高铬钢激光熔凝处理后的组织与耐蚀性能

快速凝固技术是改善高铬钢表面性能的有效手段,其中激光熔凝处理最为简单经济.过去,对采用激光熔凝处理来提高材料耐蚀性的报道不多,为此,采用5 kW横流CO2激光器对高铬钢进行熔凝强化处理,借助电化学测试、扫描电镜等方法研究了高铬钢激光熔凝处理后的显微组织及耐蚀性能.结果表明:高铬钢的表面腐蚀始于碳化物与基体交界处,导致基体腐蚀严重,大量碳化物暴露于表面;激光熔凝处理明显改善了高铬钢的组织形态,使其晶粒细化,碳化物完全溶解,碳及合金元素固溶于奥氏体枝晶中,耐蚀性明显提高,腐蚀表面均匀平整.

Microstructure and Corrosion Resistance of Laser Surface Melting Modified Layer on High Chrome Steel

A 5 kW continuous CO2 laser sys-tem was performed for laser surface melting of high chrome steel.The microstructure and corrosion resistance of the laser surfacemelting modified layer were analyzed by using a scanning electronmicroscope and an electrochemical test rig. Results show that thehigh chrome steel experienced initial corrosion attack at theboundary of the carbides and matrix, leading to severe corrosionof the matrix and exposure of a large amount of carbides on thecorroded surface. Laser surface m...