BS 3518-3-1963 Methods of fatigue testing - Direct stress fatigue tests《疲劳试验方法 第3部分 直接应力疲劳试验》.pdf

1、BRITISH STANDARD BS3518-3: 1963 Methods of Fatigue Testing Part 3: Direct stress fatigue testsBS3518-3:1963 This British Standard, having been approved by the MechanicalEngineering IndustryStandards Committee and endorsed by the Chairman ofthe Engineering Divisional Council, was published under thea

2、uthority of the General Council on 16th April,1963 BSI 03-1999 The following BSI references relate to the work on this standard: Committee references MEE/37 and MEE/37/12 Draft for comment D62/4058 ISBN0580035921 Co-operating organizations The Mechanical Engineering Industry Standards Committee, und

3、er whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Admiralty Gas Council Air Ministry High Commission of India Associated Offices Technical Committee Institute of Marine Engineers

4、 Association of Consulting Engineers Institute of Petroleum (Incorporated) Institution of Civil Engineers Association of Mining Electrical and Institution of Gas Engineers Mechanical Engineers Institution of Heating and Ventilating British Chemical Plant Manufacturers Engineers Association Instituti

5、on of Mechanical Engineers British Compressed Air Society Institution of Mechanical Engineers British Electrical and Allied Manufacturers (Automobile Division) Association Institution of Production Engineers* British Engineers Association Locomotive and Allied Manufacturers British Gear Manufacturer

6、s Association Association of Great Britain British Internal Combustion Engine Machine Tool Trades Association Manufacturers Association Ministry of Labour (H.M. Factory Inspectorate) British Iron and Steel Federation* Ministry of Power British Railways Board* Ministry of Public Building and Works Cr

7、own Agents for Oversea Governments and Ministry of Transport Administrations National Coal Board D.S.I.R. National Engineering Laboratory* National Physical Laboratory (D.S.I.R.)* Electricity Council, The Generating Board and Radio Industry Councils the Area Boards in England and Wales War Office* E

8、ngineering Equipment Users Association The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this standard: Aluminium Federation Insti

9、tute of Welding British Cast Iron Research Association Institution of Engineering Inspection British Non-ferrous Metals Research Ministry of Aviation Association Royal Aeronautical Society British Welding Research Association Society of British Aircraft Constructors Copper Development Association Sp

10、ring Manufacturers Research Association D.S.I.R. Building Research Station Individual manufacturers of testing machines D.S.I.R. Forest Products Laboratory Amendments issued since publication Amd. No. Date CommentsBS 3518-3:1963 BSI 03-1999 i Contents Page Co-operating organizations Inside front cov

11、er Foreword ii 1 Scope 1 2 Object of test 1 3 Principle of test 1 4 Symbols and definitions 1 5 Size and shape of test piece 2 6 Preparation of test piece 3 7 Mounting of test piece 3 8 Speed of testing 4 9 Application of load 4 10 Endurances 4 11 Presentation of results 4 Figure 1 Test pieces of ci

12、rcular cross-section 1 Figure 2 Test pieces of rectangular cross-section 2BS3518-3:1963 ii BSI 03-1999 Foreword In order to keep abreast of progress in the industries concerned, British Standards are subject to periodical review. Suggestions for improvements will be recorded and in due course brough

13、t to the notice of the committees charged with the revision of the standards to which they refer. A complete list of British Standards, numbering over4000, indexed and cross-indexed for reference, together with an abstract of each standard, will be found in the Institutions Yearbook, price15s. This

14、standard makes reference to the following British Standards: BS 872, Abrasive papers and cloths (technical products). BS 3518, Methods of fatigue testing. Part 1, General principles. This British Standard, which forms part of a series of standards dealing with fatigue testing, specifies the requirem

15、ents for carrying out direct stress fatigue tests in normal temperature and pressure conditions, and is intended for use in conjunction with BS 3518-1, “General principles”, which gives guidance in this specialized form of mechanical testing. In preparing this standard, the drafting committee has gi

16、ven consideration to current general practice, and recommendations are made concerning the size and form of test pieces to be employed. It is strongly emphasized that care should be taken in preparing test pieces, and details concerning the machining operations and surface finish required are includ

