Friction welding of two carbon low alloy steels 42CrMo and 36Mn2V: Effects of forging pressure and post-weld heat treatment on microstructure and mechanical properties

Two carbon low alloy steels 42CrMo and 36Mn2V were successfully jointed using continuous drive friction welding. The effects of forging pressure and post-weld heat treatment on microstructure and mechanical properties of joints were investigated in detail. Results reveal that with increasing the forging pressure, the tensile and yield strength increase firstly and then decrease. The as-welded joint with the highest yield strength (708 MPa), largest elongation (14.2%), and high impact toughness (57.24 J) were obtained with the 35 MPa forging pressure. After post-weld heat treatment, the joint yield strength, elongation, and impact toughness were increased to 798 MPa, 18.1%, and 71.02 J, respectively. The microhardness measurement results indicate that the as-welded joints show higher Vicker hardness than the two base metals. After post-weld heat treatment, the microhardness was decreased owing to martensite elimination. The above findings provide a basis for the implementation of friction welding of dissimilar steels used for drills in the coal-mining industry.