Creep properties of a Type 308 stainless steel pressure vessel weld with controlled residual elements

A SMA Type 308 stainless steel pressure vessel test weld with the CRE (controlled residual elements) boron (0.007 percent), titanium (0.06 percent), and phosphorus (0.04 percent) has been tested in creep between 482 and 6500C. Improved ductility compared with that of standard welds in tests lasting several thousands of hours is observed. Systematic variations of creep properties through the weld are due to thermal and mechanical cycling during the welding process. Anisotropic deformation related to local substructure and preferred crystallographic orientation occurs. Creep strengths are acceptable by present design rules