Comparative study on the stress corrosion cracking of X70 pipeline steel in simulated shallow and deep sea environments

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• 作者：Feilong Sun^a ; ^b ; ^c ; ¹ ; Shuai Ren^a ; ^b ; ¹ ; Zhong Li^d ; Zhiyong Liu^a ; ^b ; ^{liuzhiyong7804@ustb.edu.cn} ; Xiaogang Li^a ; ^b ; Cuiwei Du^a ; ^b
• 关键词：Pipeline steel ; Polarization ; SEM ; Stress corrosion
• 刊名：Materials Science and Engineering: A
• 出版年：2017
• 出版时间：8 February 2017
• 年：2017
• 卷：685
• 期：Complete
• 页码：145-153
• 全文大小：6470 K
• 卷排序：685

文摘

The stress corrosion cracking (SCC) behavior of X70 steel in simulated shallow and deep sea environments was studied using potentiodynamic polarization measurement, a slow strain rate tensile (SSRT) test and scanning electron microscopy (SEM). The results indicate that the predominant cathodic reaction changes from an oxygen reduction reaction to the hydrogen evolution reaction as the dissolved oxygen (DO) content decreases. In the simulated deep sea environment, the SCC susceptibility of X70 steel decreased first, reached its lowest point at 15 MPa and then increased as the simulated sea hydrostatic pressure (HP) further increased. This is consistent with the regularity for the change of the cathodic hydrogen evolution reaction current density iH at Ecorr, which indicates that the HP may influence the SCC susceptibility of X70 steel by changing the permeated hydrogen concentration.