Designation

This standard is issued under the fixed designation E4; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (ε) indicates an editorial change since the last revision or reapproval.

This standard has been approved for use by agencies of the U.S. Department of Defense.

1. Scope*

1.1

These practices cover procedures for the force calibration and verification, by means of force measurement standards, of tension or compression, or both, static or quasi-static testing machines (which may, or may not, have force-indicators). These practices are not intended to be complete purchase specifications for testing machines.

1.2

Testing machines may be verified by one of the three following methods or combination thereof. Each of the methods require a specific measurement uncertainty, displaying metrological traceability to The International System of Units (SI).

1.2.1

Use of standard weights,

1.2.2

Use of equal-arm balances and standard weights, or

1.2.3

Use of elastic force measurement standards.

1.3

The procedures of 1.2.1–1.2.3 apply to the calibration and verification of the force-measuring systems associated with the testing machine, including the force indicators such as a scale, dial, marked or unmarked recorder chart, digital display, etc. In all cases the buyer/owner/user must designate the force-measuring system(s) to be verified and included in the certificate and report of calibration and verification.

1.4

Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.

1.4.1

Other non-SI force units may be used with this standard such as the kilogram-force (kgf) which is often used with hardness testing machines

1.5

Forces indicated on displays/printouts of testing machine data systems—be they instantaneous, delayed, stored, or retransmitted—which are verified with provisions of 1.2.1, 1.2.2, or 1.2.3, and are within the specifications stated in Section 16, comply with Practices E4.

1.6

The requirements of these practices limit the major components of measurement uncertainty when calibrating testing machines. These Standard Practices do not require the allowable force measurement error to be reduced by the amount of the measurement uncertainty encountered during a calibration. As a result, a testing machine verified using these practices may produce a deviation from the true force greater than ±1.0 % when the force measurement error is combined with the measurement uncertainty.

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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.8

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

2. Referenced Documents

2.1

2.2

3. Terminology

3.1

3.2

3.3

4. Summary of Practice

4.1

4.2

4.3

5. Significance and Use

5.1

5.2

6. Elastic Force Measurement Standards

6.1

7. Advantages and Limitations of Methods

7.1

7.2

7.3

8. System Calibration

8.1

8.2

8.3

8.4

9. Gravity and Air Buoyancy Corrections

9.1

9.2

9.3

10. Application of Force

10.1

10.2

10.3

10.4

11. Determine the Resolution of the Force-measuring System:

11.1

11.2

11.3

11.4

11.5

12. Selection of Calibration Forces

12.1

12.2

12.3

12.4

12.5

13. Eccentricity of Force

13.1

14. Methods of Calibration

14.1

14.2

14.3

15. Lever-Type Creep-Rupture Testing Machines

15.1

15.2

16. Basis of Verification

16.1

16.2

16.3

16.4

17. Corrections

17.1

18. Time Interval Between Verifications

18.1

18.2

18.3

19. Measurement Accuracy Assurance Between Verifications

19.1

19.2

19.3

19.4

19.5

19.6

19.7

20. Certificate and Report of Calibration and Verification

20.1

20.2

21. Keywords

21.1

ASTM E4 - 24

Standard Practices for Force Calibration and Verification of Testing Machines

Current

Published:

1 Sep 2024