Failure analysis of stainless steel tubes in a recuperator due to elevated temperature sulphur corrosion

An attempted has been made to unravel the exact reasons for premature failure of stainless steel tubes inside a recuperator used for preheating air for combustion inside a slab-reheating furnace of a Hot Strip Mill. Analysis suggests that the tubes failed due to sulphidation. Suitable materials have been recommended which could exhibit superior life and measures to minimize the adverse effects of the environment at the operating temperature.