Effect of laser cladding on microstructural transformation and mechanical properties of heat affected zone of EA4T steel

Abstract

In this study, laser cladding on EA4T steel was carried out. The Composition of HAZ of the EA4T steel was analyzed by OM and SEM. The effect of laser cladding on microstructural transformation of HAZ of EA4T steel was discussed. The distribution of alloying elements and the micromechanical properties of the interface were tested. The results show that the microstructures of the laser cladding heat-affected zone of the EA4T steel are mainly lath martensite. The homogenization of austenite and the dissolution of carbides near the interface are not sufficiently developed, and coarse grains are observed. In the fine-grained area of the HAZ, the microstructure is mainly composed of martensite and a small amount of sorbite with a certain orientation. In addition, among all laser cladding conditions, the highest temperature experienced in the HAZ of the EA4T steel plays a decisive role in the evolution of the microstructure and mechanical properties. A sudden change in alloying elements occurs at the junction site, and the grain orientation is clearly found. Moreover, the shear strength of the HAZ increases, whereas the degree of packing decreases.