摘要
目的研究酸性土壤环境中剥离涂层下X80管线钢应力腐蚀行为及机理。方法采用电化学极化曲线测试、慢应变速率拉伸试验和腐蚀形貌扫描电子显微镜观察,对服役于鹰潭土壤环境的X80管线钢在剥离涂层下滞留液中的应力腐蚀行为及机理进行了分析研究。结果 X80管线钢在剥离涂层下的滞留液中具有一定的SCC敏感性,应力腐蚀开裂类型属于TGSCC,敏感性较大位置为近漏点处、剥离区中下部及剥离区底部,且近漏点处滞留液体系中X80钢的SCC机理受阳极溶解(AD)机制控制,剥离区底部滞留液中SCC机理受阳极溶解+氢脆(AD+HE)的混合机制控制。结论服役于酸性土壤中的X80管线钢在外防腐涂层破损后,除开放破损处将发生腐蚀外,剥离涂层下的管线钢还会存在一定的应力腐蚀敏感性。
Objective To study the stress corrosion cracking （SCC） behavior and mechanism of X80 pipeline steel in the simulated trapped solution of Yingtan-soil in China under disbonded coating. Methods The potentiodynamic polarization, slow strain rate test （SSRT） and corrosion morphologies examination by scanning electronic microscopy （SEM） were applied for the research. Results X80 pipeline steel had high SCC sensitivity in simulated trapped solution, and the corrosion type was TGSCC. The SCC susceptibility of X80 pipeline steel in trapped solution of near-breakage region, lower parts and bottom was higher than others. The mechanism in trapped solution of near-breakage region was controlled by anodic dissolution （AD）. And in trapped solution of bottom, the mechanism of X80 pipeline steel was mix-controlled by anodic dissolution and hydrogen embrittlement （AD＋HE）. Conclusion When a coating of X80 pipeline steel used in acid soil environment was disbonded, in addition to corrosion at the open breakage, stress corrosion cracking also occurred under the disbonded coating.
出处
《表面技术》
EI
CAS
CSCD
北大核心
2016年第7期1-7,共7页
Surface Technology
基金
国家重点基础研究发展计划(973计划
2014CB643300)
国家自然科学基金项目(51171025
51371036
51131001
51471034)
北京市青年英才计划资助~~
关键词
X80管线钢
酸性土壤
应力腐蚀(SCC)
剥离涂层
滞留液
X80 pipeline steel
acid soil
stress corrosion cracking （SCC）
disbonded coating
trapped solution
