采用脉冲单电源在Q195钢表面进行了等离子钨钼共渗+渗碳、淬火、回火处理, 形成了表面高速钢渗层; 采用光学显微镜、扫描电镜、X射线衍射仪、硬度仪和磨损试验机对表面组织和性能进行了研究。结果表明: 采用脉冲单电源可以在钢表面形成了明显的共渗层; 在1 000 ℃保温8 h的工艺条件下, 渗层厚度约为110 μm, 渗层表面钨、钼含量分别约为8.4%和9.8%, 表面钨当量超过20%; 渗层主要由Fe7W6和Fe3Mo金属间化合物相组成; 经过渗碳、淬火后碳化物的主要类型是MC、M2C和M6C, 碳化物细小且分布弥散; 再经200 ℃回火后钢的耐磨性较经750 ℃水淬+200 ℃回火T10钢的提高了1.7倍; 经过复合处理后该钢抗回火软化性与W6Mo5Cr4V2钨钼高速钢的近似, 700 ℃回火后硬度仍达到610 HV。

Q195 steel was treated by plasma W and Mo co-cementation process using pulse single power source and followed by carburizing, quenching and tempering, then surface high speed steel layer was formed. The microstructure and properties of the surface were studied by optical microscopy, SEM, XRD, microhardness instrument and wear testing machine. The results show that a obvious co-cementation layer was formed on surface of the steel by pulse single power source. The thickness of the layer prepared at 1 000 ℃ for 8 h was 110 μm. The contents of W and Mo were 8.4% and 9.8%, respectively, and the surface tungsten equivalent was over 20%. The main phases of the layers were intermetallic compounds Fe7W6 and Fe3Mo. After carburizing and quenching, the forms of carbides were primary MC, M2C and M6C. The carbides were fine and distributed evenly. The wear resistance of the steel after tempered at 200 ℃ was improved by 1.7 times compared to that of the T10 steel after water quenched at 750 ℃ and tempered at 200 ℃. The anti-temper ability of the compound treated steel was similar to that of the high speed steel W6Mo5Cr4V2, whose hardness was 610 HV after tempered at 700 ℃.