1、BSI Standards PublicationBS ISO 18338:2015Metallic materials Torsiontest at ambient temperatureBS ISO 18338:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 18338:2015.The UK participation in its preparation was entrusted to Technical Committee ISE/101/2, D
2、uctility testing.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2015.Publis
3、hed by BSI Standards Limited 2015ISBN 978 0 580 80646 9 ICS 77.040.10 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 September 2015.Amendments/corrigenda iss
4、ued since publicationDate T e x t a f f e c t e dBS ISO 18338:2015 ISO 2015Metallic materials Torsion test at ambient temperatureMatriaux mtalliques Essai de torsion temprature ambianteINTERNATIONAL STANDARDISO18338First edition2015-09-15Reference numberISO 18338:2015(E)BS ISO 18338:2015ISO 18338:20
5、15(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or po
6、sting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41
7、22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 18338:2015ISO 18338:2015(E)Foreword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Symbols and designations 35 Principle of test 46 Test piece 56.1 Shape and dimensions of test pieces . 56.1.1 Cylinder test pieces 56.1.2 Tube test piec
8、es 56.1.3 Preparation of test pieces. 67 Determination of original cross-sectional dimensions 77.1 Cylinder test pieces . 77.2 Tube test pieces 78 Accuracy of the testing apparatus 78.1 Testing machine . 78.2 Troptometer 79 Conditions of testing . 810 Determination of the properties 810.1 Calculatio
9、ns of shear stress and shear strain . 810.2 Determination of the slope of linear portion of shear stress-shear strain curve 810.3 Torsional proof strength, plastic torsion 910.4 Upper torsional yield strength and the lower torsional yield strength 1010.5 Determination of torsional strength . 1110.6
10、Determination of maximum plastic shear strain 1111 Test report 12Annex A (informative) Determination of the reference proof strength, plastic torsion and reference torsional strength .13Bibliography .17 ISO 2015 All rights reserved iiiContents PageBS ISO 18338:2015ISO 18338:2015(E)ForewordISO (the I
11、nternational Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee
12、has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnica
13、l standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in a
14、ccordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. De
15、tails of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and does not constitute an
16、 endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee r
17、esponsible for this document is ISO/TC 164, Mechanical testing of metals, Subcommittee SC 2, Ductility testing.iv ISO 2015 All rights reservedBS ISO 18338:2015INTERNATIONAL STANDARD ISO 18338:2015(E)Metallic materials Torsion test at ambient temperature1 ScopeThis International Standard specifies th
18、e method for torsion test at room temperature of metallic materials. The tests are conducted at room temperature to determine torsional properties.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application
19、. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 377, Steel and steel products Location and preparation of samples and test pieces for mechanical testingISO 9513, Metallic materials Ca
20、libration of extensometers used in uniaxial testingASTM E2624, Standard Practice for Torque Calibration of Testing Machines and DevicesDIN 51309, Materials testing machines Calibration of static torque measuring devices3 Terms and definitionsFor the purposes of this document, the following terms and
21、 definitions apply.3.1troptometer gauge lengthLelength of the parallel reduced section of the test piece for measurement of angle of twist by means of a troptometer3.2torqueTmoment of couple that generates or tends to generate rotation or torsion3.3maximum torqueTmfor materials displaying discontinu
22、ous yielding, highest torque that the test piece withstands during the test after the yielding period, or for materials displaying no discontinuous yielding, highest torque that the test piece withstands during the test3.4angle of twistangle of relative rotation measured between two planes normal to
23、 the test-pieces longitudinal axial over the gauge lengthNote 1 to entry: See Figure 1. ISO 2015 All rights reserved 1BS ISO 18338:2015ISO 18338:2015(E)3.5shear angleangle due to shearing displacement at surface of test piece along the gauge lengthNote 1 to entry: See Figure 1.3.6shear stressany mom
24、ent during the test, torque, T , divided by the original polar section modulus, Wp3.7shearing displacementLarc length swept out by the cylinder or major tube radius moving through the angle of twist, also being equivalent to the gauge length sweeping through the shear angleNote 1 to entry: See Figur
25、e 1.3.8shear strainbased on the gauge length, the increase of the shearing displacement, L, at any moment during the test, expressed as a percentage of the gauge length Le, or is equal to the tangent of the shear angle, 3.9slopemGslope of the linear, elastic portion of the shear stress-shear strain
26、curve3.10torsional proof strength, plastic torsionpshear stress at which the plastic component of shear strain, due to torsion at the test piece outer surface, is equal to a specified percentageNote 1 to entry: A suffix is added to the subscript to indicate the prescribed percentage, e.g. p035,.3.11
27、torsional yield strengthwhen the metallic material exhibits a yield phenomenon, shear stress corresponding to the point reached during the torsion test at which plastic deformation occurs without any increase in the torque3.11.1upper torsional yield strengtheHmaximum value of shear stress prior to t
28、he first decrease in torque when the discontinuous yielding occurs3.11.2lower torsional yield strengtheLlowest value of shear stress during discontinuous yielding, ignoring any initial transient effects3.12torsional strengthmshear stress corresponding to the maximum torque, Tm2 ISO 2015 All rights r
29、eservedBS ISO 18338:2015ISO 18338:2015(E)3.13maximum plastic shear strainmaxmaximum plastic shear strain component at the outer surface when total separation of the test piece occurs3.14reference torsional proof strength, plastic torsionrpshear stress at the outer surface of a test piece, calculated
