GMAW Welding Guide Gas Metal Arc Welding Carbon, Low Alloy, and Stainless Steels and Aluminum
Gas Metal Arc Welding • GMAW has higher electrode efficiencies, usually between 93% and 98%, when compared to other welding processes. The gas metal arc process is dominant today as a joining process among the world’s welding fabricators. Despite its sixty years of history, research and development continue to provide improvements to this process, and the effort has been rewarded with high quality results. • Higher welder efficiencies and operator factor, when compared to other open arc welding processes.
Gas Metal Arc Welding Guidelines Editor: Jeff Nadzam, Senior Application Engineer Contributors: Frank Armao, Senior Application Engineer Lisa Byall, Marketing GMAW Products Damian Kotecki, Ph.D., Consumable Research and Development Duane Miller, Design and Engineering Services Important Information on our Website Consumable AWS Certificates: www.lincolnelectric.com/products/certificates/ Material Safety Data Sheets (MSDS): www.lincolnelectric.com/products/msds/ ANSI Z49.
Contents Page History of Gas Metal Arc Welding (GMAW) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 Modes of Metal Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-10 Short-Circuit Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 Globular Transfer . . . . . . . . . .
Contents Page GMAW of Carbon and Low Alloy Steels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34-39 Selecting Carbon and Low Alloy Electrodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34 Types of GMAW Carbon and Low Alloy Steel Electrodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35-36 Mechanical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
History of Gas Metal Arc Welding The history of GMAW, gas metal arc welding, had its industrial introduction in the late 1940’s. The site was the Battelle Memorial Institute, and it was there that Hobart and Devers, sponsored by the Air Reduction Company, researched and developed the first use of a continuously fed aluminum wire electrode, shielded with 100% argon gas. In the 1990’s, research and development in welding power source technology continued to evolve.
Modes of Metal Transfer Short-Circuit Metal Transfer Description of Short-Circuiting Transfer The transfer of a single molten droplet of electrode occurs during the shorting phase of the transfer cycle (See Figure 2). Physical contact of the electrode occurs with the molten weld pool, and the number of short-circuiting events can occur up to 200 times per second.
move towards the contact tip. Cathode jet forces, that move upwards from the work-piece, are responsible for the irregular shape and the upward spinning motion of the molten droplets. Inductance Control Keywords: Rate of Current Rise Henries The process at this current level is difficult to control, and spatter is severe. Gravity is instrumental in the transfer of the large molten droplets, with occasional short-circuits.
• • • • • Axial Spray Transfer Keywords: Globular to Axial Spray Transition Current Weld Interface High operator appeal and ease of use. Requires little post weld cleanup. Absence of weld spatter. Excellent weld fusion. Lends itself to semiautomatic, robotic, and hard automation applications. Limitations of Axial Spray Transfer • Restricted to the flat and horizontal welding positions. • Welding fume generation is higher.
Pulsed Spray Transfer FIGURE 5: A Single Pulsed Event Keywords: Period (1) Front Flank Ramp-up Rate Peak Current (2) Overshoot (4) 4 Background Current (3) Peak Current (2) 2 (4) Peak Time Frequency (5) Tail-out Pulsed spray metal transfer, known by the acronym GMAW-P, is a highly controlled variant of axial spray transfer, in which the welding current is cycled between a high peak current level to a low background current level.
Components of the Welding Arc Keywords: Electromagnetic Forces When current flows through a conductor, a magnetic field builds and surrounds the conductor. In GMAW the electro-magnetic forces, which are mathematically proportional to the square of the applied current, affect the mode of metal transfer. The most common term applied to the electromagnetic force is the pinch effect. As the molten drop forms, it is uniformly squeezed from the electrode anode end by the electromagnetic force.
Shielding Gases for GMAW The selection of the correct shielding gas for a given application is critical to the quality of the finished weld. The criteria used to make the selection includes, but is not restricted to, the following: • • • • • • • • • • argon will result in a penetration profile with a finger-like projection into the base material, and this is due to the lower thermal conductivity of argon. Alloy of wire electrode. Desired mechanical properties of the deposited weld metal.
silicon and manganese retained in the weld. As a result, lower carbon dioxide levels, in a binary or ternary shielding gas blend, increase the yield and ultimate tensile strength of a finished weld (see Shielding Gas section on page 12). Common Argon + Helium Blends 75% Argon + 25% Helium — this binary blend is frequently applied to improve the penetration profile for aluminum, copper, and nickel applications. The puddle is more fluid than with 100% argon.
Common Short-Circuiting Transfer Shielding Gas Blends 75% Argon + 25% CO2 — reduces spatter and improves weld bead appearance on carbon steel applications. 80% Argon + 20% CO2 — another popular blend, which further reduces spatter and enhances weld bead appearance on carbon steel applications. 95% Argon + 5% Oxygen — general purpose axial spray or pulsed spray transfer shielding gas applied to heavier sections of carbon steel.
GMAW SHIELDING GAS SELECTION GUIDE Base Material Carbon Steel Low Alloy Steel Aluminum Austenitic Stainless Steel Electrode Type Lincoln GMAW Product Name ER70S-3 ER70S-4 ER70S-6 or E70C-6M SuperArc® ® SuperGlide ER80S-Ni1 ER80S-D2 ER100S-G ER110S-G E90C-G E110C-G ER1100 ER4043, ER4047 ER5183, ER5356 ER5554, ER5556 ER308LSi ER309LSi ER316LSi Metalshield® SuperArc and Metalshield Mode of Metal Transfer Shielding Gas Blends GMAW-S or STT 100% CO2 75-90% Argon + 10-25% CO2 Axial Spray or GMAW-
Effects of Variables Current Density Electrode Efficiencies Electrode efficiency is a term that is applied to the percentage of electrode that actually ends up in the weld deposit. Spatter levels, smoke, and slag formers affect the electrode efficiency in GMAW.
