Influence of welding current on the nugget diameter and strength of spot welded duplex stainless steel for automobile structure.

This article addresses effect of welding current on metallurgical and mechanical aspects of spot welded 1.5 mm AISI 2205 duplex stainless steel.

Welding current was selected as key parameter and there values were varied within feasible range, whereas other parameters like welding time and electrode force were kept constant.

Performance of welded joint was investigated thorough micro-examination, nugget diameter and tensile shear test. The results shows that fast cooling rate of resistance spot welding hindered the post solidification transformation of ferrite to austenite and disturb a phase balance of ferrite and austenite.

Both nugget diameter and tensile shear strength (TSS) show parabolic trend with increase in welding current. Nugget diameter increases with increase in welding current due to increase in heat input that results into higher TSS; however, at higher welding current expulsion of molten metal takes place which reduces nugget diameter as well as TSS.

Failure mode transition from interfacial to pull out failure mode, have been not observed for whole feasible welding current range.

This article is shared by G P Chudasama, Shubham Kashyap and V. D. Kalyankar