ISO 6892-4:2015规定了液态氦（沸点为？269°C或4,2 K，指定为4 K）中金属材料的拉伸试验方法，并定义了可测定的机械性能。 ISO 6892的本部分也适用于低温（低于196°C或77 K）下的拉伸试验，这需要特殊仪器、较小的试样，并考虑锯齿屈服、绝热加热和应变率效应。 根据ISO 6892的本部分，在4 K下进行拉伸试验时，将安装在低温恒温器中的试样完全浸入液氦（He）中，并在10？3 s？1或更小的标称应变率下使用位移控制进行试验。 注:稀有3He同位素的沸点为3,2 K。通常，测试在4He或高浓度4He的3He和4He混合物中进行。因此，如前所述，温度为4K。

ISO 6892-4:2015 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) and tested using displacement control at a nominal strain rate of 10？3 s？1 or less. NOTE The boiling point of the rare 3He isotope is 3,2 K. Usually, the tests are performed in 4He or a mixture of 3He and 4He with a high concentration of 4He. Therefore, the temperature is, as designated before, 4 K.