MIG/GMAW Stainless -- what shielding Gas?

27 Nov.,2024

 

MIG/GMAW Stainless -- what shielding Gas?

ONLY time straight argon is used with GMAW (aka MIG) is for aluminum (or maybe copper or magnesium or titanium, except in 'thicker' pieces where argon-helium blends would be used for additional heat).

Strong statement. But true.

GMAW with straight argon on steel ('plain' or stainless) is not recommended because of the real lack of fusion/penetration you would get and the non-recommended compatability with the wire electrodes/fillers.

GMAW on stainless steel, in short-circuit transfer mode, where you actually want to end up with still-stainless and thus use a compatible filler (such as 308/308L on 304 base material) and compatible shielding gas such as tri-mix or an argon blend such as 98-2 Ar-O2 or 95-2/95-5 Ar-CO2. If you use shielding gas with a higher CO2 percentage than that, you can (or may, especially if running multiple passes) run into excess carbon pick-up and thus no-longer-stainless weld beads.

murphy, C25 is just fine and recommended for most GMAW on mild steel with solid wire filler/electrodes in short-circuit transfer mode.

As to using a shielding gas with an FCAW wire? Forget about it. FCAW-G (aka 'dual-shield', which is a ESAB 'registered' product line/name for their FCAW-G wires) are certainly fine and have their uses, but the 'little' wire-feed welders such as the OP's Lincoln 135 (120V machine) do not have the correct amperage-voltage output power in order to run those wires at anywhere near the correct operating parameters. Not to mention the FCAW-G wires all seem to come on the 'bigger' spools and would not even fit in his 'little' welder's wire compartment (which can fit 4 inch and maybe 8 inch diameter spools, but will not fit the 12+ inchers) or the 'bigger' wire diameters such as 0.045 and up (Lincoln is listing some 0.045 dual-shield wires on 15 lb 8 inch spools, but his 'little' machine doesn't have the output power to run that diameter and type of wire anyway, example Lincoln 0.045 Outershield 71Elite at 21+ V and 125+ amps, unless he really-really-really wants to find and pay for some Lincoln Outershield 71M p/n ED in 0.035 on a 15 lb 8 inch spool and run it at ~20V and ~100 amps with C25. But that would be for plain mild steel and not stainless steel anyway. ).

As the the OP's desire for "pretty welds", especially on some stainless, that usually means GTAW aka TIG. A pretty skilled MIG welder can make those 'pretty' welds, but those kinds of welders are usually very-very skilled. As in they are kind of sentient robots, ala ZTFab (check out his MIG welds, just fereaking b-e-a-u-t-i-f-u-l).

Use the right 'tools' for the job. When welding, that includes the machine and the filler and the shielding gas and the operating parameters and the person.

Thetime straight argon is used with GMAW (aka MIG) is for aluminum (or maybe copper or magnesium or titanium, except in 'thicker' pieces where argon-helium blends would be used for additional heat).Strong statement. But true.GMAW with straight argon on steel ('plain' or stainless) is not recommended because of the real lack of fusion/penetration you would get and the non-recommended compatability with the wire electrodes/fillers.GMAW on stainless steel, in short-circuit transfer mode, where you actually want to end up with still-stainless and thus use a compatible filler (such as 308/308L on 304 base material)compatible shielding gas such as tri-mix or an argon blend such as 98-2 Ar-O2 or 95-2/95-5 Ar-CO2. If you use shielding gas with a higher CO2 percentage than that, you can (or may, especially if running multiple passes) run into excess carbon pick-up and thus no-longer-stainless weld beads.murphy, C25 is just fine and recommended for most GMAW on mild steel with solid wire filler/electrodes in short-circuit transfer mode.As to using a shielding gas with an FCAW wire? Forget about it. FCAW-G (aka 'dual-shield', which is a ESAB 'registered' product line/name for their FCAW-G wires) are certainly fine and have their uses, but the 'little' wire-feed welders such as the OP's Lincoln 135 (120V machine) dohave the correct amperage-voltage output power in order to run those wires at anywhere near the correct operating parameters. Not to mention the FCAW-G wires all seem to come on the 'bigger' spools and would not even fit in his 'little' welder's wire compartment (which can fit 4 inch and maybe 8 inch diameter spools, but will not fit the 12+ inchers) or the 'bigger' wire diameters such as 0.045 and up (Lincoln is listing some 0.045 dual-shield wires on 15 lb 8 inch spools, but his 'little' machine doesn't have the output power to run that diameter and type of wire anyway, example Lincoln 0.045 Outershield 71Elite at 21+ V and 125+ amps, unless he really-really-really wants to find and pay for some Lincoln Outershield 71M p/n ED in 0.035 on a 15 lb 8 inch spool and run it at ~20V and ~100 amps with C25. But that would be for plain mild steel and not stainless steel anyway.).As the the OP's desire for "pretty welds", especially on some stainless, that usually means GTAW aka TIG. A pretty skilled MIG welder can make those 'pretty' welds, but those kinds of welders are usually very-very skilled. As in they are kind of sentient robots, ala ZTFab (check out his MIG welds, just fereaking b-e-a-u-t-i-f-u-l).Use the right 'tools' for the job. When welding, that includes the machine and the filler and the shielding gas and the operating parameters and the person.

