Cold cracking studies on low alloy steel weldments: effect of filler metal composition

Abstract

The resistance to hydrogen cracking of Cr - Mo, Ni - Cr - Mo and Si - Mn steels which are employed in armoured vehicle construction was evaluated under implant test conditions. Austenitic stainless steel filler (AWS E312), which is reported to be resistant to hydrogen assisted cracking, was used to study the cracking tendency of all the three steels. Four other fillers, namely a nickel based filler (ENiCrFe-3), a low carbon, low alloy steel, a mild steel (AWS E6013) and a matching filler for Cr - Mo, were employed to evaluate their relative cracking tendency. Cr - Mo and Ni - Cr - Mo steels exhibited high cracking tendency while Si - Mn steel was resistant to cracking with the E312 filler. Cr - Mo steel was resistant to cracking with the nickel based filler, the low carbon, low alloy steel and the matching filler. The observed cracking tendency of the steels is linked to a susceptible interface/fusion boundary microstructure.