1、Designation: B 593 96 (Reapproved 2009)1Standard 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, th
2、e year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1NOTEEditorially updated in August 2009
3、.1. Scope1.1 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 deflection (that is, constant amplitude ofdisplacement)-type testing machines. This meth
4、od is limited toflat stock ranging in thickness from 0.005 to 0.062 in. (0.13 to1.57 mm), to a fatigue-life range of 105to 108cycles, and toconditions where no significant change in stress-strain relationsoccurs during the test.NOTE 1This implies that the load-deflection characteristics of themateri
5、al do 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 to beregarded as standard. The values given in parentheses aremathematical conversions to SI units that a
6、re provided forinformation only and are not considered standard.1.3 The following safety hazard caveat pertains only to thetest methods(s) described in this test method.1.3.1 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility
7、 of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B 846 Terminology for Copper and Copper AlloysE 206 Discontinued 1988; Definitions of Terms Relating
8、toFatigue Testing and the Statistical Analysis of FatigueData; Replaced by E 11503E 468 Practice for Presentation of Constant Amplitude Fa-tigue Test Results for Metallic Materials2.2 Other ASTM Documents:4ASTM STP 91-A3. Terminology3.1 For terminology relating to this test method, refer toDefinitio
9、ns E 206 and Practice E 468.3.2 For determination of terms relating to copper and copperalloys, refer to Terminology B 846.4. 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-deflectio
10、n type fatigue testing machine.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 bending fatigue test described i
11、n this test methodprovides 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
12、test method is primarily 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 suit
13、able for direct application in designonly when all design factors such as loading, geometry of part,frequency of straining, and environmental conditions are1This test method is under the jurisdiction of ASTM Committee B05 on Copperand Copper Alloys and is the direct responsibility of Subcommittee B0
14、5.06 onMethods of Test.Current edition approved April 1, 2009. Published August 2009. Originallyapproved in 1973. Last previous edition approved in 2003 as B 593 96 (2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For An
15、nual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer
16、Service at serviceastm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.known. 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 d
17、ata.6. Apparatus6.1 Testing MachineThe fatigue testing machine is afixed-cantilever, constant-deflection type machine. In this ma-chine (Fig. 1) the test specimen shall be held as a cantileverbeam in a clamp at one end and deflected by a concentratedload applied near the other end of the apex of the
18、 taperedsection (Fig. 2). Either the clamp or the loading member maybe adjusted so that the deflection of the free end of thecantilever is either completely reversed (mean displacementequal to zero) or greater in one direction of bending (meandisplacement not equal to zero).6.2 A suitable counter an
19、d monitoring circuit is required 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.Examples of specimens that are typically used are shown inFig. 2.7.2 It is important
20、, therefore, that 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, incl
21、uding back-upplates, 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
22、 properties of the 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.NO
23、TE 2It is not practicable 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 lab
24、oratories.7.3 The 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.5Burrs,however, may be removed by light stoning.7.4 Test specimens from material that is used in a thermallytreated co
25、ndition, such as 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:5Geor
26、ge, R. G., and 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 (2009)12S 5 6PL/bd2(1)where:S = desired bending stress, lb/in.2,P = applie
27、d 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 fixture such as that shown in Fig. 3 may beus
28、ed 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 thedeflection of loading pin, d, which follows the motion of theape
29、x formed by the 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
30、, mean, and maximum 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
31、stock.69.1.2 Measure the machine displacement under dynamicconditions. This may be accomplished by optical means. Usespecimens having foil-type electrical resistance strain gages6Perry, C. C., and Lissner, H. R., Strain Gage Primer , McGraw-Hill, NewYork, NY.NOTE 1All dimensions are in inches: in. 3
32、 25.4 = mm.FIG. 2 Sheet or Strip Fatigue Test SpecimensB 593 96 (2009)13mounted on the tapered area to verify that static and dynamicstrains gages mounted on the tapered area to verify that staticand dynamic strains are identical for a given displacement.From the load-deflection curve, plot a stress
33、 versus deflectioncurve 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 s
34、train, the errorbetween 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 con
35、sulting ASTM STP 91-A.711. 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
36、stress, grain size, 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
37、standard values for one or more materials based onmany measurements or round robin test data.8,9Such standardreference values or test data are presently not available.13. Keywords13.1 bending fatigue; bending fatigue testing; copper alloyflat strip; copper alloy spring; fatigue testing7A Guide for F
38、atigue Testing and the Statistical Analysis of Fatigue Data,Second Edition, ASTM STP 91-A, AST-TA, 1963.8Torrey, M. N., and Gohn, G. R., “A Study of the Statistical Treatments ofFatigue Data,” Proceedings ASTM, Vol 56, p. 1091, 1956.9Torrey, M. N., Gohn, G. R., and Wilk, M. B., “ A Study of The Vari
39、ability inThe Mechanical Properties of Alloy A Phosphor Bronze Strip,” Proceedings ASTM,Vol 58, p. 893, 1958.FIG. 3 Load deflection test fixture for standard Bell Telephone Laboratories sheet metal fatigue test specimenB 593 96 (2009)14ASTM International takes no position respecting the validity of
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42、ur comments 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 cop
43、yrighted 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 (2009)15
