ASTM E1685-20

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1685 − 13 E1685 − 20
Standard Practice for
Measuring the Change in Length of FastenersBolts Using
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the Ultrasonic Pulse-Echo Technique
This standard is issued under the fixed designation E1685; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This practice covers a procedure for measuring changes in length of threaded fastenersbolts using conventional ultrasonic
pulse-echo bolt-measuring instrumentation which has been properly calibrated.the ultrasonic pulse-echo technique.
1.2 This procedure is normally intended for metal bolting 6.3 mm or more in nominal diameter with effective length-to-diameter
ratios of 2:1 or greater.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.5 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
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2.1 ASTM Standards:
E6 Terminology Relating to Methods of Mechanical Testing
E111 Test Method for Young’s Modulus, Tangent Modulus, and Chord Modulus
E1316 Terminology for Nondestructive Examinations
E1544 Practice for Construction of a Stepped Block and Its Use to Estimate Errors Produced by Speed-of-Sound Measurement
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Systems for Use on Solids (Withdrawn 2012)
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2.2 ASME Standards:
ASME B46.1–2009 Surface Texture (Surface Roughness, Waviness, and Lay)
3. Terminology
3.1 The definitions of calibration, extensometer system, metrological traceability, reference standard, testing machine, and
verification, in this practice are in accordance with used as defined in Terminology E6 and Section I of Terminology E1316.
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This practice is under the jurisdiction of ASTM Committee E28 on Mechanical Testing and is the direct responsibility of Subcommittee E28.13 on Residual Stress
Measurement.
Current edition approved Nov. 1, 2013Oct. 1, 2020. Published January 2014December 2020. Originally approved in 1995. Last previous edition approved in 20062013
as E1685–00(2006).E1685–13. DOI: 10.1520/E1685-13.10.1520/E1685-20.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
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The last approved version of this historical standard is referenced on www.astm.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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E1685 − 20
3.2 The definitions of attenuation, couplant, echo, longitudinal wave, pulse, pulse echo method, reference block, reflector,
resolution, time-of-flight, transducer, and ultrasonic are used as defined in Section I of Terminology E1316.
3.3 Definitions of Terms Specific to This Standard:
3.3.1 change in length [L], n—physical change in length of a threaded fastener due to a change in tension within the fastener.
3.3.2 effective length [L], n—the length of a bolt that is responsive to stress. stress, defined here as the bolt length between head
and nut plus half the thickness of the head plus half the thickness of the nut.
3.2.2.1 Discussion—
This quantity lies somewhere between the overall length of the bolt and the grip length. It is usually estimated as the grip length
plus one half the thickness of the head and one half the thickness of the nut.
3.2.3 longitudinal wave, n—those waves in which the particle motion of the material is in the same direction as the wave
propagation.
3.3.3 pulse-echo bolt-measuring instrument—an assembly of ultrasonic instruments designed specifically to measure changes in
the lengths of bolts. See Appendix
...