Depending upon the mode of metal transfer, as indicated in the Electrode Efficiency section on page 16, the factor for the particular mode of metal transfer employed is applied to the melt-off rate. Contact tip to work distance (CTWD) is a term that lends itself well to the electrode extension for mechanized or robotic welding applications. It is measured from the end of the contact tip to the work piece.
Advanced Welding Processes for GMAW Keywords: Waveform Control Technology™ The adaptive arc is an arc that quickly adjusts to changes in the electrode extension to maintain the same arc length. The objective for adaptive control is to improve arc performance and maintain finished weld quality.
GMAW-P Waveform Components Peak Current Time (4) Peak current time describes the length of time that the current is at its peak. It is associated with droplet size. Peak time is expressed in terms of milliseconds. As the peak time increases, the droplets decrease in size. As the peak time decreases, the droplet size increases. The traditional expectation is that a single molten droplet is transferred with each pulse peak.
The Adaptive Loop Keywords: Advanced Waveform Control Technology Scale Factor Surface Tension Transfer™ (STT™) Adaptive Loop Keywords: Arc Length Regulation Peak Current Constant Current Background Current In a constant current scenario, as the CTWD is increased, the arc length also increases. As the CTWD decreases, the arc length also decreases. To control the length of the arc despite changes in CTWD, an adaptive control is necessary.
Surface Tension Transfer™ (STT™) STT Arc Controls Tailout Tailout Control FIGURE 14: Typical Waveform for STT .035/.045 Electrode SwitchSwitch .035/.
Tandem GMAW Keywords: • Lower hydrogen weld deposit. • Lower spatter levels when compared to other processes and modes of metal transfer. • Capable of high deposition welding for heavy plate fabrication. • May be used for out-of-position welding. High Deposition Higher Travel Speed The Tandem GMAW system was developed to take advantage of the potential for higher travel speeds and higher deposition rates when using two electrodes in the same molten puddle.
Tandem Torch Alignment and Contact Tip to Work Distance Sheet Metal Applications Central to the successful operation of tandem GMAW is an understanding of the set up of the special tandem GMAW welding torch. In all cases, the central axis of the torch should be normal to the weld joint. The lead arc has a built in 6° lagging electrode angle, and the trail has a built in 6° leading electrode angle.
Equipment for GMAW The basic design of an industrial, GMAW system includes four principle components: • Constant voltage fixed power sources with a selection of wire drives and accessories for three-phase input power. They range from 250 – 655 amps of welding output. For example, see Figure 19. 1. Power source. 2. Wire drive and accessories (drive rolls, guide tubes,reel stand, etc.). 3. GMAW gun and cable assembly designed to deliver the shielding gas and the electrode to the arc. 4.
• Advanced process power sources dedicated to Surface Tension Transfer™ and GMAW-P. They range in output from 225 - 655 amps, and all of these systems require three-phase input power. For example see Figure 21. Voltage, V • Engine driven power sources that range from 200 - 600 amps of output. See page 31 for an example of a portable engine driven GMAW system.
The Wire Drive and Accessories FIGURE 24: Unaffected Arc Length with Constant Voltage Power Sources GMAW wire drive designs provide for the use of a wide range of solid or metal-cored electrodes, 0.025” – 1/16” (0.6 – 1.6 mm). The wire feed speed may be pre-settable via a digital readout or a calibrated marking system on the wire feed speed control. The ability to provide a precise wire speed is important to good welding procedure control.
Two- or four-roll drive systems deliver the electrode to the welding torch. Two-roll systems are standard with smaller non-industrial systems, but the four-roll system is popular for industrial applications. A mounting block for the power cable permanently fixes to the GMAW torch receiver of the wire drive. The use of a wire straightening device incorporates the ability of the wire drive to provide three important features for the arc: 1.
Special Wire Feeding Considerations Spool guns are designed to provide a means for delivering aluminum, and other small 1 and 2 lb. (0.45 and 0.90 kg) packages of electrode to the arc. The spool gun incorporates a wire drive motor, a wire feed speed control, and an electrode enclosure in a comfortable lightweight design. Binzel™ Push-Pull System for Aluminum Feeding Shielding Gas Regulation Spool Gun The delivery of a shielding gas to the arc is important to the quality of the finished weld.
Bulk Electrode Packaging Horizontal Reels - Moving Reel Type are used with reels of electrode that require the rotation of the entire spool. The mechanical advantage of this type of dispensing system allows reduced pulling of the electrode from the reel to the wire drive. Longer feeding distances sometimes require an assist motor. In order to minimize the electrode packaging changes, GMAW welding stations may incorporate bulk electrode dispensing systems.
FIGURE 25: Automatic GMAW System Electrode Supply Power Feed 10R Wire Drive DO NOT TIP NE PAS INCLINER NO INCLINAR www.lincoln electric.com Gas Cylinder with Flow Meter NER INCLI NE PAS NAR CLI NO IN .com lectric .lincolne www Travel Carriage Welding Torch Power Wave 455M Robotic Power Source Welding Control Touchscreen FIGURE 26: Semiautomatic GMAW System Electrode Supply LN-10 Wire Drive Gas Cylinder with Flow Meter CV-400 Power Supply Welding Torch Workpiece GMAW 30 www.
