Q235钢表面氩弧热源熔覆镍基自熔合金层的组织及性能

Preparation of Ni-Based Self-Fluxing Alloy Coatings on Q235 Steel by Argon-Arc Cladding and Evaluation of Wear Resistance of the Cladding Coatings

目前,鲜见氩弧熔覆镍基合金粉末工艺参数对熔覆层表面耐磨性能影响的研究报道,先将镍基自熔合金粉末涂覆于Q235钢表面,再利用氩弧热源熔覆。采用金相显微镜观察熔覆层表面和截面组织,采用硬度计及磨损试验分析熔覆层的表面硬度及耐磨性,研究了涂覆层厚度、熔覆电流对熔覆层表面组织、力学性能的影响。结果表明:基体与熔覆层形成了良好的冶金结合;随熔覆电流的增加,熔覆层表面硬度和耐磨性先增加后降低;随涂覆层厚度的增加,熔覆层表面硬度和耐磨性随之增加;涂覆层厚3 mm,熔覆电流为180 A时,熔覆层表面金相组织为少量初生固溶体枝晶和大量奥氏体与碳、硼化物的共晶,熔覆层表面硬度最大,为45.0 HRC,耐磨性最好。

Ni-based self-fluxing alloy powder was coated onto the surface of Q235,followed by Ar-are cladding to afford Ni-based self-fluxing alloy coatings.The surface and cross-section morphologies of the as- prepared Ni- based self- fluxing alloy cladding coatings were observed with a metallographic microscope,and their hardness and wear resistance were evaluated with a hardness meter and a friction and wear tester.Furthermore,the effects of cladding coating thickness and cladding current on the microstructure and mechanical properties of the cladding coatings were investigated.Results indicated that the cladding coatings were well combined with the steel substrate by metallurgical bonding.The surface hardness and wear resistance of the cladding coatings tended to rise initially but decline later with increasing cladding current,and they tended to rise with increasing cladding coating thickness.Particularly,the cladding coating obtained under a cladding current of 180 A,with a thickness of 3 mm,consisted of a small amount of primary dendrite of austenite solid solution and a large amount of the eutectics of austenite as well as carbides and borides;and it exhibited the highest hardness of 45.0 HRC as well as the best wear resistance.