Creep deformation, rupture and ductility of Esshete 1250 weld metal

Esshete 1250 is an austenitic steel with high creep strength and is well established as a superheater boiler tube material in UK power stations. In addition, Esshete 1250 is readily welded with either inert gas welding or metal arc welding and has been used for piping and headers in super critical power stations. The latter thick section components are either solution heat treated after welding or enter service in the as-welded condition. Components that enter service in the as-welded condition contain high residual stresses, which pose a threat to the structural integrity of these welds. In order to perform life assessments of as-welded Esshete 1250 welds, it is necessary to have data on the creep deformation, stress relaxation, rupture and ductility of the weld metal, which are described in this paper.