1、Designation: B 593 96 (Reapproved 2003)e1Standard Test Method forBending Fatigue Testing for Copper-Alloy Spring Materials1This standard is issued under the fixed designation B 593; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.e1NOTEParagraph 1.2 was updated edito
3、rially in January 2004.1. Scope*1.1 This test method describes procedures for the determi-nation of the reversed or repeated bending fatigue properties ofcopper alloy flat-sheet or strip-spring materials by fixed canti-lever, constant amplitude of displacement-type testing ma-chines. This method is
4、limited to flat stock ranging in thicknessfrom 0.005 to 0.062 in. (0.13 to 1.57 mm), to a fatigue-liferange of 105to 108cycles, and to conditions where nosignificant change in stress-strain relations occurs during thetest.NOTE 1This implies that the load-deflection characteristics of thematerial do
5、not change as a function of the number of cycles within theprecision of measurement. There is no significant cyclic hardening orsoftening.1.2 UnitsThe values stated in inch-pound units are re-garded as standard. The values given in parentheses aremathematical conversions to SI units that are provide
6、d forinformation purposes only and are not considered standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applic
7、a-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:E 206 Definitions of Terms Relating to Fatigue Testing andthe Statistical Analysis of Fatique Data2E 468 Practice for Presentation of Constant Amplitude Fa-tigue Test Results for Metallic Materials33. Terminolo
8、gy3.1 For terminology relating to this test method, refer toDefinitions E 206 and Practice E 468.4. Summary of Test Method4.1 A prepared test specimen of a specific wrought copperalloy flat-sheet or strip-spring material is mounted into a fixedcantilever, constant-deflection type fatigue testing mac
9、hine.The specimen is held at one end, acting as a cantilever beam,and cycled by flexure followed by reverse flexure untilcomplete failure. The number of cycles to failure is recorded asa measure of fatigue-life.5. Significance and Use5.1 The flexural fatigue test described in this test methodprovide
10、s information on the ability of a copper alloy flat-springmaterial to resist the development of cracks or general me-chanical deterioration as a result of a relatively large number ofcycles (generally in the range 105to 108) under conditions ofconstant displacement.5.2 This test method is primarily
11、a research and develop-ment tool which may be used to determine the effect ofvariations in materials on fatigue strength and also to providedata for use in selecting copper alloy spring materials forservice under conditions of repeated strain cycling.5.3 The results are suitable for direct applicati
12、on in designonly when all design factors such as loading, geometry of part,frequency of straining, and environmental conditions areknown. The test method is generally unsuitable for an inspec-tion test or a quality control test due to the amount of time andeffort required to collect the data.6. Appa
13、ratus6.1 Testing MachineThe fatigue testing machine is afixed-cantilever, constant-deflection type. In this machine (Fig.1) the test specimen shall be held as a cantilever beam in aclamp at one end and deflected by a concentrated load appliednear the other end of the apex of the tapered section (Fig
14、. 2).Either the clamp or the loading member may be adjusted sothat the deflection of the free end of the cantilever is eithercompletely reversed (mean displacement equal to zero) orgreater in one direction of bending (mean displacement notequal to zero).1This test method is under the jurisdiction of
15、 ASTM Committee B05 on Copperand Copper Alloys and is the direct responsibility of Subcommittee B05.06 onMethods of Test.Current edition approved Apr. 10, 2003. Published June 2003. Originallyapproved in 1973. Last previous edition approved in 1996 as B593 96.2Discontinued, see 1986 Annual Book of A
16、STM Standards, Vol 03.01.3Annual Book of ASTM Standards, Vol 03.01.1*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.6.2 A suitable counter and monitoring circuit is req
17、uired toprovide a direct readout of the number of cycles to completefailure, that is, separation into two pieces.7. Test Specimen7.1 The test specimen shall be of the fixed-cantilever type.Several such specimens which have been used successfully areshown in Fig. 2.7.2 It is important, therefore, tha
18、t care be exercised in thepreparation of test specimens, particularly in machining, toassure good workmanship. Improperly prepared test specimenscause unsatisfactory test results.7.2.1 The specimens are best prepared by cross milling astack, approximately 0.75 in. (19 mm) thick, including back-uppla
19、tes, for which 0.12-in. (3-mm) thick brass sheet stock maybe used.7.2.1.1 It is necessary to ensure that any cutting or machin-ing operation required to either rough cut the test specimenfrom the blank, or to machine it to size does not appreciablyalter the metallurgical structure or properties of t
20、he material.All cuts taken in machining should be such as to minimizework hardening of the test specimen.7.2.1.2 In selecting cutting speeds and feed rates, due regardshould be paid to the test-specimen material, and for finishingcuts, to the quality of the surface finish required.NOTE 2It is not pr
21、acticable to recommend a single procedure forfeeds, speeds, and depth of cut, since this will vary with the materialtested. The procedure used, however, should be noted in reporting testresults, since differences in procedure may produce variability in testresults among different laboratories.7.3 Th
