| In case of cryogenic structures such as superconducting magnets and pressure vessels, the structural material experiences unrestricted force. It is, therefore, desirable to characterize the load-controlled tensile properties at cryogenic temperatures to simulate operating condition. At 4 K, however, discontinuous yielding occurs, which arises mainly from low specific heat and thermal conductivity of the materials at low temperatures, and it affects the load-displacement or stress-strain curves. In this study, load-controlled tensile tests were conducted at 77 ad 4K on AISI 300 series stainless steels. The load rate was varied from 5 to 5000 N/s. The effect of load rate and testing temperature on tensile properties of 300 series stainless steels were observed. A model which correlate discontinuous yielding and ultimate tensile strength was proposed. |
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