An experience with the performance of modified 9 Cr-1 Mo alloy steel tubes in a power plant

摘要: Modified 9Cr-1Mo (T-91) is becoming a popular grade for super heater in place of austenitic stainless steel in thermal power plants. However, experience with regard to its service performance is very limited. Premature failure of superheater is generally encountered on account of overheating and presently this is attributed to oxide scale formation on steam side. The present paper emphasizes the need for analyzing all the relevant information in an integrated manner to arrive at the cause of the failure.