BS ISO 6892-4:2015 pdf free.Metallic materials – Tensile testing Part 4: Method of test in liquid helium.
This part of Iso 6892 specifies the method of tensile testing of metallic materials in liquid helium (the boiling point is —269 °C or 4,2 K, designated as 4 K) and defines the mechanical properties that can be determined.
This part of ISO 6892 may apply also to tensile testing at cryogenic temperatures (less than —196 °C or 77 K), which requires special apparatus, smaller test pieces, and concern for serrated yielding, adiabatic heating, and strain-rate effects.
To conduct a tensile test according to this part of ISO 6892 at 4 K, the test piece installed in a cryostat is fully submerged in liquid helium (He) anti tested using displacement control at a nominal strain rate of 10-s s1 or less.
NOTE The boiling point of the rare 3He Isotope is 3,2 K. Usually, the tests are performed in 41-le or a mixture of 3He and 4He with a high concentration of 4He. Therefore, the temperature is, as designated before. 4 K.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are Indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 6892-1:), Metallic materials — Tensile testing — Part 1: Method of test at room temperature ISO 6892-3, Metallic materials — Tensile testing — Part 3: Method of test at low temperature
ISO 7500.11, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1: Tension/compression testing machines — Calibration and verfication of the force-measuring system
ISO 9513, Metallic materials — Calibration of extensoineter systems used in uniaxial testing
3 Terms and definitions
For the purpose of this document, the terms and definitions given in ISO 6892-1 and in ISO 6892-3 apply.
3.1 adiabatic heating internal heating ola test piece resulting from deformation under conditions such that the heat generated by plastic work cannot be quickly dissipated to the surrounding cryogen.
3.2 axial strain longitudinal strains measured at opposite or equally spaced surface locations on the sides of the longitudinal axis of symmetry of the test piece.BS ISO 6892-4 pdf download.