大型电站用中强钢氢致开裂模式探讨

在低应变速率条件下对不同氢含量的大型电站用中强钢氢致开裂行为进行了研究。结果表明，此类中强钢具有与高强钢不同的氢致开裂模式──随钢中氢含量增加而相继表现出微孔聚合式韧性开裂、变态脆化的微孔聚合式开裂和低能解理式脆性开裂。此模式的主要控制因素为氢在裂尖区域的定向迁移。

INVESTIGATION ON THE MODE OF HYDROGEN-INDUCED GRACKING FOR MEDIUM STRENGTH STEEL

The hydrogen-induced cracking behavior of large section medium strength steels with various hydrogen contents were investigated by means of the strain rates.The results show that the medium strength steels have the special forms of hydrogeninduced cracking (HIC) which differ from high-strength steels.With the varing of hydrogen contents from low to high,HIC is first normal tough cracking of microvoid coalescence; then Particular embrittlement cracking of microvoid coalescence; and finally low energy rapid cleavage cracking. This mode of the medium strength steels hydrogen-induced cracking are controlled by hydrogen-removemet process at the crack tip along certain direction.