船用E500钢在海水中阴极极化氢脆敏感性研究

Susceptibility to Hydrogen Embrittlement of E500 Steel for Vessel in Seawater

目的研究阴极保护电位对E500钢在海水中氢脆敏感性的影响。方法采用慢应变速率拉伸试验(SSRT),同时利用三电极体系进行不同电位极化,并结合扫描电镜进行试样断口观察。结果随着阴极保护电位负移,E500钢在海水中的氢脆敏感性增加,阴极保护电位为-0.95 V(vs.SCE)时,拉伸试样出现脆性解理断裂特征,电位为-1.00 V时,E500钢断口呈脆性断裂特征。结论根据氢脆系数拟合曲线得出,当氢脆系数达到25%时,E500钢最负阴极保护电位应为-0.913 V。

Objective To study influences of cathodic protection potential on susceptibility to hydrogen embrittlement （HE） of E500 steel in seawater. Methods Different polarization activities were investigated in seawater through three electrode elec-trochemical system under slow strain rate tests and combined with scanning electron microscopy （SEM） of fracture surfaces. Results The susceptibility to hydrogen embrittlement of E500 in seawater increased with the decrease of cathodic protection potential. The fracture surface of specimen after slow strain rate test exhibited cleavage brittle fracture at -0.95 V （vs.SCE）. E500 steel was subject to HE in sea water at -1.00 V. Conclusion According to the fitting curve of hydrogen embrittlement coefficient, when hydrogen embrittlement coefficient reaches 25%, the most negative cathodic protection potential for E500 steel should be -0.913 V.