Significance and Use
4.1 Material testing requires repeatable and predictable testing machine speed. The speed measuring devices integral to the testing machines may be used for measurement of crosshead speed over a defined range of operation. The accuracy of the speed value shall be traceable to a National or International Standards Laboratory. Practices E2658 provides procedures to verify testing machines, in order that the indicated speed values may be traceable. A key element to having traceability is that the devices used in the verification produce known speed characteristics, and have been calibrated in accordance with adequate calibration standards.
4.2 Verification of testing machine speed at a minimum consists of either or both of the following options:
4.2.1 Verifying the capability of the testing machine to move the crosshead at the speed selected.
4.2.2 Verifying the capability of the testing machine to adequately indicate the speed of the crosshead.
4.3 Where applicable, determine the testing machine’s ramp-to-speed condition. This condition can be significant especially when verifying fast speeds or testing conditions with very short testing durations.
4.4 This procedure will establish the relationship between the actual crosshead speed and the testing machine indicated speed and or selected setting. It is this relationship that will allow confidence in the reported displacement over time data acquired by the testing machine during use.
NOTE 1: Many material tests never reach the desired test speed. Unless the actual data from the material test is examined, it is often impossible to know if the test speed has been reached or is repeatable from test to test.
Scope
1.1 These practices cover procedures and requirements for the calibration and verification of testing machine speed by means of standard calibration devices. This practice is not intended to be complete purchase specifications for testing machines.
1.2 These practices apply to the verification of the speed application and measuring systems associated with the testing machine, such as a scale, dial, marked or unmarked recorder chart, digital display, setting, etc. In all cases the buyer/owner/user must designate the speed-measuring system(s) to be verified.
1.3 These practices give guidance, recommendations, and examples, specific to electro-mechanical testing machines. The practice may also be used to verify actuator speed for hydraulic testing machines.
1.4 This standard cannot be used to verify cycle counting or frequency related to cyclic fatigue testing applications.
1.5 Since conversion factors are not required in this practice, either SI units (mm/min), or English [in/min], can be used as the standard.
1.6 Speed measurement values and or settings on displays/printouts of testing machine data systems-be they instantaneous, delayed, stored, or retransmitted-which are within the Classification criteria listed in Table 1, comply with Practices E2658.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
