阴极极化对10Ni9CrMoV高强钢氢脆敏感性的影响

采用电化学测试﹑慢应变速率拉伸实验(SSRT)并结合断口形貌观察,研究了海水环境中阴极极化对10Ni9CrMoV钢氢脆敏感性的影响。结果表明:随阴极极化程度加强,阴极反应控制步骤逐步由氧的去极化反应转变为氢的去极化反应;随阴极极化电位负移,10Ni9CrMoV钢的强度没有明显变化,但其断面收缩率和伸长率均减小,断口形貌由韧窝型韧性断裂向解理断裂转变,氢脆敏感性提高;当极化电位为-926 mV时,氢脆系数达到25%,说明10Ni9CrMoV钢在海水中的最高保护电位为-926 mV。

Effect of cathodic polarization on hydrogen embrittlement susceptibility of 10Ni9CrMoV high strength steel

The effects of the cathodic polarization potential on the hydrogen embrittlement susceptibility of 10 Ni9 CrMoV steel in seawater were studied using a slow strain rate tensile test(SSRT) combined with observation of the fracture morphology and electrochemical measurements. The results show that the rate controlling step of the cathode reaction changes from the oxygen depolarization reaction to the hydrogen depolarization reaction. With the negative shift in the polarization potential, the sample’s reduction of area and elongation decrease, and the fracture surfaces of the specimens display a transition from ductile microvoid coalescence to cleavage;however, the strength of the 10 Ni9 CrMoV steel does not change significantly. The hydrogen embrittlement coefficient reaches a threshold of 25%, while the polarization potential is approximately-926 mV(vs. SCE). In conclusion, the limiting cathodic protection potential of 10 Ni9 CrMoV steel in a seawater environment is-926 mV.