1、Designation: B598 09B598 14Standard Practice forDetermining Offset Yield Strength in Tension for CopperAlloys1This standard is issued under the fixed designation B598; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t 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.1. Scope*1.1 This practice establishes the requ
3、irements for determining offset yield strength (0.01 %, 0.02 %, and 0.05 % offset) at roomtemperature. It is intended for copper alloys in tempers commonly used for spring applications, and materials thicker than 0.010in. (0.25 mm).1.1.1 The primary application of this practice is intended for flat
4、strip materials that are used for springs; however, this practicecan be used for other product forms, such as wire, rod, and bar.1.2 UnitsThe values Values stated in inch-pound units are to be regarded as standard. The values given in parentheses aremathematical conversions to SI units thatwhich are
5、 provided for information only and are not considered standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applic
6、ability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B950B846 Guide for Editorial Procedures and Form of Product Specifications for Terminology for Copper and Copper AlloysE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of
7、 Mechanical TestingE8/E8M Test Methods for Tension Testing of Metallic MaterialsE74 Practice of Calibration of Force-Measuring Instruments for Verifying the Force Indication of Testing MachinesE83 Practice for Verification and Classification of Extensometer Systems3. Terminology3.1 For definitions o
8、f terms related to copper and copper alloys, refer to Terminology B846.3.2 For definitions of terms relatingrelated to mechanical testing, refer to Terminology E6.4. Summary of Practice4.1 To determine the offset yield strength, it is necessary to acquire data (autographic or numerical) from which a
9、 stress-straindiagram may be drawn. The stress at which a specified deviation of strain from the linear portion of the stress-strain curve occursis the yield strength at that particular offset.5. Significance and Use5.1 This practice may be used for approximating a limiting design stress at room tem
10、perature and, in some cases, forapproximating the range of elastic behavior. Elastic limit, or the greatest stress that a material is capable of sustaining without anypermanent strain remaining upon complete release of the stress, is a more technically accurate design parameter; however, the1 This p
11、ractice is under the jurisdiction of ASTM Committee B05 on Copper and Copper Alloys and is the direct responsibility of Subcommittee B05.06 on Methods ofTest.Current edition approved April 1, 2009April 1, 2014. Published May 2009May 2014. Originally approved in 1974. Last previous edition approved i
12、n 20042009 asB598 98 (2004).B598 09. DOI: 10.1520/B0598-09.10.1520/B0598-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on th
13、e ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users co
14、nsult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocke
15、n, PA 19428-2959. United States1elastic limit is extremely difficult to measure in routine testing. Caution should be used in applying such values to predict thebehavior of flat or wire springs in bending, torsion or other stress modes, or at temperatures other than that at which thedetermination is
16、 made.6. Apparatus6.1 Standard testing machine of adequate capacity, conforming to the requirements of Practices E4 and E74.6.2 Class B-1 or more accurate Extensometers, conforming to the requirements of Practice E83 and suitable to the tension testspecimen required for the application.6.3 Extensome
17、ter Calibrator, or similar device accurate to 0.00002 in. (0.0005 mm).7. Test Specimen7.1 Tension test specimens shall be selected from Test Methods E8/E8M as appropriate for the product form.8. Procedure8.1 Follow the accepted practices for preparation to perform a tension test in accordance with T
18、est Methods E8/E8M. Specialcare in the preparation of thin-gage samples, including contour and edge preparation should be used.8.2 Select the load range so that the yield strength falls within the upper half of the chart load range used. Choose a strainmagnification so that the 0.0001, 0.0002 or 0.0
19、005-in./in. (or mm/mm) increment of strain can be readily determined from thechart.8.3 Apply a preload of nominally 10 % of the known or anticipated offset yield strength to the test specimen to align the gripsand to remove all slack and curvature from the specimen.8.4 Seat the extensometer firmly o
20、n the test specimen while maintaining the preload.Apply the load uniformly until the desiredtesting speed is attained. The rate of stress application shall not exceed 100 000 psi/min (11.5 MPa/s). Take care that the recordingequipment is functioning correctly and indicating the load properly.8.5 Rem
21、ove the extensometer when the curve indicates adequate departure from linear behavior to reveal the desired offset,without stopping the test.8.6 Determine the offset yield strength from the stress-strain diagram as described in Test Methods E8/E8M.9. Calculation and Report9.1 Determine the load wher
22、e the offset line intersects the stress-strain curve. This load in pounds divided by the original crosssection area is the yield strength and is reported as yield strength (offset value).10. Precision and Bias10.1 PrecisionThe following parameters are reported to impact upon the precision of this pr
23、actice:10.1.1 Characteristics of the specimen such as orientation of grains relative to the axial stress, grain size, residual stress,previous strain history, dimensions, and eccentricity.10.1.2 Testing conditions such as alignment of the specimen, speed of testing, temperature, temperature variatio
24、ns, conditionsof test equipment, ratio of error in load to the range in load values, and ratio of error in extension measurement to the range inextension values.10.1.3 Interpretation of data such as whether graphical or digital data were taken, calibration of recording or data-loggingdevice, number
25、of data pairs used to obtain slope of stress-strain curve.10.2 BiasA statement of bias of this practice requires reference standard values for one or more materials based on manymeasurements or round-robin test data. Such standard reference values or test data are presently not available.11. Keyword
26、s11.1 offset yield strength; tensile test; yield strengthB598 142SUMMARY OF CHANGESCommittee B05 has identified the location of selected principal changes to this standard since the last issue(practice that have been incorporated since the B598 98 (2004)B598 09) that may impact the use of thisstanda
27、rd. issue as follows (Approved April 1, 2009.)2014):(1) The specification was revised in many sections to comply with the selected wording in Guide B950.(1) Minor editorial changesAdded Terminology B846 to sectionsthe 1.2,Terminology 2.1, (removedSection 3 2.2),and 3.1,to7.1,the 8.1,Referenced 8.4,D
28、ocuments 8.6,Section 2and Keywords. No technical changes have been madeASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of
29、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 five years andif not revised, either reapproved or withdrawn.Your comments are
30、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 technical committee, which you may attend. If you feel that your comments have not recei
31、ved 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, PA 19428-2959,United States. Individual reprints (single or multiple copies) of
32、 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 photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).B598 143
