45钢表面激光相变硬化改性组织及耐蚀性能

摘要

目的：为了改善45钢表面状态，提高其表面性能，采用CO2激光器对其表面进行激光相变硬化处理。方法利用带有能谱的扫描电子显微镜( SEM/EDS )、盐雾试验机等，对激光相变硬化层组织及耐蚀性能进行了观察和分析。结果激光相变硬化层由熔化区、相变硬化区和热影响区三部分组成，其组织依次为：混合马氏体+未溶碳化物、针状马氏体、残余奥氏体。随扫描速度增加，耐蚀性先变好而后变差。结论激光相变硬化处理可改善45钢的表面性能，显著提高其耐蚀性能。%In order to improve the surface properties of 45 steel, the laser transformation hardening treatment was car-ried out by CO2 laser on its surface. The microstructure and properties of alloying layer were analyzed by scanning electron microscope with energy spectrum ( SEM/EDS) , salt spray tester, etc. The laser transformation hardening layer was consti-tuted by melting zone, transformation hardened zone and heat affected zone. The microstructure included the mixed mar-tensite plus undissolved carbides, acicular martensite, and retained austenite. With the increase of the scanning speed, the corrosion resistance increased first and then decreased. After laser transformation hardening treatment, the surface proper-ties of 45 steel were improved, which significantly increased the corrosion resistance.