Effect of Welding Method on the Mechanical Properties at Low Temperature of Welded Joints of Austenitic Stainless Steels (Study on Low Temperature Materials Used in WE-NET 8)

摘要

Mechanical tests were performed in the range from room temperature to liquid helium environment (4K) on TIG, SAW, and MAG welds made on SUS304L and SUS316L for use in hydrogen storage tanks and transport systems, and the effects of weld methods on mechanical properties were investigated. It was found that, for all weld conditions for both the 304L and 316L tensile strength increased and elongation and reduction of area decreased as temperature decreased, however, no tendencies toward brittle fracture were observed. Absorbed energy and fracture toughness decreased as temperature was lowered from room temperature, with that of SAW and MAG lower than TIG. In general, the lower the temperature the less prominent became the differences in the effects due to weld method for TIG, SAW, and MAG. The amounts of inclusions for SAW and MAG were also higher than for TIG, it is thought that these inclusions were a causative factor in the reduction of impact properties and toughness.