300 series stainless steel heater tubes in an oil-burning furnace in the hydrocracker began to leak and the furnace was brought down. What was the probable cause of the cracking?

Question

Quizplus · Accepted Answer

Polythionic acid stress corrosion is a common cause of cracking in stainless steel components in environments where sulfur compounds are present, such as in oil refineries. The presence of sulfur can lead to the formation of polythionic acids, which can cause stress corrosion cracking in stainless steel.

300 Series Stainless Steel Heater Tubes in an Oil-Burning Furnace