40Cr轧辊表面激光熔覆涂层的组织及性能研究

Study of Microstructure and Properties of Laser Cladding Coatings on 40Cr Rollers

在40Cr轧辊表面制备出新型的激光熔覆涂层,以提高轧辊表面层的高温耐磨性。本文在40Cr基材上通过调整成分配比自行配置了一种激光熔覆合金粉末,通过激光熔覆表面改性技术,获得具有高硬度、高耐磨性且成型良好的激光熔覆层。通过金相显微镜、扫描电子显微镜、X射线衍射仪和磨损试验机研究了熔覆层的显微组织、硬度和耐磨性。结果表明:熔覆层组织中主要含有Fe Ni,还有部分Fe-Cr-Ni和Fe Cr等硬化相;显微组织形状为等轴树枝晶,熔覆层最高硬度达到709HV0. 2,激光熔覆层平均硬度是40Cr基材硬度的2. 9倍,与基体的结合为冶金结合。熔覆层磨损形貌中的磨痕相对较浅,相比基体熔覆层失重量减少了54%,耐磨性得到显著提高。

A new laser cladding coating was prepared on the surface of the 40Cr roll to improve the high temperature wear resistance of the surface layer of the roll.In this paper,a laser cladding alloy powder was designed for the 40Cr base metal by adjusting the distribution ratio.Laser cladding technology was used to obtain a laser cladding layer with high hardness,high wear resistance and no crack on the surface.The microstructure,hardness and wear resistance of the cladding layer were investigated by autobiographic microscope,scanning electron microscope,X-ray diffraction and wear tester.The results show that the cladding layer contains a large amount of FeNi,also contains some hardened phases such as Fe-Cr-Ni and FeCr.The microstructure is dendritic equiaxed crystal,the hardness of the cladding layer can reach 709 HV 0.2 and the average hardness of the laser cladding layer is 2.9 times that of the 40Cr substrate.The combination with the matrix is metallurgical bonding.The wear marks in the wear profile of the cladding layer are relatively shallow,and the weight loss of cladding layer is reduced by 54%compared with the substrate,and the wear resistance is significantly improved.