40Cr激光熔凝硬化组织形态及性能研究

Study on Microstructure and Property of Laser Melting Layer on 40Cr Surface

利用CO2轴流激光加工机对40Cr钢表面进行激光熔凝硬化处理。利用扫描电镜、显微硬度计、磨损试验机和盐雾试验机研究了不同工艺下熔凝硬化层显微组织及性能。实验表明,熔凝硬化层由熔化区、相变硬化区和热影响区组成;由表及里组织分别为极细小的马氏体+残余奥氏体、针状马氏体+碳化物+残余奥氏体、回火马氏体+残余奥氏体+铁素体+碳化物;扫描速度越小,硬化层越深;经过激光熔凝硬化处理的40Cr耐磨性以及耐蚀性都有较明显的提高。

40Cr steel was treated by laser melting using the axis flow CO2 laser. The microstructure and property of remelting hardening layer at different paramenters was analyzed by scanning electron microscope and microhardeness sclerometer and abrasion test-machine and salt-mist test-machine. The results show that the remelting hardening layer consists of melting zone, quenching zone and heat affected zone. From surface to internal, the respective microstructure is extremely small martensite and remain austenite, acerose martensite and carbides and remain austenite, backfire martensite and remain austenite and ferrite and carbides. The smaller the scanning speed, the deeper the hardening layer. Resistance and corrosion resistance of the substrate treated by the laser melting have been enhanced.