0Cr25Ni20管道焊接接头的失效分析

Failure Analysis on Butt Welded Joint Between 0Cr25Ni20 Pipes

利用扫描电镜和光学显微镜等实验手段,对某石化装置0Cr25Ni20管道的焊接接头服役后发生的开裂进行了失效分析。结果发现,焊接接头的错边、未焊透以及表面成形不好导致焊缝应力集中,加之管道输送介质中的氯离子,造成了焊接接头的应力腐蚀开裂;在敏化温度区间的长时间工作也造成了焊接接头的部分晶间腐蚀。

The failure analysis and fractography of welded joint between two 0Cr25Ni20 pipes in a petrochemical equipment fractured after service were studied by scanning electron microscopy and optical microscopy. The results show that the mismatching and poor surface forming of the welded joints, incomplete penetration and chloride medium in pipeline can induce the stress corrosion cracking. The intergranular corrosion may be induced when the joint was exposed to the sensitization temperature range for a long time.