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在恒定阴极电位下利用慢应变速率拉伸试验研究高强度船体结构钢焊缝的电化学性能和力学性能。结果表明,试样拉伸断裂主要发生在焊缝的熔合区;结构钢的阴极极化程度对抗拉强度和屈服强度的影响不大;随阴极电位负移,船体结构钢在海水中的延伸率、断裂时间和断裂应变率逐渐减小,并且当施加阴极电位为-0.89 V(vs SCE)时各项性能最佳。同时,随着阴极电位负移,断裂方式逐渐从韧性断裂向脆性断裂发展,氢脆敏感性逐渐增加,在-0.70 V～-0.89 V(vs SCE)之间氢脆敏系数低于5%,不发生氢脆;当电位负于-0.94 V(vs SCE),氢脆敏感性迅速提高,当极化电位为-0.99 V(vs SCE)时氢脆系数显著增大至20%,断口开始出现解理单元细小准解理断裂特征;在负于-1.04 V(vs SCE)时,氢脆系数已高于25%,进入危险区,且断口开始出现较多解理单元粗大的准解理、解理等氢脆断裂特征;随着电位继续负移至-1.14 V(vs SCE),断口完全出现解理组织、沿晶、穿晶结构或者两者混合的氢脆断裂特征。
Study on Electrochemical and Mechanical Properties of Welded Seams of High Strength Hull Structural Steel at Constant Cathodic Potential with Slow Strain Rate Tensile Test. The results show that tensile fracture of the specimen mainly occurs in the fusion zone of the weld. The degree of cathodic polarization of the structural steel has little effect on the tensile strength and yield strength. With the cathodic potential negative shift, the elongation of the structural steel in seawater , The fracture time and fracture strain rate decrease gradually, and the best performance is obtained when the cathode potential is -0.89 V (vs SCE). At the same time, as the cathodic potential shifts negatively, the fracture mode gradually develops from ductile fracture to brittle fracture, and the sensitivity of hydrogen embrittlement increases gradually. The hydrogen embrittlement coefficient is below 5% between -0.70 V and -0.89 V (vs SCE) Hydrogen embrittlement did not occur when the potential was negative than -0.94 V (vs SCE), the hydrogen embrittlement susceptibility increased sharply to 20% when the polarization potential was -0.99 V (vs SCE), and the fracture began to appear Cleavage unit is fine quasi-cleavage fracture characteristics; when negative to -1.04 V (vs SCE), the hydrogen embrittlement coefficient is higher than 25%, into the danger zone, and fracture began to appear more clever cleavage unit coarse quasi-cleavage, Cleavage and other hydrogen-brittle fracture characteristics. As the potential continues to negative shift to -1.14 V (vs SCE), the fractures are completely characterized by cleavage structure, intergranular, transcrystalline structure or a mixture of the two.