In this paper, the failure of the reformer furnace tube, made of HP-Nb micro alloyed heat
resistant steel is investigated. The failure was due to a longitudinal crack developing in the
circumferential weld joint close to the outlet end of the tube, where the mean wall
temperature had reached the highest value during service. According to the temperature
records during the period of 7 years of being in service, the tube had experienced
temperatures higher than the tubes designed temperature. This situation besides the …