氧化温度和冷凝液硫含量对SUS441铁素体不锈钢晶间腐蚀行为的影响  

Effects of oxidation temperature and sulfur content of condensate on the intergranular corrosion performance of SUS441 stainless steel

作　　者：但佳永 周和荣[1,2] 刘鹏洋 姚望 Dan Jiayong;Zhou Herong;Liu Pengyang;Yao Wang(College of Materials Science and Metallurgical Engineering,Wuhan University of Science and Technology, Wuhan 430081,Chin;State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology,Wuhan 430081,China)

机构地区：[1]武汉科技大学材料与冶金学院,湖北武汉430081 [2]武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北武汉430081

出　　处：《武汉科技大学学报》2018年第2期88-93,共6页Journal of Wuhan University of Science and Technology

基　　金：国家自然科学基金面上项目(50971048);国家科技基础条件平台专题(汽车腐蚀专项)

摘　　要：利用高温氧化-冷凝液浸蚀循环腐蚀方法模拟汽车排气系统内部服役环境,结合腐蚀形貌观察和析出相分析,对比研究了氧化温度及冷凝液中硫含量对SUS441铁素体不锈钢晶间腐蚀行为的影响。结果表明,经过150次氧化-冷凝液浸蚀循环腐蚀后,SUS441铁素体不锈钢表面均发生了不同程度的局部腐蚀。当氧化处理温度相同时,喷涂高硫冷凝液的试验钢的晶间腐蚀程度严重于采用低硫冷凝液的情况;而喷涂相同硫含量的冷凝液时,800℃氧化处理后试验钢的晶间腐蚀程度比400℃处理时更深。结合显微组织观察可知,当氧化温度为800℃时,试验钢晶界处有大量Fe_2Nb Laves相析出,而400℃处理后晶界处无析出相形成。由此可见,氧化温度对SUS441铁素体不锈钢晶间腐蚀行为的影响更为显著,且晶界析出相是导致该不锈钢产生晶间腐蚀的主要原因。A high temperature oxidation/condensate immersion cyclic method was employed to simulate internal service environment of automotive exhaust system.Based on the corrosion morphology observation and precipitation analysis,the effects of oxidation temperature and sulfur content in condensate on the intergranular corrosion performance of SUS441 stainless steel were investigated comparatively.The results show that after 150 cycles of oxidation/condensate immersion tests,varying degrees of localized corrosion take place on the surface of SUS441 stainless steel.When the oxidation treatment temperature is the same,the intergranular corrosion degree of samples sprayed with high-sulfur condensate is more serious than that of the samples with low-sulfur condensate.On the other hand,by spraying the condensate with the same sulfur content,the intergranular corrosion of samples treated at 800℃is more severe than at 400℃.According to the microstructure observation,a certain number of Fe 2Nb Laves phases just precipitate at the grain boundary at the treatment temperature of 800℃,but no precipitate is detected at the grain boundary of samples at 400℃.Hence,the oxidation temperature factor has a more significant influence on the intergranular corrosion performance of SUS441 stainless steel,and precipitated phase at the grain boundary can be regarded as the main cause of the intergranular corrosion of this stainless steel.

关 键 词：铁素体不锈钢 晶间腐蚀 高温氧化 冷凝液 硫含量 析出相 腐蚀形貌 

分 类 号：TG171[金属学及工艺—金属表面处理]