Improvement of wear resistance by laser shock processing and carburization composite technology used on 12CrNi3A steel

To improve the carburized layer quality and wear performance of 12CrNi3A steel, a composite technology of laser shock processing and carburization was put forward. The results of ball milling experiment showed that the specific wear rate of specimen treated by carburization after laser shock processing reduced by 51% compared with that treated by carburization only, and was reduced by 13% compared with that treated by laser shock processing after carburization. It shows that the composite technology of carburization after laser shock processing can improve the wear resistance of 12CrNi3A steel effectively. The cause of the improvement of wear resistance is the increasing of micro-hardness and the diversification of the microscopic structure, when the coefficient of friction is in a invariant state. The mechanism of wear resistance improvement was analyzed using micro-hardness and scanning electron microscope (SEM). The results indicate that the laser shock processing can promote the process of carburization. The structure of carburized layer is compact and a large number of fine carbide particles are formed in the surface treated by carburization after laser shock processing, which leads to the increasing of the second phase strengthening and solution strengthening in the carburized layer, and the micro-hardness and wear resistance are improved. But the laser shock processing after carburization only affects the surface deformation, and the improvement of micro-hardness and wear resistance is limited compared with carburization.