1、Designation: B593 96 (Reapproved 2014)1Standard Test Method forBending Fatigue Testing for Copper-Alloy Spring Materials1This standard is issued under the fixed designation B593; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、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 U.S. Department of Defense.1NOTEEditorial changes were made in
3、Sections 1.1, 1.2, 3.1 and 3.2 in September 2014.1. Scope*1.1 This test method establishes procedures for the determi-nation of the reversed or repeated bending fatigue properties ofcopper alloy flat-sheet or strip-spring materials by fixedcantilever, constant deflection (that is, constant amplitude
4、 ofdisplacement)-type testing machines. This method 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
5、 the load-deflection characteristics of thematerial 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. Values given in parentheses a
6、re math-ematical conversions to SI units which are 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,
7、associated with its use. It is theresponsibility 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:2B846 Terminology for Copper and Copper AlloysB950 Gui
8、de for Editorial Procedures and Form of ProductSpecifications for Copper and Copper AlloysE206 Definitions of Terms Relating to Fatigue Testing andthe Statistical Analysis of Fatigue Data; Replaced byE 1150 (Withdrawn 1988)3E468 Practice for Presentation of Constant Amplitude Fa-tigue Test Results f
9、or Metallic Materials2.2 Other ASTM Documents:4ASTM STP 91-A3. Terminology3.1 For definition of terms relating to this test method, referto Definitions E206 and Practice E468.3.2 For definitions of terms related to copper and copperalloys, refer to Terminology B846.4. Summary of Test Method4.1 A pre
10、pared test specimen of a specific wrought copperalloy flat-sheet or strip-spring material is mounted into a fixedcantilever, constant-deflection 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 f
11、ailure. The number of cycles to failure is recorded asa measure of fatigue-life.5. Significance and Use5.1 The bending fatigue test described in this test methodprovides information on the ability of a copper alloy flat-springmaterial to resist the development of cracks or general me-chanical deteri
12、oration 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 a research and develop-ment tool which may be used to determine the effect ofvariations in materials on fatigue strength and also to
13、 provide1This test method is under the jurisdiction of ASTM Committee B05 on Copperand Copper Alloys and is the direct responsibility of Subcommittee B05.06 onMethods of Test.Current edition approved Sept. 1, 2014. Published September 2014. Originallyapproved in 1973. Last previous edition approved
14、in 2009 as B593 96 (2009)1.DOI: 10.1520/B0593-96R14E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The l
15、ast approved version of this historical standard is referenced onwww.astm.org.4For referenced ASTM documents, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Ba
16、rr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1data for use in selecting copper alloy spring materials forservice under conditions of repeated strain cycling.5.3 The results are suitable for direct application in designonly when all design factors such as loading, geom
17、etry 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. Apparatus6.1 Testing MachineThe fatigue testing machine is afixed-
18、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 taperedsection (Fig. 2). Either the clamp or the loading member maybe ad
19、justed 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 and monitoring circuit is required toprovide a direct readout of the number
20、 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, therefore, that care be exercised in thepreparation of test specimens,
21、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-upplates, for which 0.12-in. (3-mm) thick brass sheet stock ma
22、ybe 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 the material.All cuts taken in machining should be such as
23、 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 practicable to recommend a single procedure forfeeds, speed
24、s, 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 The test specimen surface shall be in the as-receivedcondit
25、ion. 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 condition, such as precipitation hardened or stress5George, R. G., and Mant
26、le, 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 MachinesB593 96 (2014)12relieved, shall be treated in a manner reflecting the way thematerial will be used. Th
27、e 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 = desired bending stress, lb/in.2,P = applied load at the connecting pin (apex of triangle), lb,L = distance between t
28、he connecting pin and the point ofstress, in.,b = specimen width at length L from point of loadapplication, in., andd = specimen thickness, in.9. Machine Calibration9.1 A loading fixture such as that shown in Fig. 3 may beused to determine the load-deflection characteristics of thespecimen. In this
29、fixture the specimen deflection and change inmoment arm under load are measured with the two microm-eters for a given load. The vertical micrometer measures thedeflection of loading pin, d, which follows the motion of theapex formed by the tapered sides. The horizontal micrometer,e, measures the for
30、eshortening of the moment arm as applied tothe same locus. An average load-deflection curve is thenNOTE 1All dimensions are in inches: in. 25.4 = mm.FIG. 2 Sheet or Strip Fatigue Test SpecimensB593 96 (2014)13plotted from this corrected data. A minimum of three speci-mens should be used in this dete
31、rmination, representing theminimum, 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 te
32、st specimen, espe-cially for thin stock.69.1.2 Measure 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 th
33、e tapered area to verify that staticand dynamic strains are identical for a given displacement.From the load-deflection curve, plot a stress 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 an
34、d b, respectively.NOTE 3Since the specimen normally fails in the tapered region whichis designed to have a very nearly uniform outer fiber strain, 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 fle
35、x tofailure, that is, separation into two pieces. Determine thenumber of specimens and displacement levels required for agiven sample by consulting ASTM STP 91-A.711. Report11.1 Prepare reports in accordance with Practice E468.12. Precision and Bias12.1 PrecisionThe following parameters are reported
36、 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 size, residual stress,previous strain history, dimensions.12.1.2 Testing conditions such as alignment of thespecimen, temperature variations, condi
37、tions of test equipment,ratio of error in load to the range in load values.12.2 BiasA statement of bias of this method requiresreference standard values for one or more materials based on6Perry, C. C., and Lissner, H. R., Strain Gage Primer, McGraw-Hill, New York,NY.7A Guide for Fatigue Testing and
38、the Statistical Analysis of Fatigue Data,Second Edition, ASTM STP 91-A, AST-TA, 1963.FIG. 3 Load deflection test fixture for standard Bell Telephone Laboratories sheet metal fatigue test specimenB593 96 (2014)14many measurements or round robin test data.8,9Such standardreference values or test data
39、are presently not available.13. Keywords13.1 bending fatigue; bending fatigue testing; copper alloyflat strip; copper alloy spring; fatigue testingSUMMARY OF CHANGESCommittee B05 has identified the principal changes to this standard test method that have been incorporatedsince the B593-96 (Reapprove
40、d) 20091issue as follows (Approved Sept. 1, 2014):(1) The test method was revised in several sections to complywith the selected wording in Guide B950.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Use
41、rs 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 revision at any time by the responsible technical committee and must be reviewed every
42、 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 comments will receive careful consideration at a meeting of theresponsible technic
43、al 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 copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken
44、, 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). Permission rights to photocop
45、y the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 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 Variability in TheMechanical Properties of Alloy A Phosphor Bronze Strip,” Proceedings ASTM,Vol58, p. 893, 1958.B593 96 (2014)15
