Cryogenic Material Properties of Stainless Tube-to-Flange Welds

The mechanical properties stainless steel tube-to-flange welds for a cryogenic piping application were measured. A planar specimen was developed to duplicate the constraint loading and heat-sink properties of the circular joint, while reducing preparation time and cost. Specimens were evaluated containing welds between the tube material (21Cr--6Ni--9Mn) and the three stainless steels being considered for the flange materials: type 304L, type 316L and 21Cr--6Ni--9Mn. The mechanical property tests consisted of three phases: simple tensile testing to failure, tensile testing of notched specimens (where the notch simulated fabrication flaws) and fatigue testing of notched specimens for the 4 x 10 exp 4 c design life of the structure. The type 316L stainless steel flange produced welds with the best combination of strength and ductility at 295 and 4K in all three phases of testing. Graphs. 8 ref.--AA