回火温度对AM355不锈钢组织及腐蚀行为的影响  

Effect of tempering temperature on microstructure and corrosion behavior of AM355 stainless steel

作　　者：范春华 李雪莹 尹衍升 王长军[2] 梁剑雄[2] Fan Chunhua;Li Xueying;Yin Yansheng;Wang Changjun;Liang Jianxiong(College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai 201306, China;Institute of Special Steels, Central Iron and Steel Research Institute, Beijing 100081, China)

机构地区：[1]上海海事大学海洋科学与工程学院,上海201306 [2]钢铁研究总院特殊钢研究所,北京100081

出　　处：《金属热处理》2018年第5期90-95,共6页Heat Treatment of Metals

基　　金：国家重点基础研究发展计划(973计划)(2014CB643306)

摘　　要：通过循环伏安、双环电化学动电位再活化法、肖特基曲线和浸泡腐蚀试验对350、450、500、535、675℃回火4 h的AM355不锈钢的点蚀电位、晶间腐蚀敏感性和表面钝化膜性能进行研究,金相显微镜、扫描电镜和透射电镜观察微观组织和腐蚀形貌;探讨了不同回火温度对该不锈钢的腐蚀性能影响机制。结果表明：450℃回火时碳化物在原奥氏体晶界析出,在p H=1的3.5%Na Cl溶液中发生晶间腐蚀;在3.5%Na Cl溶液中,点蚀电位随回火温度的升高先降后升,500℃回火点蚀电位最低,点蚀电位的值与钝化膜内施主密度、受主密度相关性不明显,腐蚀优先在片状富Cr、Mo相周围发生。Pitting potential,susceptibility to intergranular corrosion and passive film property of AM355 stainless steel tempered at different temperatures（350 ℃,450 ℃,500 ℃,535 ℃ and 675 ℃） for 4 h were investigated by means of cyclic voltammetry,double-loop electrochemical potentiokinetic reactivation,Mott-Schottky and immersed corrosion experiments. Meanwhile,the microstructure and corrosion morphologies were observed by metalloscope,scanning electron microscope（ SEM） and transmission electron microscope（ TEM）. The effect mechanisms of tempering temperature on corrosion behavior were discussed. The results show that the intergranular corrosion develops in3. 5% Na Cl solution with p H = 1 when the steel tempered at 450 ℃ due to the precipitation of carbides at original austenite grain boundary. As the tempering temperature increases,the pitting potential of the steel in 3. 5% Na Cl solution declines at first and then increases,and it reaches the lowest level when tempered at 500 ℃. The pitting potential has no obvious relationship with the density of donors and acceptors in passive film. The pitting preferably takes place around the flake precipitations containing rich Cr and Mo.

关 键 词：AM355不锈钢 回火温度 微观组织 腐蚀 

分 类 号：TG172.5[金属学及工艺—金属表面处理]