MIG and flux-cored welding of stainless steel

The MIG (metal inert gas) welding process requires a solid wire that acts as an electrode and a filler material. In addition, this process needs a shielding gas to protect the weld pool from contamination and oxidation. Commonly used gases for MIG welding stainless steel are an argon mixture with 1-2% oxygen and a tri-mix between helium, argon and CO₂.

The flux-cored welding process also uses a wire as an electrode and a filler metal. However, flux-cored wires have specially formulated chemical compounds inside their core. These wires are tubular, like pipes. Only the outer layer is the filler metal, which conducts electricity and melts into the welded joint as a filler metal. 

Gas-shielded flux-cored wires offer higher deposition rates and are suitable for welding thick metal. Additionally, they work well for out-of-position welding because their slag helps hold the molten metal pool against gravity.

However, one of the most important advantages of gas-shielded FCAW wires for welding stainless steel is that you can use common shielding gas mixtures like argon/CO₂ or pure CO₂. Instead of investing in a tri-mix or argon/oxygen gas, you can use a standard MIG welding gas for mild steel.

Key points of operation:

Welding wire selection: Choose flux-cored wire suitable for stainless steel welding, such as E308LT1-1 and other models, which can produce stable arc and high-quality welds during welding.

Welding parameters: Adjust welding current, voltage and other parameters according to welding materials and welding positions. Flux-cored welding usually adopts lower current and voltage settings to ensure stable arc and good weld formation.

Cleaning and pretreatment: Before welding, impurities such as oil, rust and moisture in the welding area must be removed to prevent pores and cracks during welding.

Environmental control: Similar to MIG welding, flux-cored welding also needs to control the welding environment, especially to prevent the influence of wind and humidity on welding quality.