Volume 16, Issue 2 (March 1988)
Cryogenic Fatigue Properties of 304L and 316L Stainless Steels Compared to Mechanical Strength and Increasing Magnetic Permeability
For superconducting magnet applications, the 4 K fatigue life curves of the cryogenic structural materials 304L and 316L stainless steel were obtained using axial-strain control conditions. These curves were compared with others at 77 and 300 K and with data for other 300-series stainless steels in the literature. Increasing magnetic permeability with monotonic tensile and cyclic straining, due to strain-induced martensitic transformation, was also investigated, since 304L and 316L are metastable austenitic stainless steels. 4 K fatigue life curves relating magnetic permeability effects were obtained. Fatigue tests relating magnetic permeability at 77 and 300 K were also conducted for comparison. Finally, a cryogenic fatigue design criterion for preventing mechanical failure and increasing magnetic permeability was considered.