连接金具用Q235钢表面激光合金化耐磨耐蚀涂层的组织及性能研究  

Microstructure and Properties of Laser Surface Alloying Anti-wear/Corrosion Coating on Q235 Steel Surface for Electric Power Fitting

作　　者：周海飞 李凤瑞 王河 钱大虎 余璐涛 迟一鸣 姚建华 ZHOU Haifei;LI Fengrui;WANG He;QIAN Dahu;YU Lutao;CHI Yiming;YAO Jianhua(Research Institute,State Grid Zhejiang Electric Power Co.,Ltd.,Hangzhou 310014,China;Institute of Laser Advanced Manufacturing,Zhejiang University of Technology,Hangzhou 310023,China)

机构地区：[1]国网浙江省电力有限公司电力科学研究院,杭州310014 [2]浙江工业大学激光先进制造研究院,杭州310023

出　　处：《表面技术》2024年第21期208-219,共12页Surface Technology

基　　金：国网浙江省电力有限公司项目(5211DS22000R)。

摘　　要：目的解决电网连接金具存在的硬度低、耐磨性差、易腐蚀失效等问题。方法采用激光合金化工艺在常见连接金具材料Q235钢表面制备均匀致密的K500涂层和K500+WC复合涂层,研究涂层的物相组成、微观组织、WC颗粒的溶解析出行为,并对其耐磨性能和耐蚀性能进行分析。结果K500涂层由γ-(Fe,Ni,Cu)单相固溶体组成,其组织结构从底部到顶部经历了从平面晶向柱状晶、枝晶,最后到顶部等轴晶的转变。K500+WC涂层主要由γ相固溶体、WC、W2C组成,在熔池中WC颗粒边缘溶解,形成了几微米的元素扩散区域,该区域内析出枝晶状、块状碳化物,熔池底部富Fe元素区域还析出了鱼骨状Fe3W3C碳化物。K500涂层和K500+WC涂层的平均显微硬度分别为244.73HV0.2、355.27HV0.2,磨损率分别比基材降低了41.48%、85.39%,耐磨性能显著提升,这得益于γ相的固溶强化及碳化物的弥散强化效应。结论K500涂层中的Ni、Cu等元素在腐蚀初期会形成致密的氧化膜,将涂层与腐蚀性介质隔离,有效降低了腐蚀速率。加入WC颗粒后,耐蚀性良好的γ相含量降低,涂层内部微界面增多、腐蚀通道增加,导致K500+WC涂层的耐蚀性略微降低,但仍明显优于基材。Considering the deterioration of electric power fittings caused by wear and corrosion,the work aims to employ a laser surface alloying process to prepare uniform and dense K500 or K500+WC composite coatings on the surface of Q235 steel,a widely utilized material for power fittings.Comparative analysis was conducted on the microstructure,phase composition,wear resistance and corrosion resistance of these coatings.The dissolution and precipitation behavior of WC particles in composite coating was also discussed.The surface of the substrate was polished and cleaned with sandpaper,and the K500 powder was spread evenly on the surface with a thickness of 0.8 mm with a jig and a coating tool.Laser alloying experiments were carried out with a semiconductor laser(YLS-2000),and the optimized laser parameters were laser power of 1200 W,scanning speed of 6 mm/s,spot diameter of 4.2 mm,and overlap rate of 30%.For the preparation of K500+WC composite coating,the K500 powder was similarly pre-placed on the substrate.Simultaneously,WC particles were directly introduced into the molten pool through synchronous powder feeding under the same laser process parameters.The powder feeding rate was set at 10 g/min.The experimental process was carried out within a high-purity argon atmosphere protection chamber with an argon flow rate of 10 L/min.The microstructure of the coatings was observed with a scanning electron microscope(ZEISS EVO18),and the composition analysis was carried out with an attached energy spectrometer(Nano Xflash Detector 5010).An X-ray diffractometer(D/max-UltimaⅣ)was used to identify the phase constituents of the coatings.The microhardness was tested by Vickers microhardness tester(HMV-2T)at a load of 200 g for 15 s.Dry friction and wear tests were carried out at room temperature with a ball-on-disc wear tester(HT-1000)at a load of 60 N and a speed of 200 r/min.After a 60 min test,the three-dimensional morphologies and cross-section profiles of the worn surface were measured by a laser confocal microscope(VK-X100

关 键 词：激光合金化 电网连接金具 WC颗粒 耐磨性能 耐腐蚀性能 

分 类 号：TG178[金属学及工艺—金属表面处理]