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采用BL-WOL楔力加载平面应变断裂试样,研究了GC-4(40 CrMnSiMoVA) 超高强度钢在3.5％NaCl溶液和蒸馏水中的应力腐蚀裂纹扩展特性,测定了不同试验条件下的应力腐蚀开裂门槛值K_(ISCC)和裂纹扩展速度(da/dt)_(II)。结果表明,在环境介质中的应力强度因子门槛值K_(ISCC)仅及该钢断裂韧性K_(IC)的1/5～1/4。介质成份、电极电位、环境温度及热处理规范等都对裂纹扩展速度(da/dt)_(II) 有显著影响。分析表明,氢脆是导致GC-4.钢应力腐蚀开裂的重要原因之一。
The stress strain corrosion cracking of GC-4 (40 CrMnSiMoVA) ultra-high strength steel in 3.5% NaCl solution and distilled water was investigated by BL-WOL wedging. The stress corrosion cracking under different test conditions Cracking threshold K_ (ISCC) and crack growth rate (da / dt) _ (II). The results show that the stress strength factor K_ (ISCC) in the environment medium is only 1/5 ~ 1/4 of the fracture toughness K_ (IC) of the steel. Dielectric composition, electrode potential, ambient temperature and heat treatment specifications have a significant effect on the crack growth rate (da / dt) _ (II). The analysis shows that hydrogen embrittlement is one of the important causes of GC-4 steel stress corrosion cracking.