应用光学显微镜、扫描电镜、光电子谱、显微硬度仪、铁素体测量仪等对开裂失效试样进行分析．结果表明，三通和法兰开裂失效是由于氢致开裂所致；同时也具有明显的氯化物应力腐蚀破裂敏感性． The cracking failure samples were analyzed by optical microscope, scanning electron microscope, photoelectron spectroscopy, microhardness tester and ferrite tester. The results show that the failure of tee and flange cracking is caused by hydrogen induced cracking, and also has obvious sensitivity to chloride stress corrosion cracking.