The effect of different Pre-welding microstructure on the final microstructure of CLAM steel after EBW welding

Abstract In this paper, different pre-weld microstructures of clam steel were obtained by heat treatment, and the seamless connection of the test steel was achieved by EBW welding. The microstructure and fracture morphology of the samples were observed by optical microscope and scanning electron microscope, and the composition of the second phase particles was detected by EDS. The results show that the joint microstructure was mainly composed of the melting zone and HAZ zone. The δ ferrite was detected in the melting zone, and the HAZ zone with fine grains was filled with carbides in and along the grain boundaries. B and N are mainly distributed on the grain boundary, and C exists in the form of a precipitated phase on the grain boundary and in the form of a solid solution in the grain.