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Metal inert gas (MIG) welding is widely used for its dependability in the industrial fabrication industry. However, even experienced welders can run into common welding issues, like excessive spatter or poor penetration. More often than not, these problems are related to MIG welder settings that aren’t fully optimized for the specific material or production environment.
This guide breaks down the core settings that, once optimized, can result in quality welding results. We’ll cover the different settings for specific materials as well as how evaluating bead results can help fine-tune the settings.
To get the most out of your MIG welder, you need to understand how each setting affects the final results.
The voltage controls the arc length. Optimizing your voltage is crucial for your bead’s shape. For instance, with higher voltage, you’ll get hotter, flatter, wider beads. However, if the voltage is too high, there may be excessive spatter or result in an undercut. With lower voltage, you’ll get cooler, narrower beads with a more convex profile. If the voltage is too low, the weld may lack penetration or sound “cold” — in other words, the welding sound is inconsistent and pops.
The welder’s WFS determines how much filler metal enters the weld pool. Optimizing the WFS is crucial for proper penetration and consistent deposition.
WFS also directly influences the amperage. For example, when WFS is increased, so is the welding device’s amperage and, inherently, its heat input. The opposite happens when you decrease WFS. If there’s too much wire for the voltage, it often causes the wire to stub into the puddle, leading to an unstable arc, a cold, convex or piled-up bead with poor fusion, and heavy spatter.
The shielding gas is another important parameter, as it helps protect the molten weld pool from contamination. So, to have a well-set GFR means having a good-quality weld. However, if your gas flow is too low, you’re left with porosity and weak welds. High MIG welder gas settings cause turbulence and can pull air into the weld. Know that the correct GFR depends on your welding device’s nozzle size and joint design. The gas mix you use also depends on the materials you’re welding.
Even if you have the perfect machine settings, your technique also plays a role. One thing that matters is your travel speed. If you move too fast, the bead becomes too narrow and weakens the fusion. If you move too slowly, heat builds up and may distort the material and penetrate too much through it.
A skilled user may thus compensate for minor setting variations, but it’s best if you and the machine work together to achieve the best welding results.
Consider the settings in the charts below as starting points. Always run a test bead on a scrap piece of metal to fine-tune your settings before welding your actual workpiece. You can also use the welding machine’s user manual for specific recommendations.
Once you have found the optimal settings for a specific job, write them down or save them using your machine’s memory function, if available. Doing this will help you save valuable time and remove unnecessary guesswork for future projects.
Mild steel, or low-carbon steel, is generally considered a forgiving material to weld. You’ll typically use a C25 gas mix that consists of 75% argon (Ar) and 25% carbon dioxide (CO2). The argon helps with arc stability and spatter, whereas the carbon dioxide creates a hotter arc for deeper penetration. It’s a cost-effective gas mix that can deliver great results.
| MIG Welder Settings for Mild Steel | |||
|---|---|---|---|
| Material Thickness (in or mm) | Wire Diameter (in) | Voltage (V) | Wire Feed Speed (IPM) |
| 22 gauge (0.03″ or 0.75mm) | .023″ | 15-17 | 90-110 |
| 18 gauge (0.048″ or 1.2mm) | .030″ | 16-18 | 150-170 |
| 16 gauge (0.06″ or 1.5mm) | .030″ | 17-20 | 220-250 |
| 1/8″ (0.125″ or 3.2mm) | .035″ | 18-22 | 280-320 |
| 3/16″ (0.1875″ or 4.8mm) | .035″ | 19-23 | 320-380 |
| 1/4″ (0.25″ or 6.4mm) | .035″ | 21-25 | 360-420 |
| 3/8″ (0.375″ or 9.5mm) | .045″ | 23-27 | 220-270 |
| 1/2″ (0.5″ or 12.7mm) | .045″ | 28-30 | 290-340 |
The voltage and WFS for mild steel are a great standard. It’s a decent balance between the amount of heat and the filler material required to create a strong weld.
When you work with stainless steel, it’s all about focusing on controlling the heat to protect the material’s corrosion-resistant properties. This material requires a tri-mix of gases. The typical combination consists of 90% helium (He), 7.5% Ar and 2.5% CO2, especially when working with thick stainless steel. The addition of helium helps create a broader heat profile.
| MIG Welder Settings for Stainless Steel | |||
|---|---|---|---|
| Material Thickness (in or mm) | Wire Diameter (in) | Voltage (V) | Wire Feed Speed (IPM) |
| 16 gauge (0.06″ or 1.5mm) | .030″ | 18-20 | 200-230 |
| 1/8″ (0.125″ or 3.2mm) | .035″ | 20-21 | 300-350 |
| 1/4″ (0.25″ or 6.4mm) | .035″ | 21-22 | 400-425 |
| 3/8″ (0.375″ or 9.5mm) | .045″ | 24-25 | 140-170 |
| 1/2″ (0.5″ or 12.7mm) | .045″ | 29-32 | 200-230 |
The above settings may require faster travel speeds to help prevent the heat from being concentrated in an area, overheating the material. Very high temperatures may damage stainless steel’s chromium-oxide layer and cause it to warp.
Aluminum has very high thermal conductivity and a low melting point, which can make it very challenging to weld with. Aluminum also has a tough oxide layer that has a much higher melting point than the material itself. To break through this layer, you need to use a pure argon mix — 100% Ar. CO2 may react with the aluminum and negatively impact your weld.
| MIG Welder Settings for Aluminum | |||
|---|---|---|---|
| Material Thickness (in or mm) | Wire Diameter (in) | Voltage (V) | Wire Feed Speed (IPM) |
| 16 gauge (0.06″ or 1.5mm) | .035″ | 20-22 | 450-550 |
| 1/8″ (0.125″ or 3.2mm) | .035″ | 22-24 | 350-400 |
| 1/4″ (0.25″ or 6.4mm) | .045″ | 23-25 | 350-375 |
| 3/8″ (0.375″ or 9.5mm) | .045″ | 24-26 | 450-480 |
| 1/2″ (0.5″ or 12.7mm) | .045″ | 27-29 | 290-330 |
When welding aluminum, you must combat its massive heat dissipation by pumping a large amount of energy into the joint very quickly — hence its high voltage and WFS ranges. You may also need to use a spool gun. Because aluminum is soft and ductile, it can cause an issue known as “bird-nesting,” where it tangles when pushed through a standard MIG gun liner. A spool gun’s small wire pool minimizes its travel distance and thus prevents this issue.
Here are a few common symptoms of incorrect settings to help you correct them:
While optimizing your MIG welder settings plays a big role in quality results, it’s not the only determinant. Traveling speed and even the environment can have an impact, regardless of the user’s experience level. Even using the right shielding gas is just as important.
Meritus Gas Partners is a trusted provider of industrial gas mixtures and blends that many MIG applications depend on. We also offer welding tools and accessories and PPE and safety equipment that support your entire workflow.
Find a partner near you if you’re ready to refine your MIG setup or want recommendations tailored to your needs.