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What Do American Welding Society Wire Filler Metal ...

What Do American Welding Society Wire Filler Metal Designations Mean?

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Selecting Welding Wire


Welder wire classification may seem daunting at first, but they are actually rather straightforward. American Welding Society (AWS) classifies filler metals for arc welding processes, and each filler metal has its classification. However, some filler metals share the classification name for more than one welding process, while others are classified according to the welding process. For example, some wires for TIG welding share the same classification as spools of MIG wires, while flux-cored or metal-cored wires have unique designations.

AWS Filler Metal Specifications By Material and Welding Process

There are many AWS filler metal specifications, but the list below outlines the most often applied filler metals and their AWS specifications:

AWS also has specifications for aluminum, low-alloy steel, cast iron, nickel alloys, copper, and other materials. However, solid, metal-cored, and flux-cored wires are most often used to weld steel and stainless steel. So, this guide below will focus on these two materials and different gas-shielded and self-shielded wires.

How To Read AWS Filler Wire Specifications

American Welding Society filler wire specifications follow a uniform pattern for their filler metal designations. While the AWS alpha-numerical designations may seem intimidating initially, they are relatively easy to read once you get the hang of the AWS system.

We will discuss each designation on examples soon. But let&#;s quickly go through the essential alpha-numerical markers you can find on solid, flux-cored, and metal-cored wires.

  • The first letter(s) can be &#;E,&#; as electrode, &#;R&#; as welding rod, or an &#;EC,&#; which indicates a metal-cored electrode.

  • Solid carbon steel electrodes indicate a tensile strength in increments after the first letter. Usually, it&#;s &#;70,&#; as 70,000psi. However, stainless steel electrodes designate the composition of the weld metal after the first letter. For example, &#;308&#; austenitic stainless steel filler metal alloy.

  • Carbon steel electrodes have the letter &#;S,&#; which indicates that the filler metal is solid, while the letter &#;C&#; indicates a composite. What follows is one of the following digits: 2, 3, 4, 6, 7, or letters &#;G&#; or &#;GS,&#; and these indicate the chemical composition. &#;GS&#; means that the filler metal is for single-pass welds only.

  • The letter &#;T&#; indicates that the wire is a flux-cored welding electrode. The number after this letter designates the recommended welding position &#; &#;0&#; means flat and horizontal, while &#;1&#; is an all-position electrode.

  • Stainless steel wires may also have letters &#;L, H, and LR&#; in their name. The letter &#;L&#; indicates a lower carbon content, the letter &#;H&#; indicates higher carbon content, and the letters &#;LR&#; indicate low residuals.

Solid Welding Wire Electrode Designation Example:

If you&#;ve ever picked up a MIG torch, chances are high that you&#;ve welded with the ER70S-6 solid welding wire. This wire is widely used for repair jobs and joining thin sheet metal, especially when welding slightly contaminated base materials. The added silicon provides better puddle fluidity and higher resistance to weld contamination. So, let&#;s see how to read its specification from left to right:

  • E = electrode &#; can be a carrier of electricity.

  • R = rod &#; it does not have to be an electrode to be used as weld metal. An example would be cutting the solid wire into 50 cm sections for gas tungsten arc welding (GTAW).

  • 70 = 70,000 as-welded tensile strength in pounds per square inch.

  • S = solid, not tubular.

  • -6 = variation of chemical composition; for instance, an ER70S-6 wire has more silicon than an ER70S-2.

Stainless Steel Solid Welding Wire Electrode Designation Example:

If you weld stainless steel, you know about the ER308LSi welding wires. This filler metal is often used for its smooth arc characteristics thanks to its higher silicon content. The ER308LSi is an excellent choice for applications where finish quality and aesthetics are paramount. But let&#;s see how to read its specs from left to right:

  • E = electrode &#; it conducts electricity.

  • R = rod &#; it does not have to be an electrode to be used as weld metal. An example would be cutting the solid wire into 50 cm sections for gas tungsten arc welding (GTAW).

  • 308 = The stainless steel alloy of the welding wire.

  • L = low carbon, as opposed to &#;H,&#; which would be high carbon.

  • Si = higher than normal amounts of silicon improves the wetting of the weld puddle.

