U groove for use with soft wires such as aluminium
4 Loosen the wire feed tension screws and insert the wire. Ret and
tension rollers ensuring the wire is gripped suciently so as not
to slip but avoid over tightening as this can aect feed quality and
cause wire feed components to wear rapidly.
5 Fit and tighten the A torch on the 10 euro output connection. Ensure
correct torch liner and contact tip are selected.
6 Select the correct polarity for the type of wire used as indicated on
the consumable packaging. This is achieved by swapping the polarity
terminal wires. For most solid wires the terminal should be set as
torch positive.
7 For torch positive, plug the 12 short mechanical connector (link
plug) on the front panel into the 11 positive (+) terminal and the
Bwork return lead into the 14 negative (-) terminal.
8 For torch negative, plug the 12 short mechanical connector (link
plug) into the 14 negative (-) terminal, and the B work return lead
into the 11 positive (+) terminal.
8.2 Installation for MIG/MAG set up
with OPTIONAL spool gun
1 Connect the gas cylinder to the regulator. Select correct shielding gas
for the application.
2 Plug S1 spool gun euro connection into 10 euro output connection.
3 Plug S2 spool gun control cable into 13 control connection.
4 Fit wire spool to the spool gun
- Lift cover up
- Remove retaining screw by turning clockwise.
- Slide mini spool in
- Adjust spool tension using knurled ring on the spool shaft
- Feed wire through front of the torch
- Close cover
5 Select the correct polarity for the type of wire used as indicated on
the consumable packaging. This is achieved by swapping the polarity
terminal wires. For most solid wires the terminal should be set as
torch positive.
6 For torch positive, plug the 12 short mechanical connector (link
plug) on the front panel into the 11 positive (+) terminal and the
Bwork return lead into the 14 negative (-) terminal.
7 For torch negative, plug the 12 short mechanical connector (link
plug) into the 14 negative (-) terminal , and the B work return lead
into the 11 positive (+) terminal.
8 Turn machine on.
9 The 4 Spool gun indicator light will illuminate. (Please note MIG
Pulse Al function is not avaliable with the spool gun).
10 Please note wire feed speed is only active from the spool gun .
11 The MIG spool gun only takes the 100 mm mini spool of wire.
8.0 Installation
1010
Optional spool gun purchased separately (not part of this package)
WARNING Ensure that all power to machine is turned o
before connecting the spool gun
12
12
1111
1313
1414
B
B
A
S1
S2
Page 39
39BOC Smootharc 180 Multiprocess operating manual
Installation for TIG setup Installation for MMA process
8.3 Installation for TIG setup
1 Connect the gas cylinder to the regulator. Connect MIG gas hose to
the regulator. Connect the A1 TIG gas hose into the free end of the
MIG gas hose, after disconnecting the MIG gas hose from the back of
the machine. Select correct shielding gas for the application.
2 Connect the A2 dinse plug of the TIG torch to 14 negative (-)
terminal of the front panel, and fasten it clockwise.
3 Connect B work return lead to 11 positive (+) terminal on the
front panel, and fasten it clockwise. Connect the clamp end to the
workpiece.
4 The 12 short mechanical connector (link plug) should remain
hangingfree.
8.4 Installation for MMA process
1 Connect the A electrode holder to the 11 positive (+) terminal of the
machine and fasten it clockwise.
2 Connect the B work return lead into the 14 negative (-) terminal of
the machine and fasten it clockwise.
3 Please note that for manual metal arc (MMA) welding the electrode
holder can be switched to the negative pole of the welding machine
if so required by the specication of the electrode.
4 The 12 short mechanical connector (link plug) should remain
hangingfree.
12 12
11 11
13 13
14 14
10 10
A
B
B
A2
A1
Page 40
40
BOC Smootharc 180 Multiprocess operating manual
Front panel of 180 Multiprocess
Multifunctional parameter adjustment
• Coarse adjustments made by pressing and turning the knob.
• Fine adjustments made by only turning the knob without pressing.
9.1 Polarity selection
Polarity selection can be reversed when welding in MIG/MAG mode.
