低碳钢在模拟含SO_2海洋大气中的氢致开裂机理

摘要

Mechanism of hydrogen induced cracking of carbon steel was investigated by Devnathan-Stachurski double electrolytic cell and slow strain rate test（SSRT） in simulated atmospheric environment containing SO2.The fracture strain decreased with increasing the concentration of SO2 at the same strain rate 6.67×10-7S-1.The SEM fractographs of the specimens also showed that the susceptibility to stress corrosion cracking（SCC） increased with increasing the concentration of SO2.The hydrogen permeation test showed that hydrogen permeation current increased with increasing the concentration of SO2.H2SO3 hydrolyzed to H＋ was the reason of the appearance of the first peak value of current.Regeneration of acid induced the second peak value of current.%在模拟海洋大气环境中,采用电化学渗氢试验及慢应变速率拉伸方法,研究了SO2的存在对于低碳钢发生应力腐蚀断裂的影响及SO2的存在对氢渗透行为的影响。结果表明,随着SO2浓度的增大,试样断裂敏感性增大;SEM表明,其断裂特征由塑性断裂逐渐转变为脆性断裂。电化学渗氢试验表明,随着SO2浓度的增大,氢渗透电流增大,SO2对氢渗透电流具有双重促进作用,第一个峰值的出现主要与SO2的酸性有关,第二个峰值的出现主要是由于酸的再生循环导致。