某石化公司制氢转化炉炉管在运行不到40 000 h后突然破裂起火,在经过宏观检测、表面探伤、力学性能测试,能谱、金相、电镜、X射线、应力等分析后得出结论:由于炉管材料晶界碳化物过多以及疏松空洞的存在削弱了韧性,产生了较多的微观裂纹,加上管外保温材料中存在较多的Na+、Cl-、K+、Mg2+、Ca2+,便在下猪尾管到下支耳之间的应力较大部位,发生应力腐蚀开裂,58号炉管首先开裂泄漏起火,其它炉管在外部火焰烘烤下短时高温损伤,并变形鼓包直至开裂,这是失效的主要原因和过程.针对失效原因提出了今后使用过程中应采取的防护措施.

Tubes for hydrogen generation furnace were burst and fired after operation for less than 40 000 in a petrochemical company.After macroscopical examination,surface inspection,machanical test,energy spectrum analysis,metallography analysis,electron microscopy inspection,X-ray analysis and stress analysis,it could be concluded that because of the excessive carbides at grain boundaries and the existence of loose cavities,the toughness was weakened,many microcracks were generated,additionally the existence of Na+,Cl-,K+ in the heat preservation material outside of the tubes,stress corrosion cracking occured between the outlet nozzle and the bottom support where rather high stress existed.The leak and fire occured in No.58 tube firstly,other tubes were damaged because of roasting in the exterior for short time,and then bulged and cracked at last.This was main reason of the breakage.Some preventive measures were suggested.