10Cr13Ni2马氏体钢焊接接头组织及腐蚀行为

Microstructure and Corrosion Behavior of 10Cr13Ni2 Martensitic Stainless Steel Welded Joints in 5%NaCl Solution

采用G232焊条焊接10Cr13Ni2新型马氏体钢,对于在不同工艺条件下得到的3种焊接接头,通过观察其微观组织,研究了焊接工艺条件对焊接接头组织的影响;通过电化学方法测试了3种焊接接头在5%(质量分数) NaCl溶液中的Tafel极化曲线和电化学阻抗谱,对比分析了其耐腐蚀性能。结果表明:预热温度由150℃升至250℃时,焊接接头过热区附近铁素体由不规则、分散块状变为沿熔合线规则块状分布,焊缝区粗大柱状晶减少且马氏体板条尺寸明显长大,焊后610℃回火热处理使马氏体组织转变为回火索氏体;预热温度由150℃升至250℃时,焊接接头热影响区抗点蚀性能有较大提高,经过610℃回火后析出的回火碳化物导致焊缝区抗点蚀性能有一定下降。

Plates of a new-type 10 Cr13 Ni2 martensitic stainless steel were welded via multilayerand multipass-butt welding with G232 welding rod by three different pre-and post-treatment processes.The microstructure and corrosion behavior in 5%（mass fraction） NaCl solution of the welded joints were examined by means of optical microscope as well as measurements of polarization curve and electrochemical impendence spectrum. Resluts show when the pre-heating temperature rises from 150 ℃ to250 ℃, the original dispersed ferrite-phase with irregular block-like shape in the area nearby the superheated zone transformed into ones with regular block-like shape and distributed along the fusion line,while the coarse columnar grains in the weld zone decreased and the size of martensite leth grew obviously. The martensite microstructure transformed into tempered bainite microstructure after post welding heat treatment. Correspnodingly, the pitting corrosion resistance of the heat affected zone was greatly improved, hewever the tempering carbide in the weld zone results in the decreasing pitting corrosion resistance after tempering at 610 ℃.