This is important for certain types of self-shielded ux cored wires. This
can be achieved by switching the B work return lead to the 11 positive
(+) terminal and the 12 short mechanical connector (link plug) to the
14negative (-) terminal for a DC electrode negative polarity setting.
9.0 Control panels
4 Spool gun indicator
3 Multifunctional data adjustment
6 Lift TIG indicator
7 MIG indicator
8 MIG Pulse Al indicator
5 MMA indicator
9 MMA/Lift TIG/MIG/MIG Pulse Al
1 Multifunctional data display
2 Data selection
Page 41
41BOC Smootharc 180 Multiprocess operating manual
Illustration 1. Start-up display
Illustration 2. MIG Mode
Illustration 3. MIG Pulse Al Mode
Illustration 4. MIG mode – Display status when welding
10.1 Starting up
Switch on the machine. The 1 Multifunctional data display will ash for
5 seconds. The panel will display the previous settings that were saved
in the last shutdown.
10.2 Operation instruction under MIG mode
1 Set welding mode
Press the 9 Function Switch Key to choose the welding mode. The
machine enters into MIG mode (Illustration 2) when 7 MIG indicator
lights up, and enters into MIG Pulse Al mode (Illustration 3) when
8MIG Pulse Al indicator lights up.
As shown in Illustrations 2 & 3, the 1 Multifunctional Data Display
shows the preset voltage and the preset wire feeding speed.
Under MIG mode, the wire can be fed through the torch at high speed
by pressing and holding the torch switch without welding. To stop
wire feeding, press the torch switch again.
2 2T/4T mode
Under MIG mode, press 2 Data Selection Key for 2 Seconds to choose
the 2T/4T mode.
The welding mode (2T/4T)* can be selected by depressing the
2 Data Selection Key. The selected mode will be shown on the
1 Multifunctional Data Display. (Refer to the section on MIG
Fundaments in this manual for an explanation for 2T and 4T
operation).
The welding parameters can be adjusted during welding by turning
the 3 Multifunctional Data adjustment. This action will synergically
change both parameters (volts and wire feed speed).
* 2T is non-latched trigger operation (press and hold to keep welding and let go
tostop). 4T is latched trigger operation (click trigger to start welding and click
again tostop).
3 Adjusting parameters
Under MIG mode, you can adjust the voltage, inductance and wire
feeding speed.
Press the 2 Data Selection Key once, the 1Multifunctional Data
Display shown in Illustration 4, which means the selected preset
welding voltage is adjustable within a range of ±20%.
10.0 Operation
Page 42
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BOC Smootharc 180 Multiprocess operating manual
Illustration 8. MIG mode – When stopped welding
Illustration 6. MIG mode – Using optional spool gun
Illustration 5. MIG mode – Current preset
Press the 2 Data Selection Key twice. The 1 Multifunctional Data
Display is shown as Illustration 5, this allows inductance adjustment
in the range of ±10%
Without any operation after 5 seconds, the 1 Multifunctional Data
Display will revert back to the default setting. The settings will be
retained when the machine is turned o, and displayed when the
machinerestarts.
See the table below for detail of welding process parameters.
Welding process parameters
Mode Materials Wire dia. Wire feeding speed
MIG Carbon steel 0.8 mm 3-11 m/min
Carbon steel
/Aluminum
1.0 mm 3-7 m/min
MIG Pulse Al Aluminum 1.0 mm
(Recommend)
2-8 m/min
When welding aluminum, please t the dedicated wire feeding rolls
and replace the torch liner and contact tips with wear parts suitable
for aluminum.
Operation instruction under MIG mode using spool gun
1 The machine will go in to the spool gun welding mode when
connecting with the spool gun. The 4 spool gun indicator and 7 MIG
indicator lights up (Illustration 6).
Note: While connecting to the spool gun (optional), the wire feeding speed is
adjusted on the spool gun.
While connecting with the spool gun, the 7 Function Switch Key is not
adjustable.
2 The panel will display the data last used when restarting the
machine.
