20Cr13表面激光熔覆15-5PH涂层组织和性能研究

Microstructure and Properties of 15-5PH Coating by Laser Cladding on 20Cr13 Surface

为改善20Cr13不锈钢零部件表面性能,利用激光熔覆技术在20Cr13不锈钢基材表面制备15-5PH合金涂层实现其表面强化。采用超景深显微镜、光学显微镜、X射线衍射仪、扫描电子显微镜、能谱仪、显微硬度计及摩擦磨损试验机等,对利用信噪比分析获得的较优工艺参数下的15-5PH合金涂层的几何形貌、微观组织、物相、显微硬度及摩擦磨损性能等进行分析。结果表明:熔道的熔宽、熔高、熔深与激光比能之间成正比;15-5PH涂层与20Cr13不锈钢冶金结合良好,无裂纹、气孔等缺陷;涂层组织以等轴晶和柱状晶等组成,涂层中析出了颗粒状NbC、NiCx、ε-Cu等硬质相。显微硬度和摩擦磨损性能结果表明,涂层显微硬度约为基材的2.4倍,同时涂层耐磨性较基材有明显提升,其磨损形式为黏着磨损及磨粒磨损。

To improve the surface performance of 20Cr13 stainless steel parts,the laser cladding technology was used for producing 15-5PH alloy coating on the surface of 20Cr13 stainless steel substrate so that its surface strengthening can be achieved.The geometric morphology,microstructure,phase,friction and wear properties,and microhardness of the cladding layer under the better process parameters obtained by signaltonoise ratio analysis were analyzed by using a digital microscope,optical microscope,Xray diffractometer,scanning electron microscope,energy dispersive spectroscopy,microhardness tester,and friction and wear tester.The results show that positive relationship between melt width,melt height,melt depth,and laser specific energy of the melt channel,the metallurgical combination between the 15-5PH cladding layer and 20Cr13 stainless steel is good without defects like cracks and pores.The structure of the coating is composed of equiaxed and columnar crystals,and hard phases such as granular NbC,NiCx,andε-Cu are precipitated in the coating.The microhardness and friction and wear performance results show that the microhardness of the coating is about 2.4 times of that of the substrate.At the same time,the wear resistance of the coating is significantly improved compared with that of the substrate,and its wear forms are adhesive wear and abrasive wear.