The Improvement of the Wear Resistance of T15 Laser Clad Coating by the Uniformity of Microstructure

Abstract

The uniformity of microstructure and wear properties exist in the T15 coating for the laser cladding on 42CrMo steel. It can be improved by a post-heat treatment process. Temperature ranges from 1100 to 1240 °C were applied on the cladding layer to investigate the effect of the heat treatment on the wear resistance and hardness gradient. The post-heat treatment can efficiently improve the inhomogeneity of microstructure. The lower wear rate is obtained after the quenching process at 1100 °C, and the wear rate is increased though the tempering process. The carbides at the grain boundary are decomposed and integrated into the matrix during the high temperature quenching process. The carbides are precipitated and dispersed in the grain during the tempering process. The content of martensite and alloy carbide is significantly increased through the heat treatment process. The microhardness of the cladding layer is 910 HV after quenching and 750 HV after tempering. The wear mechanism of the cladding layer is mainly abrasive wear and fatigue wear. The crack and falling off from cladding layers are significantly reduced for the quenching–tempering process.