EFFECT OF delta -FERRITE ON LOW TEMPERATURE TOUGHNESS OF TYPE 316L AUSTENITIC STAINLESS STEEL WELD METAL: - LOW TEMPERATURE TOUGHNESS OF AUSTENITIC STAINLESS STEEL WELD METAL (REPORT 1).

With the development of cryogenic technique such as LNG tankers, storage tanks and superconductivity apparatus, the demand on austenitic stainless steel as a promising material for cryogenic service has been increasing. However, since the toughness of austenitic stainless steel welds is in general inferior to that of the base metal, a considerable effort has been directed toward improving the toughness of weld metal by high alloy filler-metal wire or low heat-input welding. The purpose of this study is to clarify the correlation among delta -ferrite content, ferrite morphology, notch toughness and fracture toughness by using specimens prepared from single-pass welds with varied delta contents.