1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 1352:2011Metallic materials Torque-controlled fatigue testingBS ISO 1352:2011 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 1352:2
2、011.The UK participation in its preparation was entrusted to TechnicalCommittee ISE/101/6, Fatigue testing of metals and metal matrixcomposites.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necess
3、aryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 53937 4ICS 77.040.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Commit
4、tee on 31 August 2011.Amendments issued since publicationDate Text affectedBS ISO 1352:2011Reference numberISO 1352:2011(E)ISO 2011INTERNATIONAL STANDARD ISO1352Second edition2011-04-15Metallic materials Torque-controlled fatigue testing Matriaux mtalliques Essais de fatigue par couple de torsion co
5、mmand BS ISO 1352:2011ISO 1352:2011(E) COPYRIGHT PROTECTED DOCUMENT ISO 2011 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in w
6、riting from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2011 All rights reservedBS ISO
7、1352:2011ISO 1352:2011(E) ISO 2011 All rights reserved iiiContents Page Foreword iv 1 Scope1 2 Normative references1 3 Terms and definitions .1 4 Symbols and abbreviated terms 3 5 Principle of test3 6 Test plan.4 7 Shape and size of specimen 4 7.1 Form4 7.2 Dimensions 5 8 Preparation of specimens.6
8、8.1 General .6 8.2 Machining procedure 6 8.3 Sampling and marking6 8.4 Surface conditions of specimen 7 8.5 Dimensional checks7 8.6 Storage and handling7 9 Apparatus.7 9.1 Testing machine 7 9.2 Instrumentation for test monitoring 9 10 Test procedure.9 10.1 Mounting of specimen 9 10.2 Speed of testin
9、g.9 10.3 Application of torque 9 10.4 Calculation of nominal torsional stress10 10.5 Recording of temperature and humidity.10 10.6 Failure and termination criteria10 11 Test report10 Annex A (informative) Presentation of results.14 Annex B (informative) Verification of alignment of torsional fatigue
10、 testing machines .18 Annex C (informative) Measuring uniformity of torsional strain (stress) state20 Bibliography23 BS ISO 1352:2011ISO 1352:2011(E) iv ISO 2011 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodie
11、s (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 has been established has the right to be represented on that committee. International organizations,
12、 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 electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO
13、/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the m
14、ember bodies casting a vote. 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. ISO 1352 was prepared by Technical Committee ISO/TC 164, Mechanical test
15、ing of metals, Subcommittee SC 5, Fatigue testing. This second edition cancels and replaces the first edition (ISO 1352:1977), which has been technically revised. BS ISO 1352:2011INTERNATIONAL STANDARD ISO 1352:2011(E) ISO 2011 All rights reserved 1Metallic materials Torque-controlled fatigue testin
16、g 1 Scope This International Standard specifies the conditions for performing torsional, constant-amplitude, nominally elastic stress fatigue tests on metallic specimens without deliberately introducing stress concentrations. The tests are typically carried out at ambient temperature in air (ideally
17、 at between 10 C and 35 C) by applying a pure couple to the specimen about its longitudinal axis. While the form, preparation and testing of specimens of circular cross-section and tubular cross-section are described in this International Standard, component and other specialized types of testing ar
18、e not included. Similarly, low-cycle torsional fatigue tests carried out under constant-amplitude angular displacement control, which lead to failure in a few thousand cycles, are also excluded. 2 Normative references The following referenced documents are indispensable for the application of this d
19、ocument. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 554:1976, Standard atmospheres for conditioning and/or testing Specifications 3 Terms and definitions For the purposes of this
20、document, the following terms and definitions apply. 3.1 maximum stress maxhighest algebraic value of shear stress in the stress cycle 3.2 minimum stress minlowest algebraic value of shear stress in the stress cycle 3.3 mean stress mstatic component of the shear stress NOTE It is one half of the alg
