(Last Updated On: October 3, 2020)
When welding thin or thick materials like metal, the primary aim is to avoid warping, burn-through, and excessive heat-affected zones. The user has to make sure that the weld has enough mechanical strength required for welding. The Short-circuit transfer MIG (short arc), TIG, and pulsed TIG welding processes offer the most control to handle welding sheet metal challenges. In this buying guide, we will give you tips for welding sheet metal with MIG or TIG.
MIG Welding Sheet Metal
For MIG welding sheet metal, the best idea is to use the smallest wire diameter because the smaller wires take less heat to melt. Short cables also provide the perfect for control over the bead and don’t let the metal heat up. It also gives a better chance of recovering mistakes due to lower deposition rates. For welding the sheet metal with MIG, it is recommended to use a .023- or .024-inch wire. If the material is 18-gauge thicker, you can easily use a .030-inch wire. It will be best to use an American Welding Society classification wire for mild welding steel such as ER70S-6. Such wires feature a weld puddle that wets out comfortably. Using a higher argon-based shielding gas, such as 75% argon/25% carbon dioxide, will be the most convenient choice. Argon doesn’t carry much heat compared to average CO2, so you will experience fewer spatters.
If you are welding 304 stainless steel, ER308, ER308L, and ER308LSI wires are the most compatible. For welding 316L stainless, you will need a 316L wire. While using these materials, use a tri-mix gas that contains at least 90% helium, 8% argon, and 2% CO2.Welding the sheet metal with solid wires will become easy if you use electrode positive (EP, or reverse polarity). The thin materials like sheet metal with flux-cored wires put a lot of heat into the base metal, so don’t attempt to use MI welding for it.
TIG Welding Sheet Metal
For the perfect TIG welding, you cannot use the large 1/8-inch tungsten electrode. The Ceriated tungsten is preferred the most, while thoriated tungsten is an excellent second option. If it features the diameters down to .020, .040, and 1/16-inch, it will better facilitate TIG welding for the sheet metals. The small electrodes are easy to start, and they perform better at lower heat settings. The best thing is that it will prevent the burn-through and focus the arc in a smaller area.
You have to keep the tungsten pointed for handling the metal steels while the grind is parallel with the length. ER70S-2 filler metal happens to be the most common choice for steels as it is soft and reduces the heat required for welding. It is essential to select the filler metal that is smaller in size than the metal base. You need to stop the base material from heating much before the filler metal joins it. The pointed electrode will not only offer greater arc control, but it will also help to direct the arc precisely at the joints.
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