Welding Studies on WB36 for Feed Water Piping

To increase efficiency, reduce emissions, cost and to reduce weight of boiler per MW, the power manufacturing sectors are going towards the once through technology (super critical boiler) instead of sub- critical. Once through supercritical (OTSC) technology has become a focal point for effective utilization of coal-based thermal power generation sector in India. Another main advantage of moving towards OTSC technology is reducing the weight of the boiler per MW, which can be done by going for material capable of handling higher pressure and temperature than the conventional material. So, in order to keep pace with these technologies, research on newer materials for every boilers line, which can operate at both higher pressure and temperature, has been initiated. So, in this article, we have taken one such feed water system and headers, where WB 36 steel (15 MiCuMoNiNb5) can be used instead conventional standard carbon steel like A106 grade B or C, which are usually used. For super critical, ultra super critical power plants this conventional materials like A106 grade B or C, leads to very thick piping system. V&M has developed WB 36 steel (15 MiCuMoNiNb5) for high pressure piping of boiler feed water system. This heat-resistant, copperalloyed ferritic steel 15MiCuMoNiNb5 has been widely used in European nuclear and conventional power plants for decades for feed water system. This widespread application is due to the toughness and strength, caused by the precipitation of copper, that are exhibited even at elevated temperatures which other fine-grained structural steels have at room temperature. The aim of this project “Welding Studies on WB36 Steel for Feed Water Piping” was taken to understand the metallurgy and the behavior of the new materials under different manufacturing operations.