A Case Study of High Temperature Reheater Boiler Tube Failure

Several investigations on the failure of boiler tubes of thermal power plant have been carried out. This paper presents the failure analysis of a reheater tube of 210 MW thermal power plant. The reheater tube got damaged after service exposure a life of 1,65,900 hrs. The failed tube has a slit type opening with minor circumferential expansion at the rupture section. Scale was observed on the inside and outside surface of the tube. The scale formed on the outside and in-side surface of the tube was analysed through EDX and XRD to know the constituents of the scale and in evaluating the cause of failure of the tube. The tube was observed through its cross-sectional for the wall thinning. The area around the failed reheater tube sample was prepared and studied for structural degradation; hardness mapping was also carried out on the tube to find the cause of failure.