Abstract:  In order to compare the feasibility of high-speed laser cladding coatings replacing electroplated hard chrome coatings under different service conditions of hydraulic cylinders, martensite stainless steel cladding layers XG-1, XG-2 and electroplated hard chrome coatings were prepared respectively. The microstructure, hardness, corrosion performance and wear performance under simulated different conditions(scratch wear, dry sand grinding wear, sliding friction wear) of the three coatings were tested, and the coating failure behavior and application conditions were discussed. The results show that the microstructures of XG-1 and XG-2 coatings are dense and uniform, with an average microhardness of 720.5 HV and 653 HV, respectively. The electroplated hard chrome coatings contain defects such as pores and cracks, and the self-corrosion current density is about 10.45 μA/cm2, indicating the worst corrosion resistance. Under the three wear modes, the electroplated hard chrome coatings have cracked and peeled off, while the high-speed laser cladding coatings exhibit better wear resistance, which are suitable for the service conditions of hydraulic cylinders such as piston rod easily to be scratched, surrounding environment being rich in hard particle pollutants, and large lateral loads.

Key words: high-speed laser cladding, electroplated hard chromium, wear behavior, hydraulic cylinder piston rod, martensitic stainless-steel coating

摘要： 为对比研究不同液压缸服役工况下高速激光熔覆涂层替代电镀硬铬层的可行性，分别制备了马氏体不锈钢熔覆层XG-1、XG-2和电镀硬铬涂层，开展了三种涂层组织、硬度、腐蚀性能及模拟不同工况（划伤磨损、干砂摩擦磨损、滑动摩擦磨损）下磨损性能测试，探讨了涂层失效行为及其应用工况。结果表明：XG-1、XG-2涂层微观组织致密且均匀，平均显微硬度为720.5 HV、653 HV；电镀硬铬涂层分布孔隙和裂纹等缺陷，自腐蚀电流密度为10.45 μA/cm2，耐腐蚀性能最差；三种磨损形式下电镀硬铬涂层均发生了开裂及剥落，高速激光熔覆涂层表现出更优异的耐磨性能，适用于活塞杆易拉伤、外界富集硬质颗粒污染物、大侧向载荷等液压缸服役工况。

关键词: 高速激光熔覆, 电镀硬铬, 磨损行为, 液压缸活塞杆, 马氏体不锈钢涂层