Metal-Cored Arc Welding Wire Example:

A common low-carbon steel metal-cored arc welding wire is E70C-6M-H4, designed for high travel speed applications with minimum spatter, provides excellent arc for automated and manual welding. Its specs from left to right are:

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  • E* = electrode &#; it conducts electricity.

  • *Note that there is no &#;R&#; following the &#;E&#; in E70C-6M-H4; this is because this wire must be used as an electrode.

  • 70 = 70,000 as-welded tensile strength in pounds per square inch.

  • C = composite, as opposed to solid.

  • -6 = variation of chemical composition.

  • M = shielding gas type; &#;M&#; means a blend (typically 75% Argon/25% CO2), and &#;C&#; designates 100% CO2.

  • -H4 = maximum diffusible hydrogen level of 4 ml/100 grams of weld metal.

Gas-Shielded Flux-Cored Welding Wire Example:

The E70T-1C-JH8 is typically used for heavy-duty structural fabrication and shipbuilding and makes a good example of a gas-shielded flux-cored arc welding wire. It offers exceptional arc performance and bead appearance at high deposition rates. This wire generates low fumes and works with a 100% CO2 shielding gas, which reduces operational costs and improves weld penetration. So, let&#;s see how to read its specs from left to right:

  • E* = electrode; this means that it is capable of being a carrier of electricity.

  • *Note that there is no &#;R&#; following the &#;E&#; in E70T-1C-JH8; this is because this wire must be used as an electrode.

  • 7 = 70,000 as-welded tensile strength in pounds per square inch.

  • 0 = With flux-cored arc welding wires, the digit after the as-welded tensile strength designation is used to define the welding position capability of the wire; a &#;0&#; indicates flat or horizontal only, whereas a &#;1&#; indicates all positions, including vertical and overhead.

  • T = tubular, as opposed to solid.

  • -1 = operating attributes; can help determine the electrical polarity that should be used for best performance and other welding attributes relative to other flux-cored wires

  • C = shielding gas type; &#;C&#; designates 100% CO2, &#;M&#; means a blend (typically 75% Argon/25% CO2).

  • -J = indicates that the welding wire is notable for its impact strength and toughness at cold temperatures relative to wires without the &#;J&#; designation.

  • H8 = maximum diffusible hydrogen level of 8 ml/100 grams of weld metal.

Self-Shielded Flux-Cored Welding Wire Example:

A typical example of a self-shielded flux-cored wire is E71T-14. With its soft, consistent arc and fast travel speed abilities, the E71T-14 is used in many automated and manual welding applications. Reading its specification from left to right is similar to the gas-shielded flux-cored wire above, but it doesn&#;t have a designation for the shielding gas. 

  • E* = electrode &#; this means that it can be a carrier of electricity.

  • *Note that there is no &#;R&#; following the &#;E&#; in E71T-14; this is because this wire must be used as an electrode.

  • 7 = 70,000 as-welded tensile strength in pounds per square inch.

  • 1 = The digit after the as-welded tensile strength designation defines the welding position capability of the wire; a &#;0&#; indicates flat or horizontal only, while &#;1&#; indicates all positions, including vertical and overhead.

  • T = tubular, as opposed to &#;S,&#; which means solid; the flux-cored wire must be tubular because the flux is deposited in its core.

  • -14 = operating characteristics; this is an arbitrary number used to relate to other flux-cored wires.

Get Your Equipment From Red-D-Arc

You can find any welding wire you need here, including wires for stainless steel, bronze, and aluminum alloys. We stock wires from Lincoln Electric, Hobart, ESAB, and other renowned manufacturers for your peace of mind &#; clean, uniform, and protected from oxidation wires provide far better welding results than off-brands with questionable production quality. 

Investing in welding equipment is a crucial investment for any welder, whether you&#;re a professional welder or a DIY enthusiast. With Red-D-Arc, you can rest assured that you are getting high-quality equipment from top manufacturers. Whether you need welding machines, wire, or other accessories, Red-D-Arc has a vast selection to choose from. Contact us today to learn more. 

You can find a range of welding wire options here.

Red-D-Arc, an Airgas company, rents and leases welders, welding positioners, welding-related equipment, and electric power generators &#; anywhere in the world. Our rental welders, positioners and specialty products have been engineered and built to provide Extreme-Duty&#; performance and reliability in even the harshest environments, and are available through over 70 Red-D-Arc Service Centers, strategically located throughout the United States, Canada, the United Kingdom, France, and the Netherlands, as well as through strategic alliances in the Middle East, Spain, Italy, Croatia, and the Caribbean. From our rental fleet of over 60,000 welders, 3,700 weld positioners, and 3,700 electric-power generators, we can supply you with the equipment you need &#; where you need it &#; when you need it.

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