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

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 signal-to-noise ratio analysis were analyzed by using a digital microscope, optical microscope, X-ray diffractometer, scanning electron microscope, energy dispersive spectroscopy, micro-hardness 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, and epsilon-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.