Abstract: Some furnace tubes made of the austenitic stainless steel 1Cr18Ni9Ti for heating crude oil ex- hibited leakage and were on fire in a refinery.Cor- rosion failure analysis was conducted to explore the cause of failure.Macro-and microexamination in- dicated the failure to be stress corrosion cracking by chloride and sulphide with cracks initiating on the inner surface in weld or heat affected zone.Veri- fying tests demonstrated that the cracks occurred during operating period.The cause of failure was related to the critical situation of the refinery:lack of desalination equipment,lots of steam with liquid film on inside tube walls owing to mixing crude oil with a great amount of water,increasing decompo- sition of inorganic salts and lowering the tempera- ture in furnace tubes.

Key words: stress corrosion cracking, failure analysis, chloride, hydrogen sulphide