Cryogenic material properties of stainless steel tube-to-flange welds

The mechanical properties of 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 (21 Cr-6Ni-9Mn) and the three stainless steels being considered for the flange materials: type 304L, type 316L and 21 Cr-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 × 10 4 cycle design life of the structure. The type 316L stainless steel flange produced welds with the best combination of strength and ductility at 295 and 4 K in all three phases of testing.