Effect of Ni interlayer on the microstructure, mechanical and corrosion properties of the dissimilar 1MnCrMoNi/X70 steels friction welding joint

Pure Ni was employed as an intermediate interlayer in the dissimilar 1MnCrMoNi/X70 steels friction welding joint. The effect of the Ni interlayer on the microstructure, mechanical and corrosion properties of the joint was investigated. Compared with the Ni-free joint, the joint with the Ni interlayer had coarser microstructure and lower microhardness. Furthermore, the weld zone of the 1MnCrMoNi steel was abnormally harder than the adjacent thermo-mechanically affected zone. The tensile strength of the joint with the Ni interlayer was improved, and this joint also demonstrated a lower yield ratio, equivalent impact toughness, and enhanced corrosion resistance.