45钢多次激光相变硬化组织与性能研究

Study on Microstructure and Performance of 45 Steel Treated by Malti-time Laser Transformation Hardening

采用5kW横流CO2激光器对45钢表面进行了多次激光相变硬化,并对硬化区进行了X射线衍射谱分析、光学显微分析和硬度测试。结果表明:激光相变硬化区主要由马氏体、少量残余奥氏体组成,随着扫描次数的增多,组织进一步细化、弥散,缺陷密度更高,奥氏体的形核更容易,长大速度更快,临界硬化温度更低,导致硬化层深度增加,硬度提高。

The 45 steel was treated by multi-time laser transformation hardening with 5kW CO2 laser equipment. XRD patterns, optic microstructure and performance of hardening zone were studied, The results showed that laser transformation hardening zone was composed of martensite with a little content of austenite With increase of time of scanning, the structure became finer, more dispersed, greater density of defects, bigger rate of austenite forming and growing, and lower critical hardening temperature, which all led to a larger deepness and higher rigidity of hardening zone.