FIGURE 27: Portable Engine Driven GMAW System Gas Cylinder with Flow Meter Ranger 305D Power Supply Workpiece LN-25 Wire Feeder Welding Torch GMAW Torches Gun Housing Power Cable Insulation Conductor Tube Keywords: Torch Nozzle Water-Cooled Torch Contact Tip Air-Cooled Torch Torch Barrel Water Cooler Gas Diffuser Braided Copper Power Cable Nozzle Hanger Torch Duty Cycle Trigger Leads Cable to Conductor Tube Connection Torch Liner The selection of the proper GMAW torch, commonly called a
FIGURE 29: GMAW Torch Cutaway The selection of a water-cooled torch for GMAW has several advantages. They are rated 100% duty cycle for their given capacity. They increase the life of the consumable components of the torch by approximately 50%. Water–cooled torches have operator appeal because they reduce the heat transferred to the GMAW torch handle. The downside of a water-cooled torch is that they tend to require more maintenance.
GMAW Torches for Hard Automation Fixed Length Automatic Torch for Hard Automation Hard automation requires the torches meet the demands of high productivity. The choice of water-cooled torches versus an air-cooled torch depends on the same criteria applied to the selection of a torch for semiautomatic welding. Most hard automation systems incorporate a system design that provides the need for a torch no longer than 3 ft. (1 m). This aids in feeding, and reduces maintenance time and cost.
GMAW of Carbon and Low Alloy Steels Electrode Selection Checklist The following are suggestions for selecting the proper GMAW steel electrode for a given application: Selecting Carbon and Low Alloy Steel Electrodes Selecting the proper filler metal for use with GMAW is similar to the process that must be employed when determining the applicable electrode for any welding process: A.
Types of Carbon and Low Alloy Steel Electrodes pipe. Due to the deoxidizers, the ER70S-2 is indicated for use on steels with moderate levels of mill scale. The use of this electrode has decreased in recent years, and it is replaced, typically, by either ER70S-3 or ER70S-6 carbon steel electrode. Keywords: AWS A5.18 AWS A5.28 ER70S-3 (SuperArc® L-50) The ER70S-3 GMAW electrode contains medium levels of silicon and manganese. It is popularly employed in both single and multiple pass welding applications.
AWS A5.28 GMAW Low Alloy Solid Steel Wires chemical compositions or mechanical property requirements. Lincoln Electric’s SuperArc LA-100 premium GMAW wire electrode meets the ER100S-G, ER110S-G, and the Military Specification MIL-100S-1 classification requirements. This electrode meets a minimum tensile strength of 100 ksi and minimum yield strengths of 82 ksi. It contains 0.5% molybdenum and 1-2% nickel, making it an excellent choice for welding HY-80 and ASTM A514 steels.
Solid & Composite Steel Wire Electrode Chemical Composition as total copper in the finished product. Benefits of copper coating include better conductivity, and therefore, better arc starts, and longer contact tip life. Carbon (C) – Carbon is a critical element found in GMAW solid wire electrodes. It is added in precise amounts to provide strength and ductility in the weldment. Titanium (Ti) – Titanium is found in ER70S-2 mild steel GMAW wire electrode and is added as a deoxidizer.
AWS Specifications for Manufacturing GMAW Wires Coil Style Packaging Winding Check Keywords: Cast Helix Heat or Lot Cast The American Welding Society has manufacturing specifications and acceptance standards for GMAW electrodes.
The next size spool is an eight inch diameter spool that holds ten lbs. (5 kg) through 12.5 lbs. (6 kg) of GMAW solid wire electrode. This package is also primarily used on self-contained wire feeder welders, but due to the increase in consumable weight, it has also found use in industrial applications. It is an excellent choice for use with the Lincoln’s LN-15 across-the-arc portable wire feeder.
GMAW of Stainless Steels Stainless steels are defined as iron base alloys which contain at least 10.5% chromium. The thin but dense chromium oxide film which forms on the surface of a stainless steel provides corrosion resistance and prevents further oxidation. There are five types of stainless steels depending on the other alloying additions present, and they range from fully austenitic to fully ferritic types.
TABLE 7 — Nominal Compositions of Ferritic Stainless Steels NOMINAL COMPOSITIONS Composition - Percent * Cr Ni 11.5-14.5 10.5-11.75 14.0-16.0 16.0-18.0 16.0-18.0 16.0-18.0 16.0-19.5 0.75 16.0-18.0 16.0-18.0 Type 405 409 429 430 430F** 430FSe** 430Ti 434 436 UNS Number S40500 S40900 S42900 S43000 S43020 S43023 S43036 S43400 S43600 C 0.08 0.08 0.12 0.12 0.12 0.12 0.10 0.12 0.12 Mn 1.00 1.00 1.00 1.00 1.25 1.25 1.00 1.00 1.00 Si 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 442 444 S44200 S44400 0.
composition of these and other austenitic stainless steels are listed in Table 9. Filler metals for these alloys should generally match the base metal but for most alloys, provide a microstructure with some ferrite to avoid hot cracking as will be discussed further. To achieve this, Type 308 is used for Type 302 and 304 and Type 347 for Type 321. The others should be welded with matching filler. Type 347 can also be welded with Type 308H filler.
Sensitization The degree of carbide precipitation increases with: Two problems are associated with welds in the austenitic stainless steels: 1) sensitization of the weld heat affected zone, and 2) hot cracking of weld metal. 1. Higher carbon content (for example, because 301 and 302 grades have a maximum carbon content of 0.15% they are more susceptible to carbon precipitation than grade 304 which has a maximum carbon content of only 0.08%).
The low carbon content in ELC grades leaves more chromium to provide resistance to intergranular corrosion. If welding is necessary, special E312-XX or E309-XX electrodes are recommended because their high ferrite reduces cracking tendencies. Use techniques that reduce admixture of base metal into the weld metal and produce convex bead shapes.
