304LN不锈钢表面激光熔覆钴基合金组织和性能

为了提高304LN不锈钢的耐磨性，延长控制棒导向筒组件使用寿命，采用激光熔覆技术在304LN不锈钢表面制备了Stellite 6钴基熔覆层.利用光学显微镜(OM)、能谱仪(EDS)、显微硬度计、摩擦磨损试验机、腐蚀试验装置等多种试验测试设备，分析了熔覆层组织形貌、成分、显微硬度、摩擦磨损性能及腐蚀行为，确定了多道多层钴基熔覆层的工艺参数.结果表明，熔覆层与基体之间形成了冶金结合，显微组织主要由平面晶区、胞状和柱状晶区、树枝晶区和等轴晶区组成.熔覆层硬度为500 ~ 550 HV，摩擦磨损系数为0.30 ~ 0.35，熔覆层均匀腐蚀速率和缝隙腐蚀速率分别为0.153 和0.143 mg/(dm2·d). 激光熔覆钴基合金可以有效提高304LN不锈钢表面的硬度、耐磨性能和耐腐蚀性能.

Microstructure and property of cobalt alloy by laser cladding on 304LN stainless steel surface

In order to improve the wear resistance of 304LN stainless steel and prolong the service life of the control rod guide cylinder assembly, a Stellite6 cobalt-based layer was prepared on the surface of 304LN stainless steel by laser cladding technology. The microstructure, composition, microhardness, friction and wear resistance and corrosion behavior of the cladding layer were analyzed by optical microscope (OM), energy dispersive spectrometer (EDS), microhardness tester, friction and wear tester, corrosion test device and other test equipment. The processing parameters of the multi-layer cobalt-based cladding layer were determined. A metallurgical bond is formed between the cladding layer and the matrix, and the microstructure is mainly composed of planar crystal regions, cellular and columnar crystal regions, dendrite regions and equiaxed crystal regions. The hardness of the cladding layer is 500 ~ 550 HV, the friction and wear coefficient is 0.3 ~ 0.35, and the uniform corrosion rate and crevice corrosion rate of the cladding layer are 0.153 mg/(dm²·d) and 0.143 mg/(dm²·d) respectively. Laser cladding cobalt base alloy can effectively improve the hardness, wear resistance and corrosion resistance of 304LN stainless steel surface.