奥氏体不锈钢三通开裂原因分析

CAUSE ANALYSIS OF THE CRACK IN AUSTENITIC STAINLESS STEEL

通过对深冷条件下使用的奥氏体不锈钢三通产生的裂纹进行分析,认为裂纹是由氯离子引起组织结构变化进而产生了内应力引起的应力腐蚀裂纹。产生组织内应力的原因是由于三通中氯离子的存在导致金相组织存在大量的形变马氏体(即“α”马氏体)和相变马氏体。分析表明:低温下使用的亚稳定奥氏体不锈钢,不仅要严格控制其化学成分、力学性能,还要通过金相分析检验其组织形态,并提出在三通件上进行硬度测试和金相检验的最合理位置。

Based on the analysis of crack in austenitic stainless steel used in extraordinary cool circumstance, the stress corrosion crack is caused by chlorine, which results in structure inherent force. The analysis indicates that for stainless steel being used in low tempera- ture, not only its chemical composition and mechanical property should be strictly controlled, but also its structure should be analyzed based on metallurgical test. The most suitable position for hardness test and metallurgical test are also proposed.