Lincoln Electric STT II User Manual

Invertec®STT®II

STT

PHASE

Featuring the Surface Tension Transfer® (STT) Process

Control Heat Input, Spatter and Fume

The revolutionary STT II power source combines high frequency inverter technology with advanced Waveform Control Technology™ to provide a better welding solution than traditional short arc MIG. Unlike CV MIG machines, the STT machine has no voltage control knob. STT uses current controls to adjust the heat independent of the wire feed speed, so changes in electrode extension do not affect heat. Low heat input welds can be produced without overheating or burning through, and distortion is minimized. Spatter and fumes are reduced because the electrode is not overheated — even when welding with larger diameter wires and 100% CO2shielding gas.

MIG WELDERS

Processes

GMAW-STT

Advantage Lincoln

• Controlled penetration and outstanding heat input control — Ideal for welding joints with open root, gaps, or on thin material with no burnthrough.

• Reduced spatter and fumes — Current is controlled to achieve optimal metal transfer.

• Reduced welding costs — Ability to use 100% CO2shielding gas with larger diameter wires.

• Various shielding gases — STT may be used with various gas blends of Argon including Helium.

• Good bead control and faster travel speeds — Can replace TIG (GTAW) in many applications without sacrificing appearance.

• Background and Tailout Current accurately control fine and coarse heat input for reduced distortion and burnthrough as well as proper penetration.

• Adjustable Hot Start controls the heat at the start of the weld.

• Manufactured under a quality system certified to ISO 9001 requirements and ISO 14001 environmental standards.

• Three-year Lincoln warranty on parts and labor.

Description

Output Input

Base Unit Includes

Twist-Mate® Cable Plugs (Qty. 2), STT II Sense Lead Kit, 25 ft. (7.6m)

Recommended General Options

Power Source Remote Output Control, Inverter and Wire Feeder Cart, Dual Cylinder Kit, STT II Sense Lead Kit, Coaxial Cable, Twist-Mate Cable Plug, Twist-Mate Cable Receptacle, Twist-Mate to Lug Adapter

Recommended Wire Feeder Options

STT-10 Wire Feeder, LN-742 Wire Feeder, LN-15 Control Cable Model, Magnum Gun and Cable Assembly, Magnum Connector Kit

Order

K1525-1 STT II 208/230/460/3/60 K1526-1 STT II International 200/220/380/415/440/3/50/60 K1526-2 STT II International 200/208/380/400/415/3/50/60 K1527-1 STT II CE-Approved 200/220/380/415/440/3/50/60 K1527-2 STT II CE-Approved 200/208/380/400/415/3/50/60

TECHNICAL SPECIFICATIONS

Dimensions

Product Product Input Rated Output Input Current@ Output H x W x D Weight

Name Number Power Current/Voltage/Duty Cycle Rated Output Range inches (mm) lbs. (kg)

Invertec K1525-1 208/230/460/3/60 225A / 29V / 60% 32/30/16A Peak Current: 23.2 x 13.2 x 24.4 117

STT II 200A / 28V / 100% 0-450A (589 x 336 x 620) (53)

K1526-1 200/220/380/415/ Max. OCV: 85V 33/30/18/17/16A Background

International 440/3/50/60 Current:

0-125A

K1526-2 200/208/380/400/ 36/34/20/19/18A

International 415/3/50/60

K1527-1 200/220/380/415/ 33/30/18/17/16A

CE-Approved 440/3/50/60

K1527-2 200/208/380/ 36/34/20/19/18A

CE-Approved 400/415/3/50/60

Publication E4.52 3/05

www.lincolnelectric.com

A CLOSER LOOK

WHAT IS NEXTWELD®?

Nextweld integrates Lincoln’s technologies, processes and products to create a comprehensive, flexible, user-friendly welding system that can increase efficiency and reduce fabrication costs. Waveform Control Technology™ and digital communications

provide the foundation for Nextweld innovations like Pulse-OnPulse™, Power Mode™, STT for ultimate arc control, high efficiency/reliability and seamless system integration.

Waveform Control Technology®

Driving Superior Welding Performance

Lincoln’s Waveform Control Technology controls and shapes the output waveforms (or weld modes) to adapt to virtually any application, material or weld position. Waveform Control Technology makes it possible to take advantage of Lincoln Nextweld innovations like the STT Process using the STT II.

For more information see Nextweld Document NX-1.10

STT®(Surface Tension Transfer®) is a controlled GMAW short circuit transfer process that uses current controls to adjust the heat independent of wire feed speed, resulting in superior arc performance, good penetration, low heat input control, and reduced spatter and fumes.

For more information see Nextweld Document NX-2.20

and ArcLink®. Look for Nextweld

The STT Process

Conventional CV short

circuit transfer using CO

and .045” solid wire.

STT using CO

and .045” solid wire.

Note reduced spatter and fume.

A. STT produces a uniform molten ball and maintains it

until the "ball' shorts to the puddle.

B. When the "ball" shorts to the puddle, the current is

reduced to a low level allowing the molten ball to wet into the puddle.

C. Automatically, a precision PINCH CURRENT wave

form is applied to the short. During this time, special circuitry determines that the short is about to break and reduces the current to avoid the spatter producing "explosion".

D. STT circuitry re-establishes the welding arc at a low

current level.

AEDCBA

[2]

E. STT circuitry senses that the arc is re-established, and

automatically applies PEAK CURRENT, which sets the proper arc length. Following PEAK CURRENT, internal circuitry automatically switches to the BACKGROUND CURRENT, which serves as a fine heat control.

Invertec® STT® II

www.lincolnelectric.com

A CLOSER LOOK

USING STT FOR OPEN ROOT WELDING

Open root welding is used for pipe and single-sided plate welding in situations that preclude welding from both sides of the material. This type of welding is common in the petrochemical and process piping industries.

Advantages of STT Open Root

Penetration Control

• Provides reliable root pass and complete back bead. Ensures excellent sidewall fusion.

Cost Reduction

• Uses 100% CO2, the lowest cost gas, when welding carbon steel.

Flexibility

• Provides the capability of welding stainless steel, nickel alloys, and mild or high strength steels without compromising weld quality.

• Capable of welding out of position.

Low Heat Input

• Reduces burnthrough and distortion.

Low Hydrogen Weld Metal Deposit

Stick welding with cellulose

electrodes provides good fusion

characteristics, but leaves deep

wagon tracks (requiring more labor

for grinding), a very convex root

weld, and a high hydrogen

deposit.

Open Root Pass with Stick

Electrode

Speed

• High quality open root welds at faster travel speeds than GTAW.

Current Control Independent of Wire Feed Speed

• Allows operator to control the heat input to the weld puddle.

Ease of Operator Use

• More forgiving process than conventional short arc welding with CV machines.

STT Open Root Application

Open Root Pass with STT

provides a weld ligament thickness

of approximately 0.22˝.

• Superior weld profile (no wagon tracks)

• Slight convexity of root weld

• Low hydrogen deposit

Inside of an 8 in. x .375 in.

wall API 5L-X52 pipe,

welded in 5G position.

STT process using 100% CO2 and .045 in. (1.2mm) wire.

[3]

www.lincolnelectric.com

Invertec® STT® II

+ 5 hidden pages