Failure analysis of AISI 310S plate in an inert gas generator used in off-shore oil platform

In this work a failure analysis was conducted in a mirror plate made of austenitic stainless steel AISI 310. The mirror is part of the inert gas generator, which is a combustion chamber dedicated to produce inert gas atmosphere (N2 + CO2) to be used during the oil transfer in off-shore platforms. The mirror failed in two distinct regions. The first crack was observed in a region where the temperatures reached were sufficiently high to provoke intense sigma phase precipitation. Other cracks were observed in a region subject to seawater refrigeration, named “cold zone”. These two failures were mitigated in order to propose solutions to avoid similar failures in the new equipment.

► Mirror plate of ASI 310 steel failed in two regions.
► Sigma phase precipitation was observed in the high temperature zone.
► Intergranular chromium carbides were observed in the low temperature zone.
► Thermal fatigue and stress corrosion cracking were identified.