ESAB ST-21M User Manual
INSTRUCTIONS for
F-11-964-G
October, 2013
ST-21M MIG WELDING TORCH
P/N 690509
These INSTRUCTIONS are for experienced operators. If you are not fully familiar with the principles of operation and safe practices for arc welding equipment, we urge you to read our booklet, “Precautions and Safe Practices for Arc Welding, Cutting,
and Gouging”, Form 52-529. Do NOT permit untrained persons to install, operate, or maintain this equipment. Do NOT attempt
to install or operate this equipment until you have read and fully understand these instructions. If you do not fully understand
these instructions, contact your supplier for further information. Be sure to read the Safety Precautions on page 2 before
installing or operating this equipment.
I. INTRODUCTION
The ST-21M (P/N 690509) is a liquid-cooled, in-line body
style, machine torch designed exclusively for mechanized mig welding installations. The current carrying
capacity of this torch is 600 amperes continuous duty,
using all types of welding wire in sizes ranging from .030
inches (0.8 mm) through 7/64-inch (2.8 mm) diameters,
including ux cored wires.
The torch can be mounted directly to an EH-10A welding
head, and can be easily adapted for remote mounting.
The ST-21M is attached to the welding head by means
of an accessory mounting adaptor. To facilitate maneu-
verability and installation xturing, all service lines are
internally connected to the torch body and exit from the
rear of the torch barrel.
The torch is designed for use with either threadless
type contact tubes which are secured by a collet nut,
or threaded contact tips (see Table 2). The threadless
contact tube can be quickly and easily replaced by unscrewing the metal nozzle and collet nut (in that order),
and then slipping the contact tube out. The threaded
tips can be replaced by removing the metal nozzle and
unscrewing the tip. Six metal nozzles (one for spot
welding use) are available for use with this torch (see
Table 1). Nozzle sizes 8 and 10 require a spatter liner.
NOTE: Due to the high electrical conductivity, use of tap
water or commercial anti-freeze is NOT recommended for torch cooling. Use of the a coolant
circulator using a specially formulated torch
coolant (P/N 0560950312, 1 gal. container) is
recommended for torch cooling. The coolant
also provides anti-freeze protection down to
-34° F.
II. ACCESSORY EQUIPMENT
A. REQUIRED EQUIPMENT
1. Torch Mounting Bracket, P/N 633885. The bracket
includes as insulator sleeve which insulates the torch
from the welding head. See Figs. 1 and 2.
2. Nozzle and Wire Feed Accessories. The ST-21M
also requires a nozzle, a nozzle spatter liner, and
several wire feed accessories (contact tube or tip,
liner, and inlet guide tip) of the proper size for the wire
being used. These accessories are listed in Tables0
1 and 2 following.
3. Service Line Connections and Extensions. Depending on mounting arrangements or welding head
to be used, there are several methods for connecting
the torch service lines to the gas, coolant, and power
supplies (see Fig. 4).
a. Connection block assembly (P/N 58V74) is avail-
able for mounting on the EH-10A welding head.
b. The following service lines and couplings are avail-
able:
Coolant Hose, 3-ft....................................................... 20634
Coolant Hose, 12-1/2-ft. .............................................40V76
Coolant Hose, 25-ft................................................... 406196
Gas Hose, 3-ft. ........................................................... 31504
Gas Hose, 12-1/2-ft. ................................................... 40V77
Gas Hose, 25-ft. .........................................................34V38
Power Cable, 12-1/2-ft................................................40V78
Coolant Hose Coupling...............................................11N18
Gas Hose Coupling ....................................................11N17
Power Coolant Out Coupling ...................................... 11N19
Power Cable Adaptor.................................................. 45V11
Coolant Adaptor (connects hose to 1/4-in. NPT) ........11N16
4. Welding Head Accessories. Two other accessories
whose selection depends upon wire size and type,
are the feed roll and inlet guide insert on the welding
head. Selection of these accessories is covered in
the instruction booklet supplied with the welding head.
Mounting bracket, Part No. 996497, can be used to
mount an EH-10 to adjustable slide P/N 25V39 (Fig.
