固溶处理温度对高硅锰铬镍奥氏体不锈钢晶间腐蚀的影响  

Effect of solution treatment temperature on intergranular corrosion of high silicon manganese chromium-nickel austinitic stainless steel

作　　者：彭成 黄福祥[1] 梁爽 杨阳 刘海定 Peng Cheng;Huang Fuxiang;Liang shuang;Yang Yang;Liu Haiding(College of Material Science and Engineering,Chongqing University of Technology,Chongqing 400054,China;Chongqing Materials Research Institute Co. ,Ltd. ,Chongqing 400707 ,China)

机构地区：[1]重庆理工大学材料科学与工程学院,重庆400054 [2]重庆材料研究院有限公司,重庆400707

出　　处：《金属热处理》2019年第6期128-132,共5页Heat Treatment of Metals

摘　　要：利用光学显微镜(OM)、扫描电镜(SEM)及能谱仪(EDS)等对不同温度下固溶处理高硅锰奥氏体不锈钢(UNS S21800钢)的晶间腐蚀进行了研究,分析了固溶处理和固溶+敏化处理两种工艺下进行晶间腐蚀试验后试样的组织形貌及晶间腐蚀倾向。研究结果表明:固溶处理后进行晶间腐蚀的试样中,表面均未发现裂纹,900℃固溶处理试样其晶界处存在较多的第二相,在950℃时第二相颗粒数量明显减少,当温度达到1200℃时,晶界附近已难以观测到第二相颗粒;经固溶处理+675℃敏化处理后进行晶间腐蚀试验的试样中,900℃固溶处理试样表面观测到有晶间裂纹存在,而固溶温度在950℃及其以上温度的试样未出现晶间裂纹。形成晶间裂纹原因是由于900℃固溶处理试样经过敏化处理后晶界处析出了更多的球状和长条状的富Cr碳化物,使得晶界附近区域形成了贫铬区,发生了晶间腐蚀;而950~1200℃固溶处理+敏化处理试样由于在固溶过程中第二相已大量溶入基体,虽然在敏化过程有部分析出,但不足以形成贫铬区,因此在该温度区间内难以发生晶间腐蚀行为。The intergranular corrosion of high silicon manganese austenitic stainless steel(UNS S21800)at different solution temperatures was studied by means of optical microscopy(OM),scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS).The microstructure and intergranular corrosion tendency of the samples after intergranular corrosion test were analyzed under solution treatment or solid solution+sensitization treatment.The results show that there are no cracks observed on the surface of the intergranular corrosion specimens after solid solution treatment.There are more second phases observed at the grain boundary of the 900℃solution treatment and the number of particles of the second phase is significantly reduced at 950℃.When the temperature reaches 1200℃,it is difficult to observe the second phase particles near the grain boundary;The intergranular crack is observed on the surface of the solution treated at 900℃among the specimens which employ intergranular corrosion test after solution treatment+675℃sensitization treatment.However,the intergranular crack doesn’t occur in the specimen with a solution temperature at 950℃or higher.The reason for the intergranular crack is that the spheroidal and long strips of(Cr,C)compounds are precipitated at the grain boundary after the sensitization treatment at 900℃,which makes the region of chromium delete near the grain boundary,and intergranular corrosion occurs.The solution treatment at 950-1200℃+sensitization treatment sample has been dissolved into the matrix in the solid solution process.Although it is analyzed in the sensitization process,it is not enough to form a chromium-depleted zone.So the intergranular corrosion behavior is hard to occur in this temperature range.

关 键 词：奥氏体不锈钢 固溶处理温度 敏化处理 晶间腐蚀 

分 类 号：TG156[金属学及工艺—热处理]