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为提高不锈钢叶片的耐磨损和气蚀的性能,在材料表面以激光熔敷NiCrBSi合金层。对合金层的显微结构、与不锈钢基体结合方式和SiC等颗粒增强改性对组织结构的影响进行了研究。采用5kW连续二氧化碳激光器对不锈钢上等离子喷涂预置NiCrBSi合金层进行表面熔敷。扫描电子显微镜和X射线衍射分析结果表明:涂层显微结构为细化树枝晶,由γ基体与γ/γ′和NiB的共晶组成。合金粉中添加SiC-Mo颗粒后,熔敷层显微组织更加细化,成为与基体具有一定取向关系的枝晶组织,形成过饱和固溶体和极细的共晶体。SiC弥散分布于自溶性镍基合金中,熔敷不出现裂纹,可进一步提高涂层抗磨蚀性。该激光熔敷自溶性NiCrBSi合金挂片在黄河三门峡3号水轮机中环上现场测试结果表现出优良的抗磨蚀性。
In order to improve the wear resistance and cavitation performance of the stainless steel blade, a NiCrBSi alloy layer is laser welded on the surface of the material. The microstructure of the alloy layer, the bonding mode with the stainless steel substrate and the effect of SiC and other particles on the microstructure were studied. A 5kW continuous carbon dioxide laser was used to deposit the NiCrBSi alloy layer on the plasma sprayed stainless steel. The results of scanning electron microscopy and X-ray diffraction analysis show that the microstructure of the coating is dendrite refinement consisting of γ matrix and eutectic γ / γ ’and NiB. The addition of SiC-Mo particles to the alloy powder further refined the microstructure of the cladding layer to become a dendritic structure having a certain orientation relationship with the matrix and formed a supersaturated solid solution and a fine eutectic. SiC dispersed in self-soluble nickel-based alloy, the weld does not appear cracks, can further improve the coating abrasion resistance. The laser welding self-dissolving NiCrBSi alloy coupon in the Yellow River Sanmenxia 3 turbine ring on-site test results showed excellent abrasion resistance.