X70 管线钢在含氯环境中的点蚀萌生与扩展

Pitting Initiation and Propagation of X70 Pipeline Steel Exposed to Chloride-Containing Environments.

作者信息

Yang Zixuan, Kan Bo, Li Jinxu, Su Yanjing, Qiao Lijie, Volinsky Alex A

机构信息

Corrosion and Protection Center, Key Laboratory for Environmental Fracture (MOE), University of Science and Technology Beijing, Beijing 100083, China.

Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620, USA.

出版信息

Materials (Basel). 2017 Sep 13;10(9):1076. doi: 10.3390/ma10091076.

DOI:10.3390/ma10091076

PMID:28902156

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC5615730/

Abstract

Inclusion-induced pitting initiation mechanisms in X70 steel were investigated by scanning electron microscopy, scanning Kelvin probe force microscopy (SKPFM), immersion and electrochemical polarization tests in chloride-containing ion solutions. There are three inclusion types in the X70 steel. Corrosion test results indicated that pitting corrosion resistance of type A inclusion < type C inclusion < type B inclusion, i.e., (Mn, Ca)S < matrix < (Al, Ca)O. SKPFM test results show that the type A inclusion exhibited both lower and higher potentials than the matrix, while the type B inclusion exhibited higher potential than the matrix. The corrosion test and the SKPFM potential test results are consistent. Potentiodynamic polarization results indicate that the type A and C are active inclusions, while the type B is an inactive inclusion. Three kinds of possible mechanisms of inclusion-induced pitting corrosion are established for the X70 steel.

摘要

通过扫描电子显微镜、扫描开尔文探针力显微镜（SKPFM）、浸泡试验以及在含氯离子溶液中的电化学极化试验，研究了X70钢中夹杂物诱发点蚀的萌生机制。X70钢中有三种夹杂物类型。腐蚀试验结果表明，A型夹杂物的耐点蚀性能＜C型夹杂物＜B型夹杂物，即（Mn，Ca）S＜基体＜（Al，Ca）O。SKPFM试验结果表明，A型夹杂物的电位比基体低且高，而B型夹杂物的电位比基体高。腐蚀试验和SKPFM电位试验结果一致。动电位极化结果表明，A型和C型是活性夹杂物，而B型是惰性夹杂物。针对X70钢建立了夹杂物诱发点蚀的三种可能机制。