3 The panel displays as Illustration 7 when welding.
4 When releasing the torch switch and welding stops, the panel
displays as Illustration 8. Also, “HOLD” ashes for 3 seconds.
The 1 Multifunctional Data Display redisplays the preset current
after2Seconds.
Illustration 7. MIG mode – When welding
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43BOC Smootharc 180 Multiprocess operating manual
Illustration 11. MMA Mode with VRD Enabled
Illustration 12. MMA Mode without VRD Display
Illustration 10. LIFT TIG ModeIllustration 9. LIFT TIG Mode
10.3 Operation instruction under LIFT TIG mode.
1 Press the 9 Function Switch Key to LIFT TIG mode. The 6 LIFT TIG
indicator light will illuminate (Illustration 9).
2 Adjusting current
The welding current can be adjusted using the 3 Multifunctional Data
Adjustment Knob while welding.
The settings will be retained when the machine is turned o, and
displayed when the machine restarts.
3 The panel displays as Illustration 10 when welding. It will revert
to the preset welding current after 5 seconds when welding has
stopped.
10.4 Operation instruction under MMA mode.
1 Set welding mode
Press the 9 Function Switch Key to MMA mode. 5 MMA indicator light
will illuminate.
2 VRD function
Press the 2 Data Selection Key for 3 seconds. The VRD reduces
open circuit voltage to a safe limit. Illustration11 shows MMA mode
usingVRD.
Press the 2 Data Selection Key again for 3 seconds for the VRD
function to turn o (Illustration 12).
3 Adjusting current
Turning the 3 Multifunctional Data adjustment knob can change the
welding current during welding.
The settings will be retained when the machine is turned o, and
displayed when the machine restarts.
4 The panel displays as Illustration 11 when welding. It will revert
to the preset welding current after 5 seconds when welding has
stopped.
Page 44
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BOC Smootharc 180 Multiprocess operating manual
Illustration 13. Error Display of Wire Feeder Illustration 14. Error display of over current
Illustration 15. Error display of overheating protection
10.5 Error display
1 Error display of wire feeder
The panel displays as Illustration 13 when the wire feeder is
malfunctioning. The 1 Multifunctional Data Display ashes
continuously when the machine is not working. Restart the machine.
The panel will display the previous parameters before malfunction
occurred.
2 Error display of over-current
The panel displays as Illustration 14 when over-current occurs.
The 1Multifunctional Data Display ashes continuously when the
machine is not working. Restart the machine. The panel will display
the previous parameters before malfunction occurred.
3 Error display of overheating protection
The panel displays as Illustration 15 when overheating. The
1Multifunctional Data Display ashes continuously,when the
machine is not working. Only when the temperature of the welding
machine falls below 60°C will the overheating malfunction would
disappear, and the machine will work normally without restarting.
Page 45
45BOC Smootharc 180 Multiprocess operating manual
Page 46
11.0 Troubleshooting and Fault Finding
11.1 TIG/MMA functions
Excessive electrode consumption
Cause Solution
Inadequate gas ow Increase gas ow
Inadequate post gas ow Increase post ow time to 1 sec per 10 amps
Improper size electrode for current required Use larger electrode
Operating of reverse polarity User larger electrode or change polarity
Electrode contamination Remove contaminated portion, then prepare again
Excessive heating inside torch Replace collet. Try wedge collet or reverse collet
Electrode oxidising during cooling Increase post ow time before turning o valve
Shield gas incorrect Change to proper gas (no oxygen or CO
2
)
Erratic Arc
Cause Solution
Incorrect voltage (arc too long) Maintain short arc length
Current too low for electrode size Use smaller electrode or increase current
Electrode contaminated Remove contaminated portion, then prepare again
Joint too narrow Open joint groove
Contaminated shield gas. Dark stains on the electrode or
weld bead indicate contamination
The most common cause is moisture or aspirated air in gas stream. Use welding grade gas only.
Find the source of the contamination and eliminate it promptly
Base metal is oxidised, dirty or oily Use appropriate chemical cleaners, wire brush, or abrasives prior to welding
Inclusion of tungsten or oxides in weld
Cause Solution
Improper lift arc starting technique Follow directions as set out on page 43
Poor scratch starting technique Many codes do not allow scratch starts. Use copper strike plate. Use high frequency arc starter.
