Effect of Overlap Rate on Microstructure and Wear Resistance of Fe90 Alloy Cladding Layer by Laser Cladding on 65Mn Surface

Abstract

65Mn as an important basic material of agricultural machinery, its durability has a direct impact on product quality and benefit. This study emphasises on the surface modification of 65Mn, making use of laser cladding process to prepare 0%,15%,30%,45% Fe90 alloy cladding coating on the surface of 65Mn steel substrate. x-ray diffractometer (XRD), scanning electron microscopy (SEM) and Vickers hardness tester were used to study the phase composition, microstructure, microhardness and wear resistance of the coating. The results indicate that the laser cladding significantly improves the hardness of 65Mn alloy and the wear resistance is better than that of the substrate. The average hardness of the cladding layer with 30% bonding rate is about 942HV, which is about 3 times higher than that of the substrate, and the hardness value firstly increases and then decreases according to the increase of the bonding rate. For laser cladding Fe90 alloy, the change of bonding rate has no obvious impact on the composition of the internal phase. Compared with the cladding coating with other bonding rates, the microstructure of the cladding layer is finer with 30% bonding rate, and it is transformed from a large number of dendritic crystals + a small number of equiaxed crystals into more refined dendritic crystals and equiaxed crystals. In summary, the wear resistance is the best when the bonding rate is 30%.