| 摘要: |
| 采用动电位扫描、慢应变速率拉伸、氢渗透试验方法对X70管线钢在不同电位下含不同浓度H2S的质量分数3.5%NaCl溶液中的应力腐蚀开裂行为进行了研究。结果表明,H2S的加入使渗氢电流逐渐增大,硫化物应力腐蚀开裂(SSCC)敏感性逐渐增加,随着H2S浓度的增大,其断裂特征由塑性断裂逐渐转变为脆性断裂。在阳极极化下,X70管线钢无SSCC敏感电位区;在阴极极化程度较小时,材料对SSCC的敏感性减小;在阴极极化程度较强时,材料对SSCC的敏感性显著增加。分析表明X70管线钢的SSCC受阳极溶解和氢脆共同控制。 |
| 关键词: 硫化物应力腐蚀开裂 慢应变速率拉伸 氢渗透 |
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| 基金项目:中国石油天然气集团公司石油管力学和环境行为重点实验室资助项目 |
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| Stress corrosion cracking of X70 grade line pipe steel in H2S aqueous solutions |
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| Abstract: |
| Susceptibility to stress corrosion cracking of X70 grade line pipe steel in 3.5%NaCl aqueous solutions containing H2S was investigated by means of the potentio dynamic polarization curve, slow strain rate and hydrogen permeation measurement. The results showed that the presence of H2S would cause ductility loss. With increasing H2S concentration, the hydrogen permeation current density and susceptibility to sulfide stress corrosion cracking( SSCC) are increased. No SSCC was observed at an applied anodic potential. When cathodically polarized greatly, the susceptibility to SSCC increased remarkably. However, when cathodically polarized weakly, the susceptibility to SSCC decreased and steel was protected because anodic dissolution was inhibited. The study of the effects of the concentration and potential on susceptibility to SSCC suggested that the mechanism of SSCC for X70 grade line pipe steel is controlled by anodic dissolution and hydrogen embrittlement. |
| Key words: Sulfide stress corrosion cracking slow strain rate test hydrogen permeation |
