A Feasibility Study of Applying SS 307Si Buffer Layer for Mitigating the Hot Cracking of Ni-Based Weld Overlay

The hot cracking behavior of Ni-based Alloy 52M weld overlay with respective SS 307Si and SS 308L buffer layers was investigated. The dilution level of SS 307Si buffer layer is a little higher than that of SS 308L. However, the hot crack length of overlay with SS 307Si buffer layer is shorter and the SS 307Si layer has higher mechanical properties than that of SS 308L layer. As observed by SEM and EBSD, ferrites precipitated in SS 307Si buffer layer are in vermicular skeletons dotted with lathy precipitates, which have a little higher local stain than that of SS 308L weld. However, Alloy 52M weld around SS 307Si fusion boundary has a lower degree of local distortion. The results generalize that the SS 307Si buffer layer is marginally better for reducing hot cracking susceptibility, owing to its lower local stain and slightly higher mechanical strength.