Excessive current for tungsten size used Reduce the current or use larger electrode
Accidental contact of electrode with puddle Maintain proper arc length
Accidental contact of electrode to ller rod Maintain a distance between electrode and ller metal
Using excessive electrode extension Reduce the electrode extension to recommended limits
Inadequate shielding or excessive drafts Increase gas ow, shield arc from wind, or use gas lens
Wrong gas Do not use ArO
2
or ArCO2 GMAW (MIG) gases for TIG welding
Heavy surface oxides not being removed Wire brush and clean the weld joint prior to welding
Porosity in Weld Deposit
Cause Solution
Entrapped impurities, hydrogen, air, nitrogen, water
vapour
Do not weld on wet material. Remove condensation from line with adequate gas pre-ow time
Defective gas hose or loose connection Check hoses and connections for leaks
Filler material is damp (particularly aluminium) Dry ller metal in oven prior to welding
Filler material is oily or dusty Replace ller metal
Alloy impurities in the base metal such as sulphur,
phosphorous, lead and zinc
Change to a dierent alloy composition which is weldable. These impurities can cause a
tendency to crack when hot
Excessive travel speed with rapid freezing of weld trapping
gases before they escape
Lower the travel speed
Contaminated shield gas Replace the shielding gas
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BOC Smootharc 180 Multiprocess operating manual
Page 47
Cracking in Welds
Cause Solution
Hot cracking in heavy sections or welding on metals prone
to hot cracking
Increase weld bead cross-section size. Change weld bead contour for e.g. concave to at or
convex, check t-up gap, reduce welding speed
Post weld cold cracking due to excessive joint restraint,
rapid cooling or hydrogen embrittlement
Preheat prior to welding. Use pure or non-contaminated gas. Increase the bead size. Prevent
craters or notches. Change the weld joint design
Centreline cracks in single pass weld Increase bead size. Decrease root opening. Use preheat. Prevent craters
Underbead cracking from brittle microstructure Eliminate sources of hydrogen, joint restraint, and use preheat
Inadequate shielding
Cause Solution
Gas ow blockage or leak in hoses or torch Locate and eliminate the blockage or leak
Excessive travel speed exposes molten weld to
atmospheric contamination
Use slower travel speed or carefully increase the ow rate to a safe level below creating
excessive turbulence. Use a trailing shield cup
Wind or drafts Set up screens around the weld area
Excessive electrode stickout Reduce electrode stickout. Use a larger size cup
Excessive turbulence in gas stream Change to gas safer parts or gas lens parts
Short parts Life
Cause Solution
Cup shattering or cracking in use Change cup size or type. Change tungsten position
Short collet life Ordinary style is split and twists or jams. Change to wedge style
Short torch head life Do not operate beyond rated capacity. Do not bend rigid torches
The phenomenon listed below may happen due to relevant accessories used, welding material, surroundings and power supply.
Please improve surroundings and avoid these problems.
Phenomenon
Cause Solution
Arc starting diculty. Arc interruption happens easily Examine whether grounding wire clamp contacts with the work pieces well.
Examine whether each joint has improper contact.
The output current fails to reach the set current Check connects are tight and cables are not damaged. Ensure correct electrode size has been
selected.
The current is unstable during operation:
This situation may relate to the following factors
The voltage of electric power network changes;
Serious interference from electric power network or other electric facilities.
Gas vent in welds Examine whether the gas supply circuit has leakage.
Examine whether there is sundries such as oil, dirt, rust, paint etc. on the surface.