2) or to user designed set-up.
Be sure this information reaches the operator.
You can get extra copies through your supplier.
SAFETY PRECAUTIONS
WARNING: These Safety Precautions are for
your protection. They summarize precautionary information from the references listed in
Additional Safety Information section. Before
performing any installation or operating procedures, be
sure to read and follow the safety precautions listed below
as well as all other manuals, material safety data sheets,
labels, etc. Failure to observe Safety Precautions can result
in injury or death.
PROTECT YOURSELF AND OTHERS
-- Some welding, cutting, and gouging
processes are noisy and require ear
protection. The arc, like the sun, emits
ultraviolet (UV) and other radiation and
can injure skin and eyes. Hot metal can cause burns.
Training in the proper use of the processes and equipment is essential to prevent accidents. Therefore:
1. Always wear safety glasses with side shields in any work
area, even if welding helmets, face shields, and goggles
are also required.
2. Use a face shield fitted with the correct filter and cover
plates to protect your eyes, face, neck, and ears from
sparks and rays of the arc when operating or observing
operations. W arn bystanders not to watch the arc and not
to expose themselves to the ra ys of the electric-arc or hot
metal.
3. Wear flameproof gauntlet type gloves , heavy long-slee ve
shirt, cuffless trousers, high-topped shoes, and a welding
helmet or cap for hair protection, to protect against arc
rays and hot sparks or hot metal. A flameproof apron may
also be desirable as protection against radiated heat and
sparks.
4. Hot sparks or metal can lodge in rolled up sleeves, trou-
ser cuffs, or pockets. Sleeves and collars should be kept
buttoned, and open pockets eliminated from the front of
clothing
5. Protect other personnel from arc rays and hot sparks with
a suitable non-flammable partition or curtains.
6. Use goggles over safety glasses when chipping slag or
grinding. Chipped slag ma y be hot and can fly far. Bystanders should also wear goggles over safety glasses.
hazard.
6. After completing operations, inspect the work area to make
certain there are no hot sparks or hot metal which could
cause a later fire. Use fire watchers when necessary.
7. For additional information, refer to NFPA Standard 51B,
"Fire Prevention in Use of Cutting and Welding Processes",
available from the National Fire Protection Association,
Batterymarch Park, Quincy, MA 02269.
ELECTRICAL SHOCK -- Contact with live electrical parts
and ground can cause severe injury or death. DO NOT
use AC welding current in damp areas,
if movement is confined, or if there is
danger of falling.
1. Be sure the power source frame
(chassis) is connected to the ground system
of the input power.
2. Connect the workpiece to a good electrical ground.
3. Connect the work cable to the workpiece. A poor or miss-
ing connection can expose you or others to a f atal shock.
4. Use well-maintained equipment. Replace worn or dam-
aged cables.
5. Keep everything dry , including clothing, work area, cables,
torch/electrode holder, and power source.
6. Make sure that all parts of your body are insulated from
work and from ground.
7. Do not stand directly on metal or the earth while working
in tight quarters or a damp area; stand on dry boards or
an insulating platform and wear rubber-soled shoes.
8. Put on dry, hole-free glo ves before turning on the power .
9. Turn off the power before removing your gloves.
10. Refer to ANSI/ASC Standard Z49.1 (listed on next page)
for specific grounding recommendations. Do not mistake
the work lead for a ground cable.
ELECTRIC AND MAGNETIC FIELDS — May be danger ous.
Electric current flowing through any conductor causes
localized Electric and Magnetic Fields (EMF). Welding and
cutting current creates EMF around welding cables and
welding machines. Therefore:
FIRES AND EXPLOSIONS -- Heat from
flames and arcs can start fires. Hot
slag or sparks can also cause fires and
explosions. Theref ore:
1. Remove all combustible materials well away from the
work area or cover the materials with a protective nonflammable covering. Combustible materials include wood,
cloth, sawdust, liquid and gas fuels, solvents , paints and
coatings, paper, etc.
