Effect of heat input on microstructure and tensile properties of 1J50 alloy and 06Cr19Ni10 steel electron beam welds

This study investigated the effect of heat input on the microstructure and tensile properties of electron beam welded joints between 1J50 soft magnetic alloy and 06Cr19Ni10 stainless steel. The weld zone (WZ) was primarily composed of coarse columnar grains of FeNi solid solution with 6–8 wt% Cr. Segregation of Si and P was detected at grain boundaries. As the heat input decreased from 60.5 J/mm to 38.5 J/mm, the average grain size in the WZ reduced from 42.43 μm to 20.06 μm and the local area fraction of segregated phases decreased from 5.73 % to 1.94 %. These microstructural changes contributed to an increase in joint tensile strength from 396.7 MPa to 426.7 MPa, reaching 98 % of that of the 1J50 base metal (BM). However, the joint produced with the lowest heat input failed prematurely due to incomplete fusion. The reduction in heat input also resulted in the disappearance of fine equiaxed grains in weld center, leading to decreased joint elongation. The microhardness of the WZ was lower than that of both BMs because of the coarse columnar grains.