为找出液氢槽车不锈钢管道开裂原因，从宏微观形貌、化学成分、腐蚀产物、金相组织对裂纹及其断面进行了分析。结果表明：法兰基材碳化物含量过高，且焊缝返修使得热影响区重复受热，致使碳化物沿晶界大量析出，导致材料耐晶间腐蚀能力下降，在氯离子和应力作用下发生脆性延迟断裂。建议从设计、选材、施工、表面改性、监测等方面对不锈钢焊缝热影响区应力腐蚀进行预防。

In order to find the reasons for cracking of stainless steel pipe in a liquid hydrogen transport vehicle, a series of analysis were conducted for the cracks and fracture surface in terms of macro and micro morphology, chemical composition, corrosion products and metallurgical structure. The results show that high carbide content in flange material and repeated heating of weld heat affected zone (HAZ) because of welding repair were the reasons which caused carbide precipitation along grain boundaries and thus led to the decrease of intergranular corrosion resistance. And then a brittle delay fracture happened to the stainless steel pipe in a chloride and stress environment. It was suggested that the stress corrosion (SC) in the HAZ of stainless steel welded joint must be prevented in aspects of design, material selecting, construction, surface modification and monitoring.