30、 according to Nadais expression, when cross-section of the test piece is in partly plastic torsion and attained the proof plastic shear strainNote 1 to entry: A suffix is added to the subscript to indicate the prescribed percentage, e.g. rp035,.3.15reference torsional strengthrmmaximum shear stress
31、is calculated according to the Nadais expression for fractured test piecedidTLeTLg3334Figure 1 Basic symbols for torsion test4 Symbols and designationsSymbols and corresponding designations are given in Table 1 and Figure 1 or elsewhere in this International Standard where they appear. ISO 2015 All
32、rights reserved 3BS ISO 18338:2015ISO 18338:2015(E)Table 1 Symbols and designationsSymbol Designation UnitTest pieced original external diameter of a tube or a cylinder test piece parallel length portion mmdioriginal internal diameter of the parallel length of a tube test piece mmLcparallel length m
33、mLetroptometer gauge length mmLttotal length of the test piece mmWporiginal polar section modulus see Formulae (2) and (3) mm3TorqueT Torque NmmAngle of twist shearing displacement angle of twist rad shear angle radL shearing displacement mmShear stress shear strain shear stress MPaa increment in sh
34、ear stress MPa shear strain % Increment in shear strain %pspecified plastic shear strain %maxmaximum plastic shear strain %Yield strength proof strength torsional strengthmGslope of elastic portion of the shear stress-shear strain curvebMPaeHupper torsional yield strength MPaeLlower torsional yield
35、strength MPaptorsional proof strength, plastic torsion MPamtorsional strength MParpreference torsional proof strength, plastic torsion MParmreference torsional strength MPaa1 MPa = 1 Nmm2.bIn the elastic portion of the shear stress-shear strain curve, the value of slope may not necessarily represent
36、 the shear modulus of elasticity. The value can closely agree with the value of shear modulus of elasticity if optimal conditions (high resolution of troptometer, high accuracy of torque measuring system, perfect alignment of the test piece, etc.) are used.5 Principle of testThe test piece is subjec
37、ted to continuously increasing angle of twist, generally to fracture, for the determination of one or more of the mechanical properties such as elastic slope, torsional proof strength, torsional yield strength, torsional strength and maximum plastic shear strain.4 ISO 2015 All rights reservedBS ISO
38、18338:2015ISO 18338:2015(E)6 Test piece6.1 Shape and dimensions of test pieces6.1.1 Cylinder test piecesThe shape and dimensions for cylinder test pieces are shown in Figure 2. The shape and size for two ends of the test piece should be in coincidence with the testing machine gripping part. It is re
39、commended that the test pieces be 10 mm diameter, 50 mm or 100 mm gauge length, and 70 mm or 120 mm parallel length. If other test pieces are used, the parallel length should be the sum of gauge length and two times diameter.Keyr transition radiusNOTE The shape of the test-piece heads is only given
40、as a guide.Figure 2 Cylinder test piece6.1.2 Tube test piecesThe shape and dimensions for tube test pieces are shown in Figure 3. The parallel length for tube test pieces should be the sum of gauge length and two times external diameter. Tube test pieces should be straight and round, plugged at both
41、 ends. The plugged two ends should not be in the parallel length part of tube test pieces. The shape and size for plugs are shown in Figure 4. ISO 2015 All rights reserved 5BS ISO 18338:2015ISO 18338:2015(E)Keyg gripped end p plugd original external diameter dioriginal internal diameterFigure 3 Tube
42、 test pieceKeyg gripped end R plug transition radiusA parallel and straight part of the plug, here A 40 mmNOTE The diameter of the plug shall have a slight taper from the grip limiting line to the curved section.Figure 4 Plugs for tube test pieces6.1.3 Preparation of test piecesThe test pieces shall
43、 be taken and prepared in accordance with the requirement of the relevant International Standards for the different materials. If applicable, the test pieces shall meet the requirement of tensile test pieces specified in ISO 377.6 ISO 2015 All rights reservedBS ISO 18338:2015ISO 18338:2015(E)7 Deter
44、mination of original cross-sectional dimensions7.1 Cylinder test piecesThe external diameter of the cylinder test piece should be measured at sufficient cross-sections perpendicular to the longitudinal axis in the central region of the parallel length of the test piece. The measuring error of diamet
45、er should not exceed 0,5 %. A minimum of three cross-sections is recommended. The average diameter measured will be used for the calculation of the original polar section modulus, Wp.7.2 Tube test piecesThe external diameter and internal diameter for tube test pieces should be measured at two ends a
46、nd on two directions perpendicular to each other, respectively. The measuring error of external diameter and internal diameter should not exceed 0,5 %.The average external diameter and internal diameter measured will be used for the calculation of the original polar section modulus, Wp.8 Accuracy of
47、 the testing apparatus8.1 Testing machine8.1.1 Either one of the gripping parts of the testing machine can freely move along the axial direction during torsion test and the two gripping parts should be in good alignment.8.1.2 The angle of twist shall be applied continuously on the test piece without
48、 shock and vibration.8.1.3 The indicated torque value of testing machine shall be calibrated periodically for the range of torque used in the determination, and the relative error shall not exceed 1,0 %.8.1.4 The torque measuring system shall be calibrated periodically according to ASTM E2624 or DIN
49、 51309.8.2 Troptometer8.2.1 The troptometer used here employs an extensometer to measure the linear displacement caused by an angular displacement of the test piece. Troptometers based on other principles or using other types of displacement sensors are acceptable as long as they provide measurements with equivalent accuracies. All kinds of troptometers shouldnt be used for measuring angle of twist unless the below requirements can be satisfied.8.2.2 The troptometers shou
