【摘要】 采用电化学测试和慢应变速率实验（SSRT）研究了国产X70管线钢在近中性pH和高pH溶液中的应力腐蚀破裂（SCC）行为。结果表明,X70钢在高pH溶液和近中性pH溶液中的阳极极化曲线表现出明显的差异:在高pH溶液中有明显的活化-钝化转变而在近中性pH溶液中则无;在近中性pH溶液中,X70管线钢的开裂模式是穿晶型的,具有准解理特征,并且随着外加阴极电位的降低,SCC敏感性增加。氢致破裂占主导;随温度的下降以及溶液中CO₂含量的增加,溶液pH值降低,SCC敏感性增加。在高pH溶液中,在阴极极化时,X70钢表现出与在近中性pH溶液中类似的破裂行为和特征,即SCC敏感性随电位降低而增大,裂纹数目少而大,裂纹易扩展;但在阳极极化时,裂纹数目多而小,易萌生但难扩展。在2种溶液中阳极极化时,均存在SCC敏感电位区。更多还原

【Abstract】 The stress corrosion cracking （SCC） behaviors of home-made X70 pipeline steel in near-neutral pH and high pH solutions were studied using electrochemical measurement and slow strain rate testing （SSRT）. The anodic polarization curves showed different features in near-neutral pH and high pH solutions in terms of active-passive transition behavior. In near-neutral pH solutions, the cracking mode was transgranular with the feature of quasicleavage; the susceptibility to SCC increased with decreasing potential, pH and temperature as well as increasing CO₂, indicating a dominated mechanism of hydrogen induced cracking（HIC）. In high pH solutions, the cracking behavior was similar to that in near-neutral pH solutions when the specimens were polarized in the cathodic direction, but quite different when polarized in the anodic direction.更多还原