Development of the Ferritic Stainless Steel Welding Wire for Automotive Exhaust Systems

The 19%Cr ferritic stainless steel wire has been applied to MIG and MAG welding for the automotive exhaust systems in 14%Cr steel sheet. Authors investigated the effect of minor alloying elements on the grain size of the weld metal and ascertained that the combination of 0.08%Ti, 0.04%Al and 0.1%N is optimal to refine grains through inducing in the weld the numerous rectangular titanium and aluminun nitrides fine 0.3-0.7Ém2 in section. The developed wire bearing the above elements is coated with Cu to secure the feedability and then to lessen spatters. The bead from it is flatter in shape and more resistant to hot tear than conventional beads. The finer grained weld possesses the high temperature strength and the corrosion resistance superior to the conventional welds and the oxidation resistance equivalent to the conventional ones.