When welding 304 stainless steel, argon gas protection is used, and sometimes nitrogen gas protection is used. What is the difference between the two?
Stainless steel rust is mainly oxidation or corrosion, all stainless steel is not rust-free, including 304 stainless steel, so the high temperature when welding is also easy to make stainless steel oxidation after the welded parts rust.
Argon is one of the six inert gases, it is very difficult to react with the air at high temperature, and the chemical reaction will only happen under specific conditions. So welding with argon protection, mainly argon is an inert gas, even if inhaled by the human body is harmless, naturally will be discharged from the body.
Nitrogen is also often used for protection during welding, but it still has a smaller advantage over argon, which is present in 70% of the air. In general, however, liquid nitrogen may not be as good as liquid argon, which when in liquid form is handled primarily by their pressure.
The use of either of these two gases allows for oxidation-free welding and can reduce the likelihood of rusting.