Microstructural investigation and mechanical performance of laser cladding repaired bainite steel with AerMet100 steel

In this paper, bainitic railways were repaired designedly by laser cladding repairing method with AerMet100 steel powder as raw material. The microstructural evolution of repaired specimens was studied carefully, and the corresponding mechanical properties and wear resistance were compared to verify the feasibility of this method. Results show that the bainite microstructures formed in the AerMet100 repaired region exhibit a high microhardness of 515 HV due to high-alloyed solution strengthening and microstructure refinement. The thermal cycles during the repairing process lead to the microstructures in HAZ changing with the distance from the fusion line, and the bottom of HAZ consisting of tempered bainite becomes the microhardness valley. Tensile tests indicate that the overall mechanical properties of repaired specimens are comparable to the bainitic substrate. Compared to the bainitic matrix, wear tests present that the wear resistance of the AerMet100 repaired region is better with the mass loss decreasing by about 28%. The current experimental results suggest that laser cladding repairing with AerMet100 steels is suitable for high-performance repairing of high-strength bainitic steels.