W对Co基合金熔覆层组织和耐锌蚀性能的影响

为了提高热镀锌生产线关键部件的使用寿命并节约热镀锌成本,采用半导体激光器在316L不锈钢表面制备了具有不同成分的两种钴基合金熔覆层.分别对激光熔覆层的组织形貌、成分、相结构、显微硬度及耐锌蚀性能进行了研究.结果表明,W元素的加入使得熔覆层晶粒发生细化,熔覆层组织主要由γ-Co固溶体、Co_3Mo_2Si相和少量Cr_7C_3相组成,同时还生成了少量弥散分布的Co_6W_6C相.添加W元素后熔覆层的平均硬度可达986 HV,相比未添加W元素的Co基合金熔覆层约增加了114 HV,且约为316L不锈钢的4.5倍.与原Co基合金熔覆层相比,添加了W元素的Co基合金熔覆层中弥散分布的Co_6W_6C相使熔覆层耐锌蚀性能大幅度提高.

Effect of W on microstructure and zinc corrosion resistance of Co-based alloy cladding layers

In order to improve the service life of key components in the hot dip galvanizing production line and save the cost of hot dip galvanizing, two Co-based alloy cladding layers with different compositions were prepared on the surface of 316L stainless steel with the semiconductor laser. The microstructural morphology, composition, phase structure, microhardness and zinc corrosion resistance of laser cladding layers were studied, respectively. The results show that the addition of W element makes the grains of cladding layer refine. The microstructure of laser cladding layer is mainly composed of γ-Co solid solution, Co₃Mo₂Si and Cr₇C₃ phases. Meanwhile, a small amount of Co₆W₆C phase forms. The average hardness of cladding layer reaches 986 HV, which is 114 HV higher than that of Co-based alloy cladding layer without the W element, and is about 4.5 times as that of 316L stainless steel. Compared with the orginal Co-based alloy cladding layer, the Co₆W₆C phase sparsely distributes in the Co-based alloy cladding layer with W element, which significantly improves the zinc corrosion resistance of cladding layer.