高锰奥氏体低温钢HM400在液氨介质中的应力腐蚀敏感性研究

Study on Stress Corrosion Susceptibility of High Manganese Austenitic Cryogenic Steel HM400 in Liquid Ammonia Medium

为研究高锰奥氏体低温钢HM400在液氨介质中的应力腐蚀敏感性,采用慢应变速率试验(SSRT)考察了高锰奥氏体低温钢HM400在常温下,液氨环境(NH_(3))、空气+液氨环境(NH_(3)+Air)、0.1 mg/L H_(2)O+液氨环境(NH_(3)+0.1 mg/L H_(2)O)及对照组空气(Air)4种介质中的应力腐蚀敏感性,通过扫描电镜(SEM)、金相显微镜、X射线衍射(XRD)和硬度计分别表征了试样断口微观形貌、裂纹形貌、试验前后试样金相组织及力学性能的变化。结果表明:高锰奥氏体低温钢HM400在拉伸变形中发生了应变强化;HM400钢在液氨介质中耐应力腐蚀能力差,不宜作为液氨储运容器高参数化和轻量化用材。

For studying the stress corrosion susceptibility of high manganese austenitic cryogenic steel HM400 in liquid ammonia medium,the slow strain rate test(SSRT)was used to investigate the stress corrosion susceptibility of high manganese austenitic cryogenic steel HM400 in four media:pure liquid ammonia(NH_(3)),air+liquid ammonia(NH_(3)+Air),0.1 mg/L H_(2)O+pure liquid ammonia(NH_(3)+0.1 mg/L H_(2)O)and air(Air)at room temperature.The fracture micro morphology,crack morphology,change of microstructure and mechanical properties of the samples before and after tests were characterized by scanning electron microscope(SEM),optical microscope(OM),X-ray diffractometer(XRD)and hardness tester.Results showed that strain strengthening occurred in high manganese austenitic cryogenic steel HM400 during ten-sile deformation.Moreover,HM400 steel possessed poor stress corrosion resistance in liquid ammonia medium,and hence it was not suitable as high parameterization and lightweight materials of liquid ammonia storage and transportation containers.