Evaluating susceptibility of Ni-base alloys to solidification cracking by transverse-motion weldability test

Abstract

The transverse-motion weldability (TMW) test, in which the lower sheet in lap welding is moved at a constant speed V in the transverse direction of welding to induce solidification cracking, was applied to Ni-base alloys. Alloys 600, 625, 718 and 800 were used as example materials for demonstration. The relative susceptibility ranking of the alloys was similar to those reported. A similar ranking was calculated based on |dT/d(f_S)^1/2| near (f_S)^1/2= 1 (T: temperature; f_S: fraction solid). Based on the transverse micrograph of the weld and V, the critical local strain rate near the crack was estimated. It was significantly higher for 718 than 800, consistent with the significantly lower susceptibility of 718 shown by the TMW test.