AS 2291:2020 pdf free.Metallic materials一Tensile testing一Method of test at elevated temperature.
10 Test conditions
10.1 Setting the force zero point
The force-measuring system shall be set to zero after the testing equipment has been assembled but before the test piece is actually placed in the gripping jaws. Once the force zero point has been set, the force-measuring system may not be changed in any way during the test.
NOTE The use of this method ensures that the weight of the gripping system is compensated in the force measurement and that any force resulting from the clamping operation does not affect the force zero point.
10.2 Gripping of the test piece, fixing of the extensometer and heating of the test piece, not necessarily in the following sequence
10.2.1 Method of gripping
For requirements concerning the method of gripping, see ISO 6892-1.
NOTE Maintaining a very small tensile load (e.g. test machine in load control) during heating period and
soaking time can prevent possible compressive stresses due to thermal expansion.
10.2.2 Fixing of the extensometer and establishing the gauge length
10.2.2.1 General
Different methods of establishing the extensometer gauge length are used in practice. This can lead to
minor differences in the test results. The method used shall be documented in the test report.
10.2.2.2 Le based on room temperature (Method 1)
The extensometer is set on the test piece at room temperature with nominal gauge length. The extension is measured at test temperature and the percentage extension is calculated with the gauge length at room temperature.
The thermal extension is not considered.
10.2.2.3 Le based on test temperature (Method 2)
This Le includes the thermal extension of the test piece.
10.2.2.3.1 Nominal Le at test temperature (Method 2 a)
The extensometer is set on the test piece at the test temperature with nominal gauge length before mechanical loading.
10.2.2.3.2 Reduced Le at room temperature (Method 2 b)
An extensometer with reduced gauge length is set on the test piece at room temperature such that at test temperature, the nominal gauge length is achieved.
For the calculation of percentage extension, the nominal gauge length is used.
10.2.2.3.3 Corrected Le at test temperature (Method 2 c)
The extensometer is set on the test piece at room temperature with the nominal gauge length.
For the calculation of percentage extension, the corrected nominal gauge length at test temperature (gauge length at room temperature and thermal expansion) is used.AS 2291 pdf download.