An Investigation on the Causes of Failure in A210 Carbon Steel Boiler Tubes in an Oil Refinery

As boilers are subjected to corrosive streams and harsh operating conditions, their tubes are susceptible to corrosion and failure by different damage mechanisms. In the current study, the causes of cracking and failure of connection tubes of a boiler header are studied. These tubes were connected between the primary and secondary headers of the boiler and according to the design information were constructed of ASTM A210-A1 carbon steel. There were two cracked tubes wherein one of them had a crack in a weld HAZ region and another had a crack in the base material. To investigate the failure, different microscopical and analytical techniques such as SEM and mechanical tests were used. The results of analysis showed that the material of construction was in accordance with the design specification. Considering the cracks dagger-shaped appearance, it was concluded that thermal fatigue due to the operation conditions and utilization of water spray cooling technique was the main cause of the failure.