Time-dependent deformation of austenitic stainless steels at cryogenic temperatures

Abstract

Creep tests and constant load rate tensile tests at cryogenic temperatures were carried out on austenitic stainless steels AISI304L, 310S and 316L. A creep rate of ≈ 10 −9 s −1 was observed in a 200 h creep test under the proof stress of the materials at 77 K. The creep rate at 4 K was decreased to a tenth of that at 77 K. However, an abrupt and large deformation occurs in a constant load rate tensile test at 4 K. The magnitude of the abrupt deformation depends on the work-hardening rate and the stablity of the austenitic phase. Higher proof stress materials, especially AISI310S, do not always show better characteristics for the creep or the abrupt deformation at 4 K.