Originally Posted By: tlowe #1716
Is it 304 or 409 that is weldable with a wire welder , even to a mild steel flange?



409 stainless steel can be MIG welded, even to mild steel. It is a magnetic 400 Series ferritic stainless steel, with 11% chrome and low nickel and titanium. 409 SS was introduced in the early 1960's for automotive exhaust systems.

http://www.aksteel.com/pdf/markets_products/stainless/ferritic/409_Data_Sheet.pdf