FIGURE 33 — New 1992 WRC diagram including solidification mode boundaries. Updated from T.A. Siewert, C.N. McCowan and D.L. Olson – Welding Journal, December 1988 by D.J. Kotecki and T.A. Siewert - Welding Journal, May 1992. 18 20 22 24 26 28 30 18 4 A 16 8 16 20 14 14 14 24 10 AF 16 6 12 2 18 28 22 35 45 26 = Ni + 35C 20N + + 0.25Cu Nieq =NiNi 35C + +20N 0.25Cu eq + 0 18 30 FA 12 55 65 40 50 F 60 12 75 70 85 95 80 90 10 10 100 18 20 22 24 26 Creq =CrCr + +0.
The austenitic precipitation hardening stainless steels remain austenitic after quenching from the solutioning temperature even after substantial amounts of cold work. They are hardened only by the aging reaction. This would include solution treating between 1800 and 2050°F (982 to 1121°C), oil or water quenching and aging at 1300 to 1350°F (704 to 732°C) for up to 24 hours. Examples of these steels include A286 and 17-10P.
Duplex Stainless Steels permeability and melting range. These values should be close enough for most engineering purposes. If more precise data is required for a particular type of stainless steel, it can be found in the ASM Metals Handbook, Ninth Edition, Volume 3. Duplex Ferritic – Austenitic Stainless Steels Duplex stainless steels solidify as 100% ferrite, but about half of the ferrite transforms to austenite during cooling through temperatures above approximately 1900°F (1040°C).
TABLE 13 — Properties of Austenitic Stainless Steels NOMINAL MECHANICAL PROPERTIES Type 201 201 202 301 301 302 302B 303 304 304L 304N 304LN 305 308 308L 309 310 312 314 316 316L 316F 317 317L 321 347/348 329 330 330HC 332 384 Tensile Strength ksi MPa 115 793 185 1275 105 724 110 758 185 1275 90 620 95 655 90 620 85 586 80 552 85 586 80 552 85 586 85 586 80 551 90 620 95 655 95 655 100 689 85 586 78 538 85 586 90 620 85 586 87 599 92 634 105 724 80 550 85 586 80 552 80 550 Condition Anneal Full Hard Anne
TABLE 15 — Nominal Mechanical Properties of Precipitation Hardening and Duplex Stainless Steels NOMINAL MECHANICAL PROPERTIES Condition Type Precipitation Hardening Types Ph13-8 Mo H950 15-5PH H900 15-5PH H1150 17-4PH Sol. Ann. 17-4PH H900 Sol. Ann. 17-7PH RH950 17-7PH Sol. Ann. PH15-7 Mo RH950 PH15-7 Mo Sol. Ann. 17-10P H1300 17-10P H1350 A286 Sol. Ann. AM350 DA AM350 Sol. Ann. AM355 AM355 DA Custom 450 Anneal H900 Custom 450 Custom 455 H900 Stainless W Sol. Ann.
TABLE 16 — Corrosion Resistance of Stainless Steel in Various Environments CORROSION RESISTANCE Type Stainless Austenitic Industrial 201 5 202 5 205 5 301 5 302 5 302B 5 303 5 303Se 5 304 5 304H 5 304L 5 304N 5 305 5 5 308 309 5 5 309S 5 310 310S 5 314 5 316 3 316F 3 316H 3 316L 3 316N 3 317 3 317L 3 321 5 321H 5 329 3 330 3 347 5 347H 5 348 5 348H 5 384 Ferritic Types 405 6 409 6 429 3 430 3 430F 3 430FSe 3 434 3 436 3 442 3 446 3 Martensitic Types 403 6 410 6 6 414 416 6 6 416Se 6 420 Atmospheric Marine
Design for Stainless Steels Joint location and weld sequence should be considered to minimize distortion. Since the coefficient of thermal expansion for austenitic stainless steels is relatively high, the control of distortion must be considered in designing weldments of these alloys. The volume of weld metal in joints must be limited to the smallest size which will provide the necessary properties. In thick plate, a “U” groove, Figure 34(c), which gives a smaller volume than a “V” groove, should be used.
Selecting Solid and Metal-Cored Stainless Steel Electrodes for GMAW TABLE 17 — Solid, Metal-Cored Wires for Welding Austenitic Stainless Steels ELECTRODES Base Stainless Steel Wrought Cast 201 202 205 216 301 302 CF-20 304 CF-8 304H 304L CF-3 304LN 304N 304HN 305 308 308L 309 CH-20 309S CH-10 309SCb 309CbTa 310 CK-20 310S 312 CE-30 314 316 CF-8M 316H CF-12M 316L CF-3M 316LN 316N 317 CG-8M 317L 321 321H 329 330 HT 330HC 332 347 CF-8C 347H 348 348H Nitronic 33 Nitronic 40 Nitronic 50 Nitronic 60 254SMo AL-6X
TABLE 18 — Solid, Metal-Cored Wires for Welding Ferritic Stainless Steels ELECTRODES Base Stainless Steel Wrought Cast 405 409 429 430 CB-30 430F 430FSe 434 442 444 446 CC-50 26-1 Recommended Solid, Metal-Cored Stainless Steel GMAW Wire ER410NiMo, ER430 ER409, AM363, EC409 ER409Cb ER430 ER430 ER430 ER434 ER442 ER316L ER446 ER26-1 From AWS Filler Metal Specifications: A5.4, A5.9, A5.
TABLE 20 — Solid, Metal-Cored Wires for Welding Precipitation-Hardening Stainless Steels ELECTRODES Designation Martensitic Types 17-4PH and 15-5 PH Stainless W UNS No.