2. Hot sparks or hot metal can fall through cracks or crevices
in floors or wall openings and cause a hidden smoldering fire or fires on the floor below . Mak e certain that such
openings are protected from hot sparks and metal.“
3. Do not weld, cut or perform other hot work until the
workpiece has been completely cleaned so that there
are no substances on the workpiece which might produce
flammable or toxic v apors . Do not do hot work on closed
containers. They may explode.
4. Have fire extinguishing equipment handy for instant use ,
such as a garden hose, water pail, sand buck et, or portable
fire extinguisher. Be sure you are trained in its use.
5. Do not use equipment beyond its ratings. For example,
overloaded welding cable can overheat and create a fire
1. Welders having pacemakers
should consult their physician before
welding. EMF may interfere with some
pacemakers.
2. Exposure to EMF may have other
health effects which are unknown.
3. Welders should use the following procedures to minimize
exposure to EMF:
A. Route the electrode and work cables together. Secure
them with tape when possible.
B. Never coil the torch or work cable around your body.
C. Do not place your body between the torch and work
cables. Route cables on the same side of your body.
D. Connect the work cable to the workpiece as close as
possible to the area being welded.
E. Keep welding power source and cables as far away from
your body as possible.
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FUMES AND GASES -- Fumes and
gases, can cause discomfort or harm,
particularly in confined spaces. Do
not breathe fumes and gases. Shielding gases can cause asphyxiation.
Therefore:
1. Always provide adequate ventilation in the work area by
natural or mechanical means. Do not weld, cut, or gouge
on materials such as galvanized steel, stainless steel,
copper, zinc, lead, beryllium, or cadmium unless positive
mechanical ventilation is provided. Do not breathe fumes
from these materials.
2. Do not operate near degreasing and spraying operations.
The heat or arc rays can react with chlorinated hydrocarbon
vapors to form phosgene, a highly toxic gas, and other
irritant gases.
3. If you develop momentary eye, nose, or throat irritation
while operating, this is an indication that ventilation is not
adequate. Stop w ork and take necessary steps to improve
ventilation in the work area. Do not continue to operate if
physical discomfort persists.
4. Refer to ANSI/ASC Standard Z49.1 (see listing below) for
specific ventilation recommendations.
5. WARNING: This product, when used for welding or
cutting, produces fumes or gases which
contain chemicals known to the State of
California to cause birth defects and, in
some cases, cancer . (California Health &
Safety Code §25249.5 et seq.)
CYLINDER HANDLING -- Cylinders, if
mishandled, can rupture and violently
release gas. Sudden rupture of cylinder ,
valve, or relief device can injure or kill.
Therefore:
1. Use the proper gas for the process
and use the proper pressure reducing regulator designed
to operate from the compressed gas cylinder. Do not use
adaptors. Maintain hoses and fittings in good condition.
Follow manuf acturer's operating instructions for mounting
regulator to a compressed gas cylinder.
2. Always secure cylinders in an upright position by chain or
strap to suitable hand trucks, undercarriages, benches,
walls, post, or racks . Never secure cylinders to w ork tables
or fixtures where they may become part of an electrical
circuit.
3. When not in use, keep cylinder valv es closed. Have v alve
protection cap in place if regulator is not connected. Secure
and move cylinders by using suitable hand trucks. Avoid
rough handling of cylinders.
4. Locate cylinders away from heat, sparks, and flames.
Never strike an arc on a cylinder.
5. For additional information, refer to CGA Standard P-1,
"Precautions for Safe Handling of Compressed Gases
in Cylinders", which is available from Compressed Gas
Association, 1235 Jefferson Davis Highwa y , Arlington, V A
22202.
EQUIPMENT MAINTENANCE -- Faulty or
improperly maintained equipment can
cause injury or death. Therefore:
1. Always have qualified personnel perform
the installation, troubleshooting, and maintenance work.
Do not perform any electrical work unless you are qualified to perform such work.
2. Before performing any maintenance work inside a power
source, disconnect the power source from the incoming
electrical power.
