冷变形对国产X70管线钢硫化氢应力腐蚀开裂的影响

采用慢应变速率法SSRT(Slow Strain Rate Test)测试了在含H2S的介质中不同冷变形度条件下管线钢X70的硫化氢应力腐蚀开裂(SCCC)性能.结果表明,冷变形度是影响国产X70管线钢SSCC的重要因素之一.冷变形促进了材料局部微观缺陷内能的增加,这些缺陷所在的位置,往往是氢易被捕捉的地方,造成氢的聚集,微观变形将会促进裂纹的萌生和扩展.同时,随着冷变形度的增加,冷变形造成的位错等缺陷使强度进一步增大而韧性降低.最终氢与应力的交互作用导致X70管线钢抗SSCC性能下降.

Effect of Cold Work on Sulfide Stress Corrosion Cracking for Domestic Pipeline Steel X70

SSRT(Slow Strain Rate Test) was adopted to study the effect of cold work on the SSCC(Sulfide Stress Corrosion Cracking) of pipeline steel X70 in the sulfide solution. The results show that the cold work plays an important role in corrosion of high strength pipeline steels, it will bring about a deal of microstructure change all that are in state of higher energy. Hydrogen atoms aggregate easily on those locations, and hydrogen permeation increases. Meanwhile, higher strength caused by cold work is increased, but toughness is decreased. Finally, the corrosion resistance for domestic pipeline steel X70 is decreased by the interaction of stress and hydrogen.