45钢电子束扫描表面W合金化组织和硬度

电子束扫描表面合金化技术可以改善钢铁材料的组织及性能. 采用等离子热喷涂技术和电子束扫描技术对45钢表面进行熔覆合金化处理. 研究电子束扫描对强化层组织和硬度的影响，探讨了电子束功率、扫描速度对强化层组织和硬度的影响规律. 结果表明，45钢经表面合金化处理后，其表面可分为合金化区、热影响区和基体区. 合金化区的显微组织为针状马氏体和碳化钨颗粒，硬度为1 250 HV，是基体硬度的5倍. 热影响区的组织为针状马氏体和铁素体，硬度为860 HV，是基体的3倍. 基体区的组织为珠光体和铁素体. 电子束工艺参数对强化层组织和硬度有较大影响，强化层厚度随电子束功率的增加而增大，随着扫描速度的增加而减小.

Microstructure and hardness of W alloy on 45 steel by electron beam scanning

The microstructure and properties of iron and steel materials can be improved by electron beam scanning surface alloying. In this paper, the surface of 45 steel is treated by cladding alloy by plasma spraying technology and electron beam scanning technique. The effect of electron beam scanning on the strengthened layer was investigated. The results show that 45 steel treated by surface alloying, the surface can be divided into alloying zone, heat affected zone and the base zone. The microstructure of the alloying zone was acicular martensite and tungsten carbide particles, the microhardness is 1 250 HV, which was 5 times of the substrate; the microstructure of the heat affected zone is acicular martensite and ferrite. The microhardness was 860 HV, which was 3 times of the substrate. The microstructure of the substrate was pearlite and ferrite. The technological parameters of the electron beam had great influence on microstructure and hardness of the strengthened layer. The thickness of the strengthened layer increased with the increase of the beam power, and decreased with the increase of the scanning speed.