1、Designation: E2624 09E2624 15Standard Practice forTorque Calibration of Testing Machines and Devices1This standard is issued under the fixed designation E2624; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers procedures and requirements for the calibration of torque for static and quasi-static torque capabletesting
3、machines or devices. machines. These may, or may not, have torque indicating systems and include those devices used forthe calibration of hand torque tools. Testing machines may be calibrated by one of the three following methods or combinationthereof:1.1.1 Use of standard weights and lever arms.1.1
4、.2 Use of elastic torque measuring devices.1.1.3 Use of elastic force measuring devices and lever arms.1.1.4 Any of the methods require a specific uncertainty of measurement and a traceability derived from national standards ofmass and length.measurement, displaying metrological traceability to The
5、International System of Units (SI).NOTE 1 for further definition of the term metrological traceability, refer to the latest revision of JCGM 200: International vocabulary of metrology Basic and general concepts and associated terms (VIM).1.2 The procedures of 1.1.1, 1.1.2, and 1.1.3 apply to the cal
6、ibration of the torque-indicating systems associated with the testingmachine, such as a scale, dial, marked or unmarked recorder chart, digital display, etc. In all cases the buyer/owner/user mustdesignate the torque-indicating system(s) to be calibrated and included in the report.1.3 Since conversi
7、on factors are not required in this practice, either english units, metric units, or SI units can be used as thestandard.1.4 Torque values indicated on displays/printouts of testing machine data systemsbe they instantaneous, delayed, stored, orretransmittedwhich are Calibratedcalibrated with provisi
8、ons of 1.1.1, 1.1.2 or 1.1.3 or a combination thereof, and are within the61 % of reading accuracy requirement, comply with this practice.1.5 The following applies to all specified limits in this standard: For purposes of determining conformance with thesespecifications, an observed value or a calcul
9、ated value shall be rounded “to the nearest unit” in the last right-hand digit used inexpressing the specification limit, in accordance with the rounding method of Practice E29, for Using Significant Digits in TestData to Determine Conformance with Specifications.1.6 This standard does not purport t
10、o address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E6 Termino
11、logy Relating to Methods of Mechanical TestingE29 Practice for Using Significant Digits in Test Data to Determine Conformance with SpecificationsE74 Practice of Calibration of Force-Measuring Instruments for Verifying the Force Indication of Testing MachinesE2428 Practice for Calibration and Verific
12、ation of Torque Transducers2.2 NIST Technical Notes:NIST Technical Note 1297 Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results31 This practice is under the jurisdiction of ASTM Committee E28 on Mechanical Testing and is the direct responsibility of Subcommittee E28
13、.01 on Calibration ofMechanical Testing Machines and Apparatus.Current edition approved April 1, 2009Dec. 1, 2015. Published May 2009January 2016. Originally approved in 2009. Last previous edition approved in 2009 as E262409. DOI: 10.1520/E2624-09.10.1520/E2624-15.2 For referencedASTM standards, vi
14、sit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from National Institute of Standards and Technology (NIST), 100 Bureau Dr., Stop 10
15、70, Gaithersburg, MD 20899-1070, http:/www.nist.gov.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accu
16、rately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United Sta
17、tes12.3 BIPM Standard:4JCGM 200 : International vocabulary of metrology Basic and general concepts and associated terms (VIM)3. Terminology3.1 Definitions: In addition to the terms listed, see Terminology E6.3.1.1 accuracythe permissible variation from the correct value.3.1.1.1 DiscussionA testing m
18、achine is said to be accurate if the indicated torque is within the specified permissible variation from the actual torque.In this practice the word “accurate” applied to a testing machine is used without numerical values. For example, “An accuratetesting machine was used for the investigation.” The
19、 accuracy of a testing machine should not be confused with sensitivity. Forexample, a testing machine might be very sensitive; that is, it might indicate quickly and definitely small changes in torque, butnevertheless, be very inaccurate. On the other hand, the accuracy of the results is in general
