Investigations On Premature Failure Of 9cr-Mo Elbow During Operation Applied In Power Industry

Premature and sudden failure due to crack formation in the elbow applied in the feeder line has been examined in the present paper. The bend section was cracked in the centre, crack was transmitted along the axis of the elbow. The expected life of the part is 10-15 years, but the element failed only after instal-lation, which is within 3 months of its service. The failed component discover the exposed surface of the crack interface ascending in the middle and increases inward the axis. Microscopic structural observa-tion, rigidity testing, and visual inspection are performed from samples made from the failed section and base area. The cracked interface showed white spots due to copper scattering in the microstructure and the carbide-like structure appeared near the grain boundary of the cracked interface and the micro-scopic structure of the structure at the interface was high. This martensite can be caused by improper tempering of the material and is the result of tensile brittle fracture that lacks tensile strength, resulting in failure due to weak area along the knee axis and sudden impact during installation.(c) 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Confer-ence on Advances in Materials Processing & Manufacturing Applications.