Inferior Material Failures Available to Purchase

Three failures due to inferior material are discussed. In all cases, the specified material was 2-1/4 Cr-1 Mo and the installed material was carbon steel. A carbon steel girth weld in a hot reheat steam line failed after approximately 102,000 hours of service. The fracture was in the weld metal adjacent to the fusion interface. Creep rupture tests were performed using all weld metal and weldment specimens. The weldment life was approximately twice that of the all weld metal specimen, consistent with the effect of specimen size and oxidation on rupture life. The weldment fracture was in the weld metal adjacent to the fusion interface. The second failure was a main steam line drain failure. Based on safety considerations and as a corrective action, alloy analysis (positive material identification) was performed at three units on approximately 75 different high temperature drain lines. Inferior materials were found in straight pipes, elbows, and valves. The last series of failures were in the stub tubing at the reheat header installed by the OEM and in a superheat tube installed by the utility.