Electrode diameters as large as 3/32” (2.4 mm), but usually less than 1/16” (1.6 mm), are used with relatively high currents to create the spray arc transfer. A current of approximately 300 - 350 amps is required for a 1/16” (1.6 mm) electrode, depending on the shielding gas and type of stainless wire being used. The degree of spatter is dependent upon the composition and flow rate of the shielding gas, wire feed speed and the characteristics of the welding power supply.
Some stainless steel weld metals during welding have a tendency toward hot cracking or tearing when they contain little or no ferrite — Type 347, for example. When welding these, more welding passes than indicated in the procedures may be needed. Stringer bead techniques are also recommended rather than weaving or oscillating from side to side.
GMAW of Aluminum Alloys Axial spray and pulsed spray metal transfers are the preferred metal transfer modes for aluminum, each of these are capable of providing the required energy levels for base metal melting to assure good fusion.
Power Supplies and Wire Drives for Aluminum GMAW The software developed specifically for these newer power sources provides a wide selection for a range of filler types, diameters, and shielding gas compositions. In most cases the newer power sources provide a wide selection of pulsed spray transfer, synergic CV, and special Pulse on Pulse™ programs for use with aluminum electrodes.
The push-pull systems handle aluminum diameters from 0.030" to 1/16” (0.8 - 1.6 mm), and they reliably feed aluminum wire electrode up to 50 ft. (15.2 m) from the control cabinet. FIGURE 39: Spool Gun Aluminum Feeding Enhancements • Drive Rolls should always be highly polished "U" groove type for aluminum. The ‘U" groove is designed to cradle the softer electrode without altering its shape and the high polish prevents the accumulation of aluminum oxide in the drive roll groove.
Shielding Gas for Aluminum GMAW Aluminum GMAW Welding Technique The shielding gas section of this document provides a more expansive presentation of shielding gases for aluminum and other filler alloys (see Shielding Gas section on page 12). Keywords: Aluminum Oxide Hydrated Aluminum Oxide The recommended shielding gas for welding aluminum up to approximately 1/2” (12 mm) in thickness is 100% argon.
• Remove oils from the surface using non-petroleum based solvents first. Then wipe the parts dry using a clean (unused) shop towel. Acetone is commonly used. • Weld tabs can be used and the weld may be started and terminated on them. • A power supply with an arc decay control allows the electrode and current to tail off for a predetermined wire feed speed per unit of time. This permits a controlled fill of the aluminum weld crater. • Near the end of the weld, progressively increase the travel speed.
• • • • • • Weld metal ductility. Weld metal corrosion resistance. Weld metal shear strength in fillet and lap joints. Ease of welding (i.e., weldability). Wire electrode feedability. For applications requiring postweld anodizing, color matching with parent metal. • For high temperature applications the Al-Mg alloys with Mg content over 3% are unsuitable for service temperatures over 150°F (66°C). They are susceptible to stress corrosion cracking at higher temperatures.
One other point worth making here is the recommendation to use 5356 for making welds in 6XXX alloys that are to be anodized. If 4043 is used in these applications, it will turn dark grey on anodizing. Since the 6XXX parent materials anodize to a clear color, a 4043 weld is very visible and not desirable. 5356 will anodize to a color very similar to the parent material and is therefore the filler alloy of choice. 7XXX alloys – as mentioned previously, most of these alloys are not arc weldable.
TABLE 24: Aluminum Filler Metal Guide 319.0 333.0 354.0 355.0 380.0 356.0 357.0 359.0 413.0 444.0 443.0 511.0 512.0 513.0 514.0 7005 k 7039 710.0 711.0 712.
Current vs Wire Feed Speed FIGURE 43: Welding Current vs WFS for Carbon Steel and Low Alloy Electrodes at a Fixed Stickout FIGURE 42: Typical Melting Rates for Carbon and Low Alloy Steel Electrodes Wire feed speed, inches per minute 200 300 400 500 600 700 800 900 800 4 i 3 6 2 4 1 2 8 .2 m . (1 in 45 2 4 3 mm) in. (0.9 0.035 m) . (0.8 m 0.030 in 4 0 (0. 9m m) ) mm 35 in. in. ( 0.8 50 100 0.
FIGURE 46: Welding Current vs WFS for ER5356 Aluminum Electrodes at a Fixed Stickout 0.0 300 200 0.093 ) .4 mm in. (2 5 100 10 m ) 2 1. .( in 5 0. 04 in. 35 0.0 6 ) mm 0.9 ( 5 m) .8 m 4 (0 in. 30 0.0 8 3 6 2 4 0 0 0 50 100 150 200 250 300 350 Welding current A (DCEP) 400 1 2 450 0 0 0 20 6 0.0 200 2 in .6 . (1 ) mm 5 100 0 0 0 50 100 150 200 250 300 350 Welding current A (DCEP) 400 20 20 2 m m ) 700 5 in. (1 . 600 .( 52 .0 400 3 1. 04 500 0.
General Welding Guidelines Welding Guidelines for Carbon and Low Alloy Steel Welding Guidelines for Carbon and Low Alloy Steel Short-Circuiting Transfer — Horizontal Fillets and Flat Butt Joints CTWD(1) : 1/2” (13mm) Gas: 100% CO2 Gas flow: 25 to 35 cfh (12 to 17 L/min.) R = 0 - 1/16” (0 - 1.6mm) Plate Thickness - (mm) Electrode Dia. - in. (mm) WFS - in./min (M/min.) Amps (Approximate) Travel Speed - in./min (M/min.) Voltage (2) (DC+) (1) 24 ga (0.6) 20 ga (0.9) 16 ga (1.5) 14 ga (2) 0.025 0.030 0.
