Fracture characteristics of dissimilar electron-beam welded joints between Cr-Mo steel and austenitic steel AISI 304

The mechanical and fracture behaviors of electron-beam welded (EBW) joints between Cr-Mo steel (CS) and austenitic stainless steel type AISI 304 (SS) were investigated. A double notch was created at the middle of the weld area with three different notch depth (D) to weld metal width (2W) ratios, D/W = 0.33, 0.42, and 0.5, to study the strength of weld metal compared to that of CS. The weld metal and heat-affected zones (HAZs) were found to be free of defects. The interface region show that Cr23C6 was formed on the stainless steel side, while a martensitic structure was formed on the Cr-Mo steel side. The hardness of the weld metal was higher than that of the rest of the weld metal and the HAZs. Furthermore, the stress concentration (D/W = 0.33) was insufficient to initiate the crack at the notch root, i.e., the strength of CS was lower than that of weld metal with this defect.