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本文研究了12MnMoVNbTi低合金钢在饱和H_3S溶液中的极化和应力腐蚀行为,并与电解充氢条件下的应力破裂行为进行了对比。证明钢中Mo、Nb含量的变化与热处理条件的不同对其一般腐蚀行为影响很小,但能显著改变其抗应力腐蚀性能,12MnMoVNbTi钢在H_2S介质中的应力腐蚀破裂行为与它们在充氢条件下的应力破裂行为非常类似,显示其应力腐蚀破裂的实质是氢脆。充氢条件下应力弛豫和恒载荷拉伸试验结果表明,氢有引起钢的软化和硬化的双重作用。由于氢的进入所产生的软化作用使钢在屈服强度以下发生塑性变形,但随后的硬化过程又使变形速度逐步减慢。这种由氢的作用引起的在较低应力下发生的塑性变形过程并不直接导致断裂,但塑性变形行为和氢应力破裂行为之间的关系表明,这种变形过程中的位错运动能够帮助氢的移动和向塑变区及裂纹尖端集中,促进氢脆断裂。
In this paper, the polarization and stress corrosion behavior of 12MnMoVNbTi low alloy steels in saturated H_3S solution were studied and compared with the stress rupture behavior under the condition of electrolytic hydrogen charging. It is proved that the variation of Mo and Nb content in steel and the difference of heat treatment conditions have little effect on the general corrosion behavior but can significantly change the stress corrosion resistance. The stress corrosion cracking behavior of 12MnMoVNbTi steel in H 2 S medium and their hydrogen storage conditions Under the stress rupture behavior is very similar, showing that the essence of stress corrosion cracking is hydrogen embrittlement. Hydrogen charging stress relaxation and constant load tensile test results show that hydrogen can cause steel softening and hardening of the dual role. Due to the softening effect caused by the entry of hydrogen, the steel undergoes plastic deformation below the yield strength, but the subsequent hardening process in turn causes the deformation rate to slow down gradually. This plastic deformation process under the low stress caused by the action of hydrogen does not directly lead to the fracture, but the relationship between the plastic deformation behavior and the hydrogen stress rupture behavior shows that the dislocation movement in this deformation process can help Hydrogen movement and to the plastic zone and crack tip concentration, and promote hydrogen brittle fracture.