Welding Guidelines for Carbon and Low Alloy Steel Short-Circuiting Transfer — Vertical Up Fillets CTWD(1): 1/2” (13mm) Gas: 75% Argon, 25% CO2 Gas flow: 25 to 35 cfh (12 to 17 L/min.) Technique: Use vee weave or triangle weave Plate Thickness - in. (mm) 5/16 (8) 3/8 (10) Leg Size - in. (mm) 1/4 (6.4) 5/16 (7.9) Electrode Dia. - in. (mm) .035 (0.9) .045 (1.1) .035 (0.9) .045 (1.1) WFS - in./min (M/min.) 225 (5.7) 150 (3.8) 250 (6.4) 150 (3.8) 160 165 175 165 5 - 6 (0.13 - 0.
Welding Guidelines for Carbon and Low Alloy Steel Axial Spray Transfer — Flat Butt Joints CTWD(1): 5/8”-3/4” (16-19mm) Gas: 90% Argon, 10% CO2 Gas flow: 40 to 45 cfh (19 to 21 L/min.) 60° ° 45 1/2” (13mm) Arc Gouge 2 1 1/2” - 1” (12-25mm) 60° 1/4” (6mm) 3/16-1/4” (5-6mm) Arc Gouge Technique: Use push angle 3/4” amd up (19mm) 60° Electrode Dia. - in. (mm) WFS - in./min (M/min.) 0.035 (0.9) 500 - 600 (12.7 - 15.2) 0.045 (1.1) 375 - 500 (9.5 - 12.7) 0.052 (1.3) 300 - 485 (7.6 - 12.3) 1/16 (1.
Welding Guidelines for Carbon and Low Alloy Steel Pulsed Spray Transfer — Vertical Up Fillets - Using PowerWave® 455 Power Source CTWD(1): 5/8”-3/4” (16-19mm) Gas: 90% Argon, 10% CO2 Gas flow: 30 to 40 cfh (17 to 19 L/min.) First Pass Trim nominally set at 1.0(2) Technique: Use push angle Plate Thickness - in. (mm) (1) (2) Second Pass 3/8 (10) 1/2 (13) and up Leg Size - in. (mm) 5/16 (7.9) pass 2 and up Electrode Dia. - in. (mm) 0.045 (1.1) 0.045 (1.1) WFS - in./min (M/min.) 125 (3.
Welding Guidelines for Stainless Steels Welding Guidelines for Blue Max® GMAW ERXXXLSi Stainless Steel Electrodes Diameter, in (mm) Polarity, CTWD(1) Shielding Gas Electrode Weight Wire Feed Speed (in/min) (M/min.) Approximate Current (Amps) Arc Voltage (Volts) Deposition Rate (lbs/hr) (kg/hr) Short-Circuit Transfer 120 150 180 205 230 275 300 325 350 375 400 425 3.0 3.8 4.6 5.2 5.8 6.9 7.6 8.3 8.9 9.5 10.2 10.
Welding Guidelines for 200 and 300 Series Stainless Steel Short-Circuiting Transfer — Butt and Lap Joints CTWD(1): 3/8”-1/2” (9.5-12.7mm) Gas: Helium, + 7-1/2% Argon, +2-1/2% C02 Gas flow 15 to 20 cfh (7.1 - 9.4 L/min.) 1/16 - 1/8” (1.6 - 3.2 mm) 1/16 - 5/64” (1.6 - 2.0 mm) Electrode Dia: 0.030 in. (0.8mm) 1/16 - 1/8” (1.6 - 3.2 mm) Plate Thickness in. Plate Thickness (mm) Electrode Diameter in. Electrode Size (mm) Current (DC+) Voltage Wire Feed Speed - ipm Wire Feed Speed (mm/sec.
Welding Guidelines for Stainless Steel Short-circuit transfer — Horizontal, flat and vertical down fillets (Using Blue Max MIG Stainless Steel Electrode) CTWD(1): 1/2” (13mm) Gas: 90% Helium, +7-1/2% Argon +2-1/2% CO2 Gas flow 30 cfh (14 L/min.) DC+ Technique: Use push angle - 5° - 20° 45° 45 - 50° 45° Plate Thickness Wire Feed Speed, in/min (M/min.) Voltage Current (Amps) Travel Speed, in/min (M/min.) 18 ga (1 mm) 120 - 150 (3.0 - 3.8) 19 - 20 55 - 75 10 - 16 (0.25 - 0.41) .035” (0.9mm) Electrode Dia.
Welding Guidelines for Stainless Steel Axial Spray Transfer — Horizontal or Flat Fillets and Flat Butt Joints (Using Blue Max GMAW Stainless Steel Electrode) CTWD(1): 5/8”-3/4” (16-19mm) Gas: 90% Argon, + 2% Oxygen Gas flow 30 to 40 cfh (14 to 19 L/min.) DC+ Technique: Use push angle - 5° 45° 45 - 50° Plate Thickness, in. (mm) Wire Feed Speed, in/min (M/min.) Voltage Current (Amps) Travel Speed, in/min (M/min.) 3/16 (5) 400 - 425 (10.2 - 10.8) 23 - 24 180 - 190 18 - 19 (0.46 - 0.48) .035” (0.
Welding Guidelines for Aluminum Welding Joint Designs for Aluminum MIG Welding Groove Welding — Flat, Horizontal, Vertical and Overhead Joint Spacing Joint Spacing t (B) Temporary Backing 2t t/4 (A) 60° - 90° or 110° 60° - 90° / ” (4.8mm) 3 16 Joint Spacing Joint Spacing (D) (C) 1/16” - 3/32” (1.6 - 2.4mm) 60° 90° Joint Spacing t / ” - 3/32” 1 16 (1.6 - 2.4mm) Temporary Backing Joint Spacing 1/2” (12.7mm) 1/16” - 3/32” (1.6 - 2.4mm) t/4 (F) (E) 60° Joint Spacing / ” 1 16 (1.