3. Maintain cab les, grounding wire, connections, power cord,
and power supply in safe working order. Do not operate
any equipment in faulty condition.
4. Do not abuse any equipment or accessories. Keep
equipment away from heat sources such as furnaces, wet
conditions such as water puddles, oil or grease, corrosiv e
atmospheres and inclement weather.
5. Keep all safety devices and cabinet co vers in position and
in good repair.
6. Use equipment only f or its intended purpose. Do not modify
it in any manner.
ADDITIONAL SAFETY INFORMATION -- For
more information on safe practices for electric
arc welding and cutting equipment, ask your
supplier for a copy of "Precautions and Safe
Practices for Arc W elding, Cutting and Gouging", Form 52-529.
The following publications, which are available from the
American Welding Society, 550 N.W. LeJ uene Road, Miami,
FL 33126, are recommended to you:
1. ANSI/ASC Z49.1 - "Safety in Welding and Cutting"
2. AWS C5.1 - "Recommended Practices for Plasma Arc
Welding"
3. AWS C5.2 - "Recommended Practices for Plasma Arc
Cutting"
4. AWS C5.3 - "Recommended Practices for Air Carbon Arc
Gouging and Cutting"
5. AWS C5.5 - "Recommended Practices for Gas Tungsten
Arc Welding“
6. AWS C5.6 - "Recommended Practices for Gas Metal Arc
Welding"“
7. AWS SP - "Saf e Practices" - Reprint, W elding Handbook.
8. ANSI/A WS F4.1, "Recommended Safe Practices for Welding and Cutting of Containers That Hav e Held Hazardous
Substances."
MEANING OF SYMBOLS - As used throughout
this manual: Means Attention! Be Alert! Your
safety is involved.
Means immediate hazards which, if
not avoided, will result in immediate,
serious personal injury or loss of life.
Means potential hazards which could
result in personal injury or loss of life.
Means hazards which could result in
minor personal injury.
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PRÉCAUTIONS DE SÉCURITÉ
AVERTISSEMENT: Ces règles de sécurité ont pour objet
d’ assurer votre protection. Veillez à lire et à observer
les précautions énoncées ci-dessous avant de monter
l’ équipement ou de commercer à l’utiliser. Tout défaut
d’observation de ces précautions risque d’entraîner des
blessures graves ou mortelles.
1. PROTECTION INDIVIDUELLE-- Les brûlures de la peau
et des yeux dues au rayonnement de l’arc électrique
ou du métal incandescent, lors du soudage au plasma
ou à l’électrode ou lors du gougeage à l’arc, peuvent
s’avérer plus graves que celles résultant d’une exposition prolongée au soleil. Aussi convient-il d’observer
les précautions suivantes:
a. Portez un écran facial adéquat muni des plaques pro-
tectrices et des verres ltrants appropriés an de vous
protéger les yeux, le visage, le cou et les oreilles des
étincelles et du rayonnement de l’arc électrique lorsque
vous effectuez des soudures ou des coupes ou lorsque
vous en observez l’exécution.
AVERTISSEZ les personnes se trouvant à proximité
de façon à ce qu’elles ne regardent pas l’arc et à ce
qu’elles ne s’exposent pas à son rayonnement, ni à
celui du métal incandescent.
b. Portez des gants ignifugés à crispins, une tunique
épaisse à manches longues, des pantalons sans re-
bord, des chaussures à embout d’acier et un casque
de soudage ou une calotte de protection, an d’éviter
d’exposer la peau au rayonnement de l’arc électrique
ou du métal incandescent. ll est également souhaitable
d’utiliser un tablier ininammable de façon à se protéger des étincelles et du rayonnement thermique.
c. Les étincelles ou les projections de métal incandescent
risquent de se loger dans des manches retroussées,
des bords relevés de pantalons ou dans des poches.
