摘要
用U形试样浸泡试验和慢应变速率拉伸试验(Slow strain rate test,SSRT)方法,结合断口形貌的扫描电子显微镜观察,研究3Cr17Ni7Mo2SiN不锈钢在硫化氢介质中的应力腐蚀开裂(Stress corrosion cracking,SCC)行为。研究表明:3Cr17Ni7Mo2SiN不锈钢在2.7≤pH≤4.5、H2S质量分数大于0.1%的含Cl–介质中均具有明显的SCC敏感性,SCC萌生的孕育时间随溶液pH的升高或H2S质量分数的降低而增长。在pH较低(pH=2.7)的条件下SCC扩展较快,开始阶段以沿晶形式扩展,然后过渡为穿晶模式;当溶液pH较高(pH=4.5)时,SCC主要以阳极溶解模式扩展、裂尖钝化明显、裂纹扩展速率较慢。夹杂物的存在、氢致开裂(Hydrogen induced cracking,HIC)作用和点蚀均能促进3Cr17Ni7Mo2SiN不锈钢的SCC的发生。
Sulfide stress corrosion cracking(SCC) behavior of 3Cr17Ni7Mo2SiN stainless steel(SS) is investigated by using slow strain rate test(SSRT),U-bent specimen immersing test and fractography observation by scanning electronic microscopy(SEM).3Cr17Ni7Mo2SiN SS is subject to SCC in test solutions containing NaCl(5% in mass) and H2S(no less than 0.1%) within pH range of 2.7 to 4.5.The time to SCC occurrence of 3Cr17Ni7Mo2SiN SS increases with the rising of pH or with the lowering of mass fraction of H2S.SCC under a low pH(pH=2.7) condition grows faster than that under a high pH condition,which initiates in an intergranular mode and then propagates transgranularly,however,in a high pH(pH=4.5) solution,SCC growth is slow with a blunt cracktip due to anodic dissolution mechanism.Inclusions,effects of hydrogen induced cracking(HIC) and corrosion pits will promote the occurrence of SCC.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2011年第6期62-68,共7页
Journal of Mechanical Engineering
基金
国家自然科学青年基金资助项目(50901041)
关键词
不锈钢
硫化氢
应力腐蚀开裂
Stainless steel Hydrogen sulfide Stress corrosion cracking(SCC)
