ABSTRACT

In this study, the coating was fabricated on the AISI420 stainless steel substrate by laser cladding, and the 18Cr-0.2C Fe-based powder was used in the process. The substrate was close to the heat source exhibited a complex thermal cycle, as evidenced by the significant changes in microstructures and mechanical properties of those regions. The microstructure, phase compositions, mechanical and corrosion properties of the heat-affected zone (HAZ) were investigated systematically. The temperature distribution in the HAZ were accurately calculated. The results show that the microstructure consisted of three areas, HAZ1, HAZ2, and Substrate. The HAZ2 region exhibited agglomerated precipitated M₂₃C₆(M=Fe, Cr) carbides, the martensite was partially transformed into ferrite. Moreover, with a large number of corrosion pits that appeared after the salt spray test. Conversely, HAZ1’s mechanical and corrosion properties were comparable to those of its substrate, as evidenced by the lack of corrosion pits in HAZ1 or substrate.

摘要

在这项研究中，涂层是通过激光熔覆在 AISI420 不锈钢基体上制造的，并且在该过程中使用了 18Cr-0.2C 铁基粉末。靠近热源的基板表现出复杂的热循环，这些区域的微观结构和机械性能的显着变化证明了这一点。系统地研究了热影响区（HAZ）的微观结构、相组成、力学和腐蚀性能。准确计算了 HAZ 中的温度分布。结果表明，显微组织由三个区域组成，HAZ1、HAZ2 和基材。HAZ2 区域表现出团聚沉淀 M ₂₃ C ₆(M=Fe, Cr) 碳化物，马氏体部分转变为铁素体。而且，在盐雾试验后出现了大量腐蚀坑。相反，HAZ1 的机械和腐蚀特性与其基材的机械和腐蚀特性相当，这可以从 HAZ1 或基材中没有腐蚀坑中得到证明。