47BOC Smootharc 180 Multiprocess operating manual
Page 48
11.2 MIG/MAG functions
Power source
Component Fault symptom Cause
Primary cable No or low welding output Poor or incorrect primary connection, lost phase
Earth cable and clamp Arc will not initiate Damaged, loose or undersized cables and clamps
Connectors and lugs Overheating of connectors andlugs Loose or poorly crimped connectors
Switches Erratic or no output control Switches damaged or incorrectly set for the application
Wire feeder
Component Fault symptom Cause
Gas solenoid valve No gas ow or gas ows continuously Gas valve faulty or sticking in open position
Wire feed rolls Wire slippage, wire deformation Incorrect feed roll size, incorrect tension adjustment,
misalignment
Inlet, outlet guides Wire shaving or snarling Incorrect wire guide sizes, misalignment
Torch connector Wire restriction, gas leaks, no trigger control Torch connector not correctly mounted or secured, incorrect size
of internal guide, bent contact pins
Wire feed speed control No control over wire feed speed, no amperage
control
Faulty wire speed feed potentiometer, machine in overload or
trip condition
Wire inch switch Wire live when feeding through cable and torch
before welding
Faulty wire inch switch, activitation of torch trigger switch
Spindle Wire spool drags or overruns Spindle brake set too tight or too loose, spool not properly
located on spindle
Welding torch
Component Fault symptom Cause
Type Welding torch overheats Welding torch underrated for welding application
Liners Erratic wire feed, wire snarls up at outlet guide Liner of incorrect type and size for wire in use, worn or dirty
liner, liner too long or too short
Gas distributor Inadequate gas ow, contaminated or porous weld Damaged or blocked distributor
Nozzle Inadequate gas cover, restricted joint accessibility Nozzle too large or too small, incorrect length or shape
Contact tip Erratic feeding, wire shudder, wire burnback,
unstable arc, spatter
Incorrect size of contact tip, incorrect contact tip to nozzle
distance for metal transfer mode, tip has worn out
Nozzle insulator Arcing between contact tip and nozzle and
between nozzle and workpiece
No nozzle insulator tted, spatter build up has caused parts to
short out
Regulator / owmeter
Component Fault symptom Cause
Inlet stem No gas ow, gas leaks at regulator body or
cylindervalve
Blocked inlet stem, leaking inlet stem to body thread, bullnose
not properly seated in cylinder valve
Gas hose and tting Leaks at connections or in the hose, porosity in
theweld
Poorly tted loose connections, damaged hose, air drawn into
gas stream
Welding wire
Component Fault symptom Cause
Wire basket and spool Erratic wire feeding or wire stoppages Damaged wire basket, loose spooling, random-wound wire
Wire Wire sticks in contact tip, erratic feeding Varying wire diameter, copper aking, surface damage
Wire Weld has excessive amount of spatter Wrong polarity has been selected
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BOC Smootharc 180 Multiprocess operating manual
Page 49
Porosity in Weld Deposit
Cause Solution
Entrapped impurities, hydrogen, air, nitrogen, water
vapour
Do not weld on wet material.
Defective gas hose or loose connection Check hoses and connections for leaks
Filler material is damp (particularly aluminium) Dry ller metal in oven prior to welding
Filler material is oily or dusty Replace ller metal
Alloy impurities in the base metal such as sulphur,
phosphorous, lead and zinc
Change to a dierent alloy composition which is weldable. These impurities can cause a
tendency to crack when hot
Excessive travel speed with rapid freezing of weld trapping
gases before they escape
Lower travel speed
Contaminated shield gas Replace the shielding gas
Inadequate shielding
Cause Solution
Gas ow blockage or leak in hoses or torch Locate and eliminate the blockage or leak
Excessive travel speed exposes molten weld to
atmospheric contamination
Use slower travel speed or carefully increase the ow rate to a safe level without creating
excessive turbulence. Use a trailing shield cup
Wind or drafts Set up screens around the weld area
Excessive electrode stickout Reduce electrode stickout. Use a larger size nozzle
Excessive turbulence in gas stream Change to gas saver parts or gas lens, lower ow rate if possible
49BOC Smootharc 180 Multiprocess operating manual
Page 50
12.0 Periodic Maintenance
WARNING
Only authorised electricians should carry out repairs and internal
servicing.
Modication of the 15A primary input plug or tment of a lower rated
primary input plug will render the warranty null and void.
The working environment or amount of use the machine receives should
be taken into consideration when planning maintenance frequency of
your Smootharc welder.