Welding Guidelines for Aluminum GMAW Groove Welding — Flat, Horizontal, Vertical and Overhead Plate Weld Thickness Position(1) 1/16” (2 mm) 3/32” (2 mm) 1/8” (3 mm) 3/16” (5 mm) 1/4” (6 mm) 3/8” (10 mm) 3/4” (19 mm) Edge Prep(2) Joint Spacing In. (mm) Weld Passes Electrode Diameter In. (mm) Welding Current(3) (Amps) (DC+) Arc Voltage(3) (Volts) F A None 1 0.030 (0.8) 70-110 15-20 F G 3/32 (2.4) 1 0.030 (0.8) 70-110 15-20 F A None 1 0.030-3/64 (0.8 - 1.
Welding Guidelines for Aluminum GMAW Fillet and Lap Welding — Flat, Horizontal, Vertical and Overhead Plate Thickness(1) Weld Position(2) Weld Passes(3) 3/32” (2 mm) F, V, H, O 1 1/8” (3 mm) F 1 V, H 1 O 1 F 1 V, H 1 O 1 F 1 V, H 1 O 1 F 1 H, V 3 O 3 F 4 H, V 4-6 O 10 3/16” (5 mm) 1/4” (6 mm) 3/8” (10 mm) 3/4” (19 mm) Electrode Diameter In. (mm) 0.030 (0.8) 0.030 - 3/64 (0.8 - 1.2) .030 (0.8) 0.030 - 3/64 (0.8 - 1.2) 3/64 (1.2) 0.030 - 3/64 (0.8 - 1.2) 0.
STT® II Welding Guidelines STT II Welding Guidelines Background Current controls penetration and is responsible for the overall heat input of the weld. The ensuing procedure guidelines are intended to provide a starting point for the development of welding procedures using the STT II power source and STT 10 wire drive and control. The use of pre-flow, post-flow, and run-in speed are variables that are established based upon the needs of the application.
Carbon Steel Sheetmetal - Uncoated Diameter, Wires CTWD Shielding Gas Joint Types Material Thickness Gauge (mm) Wire Feed Speed in/min (M/min.) Peak Amps Background Amps Tailout (1) Travel Speed in/min (M/min.) Average Current 0.035” (0.9 mm), ER70S-3, ER70S-4, ER70S-6 3/8” (9 mm) 100% CO2 7 10 12 14 5.0 3.2 2.4 2.0 215 210 190 175 (5.5) (5.3) (4.8) (4.4) 300 300 290 270 80 80 70 60 0-3 0-3 0-3 0-3 7 11 12 12 (0.2) (0.3) (0.3) (0.
Stainless Steel Guidelines for STT II Stainless Steel Sheetmetal Diameter, Wires CTWD Shielding Gas Joint Types Material Thickness Gauge (mm) Wire Feed Speed in/min (M/min.) Peak Amps Background Amps Tailout Travel Speed in/min (M/min.) Average Current 0.035” (0.9 mm), Blue Max 308LSi, 309LSi, 316LSi 3/8” (9 mm) 90%He+ 7.5%Ar+ 2.5%CO2 7 10 12 14 5.0 3.2 2.4 2.0 170 160 140 130 (4.3) (4.1) (3.6) (3.3) 210 200 200 190 60 55 55 50 3-7 3-7 2 2 9 10 11 14 (0.2) (0.3) (0.3) (0.
Nickel Alloy STT II Welding Guidelines C276 Nickel Alloy Sheetmetal Diameter, Wires CTWD Shielding Gas Joint Types Material Thickness Gauge (mm) 0.035” (0.9 mm) C-22, 625, C2000 10 3/8” (9 mm) 12 90%He + 7.5%Ar + 2.5%CO2 14 Lap, T-Joints, Horizontal Fillets 16 Wire Feed Speed in/min (M/min.) Peak Amps Background Amps Tailout Travel Speed in/min (M/min.) Average Current 3.2 2.4 2.0 180 170 160 (4.6) (4.3) (4.1) 220 210 200 75 70 65 5 5 5 13 14 12 (0.3) (0.4) (0.3) 90 85 80 1.6 150 (3.
Rapid Arc® Welding Guidelines Rapid Arc Welding Guidelines for use with hard automation and robotic applications. It may be applied to semiautomatic applications, but the travel speeds will be far less than those employed with automated applications. The ensuing guidelines provide procedure settings for the use of Rapid Arc programs available on the Power Wave® 455. Rapid Arc™ is a higher travel speed GMAW-P program set developed Welding Guidelines for Super Arc® L-56 solid wire.
HORIZONTAL LAP WELD Diameter, Wires CTWD Shielding Gas Material Thickness 1/4” 3/16” Wire Feed Speed in/min (M/min.) 0.045” (1.1 mm) L-56 3/4” (19.1 mm) (6.4 mm) (4.8 mm) 550 525 10 Ga. (3.2 mm) 90% Ar/10% CO2 12 Ga. (2.4 mm) 14 Ga. (2.0 mm) Travel Speed in/min (M/min.) Trim Volts Amps (1.0) (1.3) 0.90 0.85 23 21.3 280 276 280 (14.0) (13.3) 40 50 500 (12.7) 60 (1.5) 0.85 21.4 450 (11.4) 60 (1.5) 0.80 19.5 260 375 (9.5) 60 (1.5) 0.80 19 211 Travel Speed in/min (M/min.
