Corrosion Analysis of Condensate Collector Head of Ethylene Glycol Device Evaporator

A lots of cracks appeared on the internal and external surface of the straight flange in a condensate collector head of ethylene glycol device evaporation system. The composition, microstructure, corrosion situation and cracks of the head were analyzed by spectrometer, metallurgical microscopy, SEM and XRD. The results show that the material of the head is 0Cr18Ni9 stainless steel, and the cracks on the internal and external surface were attributed to the pitting caused by enriched Cl- existing in the deformation martensite of the straight flange of the head. Subsequently, the Cl- pitting induced stress corrosion cracking of the material. In addition, the selective dissolution of martensite promoted the crack growth. According to the analyses, several reasonable suggestions about heat treatment and material selection were put forward.