2205双相不锈钢在酸性H_2S环境下的应力腐蚀行为及开裂机理

Stress Corrosion Behavior and Cracking Mechanism of 2205 Duplex Stainless Steel in Acidic H_2S Environment

采用C型环实验研究了2205双相不锈钢在饱和H_2S环境下的应力腐蚀行为及开裂机理。结果表明,2205双相不锈钢在NACE标准A溶液中具有良好的抗应力腐蚀能力。通过OM、SEM、EDS及电化学手段分析得出2205双相不锈钢的应力腐蚀开裂经历了表面点蚀、蚀坑形成、H_2S解离、H原子吸附并从蚀坑位置扩散进入金属基体,在金属基体中聚集,通过氢致开裂机制导致裂纹萌生,并逐渐扩展。

Stress corrosion behavior and cracking mechanism of 2205 duplex stainless steel（DSS） in saturated H_2S environment were studied by C-rings Stress Corrosion Cracking Test. The results show that 2205 DSS has good resistance to stress corrosion in Test Solution A of NACE Standard. Through OM, SEM, EDS and electrochemical analysis, we find that stress corrosion cracking in 2205 DSS undergoes the following procedures： pitting corrosion on surface, formation of corrosion hole, dissociation of H_2S, absorption of H atoms and their diffusion from corrosion hole to inner metal, then gathering at some place in matrix, finally initiation of cracks by hydrogen induced cracking mechanism and their gradual propagation.