It is generally recognized that the long-term ductility of AISI 316 stainless steel weld metal is inferior to that of the parent metal but is influenced by weld metal composition. The present work is the initial part of a broadly based investigation of the high-temperature mechanical properties of AISI 316 weld metals. In particular, the correlation between manual metal-arc (MMA) electrode constitution and weld deposit tensile strength and ductility at temperatures between 500 and 700°C has been examined. It was found that these material properties depended upon the basicity of the electrode coating, and the observed variations have been explained in terms of differences in weld metal composition arising from changes in the slag/metal reactions which occur during welding.

Phosphorus and boron levels have also been investigated. Variations in the former have no effect on tensile properties, while 60-ppm boron increases deposit strength without significantly reducing ductility. This is probably a consequence of the effect of boron on the microstructural stability of the weld metal.