A failure study of condenser tube manufactured from low nickel stainless steels

A failure analysis of condenser tubes manufactured from Type 204 stainless steel was conducted to find the root cause of failures. The failures were observed in the parent materials of the tube rather than from welding or heat-affected zones. A detailed metallography, corrosion test and stress analysis study has been carried out to find out the root cause of failure, and it revealed that the parent materials of the tube were highly sensitized, and post-annealing treatment had been not performed by the manufacturers. The condenser tube failed prematurely due to sensitization and the presence of thermal residual stresses exacerbates this. This study emphasizes the metallurgical analysis performed to identify the root cause of failure of condenser tubes manufactured from Type 204 stainless steel.

► Failures of condenser tubes took due to sensitization and presence of residual stresses.
► Initially cracks proceed intergranular and later on it shifted to transgranular.
► Corrosion rate of Type 204SS is high compared to standard grade such as Type 304SS.
► Type 204SS can be used as an alternative of Type 304SS in non-hostile environments.