大变形热压缩18.7Cr-5.8Mn-1.0Ni-0.23N节镍型双相不锈钢的晶间腐蚀行为研究  

Intergranular Corrosion Behavior of 18.7Cr-5.8Mn-1.0Ni-0.23N Economical Duplex Stainless Steel Under Large Deformation Thermal Compression

作　　者：刘泽辉 杨银辉[1] 张凤珍 王刘行 LIU Zehui;YANG Yinhui;ZHANG Fengzhen;WANG Liuhang(School of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China;Science and Technology Innovation Department of Kunming Iron and Steel Holding Co.,Ltd.,Kunming 650302,China)

机构地区：[1]昆明理工大学材料科学与工程学院,昆明650093 [2]昆明钢铁控股有限公司科技创新部,昆明650302

出　　处：《材料导报》2023年第12期170-179,共10页Materials Reports

基　　金：国家自然科学基金(51461024,51861019)。

摘　　要：针对70%变形量热压缩18.7Cr-5.8Mn-1.0Ni-0.23N节Ni型双相不锈钢,采用双环动电位再活化测试和EIS测试等,研究了在0.1~10 s-1/850~1150℃范围变形参数对双相不锈钢在高低两种浓度H2SO4+Na Cl+KSCN溶液中晶间腐蚀行为的影响。结果表明:高溶液浓度增大了晶间敏感值区分度,热变形参数影响两相晶粒细化程度和钝化膜稳定性,导致晶间腐蚀敏感值变化较大。晶间腐蚀主要发生在两相界面处,Cr2O3含量对维持钝化膜稳定起主导作用,耐腐蚀性降低与Mn O富集降低钝化膜致密性有关。1 s-1较高温度变形后钢的晶间敏感值低于固溶态,0.1 s-1/1050℃和1s-1/1050℃变形时,奥氏体相再结晶细化有利于钝化膜稳定性和致密性的增强,增大了耐晶间腐蚀性,铁素体相晶粒细化则有利于自身钝化。相界处钝化元素分布不均匀和高密度位错的形成降低了850℃较低温度变形时钢的耐晶间腐蚀性。The effect of deformation parameters in the range of 0.1-10 s^(-1)/850-1150℃on the IGC resistance of 18.7Cr-5.8Mn-1.0Ni-0.23N eco-nomical DSS with 70%deformation hot compression in high and low concentration solutions was studied.The results show that higher solu-tion concentration increased the discrimination of intergranular sensitivity value,and the deformation parameters affect the variation of grain refine-ment and the stability of passivation film in two phases.The occurrence of IGC mainly locates at the two-phase interfaces,and the Cr2 O3 content plays a leading role in maintaining the stability of passive film,but the decrease of corrosion resistance is related to the decrease of the passive film compactness due to the enrichment of MnO content.The IGC sensitivity values after deformation at 1 s^(-1)and higher temperature are lower than that after solid solution treatment.When deformed at 0.1 s^(-1)/1050℃and 1 s^(-1)/1050℃,the recrystallization refinement of austenite phase was contributed to enhance the stability and compactness of passive film,and then increase the IGC resistance,while the grain refinement of ferrite phase was conducive to its self-passivation.The passivated elements are not evenly distributed and the formation of high-density disloca-tions at phase boundaries reduced the IGC resistance when deformed at lower temperature of 850℃.

关 键 词：节约型 双相不锈钢 再结晶 晶间腐蚀 钝化膜 

分 类 号：TG142[一般工业技术—材料科学与工程]