Nitrogen-Strengthened Austenitic Stainless Steel for Cryogenic Magnet Structures

摘要

In support of the magnet development effort, an extensive test program was initiated to verify expected base metal properties, to develop weld processes and to establish weld and base metal design allowables. This paper presents the results of the test program which involved testing and evaluation of 25 mm thick Type 316 LN plate, shielded metal arc weld (SMAW) deposits selected for structural welds, gas tungsten arc weld (GRAW) and gas metal arc weld (GMAW) deposits selected fo seal welds. The welding development effort including measurements of impact properties at RT and 77 exp 0 K; chemical analyses; measurements of magnetic permeabilities and weld ferrite contents, metallographic and radiographic examinations of welds were performed at the Materials and Processes Laboratory of General Electric in Schenectady, New York. Measurements of tensile, fracture toughness and fatigue crack growth rate (FCGR) properties from RT to 4 exp 0 K were performed by the National Bureau of Standards in Boulder, Colorado. (ERA citation 04:053947)