17、ed. It is hoped that this Standard will help to unify testing procedure and thereby facilitate the comparison of fatigue properties. It is not intended to encourage the introduction of fatigue tests as acceptance tests for materials whose suitability for constructional purposes can be assessed by si

18、mpler means. NOTEWhere metric equivalents are stated, the figures in British units are to be regarded as the Standard. The metric conversions are approximate. More accurate values should be based on the tables in BS 350, “Conversion factors and tables”. A British Standard does not purport to include

19、 all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i

20、and ii, pages1 to 4 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.BS3518-3:1963 BSI 03-1999 1 1 Scope This British Standard gives the conditions for carrying out d

21、irect stress fatigue tests on test pieces without deliberately introduced stress concentrations. The tests are carried out at room temperature, in air, the loading applied to the test piece being along the longitudinal axis passing through the centroid of each cross-section. Whilst the form, prepara

22、tion and testing of test pieces of circular and rectangular cross-section are described, component testing and other specialized forms of test are not included in this standard. 2 Object of test Tests are made to determine fatigue properties, generally the S/N curve as described in BS 3518-1: “Gener

23、al principles”. 3 Principle of test Nominally identical test pieces are mounted in a direct stress fatigue testing machine and subjected to the required loading condition, which induces any one of the types of cyclic stress illustrated in Figure3 of BS 3518-1, “General principles”. 4 Symbols and def

24、initions In this British Standard the following symbols (seeFigure 1 and Figure 2) are used: Further symbols and definitions relating to fatigue testing are given in BS 3518-1, “General principles”. Symbol Definition D The diameter of the gripped end of the test piece. d The diameter of the test pie

25、ce where the stress is a maximum. L c Parallel length. r The transition radius from parallel length to gripped ends or the continuous radius between the gripped ends. a Thickness of test section of test piece of rectangular cross-section. b Width of test piece of rectangular cross-section where the

26、stress is a maximum. B Width of test piece of rectangular cross-section at the gripped end. Figure 1 Test pieces of circular cross-sectionBS3518-3:1963 2 BSI 03-1999 5 Size and shape of test piece a. Forms of test piece. The test piece may be of: i) Circular cross-section, with tangentially blending

27、 fillets between the parallel length and the ends (Figure 1a) or with a continuous radius between the ends (Figure 1b). ii) Rectangular cross-section of uniform thickness over the test length, with tangentially blending fillets between the parallel length and the ends (Figure 2a) or with a continuou

28、s radius between the ends (Figure 2b). The ends of the test piece should be of a form to suit the type of machine used and the material being tested. The type of test piece employed will depend on the information required from the test and the form in which the material is available. If basic fatigu

29、e properties of a material are to be determined, it is preferable, where practicable to use test pieces of circular cross-section. For materials in round bar form, test pieces of circular cross-section are an obvious choice. Test pieces of rectangular cross-section are always used for testing sheet

30、or thin plate materials. For thick plate or forged bar material either form of test piece may be employed. b. Dimensions of test pieces. All the test pieces employed for a fatigue determination shall have the same nominal dimensions. When basic fatigue data are required, the following dimensions and

31、 tolerances shall apply. For other purposes the dimensions should be chosen to give a result representative of the material under test. i) Circular cross-section. The nominal value of the diameter, d, where the stress is at a maximum shall be between0.25in (6mm) and0.5 in(12.5mm). Where applicable,

32、the parallel length shall be parallel within 0.001in (0.02mm). For the purposes of calculating the load to be applied to obtain the required stress, the actual diameter of each test piece shall be measured to an accuracy of0.0005in (0.01mm). NOTEIn tests where the stress cycle runs into compression

33、the ratio L c /d should not be greater than4. It may be necessary to reduce this ratio considerably to avoid high stresses due to buckling. ii) Rectangular cross-section. The nominal values of the thickness, a, and width, b, shall be such that the area of the cross-section where the stress is at a m

34、aximum is between0.05in 2(32mm 2 ) and1.0in 2(640mm 2 ). Where applicable, the parallel length shall be parallel within0.001in(0.02mm). Figure 2 Test pieces of rectangular cross-sectionBS3518-3:1963 BSI 03-1999 3 For the purpose of calculating the load to be applied to obtain the required stress, th

