Unless otherwise specified in the product standard, the speed of testing shall conform to the following requirements depending on the nature of the material.
10.1.1 Yield and proof strengths
10.1.1.1 Upper yield strength (ReH)
Within the elastic range and up to the upper yield strength, the rate of separation of the crossheads of the machine shall be kept as constant as possible and within the limits corresponding to the stressing rates in table 3.
| Modulus of elasticity of the material (E) N/mm² | Rate of stressing | |
|---|---|---|
| N/mm².s⁻¹ | ||
| min. | max. | |
| < 150 000 | 2 | 20 |
| ≥ 150 000 | 6 | 60 |
10.1.1.2 Lower yield strength (ReL)
If only the lower yield strength is being determined, the rate of straining during yield of the parallel length of the test piece shall be between 0,000 25/s and 0,002 5/s. The straining rate within the parallel length shall be kept as constant as possible. If this rate cannot be regulated directly, it shall be fixed by regulating the rate of stressing just before yield begins, the controls of the machine not being further adjusted until completion of yield.
In no case shall the rate of stressing in the elastic range exceed the maximum rates given in table 3.
10.1.1.3 Upper and lower yield strengths ( and )
If the two yield strengths are determined during the same test, the conditions for determining the lower yield strength shall be complied with (see 10.1.1.2).
10.1.1.4 Proof strength (non-proportional extension) and proof strength (total extension)
The rate of stressing shall be within the limits given in table 3.
Within the plastic range and up to the proof strength (non-proportional extension or total extension) the straining rate shall not exceed 0,002 5/s.
10.1.1.5 Rate of separation
If the testing machine is not capable of measuring or controlling the strain rate, a cross head separation speed equivalent to the rate of stressing given in table 3 shall be used until completion of yield.
10.1.2 Tensile strength (Rm)
10.1.2.1 In the plastic range
The straining rate of the parallel length shall not exceed 0,008/s.
10.1.2.2 In the elastic range
If the test does not include the determination of a yield stress (or proof stress), the rate of the machine may reach the maximum permitted in the plastic range.