20、limited by the sensitivity.3.1.2 error, nfor a measurement or reading, the amount it deviates from a known or reference value represented by ameasurement standard. Mathematically, the error is calculated by subtracting the accepted value from the measurement or reading.3.1.2.1 DiscussionThe word “er
21、ror” shall be used with numerical values, for example, “At a torque of 3000 lbfin., the error of the testing machinewas +10 lbfin.”3.1.3 percent error, nin the case of a testing machine or device, the ratio, expressed as a percent, of an error to the knownaccepted value represented by a measurement
22、standard.3.1.4 reference standard, nan item, typically a material or an instrument, that has been characterized by recognized standardsor testing laboratories, for some of its physical or mechanical properties, and that is generally used for calibration or verification,or both, of a measurement syst
23、em or for evaluating a test method.3.1.4.1 DiscussionTorque may be generated by a length calibrated arm and calibrated masses used to produce known torque. Alternatively, torqueapplied to a torque measuring device to be calibrated may be measured by the use of a reference torque measurement device,
24、thatis, an elastic torque calibration device, or a length calibrated arm and an elastic force measuring device.3.1.5 resolution, nfor a particular measurement device, the smallest change in the quantity being measured that causes aperceptible change in the corresponding indication.3.1.5.1 Discussion
25、Resolution may depend on the value (magnitude) of the quantity being measured.3.1.5.2 DiscussionFor paper charts or analog indicators, the resolution should not be assumed to be better (smaller) than 110 of the spacing betweengraduations. For digital devices, the best resolution potentially achievab
26、le is the smallest difference between two different readingsgiven by the display.3.1.5.3 DiscussionFor both analog and digital devices, the actual resolution can be significantly poorer than described above, due to factors such asnoise, friction, etc.3.1.6 torque, na moment (of forces) that produces
27、 or tends to produce rotation or torsion.3.2 Definitions:Definitions of Terms Specific to This Standard:3.1.1 accuracyaccuracy is defined in Terminology E6.4 Available from BIPM (Bureau International des Poids et Mesures)- Pavillon de Breteuil F-92312 Svres Cedex FRANCE http:/www.bipm.orgE2624 1523.
28、1.1.1 DiscussionA testing machine is said to be accurate if the indicated torque is within the specified permissible variation from the actual torquein these methods the word “accurate” applied to a testing machine is used without numerical values, for example, “An accuratetesting machine was used f
29、or the investigation.” The accuracy of a testing machine should not be confused with sensitivity. Forexample, a testing machine might be very sensitive; that is, it might indicate quickly and definitely small changes in torque, butnevertheless, be very inaccurate. On the other hand, the accuracy of
30、the results is in general limited by the sensitivity.3.2.1 calibrated range of torquein the case of testing machines, the range of indicated torque for which the testing machinegives results within the permissible variations specified.3.2.2 calibration torquea torque with metrological traceability d
31、erived from national standards of mass and length and ofspecific uncertainty of measurement, which can be applied to torque measuring devices.3.2.3 capacity rangein the case of testing machines, the range of torque for which it is designed. Some testing machines havemore than one capacity range, tha
32、t is, multiple ranges.3.2.3.1 DiscussionSome testing machines have more than one capacity range, that is, multiple ranges.3.2.4 correctionin the case of testing machines, the difference obtained by subtracting the indicated torque from the referencevalue of the applied torque.3.2.5 elastic torque-me
33、asuring devicea device or system consisting of an elastic member combined with a device forindicating the measured values (or a quantity proportional to the measured value) of deformation of the member under an appliedtorque.NOTE 1The instrumentation for the elastic devices may be either an electric
34、al or a mechanical device, i.e., a scale or pointer system.3.2.5.1 DiscussionThe instrumentation for the elastic devices may be either an electrical or a mechanical device, that is, a scale or pointer system.3.1.7 error (or the deviation from the reference value)in the case of a testing machine or d