3 O’CLOCK LAP WELD Diameter, Wires CTWD Shielding Gas Material Thickness 1/4” 3/16” Wire Feed Speed in/min (M/min.) (9.4) (9.1) Travel Speed in/min (M/min.) 40 50 Trim Volts Amps (1.0) (1.3) 0.85 0.85 20.6 20.3 295 293 280 0.052” (1.3 mm) L-56 3/4” (19.1 mm) (6.4 mm) (4.8 mm) 370 360 10 Ga. (3.2 mm) 330 (8.4) 70 (1.8) 0.80 18.5 90% Ar/10% CO2 12 Ga. (2.4 mm) 310 (7.9) 80 (2.0) 0.85 18.5 273 14 Ga. (2.0 mm) 280 (7.1) 90 (2.3) 0.80 16.6 252 Travel Speed in/min (M/min.
VERTICAL DOWN LAP WELD Diameter, Wires CTWD Shielding Gas Material Thickness 1/4” 3/16” Wire Feed Speed in/min (M/min.) (12.7) (12.7) Travel Speed in/min (M/min.) 35-40 (0.9-1.0) 50 (1.3) Trim Volts Amps 0.95 0.98 24 24.5 290 297 245 0.045” (1.1 mm) MC-6 3/4” (19.1 mm) (6.4 mm) (4.8 mm) 500 500 10 Ga. (3.2 mm) 400 (10.2) 50 (1.3) 0.95 22.5 90% Ar/10% CO2 12 Ga. (2.4 mm) 400 (10.2) 60 (1.5) 0.98 23 245 14 Ga. (2.0 mm) 360 (19.1) 70 (1.8) 0.
HORIZONTAL LAP WELD Diameter, Wires CTWD Shielding Gas Material Thickness 1/4” 3/16” (6.4 mm) (4.8 mm) Wire Feed Speed in/min (M/min.) 300 290 (7.6) (7.4) Travel Speed in/min (M/min.) 35 45 Trim Volts Amps (0.9) (1.1) 1.00 0.90 24 21 351 327 292 1/16” (1.6 mm) MC-6 3/4” (19.1 mm) 10 Ga. (3.2 mm) 240 (6.1) 65 (1.7) 0.85 19.3 90% Ar/10% CO2 12 Ga. (2.4 mm) 210 (5.3) 70 (1.8) 0.85 18 266 14 Ga. (2.0 mm) 190 (4.8) 70 (1.8) 0.90 18.5 252 Travel Speed in/min (M/min.
The improved Rapid Arc program features a modified wave control that acts as a fine tune adjustment of the arc. Similar to conventional pulse programs, an increase in wave control will results in a higher frequency and a more focused arc plasma. The results will be especially noticeable in the metal core rapid arc programs. Increasing wave control will improve welding performance in robotic applications. The preferred electrode diameter depends on the application.
Glossary Inductance An essential component for the successful operation of short-circuiting transfer. Inductance provides control of the rate of rise of short-circuit current. Inductance control has the effect of reducing spatter loss and controlling the level of spatter generated by traditional short-circuiting metal transfer. Adding inductance to the arc increase the amount of time that the arc is on, increases the transferred metal droplet size, and adds to the puddle fluidity.
Spray Arc A non-standard term used to describe the high-energy mode of metal transfer known as axial spray transfer. Waveform Generator A specific term applied to inverter transfer power sources, which depend upon internal software to modulate the output of the power source. These types of power sources are unique to STT and other modes of GMAW transfer. Surface Tension The forces that act in a molten droplet of weld metal to prevent it from flowing.
diate vicinity of the helper’s breathing zone. The principle composition or particulate matter (welding fume) which may be present within the welder’s breathing zone are listed in the Supplement of Safe Practices. Sampling should be in accordance with ANSI/ AWS F1.1, Method for Sampling Airborne Particulates Generated by Welding and Allied Processes. SAFE PRACTICES Introduction. The general subject of safety and safety practices in welding, cutting, and allied processes is covered in ANSI Z49.
BIBLIOGRAPHY AND SUGGESTED READING AWS F1.1, Method for Sampling Airborne Particulates Generated by Welding and Allied Processes. ANSI Z87.1, Practice for Occupational and Educational Eye and Face Protection, American National Standards Institute, 11 West 42nd Street, New York, NY 10036. AWS F1.2, Laboratory Method for Measuring Fume Generation Rates and Total Fume Emission of Welding and Allied Processes. Arc Welding and Your Health: A Handbook of Health Information for Welding.
i i SAFETY WARNING CALIFORNIA PROPOSITION 65 WARNINGS The engine exhaust from this product contains chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. The Above For Gasoline Engines Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer, birth defects, and other reproductive harm. The Above For Diesel Engines ARC WELDING CAN BE HAZARDOUS.
ii ii SAFETY ARC RAYS can burn. ELECTRIC SHOCK can kill. 4.a. Use a shield with the proper filter and cover plates to protect your eyes from sparks and the rays of the arc when welding or observing open arc welding. Headshield and filter lens should conform to ANSI Z87. I standards. 3.a. The electrode and work (or ground) circuits are electrically “hot” when the welder is on. Do not touch these “hot” parts with your bare skin or wet clothing. Wear dry, hole-free gloves to insulate hands. 4.b.
iii iii SAFETY WELDING SPARKS can cause fire or explosion. CYLINDER may explode if damaged. 6.a. Remove fire hazards from the welding area. If this is not possible, cover them to prevent the welding sparks from starting a fire. Remember that welding sparks and hot materials from welding can easily go through small cracks and openings to adjacent areas. Avoid welding near hydraulic lines. Have a fire extinguisher readily available. 7.a.
Notes CUSTOMER ASSISTANCE POLICY The business of The Lincoln Electric Company is manufacturing and selling high quality welding equipment, consumables, and cutting equipment. Our challenge is to meet the needs of our customers and to exceed their expectations. On occasion, purchasers may ask Lincoln Electric for advice or information about their use of our products. We respond to our customers based on the best information in our possession at that time.
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