通过金相检验、断口分析以及腐蚀产物能谱分析等方法，对某石化公司环氧乙烷精制塔开裂的原因进行了分析。结果表明：材料在焊接过程中，焊接热影响区的组织受到敏化影响，铬的碳化物沿晶界析出，造成该区域贫铬，从而在应力和腐蚀介质的共同作用下，发生了晶间腐蚀开裂。最后提出了相应的预防措施。

The cracking reason of ethylene oxide evaporator in one petrochemical company was studied by means of metallographic examination, fracture analysis of the failure samples, energy spectrum analysis of the corrosion product and so on. The results showed that the microstructure near the welding heat affected zone was sensitized due to the welding process, which led to the precipitation of chromium carbide along grain boundary and the lack of Cr precipitation near grain boundary. Furthermore, under the combined action of the stress and corrosive medium, the intergranular stress corrosion cracking took place in welding heat affected zone of the ethylene oxide evaporator.