Weldability of HAYNES 282 superalloy after long-term thermal exposure

Abstract

HAYNES® 282® alloy is a wrought gamma-prime (γ') strengthened Ni-base superalloy that was developed for high-temperature structural applications, especially those in aero-and land-based gas turbine engines. The 282 alloy exhibits excellent creep strength and thermal stability in the 649 to 927 °C temperature range, and was specifically designed for improved fabricability relative to other Ni-base superalloys. When welded in the annealed condition, 282 alloy exhibits excellent weldability for a γ'-strengthened alloy. To provide an estimate of its weldability and weld repairability after service exposure, welding experiments were conducted on 282 alloy after long-term thermal exposure (LTTE). Welds were successfully completed on the LTTE material and transverse weld tensile properties were determined. To evaluate susceptibility to heat-affected zone (HAZ) liquation cracking during welding, Gleeble ® hot-ductility tests were performed on the LTTE material. The experimental results were complemented by microstructure characterization and thermodynamic calculations. The capability of weld repair and rejuvenation of 282 alloy components in the LTTE condition was demonstrated. © 2014 Owned by the authors, published by EDP Sciences.