冷轧变形对Ti425钛合金耐蚀性能的影响  

Effect of Cold Rolling Deformation on Corrosion Resistance of Ti425 Titanium Alloy

作　　者：赵佩文 程晓英[1] 汪犁 彭浩 蔡贞祥 ZHAO Peiwen;CHENG Xiaoying;WANG Li;PENG Hao;CAI Zhenxiang(Institute of Materials Science,Shanghai University,Shanghai 200072,China)

机构地区：[1]上海大学材料研究所,上海200072

出　　处：《上海金属》2022年第3期21-27,共7页Shanghai Metals

摘　　要：研究了Ti425钛合金不同变形量冷轧后的显微组织与残余应力变化,并通过在模拟油气管服役环境中的电化学测试、浸泡腐蚀以及应力腐蚀试验,研究了冷轧变形量对合金耐蚀性能的影响。结果表明:随着冷轧变形量的增加,α板条厚度逐渐减小,α板条和β相结构出现扭结。残余应力随距表面深度的不同而变化,不同变形量试样表面均呈现残余压应力。20%和30%变形量试样内部为残余拉应力且晶粒尺寸不均匀;40%和50%变形量试样内部仍为残余压应力且晶粒尺寸较均匀;未变形试样由于热处理等因素,其内部仍存在残余拉应力,且随深度的增加变化较平缓。不同冷轧变形量试样的自腐蚀电位与容抗弧半径的大小顺序为50%>40%>0>20%>30%;自腐蚀电流密度则表现为相反的规律。不同变形量试样表面的腐蚀严重程度及抗应力腐蚀性能与自腐蚀电位的变化规律相同。The changes in microstructure and residual stress in Ti425 titanium alloy after cold rolling to different deformation extents were studied,and the effects of cold rolling deformation on corrosion resistance of the alloy were studied through the electrochemical test,immersion corrosion test and stress corrosion test in a simulated service environment of oil and gas pipes.The results showed that with the increase in cold rolling deformation,the thickness ofα-lath decreased gradually,and the structure ofα-lath andβ-phase kinked gradually.The residual stress varied with the depth from the surface.The surface of samples deformed to different extents all presented compressive residual stress.The samples deformd to 20%and 30%presented tensile residual stress in the interior and uneven grain size,whereas the samples deformed to 40%and 50%presented compressive residual stress in the interior and relatively uniform grain size.Due to heat treatment and other factors,the tensile residual stress still existed in the interior of undeformed sample,and changed gently with the increase in depth.The order of selfcorrosion potential and capacitive arc radius of samples cold rolling to different deformation extents was 50%>40%>0>20%>30%;the self-corrosion current density showed the opposite rule.The rules variation in corrosion severity and stress corrosion resistance of the samples deformed to different extents were the same as that of self-corrosion potential.

关 键 词：钛合金 油气管道 冷轧变形 腐蚀 电化学 

分 类 号：TG172[金属学及工艺—金属表面处理]