Microstructure and precipitation studies of gas tungsten arc welded haynes 282 superalloy

Improvement in efficiency of energy conversion requires the use of high temperature materials in thermal power plants. This has led to the development of new γ' strengthened nickel based superalloy (Haynes 282). This alloy is used for advanced ultra-supercritical (AUSC) plants which are operated under the service conditions of 760 °C temperature and 35 MPa pressure. Bead on plate gas tungsten arc welding experiments were done with optimized process parameters. Thermal cycle in heat affected zone was measured by K-type thermocouple attached to a data acquisition system. Welding simulations were carried out in simufact welding® by using experimental parameters and thermal field was established. Base metal is characterized with γ solid solution and randomly distributed MC carbides. SEM results showed that the carbides are of MC type. The carbide precipitate distribution correlates with the segregation pattern during solidification of the weld.