硫化氢环境中17-4PH钢抗氢致开裂与应力腐蚀开裂性能

Resistances to SCC and HIC for 17-4PH Steel in H_2S Environment

根据美国NACE标准研究了17-4PH钢在酸性H2S水溶液中的抗氢致开裂(HIC)和应力腐蚀开裂(SCC)的性能,利用光学显微镜及扫描电镜(SEM)观察了裂纹及组织形貌,并结合理论分析了材料的氢致开裂与应力腐蚀开裂行为。结果表明:17-4PH钢在标准NACE试验溶液中会产生氢致裂纹,试样内部微裂纹主要在晶界、夹杂等缺陷处成核并扩展;标准C型环试样在0.8σs的恒应力作用下,浸泡于饱和硫化氢溶液中,720h内3组试样均发生断裂,表明其SCC敏感性较大,试样的宏观裂纹由边缘向内部扩展;扫描电镜结果显示,SCC断口有明显的脆性断裂(解理断口)特征,应力腐蚀开裂是由HIC引起,且裂纹扩展形式多为穿晶型。

According to the American NACE standard the resistances of 17-4PH steel to hydrogen induced cracking （HIC） and stress corrosion cracking （SCC） in wet H2 S environment were studied, and the microstructure and cracks were observed using optical microscopy and scanning electronic microscopy （SEM）. The HIC and SCC behaviors were analyzed in combination with theoretical analysis. The results show that the hydrogen induced cracks appeared in the 17-4PH steel in standard NACE test solution, the internal micro-cracks formed and grew in boundaries, inclusions and other defects mainly. Within 720 hours, three standard C-ring specimens were broken under the constant load stress of 0. 8σ in a saturated solution of hydrogen sulfide, indicating the high susceptibility to SCC of the specimens, and macroscopic cracks extended from sample edge to the inside. SEM examination show that SCC fracture was distinguished by brittle fracture. Stress corrosion cracking was caused by HIC, most cracks extended as transgranular forrlL