Study on corrosion resistance of cladding layer of Mn-N duplex stainless steel surfacing

Mn-N双相不锈钢堆焊熔覆层耐点蚀性能研究 Study on corrosion resistance of cladding layer of Mn-N duplex stainless steel surfacing 许伟康 XU Weikang 1 first-author 包晔峰 BAO Yefeng 1 谢秉锜 XIE Bingqi 1 王秋雨 WANG Qiuyu 1 河海大学机电工程学院 河海大学机电工程学院 College of Mechanical and Electronic Engineering,Hohai University College of Mechanical and Electronic Engineering,Hohai University 采用粉末堆焊和固溶热处理的方法制备Mn-N系双相不锈钢堆焊层试样。观察堆焊层的金相组织,通过FeCl 3 -HCl浸泡试验和动电位极化曲线法研究堆焊层的耐腐蚀性能,并与2209双相不锈钢及304奥氏体不锈钢堆焊层进行对比。结果表明:研制的Mn-N型双相不锈钢堆焊层的金相组织为奥氏体和铁素体,两相比例接近1∶1,铁素体的存在为晶界提供了充足的Cr,减小了Cr的碳化物沉淀,耐点腐蚀性优于304奥氏体不锈钢;Mn-N双相不锈钢的耐腐蚀性能略差于2209双相不锈钢,原因是其Cr、Mo元素含量低于2209,使其钝化膜的稳定性和再钝化能力有所下降。 Mn-N duplex stainless steel surfacing samples were prepared by powder surfacing and solution heat treatment.The metallographic structure of the surfacing layer was observed.The corrosion resistance of the surfacing layer was studied by the ferric chloride immersion experiment and the polarization curve method,and was compared with the surfacing layers of 2209 duplex stainless steel and 304 austenitic stainless steel respectively. The results show that the metallographic structure of the self-made Mn-N duplex stainless steel surfacing layer is austenite and ferrite,and the two-phase ratio is close to 1:1. The presence of ferrite provides sufficient Cr for the grain boundary and reduces the carbon precipitation of Cr,and the pitting resistance is better than 304 austenitic stainless steel;the corrosion resistance of Mn-N duplex stainless steel is slightly worse than that of 2209 duplex stainless steel,the reason is that its chromium and molybdenum are lower than those of 2209 duplex stainless steel,which reduces the stability and repassivation ability of the passivation film. 堆焊 Mn-N型双相不锈钢 耐腐蚀性能 surfacing Mn-N type duplex stainless steel corrosion resistance TG455 国家自然科学基金资助（51879089）;中央高校基本科研业务费（学生项目）2018B735X14 2022-03-08 3 50