35、e cross-sectional area shall be calculated from measurements of the appropriate dimensions with an error not more than 0.5per cent in each dimension. NOTE 1A larger range of cross-sectional area is permitted for test pieces of rectangular cross-section than for test pieces of circular cross-section,

36、 as the rectangular form is frequently used for obtaining data on sheet and plate material of widely varying thicknesses. NOTE 2The error of measurement permitted for test pieces of rectangular cross-section takes into account the possibility that such test pieces may be tested with their surfaces i

37、n the “as received” condition. iii) General. For either form of test piece where the test length is formed by a continuous radius, this shall not be less than6d or6b. The gripped ends of the test piece shall be symmetrical about the axis of the reduced test section. 6 Preparation of test piece a. Me

38、thod of machining. It is necessary to ensure that any shaping or machining operation required, either to rough the test piece out from a blank, or to machine it to size, does not alter the metallurgical structure or properties of the test piece. All cuts taken in machining shall be such as to minimi

39、ze work hardening of the surface of the test piece. Grinding may be used, particularly in finishing to size specimens of the harder steels, but an adequate supply of coolant shall be ensured so as to avoid undue heating of the surface. Throughout any machining or grinding procedures, the tool or cut

40、ter sharpness and setting, the condition of the wheel and the grinding machine and speeds and feeds should conform with good workshop practice for the material. The procedures should not cause heating or tearing of the surfaces of the test pieces. b. Turning. It is recommended that the following pro

41、cedure be adopted: i) In rough turning the test piece from a diameter x +0.2in (x +5mm) (x will generally be the diameter, d, plus a suitable allowance for surface finishing) to x +0.02in (x +0.5mm) the sequence and the depth of cuts should be: 0.05in (1.25mm), 0.03in (0.75mm), 0.01in(0.25mm). ii) F

42、rom a diameter of x+0.02in (x+0.5mm) tox, the sequence and depth of cuts should be: 0.005in (0.125mm),0.003in (0.075mm), 0.002in (0.05mm), using for these finishing cuts a feed not exceeding0.0025in (0.06mm) per revolution. c. Milling. This process may be applied in the extraction of test piece blan

43、ks from billets or plates, and, in the case of flat specimens, for machining such blanks to the finished test piece size. In selecting cutting speeds and feed rates, due regard shall be paid to the test piece material and for finishing cuts, to the quality of surface finish required. NOTEIt is not p

44、racticable to recommend a set procedure for milling. Cutting speeds and depths of cut differ for plain milling and face milling, whilst material composition and condition also influence these values. d. Grinding. For test pieces in material which cannot be readily turned or milled, it is recommended

45、 that the finishing operations are carried out by grinding. Where the strength properties of the material are developed in heat treatment, this may be carried out before grinding after rough machining to within x +0.02in (x +0.5mm). Test pieces should then be ground to size in the following manner:

46、0.001in (0.025mm) depth of cut to0.004in (0.1mm) oversize. 0.0002in (0.005mm) depth of cut to0.0012in (0.030mm) oversize. 0.0001 in (0.0025mm) depth of cut to size. e. Surface finishing. When the test piece has been machined or ground to nominal dimensions, it shall be polished either by hand or by

47、machine, using successively finer grades of emery paper. The polishing should generally be in a longitudinal direction, although intermediate stages may be done circumferentially in order to ensure that longitudinal scratches made by the coarser emery papers are removed. The direction of the final p

48、olishing stage should always be longitudinal. The polishing sequence employed shall be such that the finished test piece has a surface texture of d 54 in CLA. It will usually be found satisfactory to arrange the sequence of polishing so that the last paper used is600grade waterproof silicon carbide

49、paper. NOTEThe procedures given in sub-clauses “b”, “d”, and “e” represent standard practice for a wide range of materials. It should not be inferred that they are wholly applicable to all materials, or investigations e.g.where tests are made to investigate the effects on fatigue performance of particular surface finishes such as rough machined, fine machined, electrochemically plated, “as received” condition of rolled sheet and plate, extruded, etc. 7 Mounting of test piece Each test piece shall be mounted in the testing machine in such a manner that str