Aussi convient-il de garder boutonnés le col et les
manches et de porter des vêtements sans poches à
l’avant.
d. Protégez des étincelles et du rayonnement de l’arc
électrique les autres personnes travaillant à proximité
à l’aide d’un écran ininammable adéquat.
e. Ne jamais omettre de porter des lunettes de sécurité
lorsque vous vous trouvez dans un secteur où l’on
effectue des opérations de soudage ou de coupage
à l’arc. Utilisez des lunettes de sécurité à écrans ou
verres latéraux pour piquer ou meûler le laitier. Les
piquetures incandescentes de laitier peuvent être pro-
jetées à des distances considérables. Les personnes
se trouvant à proximité doivent également porter des
lunettes de protection.
f. Le gougeage à l’arc et le soudage à l’arc au plasma
produisent un niveau de bruit extrêmement élevé (de
100 à 114 dB) et exigent par conséquent l’emploi de
dispositifs appropriés de protection auditive.
2. PRÉVENTION DES INCENDES-- Les projections de
laitier incandescent ou d’étincelles peuvent provoquer
de graves incendies au contact de matériaux combus-
tibles solides, liquides ou gazeux. Aussi faut-il observer
les précautions suivantes:
a. Éloigner sufsamment tous les matériaux combustibles
du secteur où l’on exécute des soudures ou des
coupes à l’arc, à moins de les recouvrir complètement
d’une bâche non-inammable. Ce type de matériaux
comprend notamment le bois, les vêtements, la sciure,
l’essence, le kérosène, les peintures, les solvants, le
gaz naturel, l’acétylène, le propane et autres substances
combustibles semblables.
b. Les étincelles ou les projections de métal incandescent
peuvent tomber dans des ssures du plancher ou dans
des ouvertures des murs et y déclencher une ignition
lente cachée. Veiller à protéger ces ouvertures des
étincelles et des projections de métal.
c. N’exécutez pas de soudures, de coupes, d’opérations
de gougeage ou autres travaux à chaud à la surface de
barils, bidons, réservoirs ou autres contenants usagés,
avant de les avoir nettoyés de toute trace de substance
susceptible de produire des vapeurs inammables ou
toxiques.
d. En vue d’assurer la prévention des incendies, il convient
de disposer d’un matériel d’extinction prêt à servir immédiatement, tel qu’un tuyau d’arrosage, un seau à eau,
un seau de sable ou un extincteur portatif.
e. Une fois le travail à l’arc terminé, inspectez le secteur
de façon à vous assurer qu’aucune étincelle ou projection de métal incandescent ne risque de provoquer
ultérieurement un feu.
3. CHOC ÉLECTRIQUE-- Le gougeage à l’arc et à l’arc
au plasma exige l’emploi de tensions à vide relativement importantes; or, celles-ci risquent de causer des
dommages corporels graves et même mortels en cas
d’utilisation inadéquate. La gravité du choc électrique
reçu dépend du chemin suivi par le courant à travers
le corps humain et de son intensité.
a. Ne laissez jamais de surfaces métalliques sous tension
venir au contact direct de la peau ou de vêtements
humides. Veillez à porter des gants bien secs.
b. Si vous devez effectuer un travail sur une surface mé-
tallique ou dans un secteur humide, veillez à assu-rer
votre isolation corporelle en portant des gants secs et
des chaussures à semelles de caoutchouc et en vous
tenant sur une planche ou une plate-forme sèche.
c. Mettez toujours à la terre le poste de soudage/coupage
en le reliant par un câble à une bonne prise de terre.
d. N’utilisez jamais de câbles usés ou endommagés. Ne
surchargez jamais le câble. Utilisez toujours un équipe-
ment correctement entretenu.
e. Mettez l’équipement hors tension lorsqu’il n’est pas en
service. une mise à la masse accidentelle peut en effet
provoquer une surchauffe de l’équipement et un danger
d’incendie. Ne pas enrouler ou passer le câble autour
d’une partie quelconque du corps.
f. Vériez si le câble de masse est bien relié à la pièce en
un point aussi proche que possible de la zone de travail.
Le branchement des câbles de masse à l’ossature du
bâtiment ou en un point éloigné de la zone de travail
augmente en effet le risque de passage d’un courant de
sortie par des chaînes de levage, des câbles de grue
ou divers chemins électriques.
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