CREEP PROPERTIES OF A TYPE 308 STAINLESS STEEL PRESSURE VESSEL WELD WITH CONTROLLED RESIDUAL ELEMENTS

摘要

A SMA type 308 stainless steel pressure vessel test weld with the controlled residual elements (CRE) boron (0.007％ ), titanium (0.06％ ), and phosphorus (0.04％ ) was tested in creep between 482 and 650℃ (900 and 1200℉ ). Improved ductility compared to that of standard welds in tests lasting several thousands of hours is associated with the absence of interphase separation. Systematic variations of microstructure and creep properties through the weld and in the heat-affected zone are due to thermal and mechanical cycling during the welding process. Anisotropic deformation occurs and is related to local substructure and preferred crystallographic orientation. Creep strengths are acceptable by present design rules.