21、ebraic sum of the maximum shear stress and the minimum shear stress: max minm2+= BS ISO 1352:2011ISO 1352:2011(E) 2 ISO 2011 All rights reserved3.4 stress amplitude avariable component of stress NOTE It is one half of the algebraic difference between the maximum shear stress and the minimum shear st
22、ress: max mina2= 3.5 number of cycles N number of cycles applied at any stage during the test 3.6 stress ratio R algebraic ratio of the minimum shear stress to the maximum shear stress in one cycle NOTE It is expressed as minmaxR =3.7 stress range range between the maximum and minimum shear stresses
23、 NOTE It is expressed as max min= 3.8 fatigue life at failure Nfnumber of stress cycles to failure in a specified condition 3.9 fatigue strength at N cycles Nvalue of the shear stress amplitude at a stated stress ratio under which the specimen would have a life of N cycles 3.10 torque T twisting for
24、ce producing shear stress or twisting deformation about the axis of the specimen BS ISO 1352:2011ISO 1352:2011(E) ISO 2011 All rights reserved 34 Symbols and abbreviated terms D diameter or width across flats of the gripped ends of the specimen NOTE The value of D may be different for each end of th
25、e specimen. d diameter of specimen of circular cross-section, where stress is maximum do outer diameter of test section of specimen of tubular cross-section, where stress is maximum di inner diameter of test section of specimen of tubular cross-section Lc length of test section Lp parallel length of
26、 specimens test section Lg gauge length of the specimens test section r transition blending radius at ends of test section which starts the transition from d to D (see Figures 3 and 4) NOTE This curve need not be a true arc of a circle over the whole of the distance between the end of the test secti
27、on and the start of the enlarged end for specimens of the types shown in Figure 3. 5 Principle of test Nominally identical specimens are mounted on a torsional fatigue testing machine and subjected to the loading condition required to introduce cycles of torsional stress. Any one of the types of cyc
28、lic stress illustrated in Figure 1 may be used. The test waveform shall be constant-amplitude sinusoidal, unless otherwise specified. In an axially symmetrical specimen, change of mean torque does not introduce a different type of stress system and mean stress in torsion may always be regarded as po
29、sitive in sign. The torque is applied to the specimen about the longitudinal axis passing through the centroid of the cross-section. The test is continued until the specimen fails or until a predetermined number of stress cycles has been exceeded. Cracks produced from torsional fatigue testing may b
30、e parallel to the longitudinal axis of the specimen, perpendicular to the longitudinal axis or at any angle between these two. Tests shall be conducted at ambient temperature (ideally between 10 C and 35 C) unless otherwise agreed with the customer. The results of fatigue testing can be affected by
31、atmospheric conditions, and where controlled conditions are required, ISO 554:1976, 2.1, applies. BS ISO 1352:2011ISO 1352:2011(E) 4 ISO 2011 All rights reserved6 Test plan Before commencing testing, the following shall be agreed by the parties concerned and any modifications shall be mutually agree
32、d upon: a) the form of specimen to be used (see Clause 7); b) the stress ratio(s) to be used; c) the objective of the tests, i.e. which of the following is to be determined: the fatigue life at a specified stress amplitude; the fatigue strength at a specified number of cycles; a full Whler or SN cur
33、ve; d) the number of specimens to be tested and the test sequence; e) the number of cycles a specimen is subjected to before the test is terminated. NOTE 1 Some methods of data presentation are given in Annex A. See ISO 12107 for details, including data analysis procedure and statistical presentatio
34、n. NOTE 2 Commonly employed numbers of cycles for test termination are 107cycles for structural steels, and 108cycles for other steels and non-ferrous alloys. 7 Shape and size of specimen 7.1 Form Generally, a specimen having a fully machined test section of one of the types shown in Figures 3 and 4
35、 should be used. The specimen may be of circular cross-section, with tangentially blending fillets between the test section and the ends (see Figure 3), or tubular cross-section, with tangentially blending fillets between the test section and the ends in the outer surface (see Figure 4). For tubular