35、evice, the difference obtained bysubtracting the torque indicated by the calibration device from the torque indicated by the testing machine or device.3.1.7.1 DiscussionThe word “error” shall be used with numerical values, for example, “At a torque of 3000 lbf-in., the error of the testing machinewa
36、s +10 lbf-in.”3.2.6 expanded uncertaintya statistical measurement of the probable limits of error of a measurement.measurement, NISTTechnical Note 1297 treats the statistical approach including the expanded uncertainty.3.2.7 lower torque limit of calibration rangethe lowest value of torque at which
37、a torque measuring system can be calibrated.3.2.8 parasitic torquetorque that bypasses a desired torque path thatForces that bypass the torque axis and can cause errorsin determining the value of the torque in that path. It is usually caused by cables, conduit, or hydraulic lines attached to objects
38、that are in the torque path. These attachments absorb torque and cause subsequent errors in the measured torque.3.2.8.1 DiscussionUsually the result of off axis loading (bending moments) caused by cables, conduit, or hydraulic lines attached to objects that arein the torque path and cause subsequent
39、 errors in the measured torque.3.1.11 percent errorin the case of a testing machine or device, the ratio, expressed as a percent, of the error to the referencevalue of the applied torque.3.1.11.1 DiscussionThe test torque, as indicated by the testing machine, and the applied torque, as computed from
40、 the readings of the calibrationdevice, shall be recorded at each test point. The error, E, and the percent error, Ep, shall be calculated from this data as follows:E2624 153E 5A 2B (1)Ep 5A 2B!/B!3100where:A = torque indicated by the machine being calibrated, N-m (lbf-in.), andB = reference value o
41、f the applied torque, N-m (lbf-in.), as determined by the calibration device.3.2.9 permissible variation (or tolerance) in the case of testing machines, the maximum allowable error in the value of thequantity indicated.3.2.9.1 DiscussionIt is convenient to express permissible variation in terms of p
42、ercentage of error. The numerical value of the permissible variationfor a testing machine is so stated hereafter in these practices.3.1.13 reference standarda standard used to generate or to measure torque applied to the testing machine to be calibrated.NOTE 2Torque may be generated by a length cali
43、brated arm and calibrated masses used to produce known torque. Alternatively, torque applied toa torque measuring device to be calibrated may be measured by the use of a reference torque measurement device, i.e., an elastic torque calibration device,or a length calibrated arm and an elastic force me
44、asuring device.3.1.14 resolution of analog type torque indicators (scales, dials, recorders, etc.)the resolution is the smallest change in torqueindicated by a displacement of a pointer, or pen line. The resolution is calculated by multiplying the torque corresponding to onegraduation by the ratio o
45、f the width of the pointer or pen line to the center to center distance between two adjacent graduationmarks.3.1.15 resolution of digital type torque indicators (numeric, displays, printouts, etc.)the resolution is the smallest change intorque that can be displayed on the digital torque indicator, a
46、t any applied torque. Appendix X1 describes a method for determiningresolution.3.1.15.1 DiscussionIf the torque indication, for either type of torque indicator, fluctuates by more than twice the resolution, as described in 3.1.15 or3.1.16, the resolution, expressed as torque, shall be equal to one-h
47、alf the range of the fluctuation.3.1.16 resolution of the torque indicatorsmallest change of torque that can be estimated or ascertained on the torque indicatingapparatus of the testing machine or device, at any applied torque. Appendix X1 describes a method for determining resolution.3.1.17 torquev
48、ector product of force and length, expressed in terms of N-m, lbf-in., etc.3.2.10 torque capable torque-capable testing machinea testing machine or device that has provision for applying a torque toa specimen.4. Significance and Use4.1 Testing machines that apply and indicate torque are used in many
49、 industries, in many ways. They may be used in a researchlaboratory to measure material properties, and in a production line to qualify a product for shipment. No matter what the end useof the machine may be, it is necessary for users to know the amount of torque that is applied, and that the accuracy of the torquevalue is traceable to the National Standards. SI. This standard provides a procedure to verify these machines and devices, in orderthat the indicated torque values may be traceable. A key element to having metrologi