22、e test specimen surface shall be in the as-receivedcondition. The edges shall not be roughed or smoothed, sincethis tends to give an apparent higher fatigue strength.4Burrs,however, may be removed by light stoning.7.4 Test specimens from material that is used in a thermallytreated condition, such as
23、 precipitation hardened or stressrelieved, shall be treated in a manner reflecting the way thematerial will be used. The procedure used should be noted inreporting test results.8. Calculation of Stress8.1 The maximum bending stress is calculated by using thesimple beam equation:S 5 6PL/bd2(1)where:S
24、 = desired bending stress, lb/in.2,P = applied load at the connecting pin (apex of triangle), lb,L = distance between the connecting pin and the point ofstress, in.,b = specimen width at length L from point of load appli-cation, in., andd = specimen thickness, in.9. Machine Calibration9.1 A loading
25、fixture such as that shown in Fig. 3 may beused to determine the load-deflection characteristics of thespecimen. In this fixture the specimen deflection and change inmoment arm under load are measured with the two microme-ters for a given load. The vertical micrometer measures the4George, R. G., and
26、 Mantle, J. B., “The Effect of Edge Preparation on theFatigue Life of Flat-Plate Specimens”, Materials Research and Standards, MTRSA,Am. Soc. Testing Mats., December 1962, p. 1000.FIG. 1 Fatigue MachinesB 593 96 (2003)e12deflection of loading pin, d, which follows the motion of theapex formed by the
27、 tapered sides. The horizontal micrometer,e, measures the foreshortening of the moment arm as applied tothe same locus. An average load-deflection curve is thenplotted from this corrected data. A minimum of three speci-mens should be used in this determination, representing theminimum, mean, and max
28、imum thicknesses of the material.9.1.1 Electrical resistance strain gages may be attached tothe specimen for simultaneous strain measurement. Adequatecorrection should be made, however, to compensate for gagethickness and possible stiffening of the test specimen, espe-cially for thin stock.59.1.2 Me
29、asure the machine displacement under dynamicconditions. This may be accomplished by optical means. Usespecimens having foil-type electrical resistance strain gagesmounted on the tapered area to verify that static and dynamicstrains gages mounted on the tapered area to verify that staticand dynamic s
30、trains are identical for a given displacement.From the load-deflection curve, plot a stress versus deflection5Perry, C. C., and Lissner, H. R., Strain Gage Primer, McGraw-Hill, New York,NY.NOTE 1All dimensions are in inches: in. 3 25.4 = mm.FIG. 2 Sheet or Strip Fatigue Test SpecimensB 593 96 (2003)
31、e13curve using as an approximation the distance from the loadpoint to the center of the tapered specimen area and the widthat that point for L and b, respectively.NOTE 3Since the specimen normally fails in the tapered region whichis designed to have a very nearly uniform outer fiber strain, the erro
32、rbetween this calculated stress value and that at the point of failure is small.10. Procedure10.1 Mount the test specimens in the machine and flex tofailure, that is, separation into two pieces. Determine thenumber of specimens and displacement levels required for agiven sample by consulting ASTM ST
33、P 91-A.611. Report11.1 Prepare reports in accordance with Practice E 468.12. Precision and Bias12.1 PrecisionThe following parameters are reported toimpact upon the precision of this test method:12.1.1 Characteristics of the specimen such as orientation ofgrains relative to the axial stress, grain s
34、ize, residual stress,previous strain history, dimensions.12.1.2 Testing conditions such as alignment of the speci-men, temperature variations, conditions of test equipment, ratioof error in load to the range in load values.12.2 BiasA statement of bias of this method requiresreference standard values
35、 for one or more materials based onmany measurements or round robin test data.7,8Such standardreference values or test data are presently not available.13. Keywords13.1 bending fatigue; bending fatigue testing; copper alloyflat strip; copper alloy spring; fatigue testing6A Guide for Fatigue Testing
36、and the Statistical Analysis of Fatigue Data,Second Edition, ASTM STP 91-A, AST-TA, 1963.7Torrey, M. N., and Gohn, G. R., “A Study of the Statistical Treatments ofFatigue Data”, Proceedings ASTM, Vol 56, p. 1091, 1956.8Torrey, M. N., Gohn, G. R., and Wilk, M. B., “A Study of The Variability in TheMe
37、chanical Properties of Alloy A Phosphor Bronze Strip”, Proceedings ASTM,Vol58, p. 893, 1958.FIG. 3 Load deflection test fixture for standard Bell Telephone Laboratories sheet metal fatigue test specimenB 593 96 (2003)e14SUMMARY OF CHANGESCommittee B05 has identified the location of selected changes
38、to this standard since the last issue(B 593-85 (1990) that may impact the use of this standard.(1) Added Summary of Test Method and Keywords sections.(2) Revised other sections to accomodate current ASTM formand style requirements.ASTM International takes no position respecting the validity of any p
39、atent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revisi
40、on at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your co
41、mments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrigh
42、ted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).B 593 96 (2003)e15