Preventative maintenance will ensure trouble-free welding and increase
the life of the machine and its consumables.
12.1 Power Source
• Check electrical connections of unit at least twice a year.
• Clean oxidised connections and tighten.
• Inner parts of machine should be cleaned
with a vacuum cleaner and soft brush.
• Do not use any pressure-washing devices.
• Do not use compressed air as pressure may pack dirt even more tightly
into components.
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BOC Smootharc 180 Multiprocess operating manual
Page 51
13.0 Technical Specications
Specications 180 Multiprocess
Part No. BOC180MULTI
Input voltage Single phase 240 V ±15 %
Frequency 50/60 Hz
MIG TIG MMA
Maximum rated input current (I
1max
)
31.2 A 24 A 31.1 A
Maximum effective supply current (I
1eff
)
14 A 12 A 13.9 A
No-load voltage 63 V
Output current 32 – 180 A 10 – 180 A 10 – 160 A
Duty cycle 20 % 180 A – 160 A
25 % – 180 A –
Wire feeder Internal or optional spool gun (sold separately)
Internal wire feeder speed 3 to 11 m/min
Post ow time 3 Seconds
Welding wire diameter 0.8/1.0 mm
Remote control No
Eciency 80 %
Power factor 0.73
Insulation grade H
Housing shielding grade IP21S
EMG grade B
Welding thickness >0.8 mm
Dimensions (L × W × H ) 420 × 220 × 439 mm
Weight 12.8 kg
Standards AS/NZS 60974-1, IEC/EN 60974-10
51BOC Smootharc 180 Multiprocess operating manual
Page 52
14.0 Warranty Information
14.1 Terms of Warranty
The Smootharc machine has a limited warranty that covers
manufacturing and material defects only. The warranty is aected on the
day of purchase and does not cover any freight, packaging and insurance
costs. Verbal promises that do not comply with terms of warranty are not
binding on warrantor.
14.2 Limitations on Warranty
The following conditions are not covered under terms of warranty: loss or
damage due to or resulting from natural wear and tear, non-compliance
with operating and maintenance instructions, connection to incorrect
or faulty voltage supply (including voltage surges outside equipment
specs), incorrect gas pressure overloading, transport or storage damage
or re or damage due to natural causes (e.g. lightning or ood). This
warranty does not cover direct or indirect expenses, loss, damage of
costs including, but not limited to, daily allowances or accommodation
and travelling costs.
Modication of the 15A primary input plug or tment of a lower rated
primary input plug will render the warranty null and void.
NOTE
Under the terms of warranty, welding torches and their consumables
are not covered. Direct or indirect damage due to a defective product
is not covered under the warranty. The warranty is void if changes are
made to the product without approval of the manufacturer, or if repairs
are carried out using non-approved spare parts. The warranty is void if a
non-authorised agent carries outrepairs.
14.3 Warranty Period
The warranty is valid for 18 months from date of purchase provided the
machine is used within the published specication limits.
14.4 Warranty Repairs
A BOC approved service provider must be informed within the warranty
period of any warranty defect. The customer must provide proof of
purchase and serial number of the equipment when making a warranty
claim. Warranty repairs may only be carried out by approved BOC service
providers. Please contact your local BOC Gas & Gear for a directory of BOC
approved service providers in your area.
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BOC Smootharc 180 Multiprocess operating manual
Page 53
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MP16-0241 FDAUS 0317
© BOC Limited 2017. BOC is a trading name of BOC Limited, a Member of The Linde Group. Reproduction without permission is strictly prohibited. Details given in this document are
believed to be correct at the time of printing. Whilst proper care has been taken in the preparation, no liability for injury or damage resulting from its improper use can be accepted.
For more information contact the
BOC Customer Engagement Centre
on 131 262 (AU) or 0800 111 333 (NZ)
BOC Limited ABN 95 000 029 729
10 Julius Avenue, North Ryde NSW 2113, Australia
www.boc.com.au
BOC Limited
WN007748
970–988 Great South Road, Penrose, Auckland, New Zealand
www.boc.co.nz
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