Solidification Cracking Susceptibility of Alloy 52 Weld Overlay on 316L Stainless Steel

摘要

Nickel-based filler metals are widely used in the nuclear power industry for overlay welding of austenitic stainless steel components. However, solidification cracking in the weld metal has been observed in a number of cases after the initial deposit of Alloy 52 filler metal on the 316L substrate. In this study, Alloy 52 and its 52M modification were employed to perform overlay welding on 316L specimens. With proper welding heat input, no solidification cracks were observed in the transition zone of both weld overlays. As the heat input increased, solidification cracks could be found in the welds but was found to a lesser extent in Alloy 52M overlays. Nevertheless, such cracks could be eliminated by applying 309L filler metal as a buffer. This could be related to lower S and P contents in the buffer layer to reduce solidification cracking susceptibility of the subsequent weld passes. Additionally, the results of spot Varestraint tests also indicated that Alloy 52M had better solidification and ductility-dip cracking resistances than Alloy 52.