36、 specimens, the diameter of the inner surface at the ends may be greater than or equal to that at the test section. For a specimen having a inner diameter at the ends greater than that at the test section, crack initiation or failure outside the test section invalidates the test, which should be cou
37、nted as a discontinued (stopped) test at the number of cycles completed. Fatigue test results determined using the specimen of tubular cross-section are not always comparable to those obtained from the specimen of circular cross-section. Therefore, caution should be exercised when comparing fatigue
38、lives obtained on the same material from specimens having different cross-sections. Typical specimen ends are shown in Figure 5. It is recommended that ends suitable for meeting the alignment criterion be chosen. BS ISO 1352:2011ISO 1352:2011(E) ISO 2011 All rights reserved 57.2 Dimensions 7.2.1 Spe
39、cimens of circular cross-section It is recommended that the geometric dimensions given in Table 1 be used (see also Figure 3). Table 1 Dimensions for specimens of circular cross-section Diameter of cylindrical gauge length, in millimetres 5 u d u 12 Length of test section Lcu 5d Transition radius (f
40、rom parallel section to grip end) r W 3d External diameter (grip end) D W 2d The tolerance on d shall be 0,05 mm. To calculate the applied torque loading, the actual diameter of each specimen shall be measured to an accuracy of 0,01 mm. Care should be taken not to damage the surface when measuring t
41、he specimen prior to testing. It is important that general tolerances of the specimen respect the two following properties: parallelism: 0,005d or better concentricity: 0,005d or better These values are expressed in relation to the axis or reference plane. 7.2.2 Specimens with tubular cross-section
42、In general, the considerations applicable to specimens of circular cross-section also apply to tests on tubular specimens. The specimen wall thickness shall be large enough to avoid instabilities during cyclic loading without violating the thin-walled tube criterion, i.e. a mean diameter-to-wall thi
43、ckness ratio of 10:1 or greater is required. It is recommended that the geometric dimensions given in Table 2 be used (see also Figure 4). Table 2 Dimensions for specimens of tubular cross-section Wall thickness in test section, t 0,05doto 0,1doOuter diameter of test section doTransition radius (fro
44、m parallel section to grip end), r W 3doLength of test section, Lc1doto 3doExternal diameter (grip end) D W 1,5doConcentricity between the outer diameter, do, and the inner diameter, di, should be maintained within 0,01t. BS ISO 1352:2011ISO 1352:2011(E) 6 ISO 2011 All rights reserved8 Preparation o
45、f specimens 8.1 General In any fatigue test programme designed to characterize the intrinsic properties of a material, it is important to observe the following recommendations in the preparation of specimens. Deviation from these recommendations is permitted if the test program aims to determine the
46、 influence of a specific factor (surface treatment, oxidation, etc.). In all cases, any deviations shall be noted in the test report. Specimens should be machined from normally stress-free material unless otherwise agreed with the customer. 8.2 Machining procedure Machining the specimens can induce
47、residual stress on the specimen surface that could affect the test results. These stresses can be induced by heat gradients at the machining stage stresses associated with deformation of the material or microstructural alterations. However, they can be reduced by using an appropriate final machining
48、 procedure, especially prior to a final polishing stage. For harder materials, grinding rather than tool operation (turning or milling) may be preferable. Grinding: from 0,1 mm of the final dimension at a rate of no more than 0,005 mm/pass. Polishing: remove the final 0,025 mm with papers of decreas
49、ing grit size. It is recommended that the final direction of polishing be along the specimen axial direction. For tubular specimens the bore should be fine-honed. Failure to observe the above can result in alteration in the microstructure of the material. This phenomenon can be caused by an increase in temperature and by the strain-hardening induced by machining; it can be a matter of a change in phase or, more frequently, of surface recrystallization. This invalidates the t
