ASTM E23-2018 Standard Test Methods for Notched Bar Impact Testing of Metallic Materials.pdf

1、Designation: E23 16bE23 18 An American National StandardStandard Test Methods forNotched Bar Impact Testing of Metallic Materials1This standard is issued under the fixed designation E23; the number immediately following the designation indicates the year of originaladoption or, in the case of revisi

2、on, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () 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 These test methods

3、describe notched-bar impact testing of metallic materials by the Charpy (simple-beam) test and the Izod(cantilever-beam) test. They give the requirements for: test specimens, test procedures, test reports, test machines (see Annex A1)verifying Charpy impact machines (see Annex A2), optional test spe

4、cimen configurations (see Annex A3), designation of testspecimen orientation (see Terminology E1823), and determining the percent of shear fracture on the surface of broken impactspecimens shear fracture appearance (see Annex A4). In addition, information is provided on the significance of notched-b

5、arimpact testing (see Appendix X1), and methods of measuring the center of strike (see Appendix X2).1.2 These test methods do not address the problems associated with impact testing at temperatures below 196 C (77 K).1.3 The values stated in SI units are to be regarded as standard. No other units of

6、 measurement are included in this standard.1.3.1 ExceptionSection 89 and Annex A4 provide inch-pound units for information only.1.4 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

7、 appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 56.1.5 This international standard was developed in accordance with internationally recognized principle

8、s on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2B925 Practices for Production and Prep

9、aration of Powder Metallurgy (PM) Test SpecimensE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE1823 Terminology Relating to Fatigue and Fracture TestingE2298 Test Method for I

10、nstrumented Impact Testing of Metallic Materials3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 absorbed energy, FL, nwork spent to fracture a specimen in a single pendulum swing, as measured by a compenstatedindicating device.3.1.2 direct verification, nprocess that ensures a

11、ll parts that may affect measured absorbed energy are within specifieddimensional tolerances.3.1.3 indirect verification, nprocess that ensures the average absorbed energy from testing a set of verification specimenscorresponds to the certified absorbed energy within a specified tolerance (see A2.4.

12、1).3.1.4 lateral expansion L, nthe maximum increase in the thickness of the specimen as a result of the impact test, expressedin mm.1 These test methods are under the jurisdiction of ASTM Committee E28 on Mechanical Testing and are the direct responsibility of Subcommittee E28.07 on ImpactTesting.Cu

13、rrent edition approved June 1, 2016June 1, 2018. Published June 2016November 2018. Originally approved in 1933. Last previous edition approved 2016 asE23 16a.E23 16b. DOI: 10.1520/E0023-16B.10.1520/E0023-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer

14、Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the 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 pre

15、vious version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult 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 Ch

16、anges section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.4.1 DiscussionLateral expansion is used as a measure of ductility.3.1.5 range capacity, nmaximum available energy for a specific pend

17、ulum setting.3.1.5.1 DiscussionOn single range machines this corresponds to the machine capacity.3.1.6 shear fracture appearance, SFA, nthe amount of fracture surface in the specimen that failed in a shear (stable) mode,expressed in percent.E23 1824. Summary of Test Method4.1 The essential features

18、of an impact test are: a suitable specimen (specimens of several different types are recognized), a setof anvils, and specimen supports on which the test specimen is placed to receive the blow of the moving mass, a moving massthat has sufficient energy to break the specimen placed in its path, and a

19、 an indicating device for measuring the energy absorbedby energy of the broken specimen.5. Significance and Use5.1 These test methods of impact testing relate specifically to the behavior of metal when subjected to a single application ofa force resulting in multi-axial stresses associated with a no

20、tch, coupled with high rates of loading and in some cases with highor low temperatures. For some materials and temperatures the results of impact tests on notched specimens, when correlated withservice experience, have been found to predict the likelihood of brittle fracture accurately. Further info

21、rmation on significanceappears in Appendix X1.6. Precautions in Operation of Machine6.1 Safety precautions should be taken to protect personnel from the swinging pendulum, flying broken specimens, and hazardsassociated with specimen warming and cooling media.7. Apparatus7.1 General Requirements:7.1.

22、1 The testing machine shall be a pendulum type of rigid construction.7.1.2 The testing machine shall be designed and built to conform with the requirements given in Annex A1.7.2 Inspection and Verification:7.2.1 Inspection procedures to verify Procedures for direct verification of impact machines di

23、rectly are provided in A2.2 andA2.3. The items listed in A2.2 must be inspectedrequire direct verification annually.7.2.2 The procedures to verify Charpy machines indirectly, Procedures for indirect verification of Charpy machines, usingverification specimens, are given in A2.4. Charpy impact machin

24、es must be verified directly and indirectly require direct andindirect verification annually.8. Test Specimens8.1 Configuration and Orientation:8.1.1 Specimens shall be taken from the material as specified by the applicable specification.8.1.2 The type of specimen chosen depends largely upon the cha

25、racteristics of the material to be tested. A given specimen maynot be equally satisfactory for soft nonferrous metals and hardened steels; therefore, many types of specimens are recognized. Ingeneral, sharper and deeper notches are required to distinguish differences in very ductile materials or whe

26、n using low testingvelocities.8.1.3 The specimens shown in Figs. 1 and 2Fig. 1 and Fig. 2 are those most widely used and most generally satisfactory. Theyare particularly suitable for ferrous metals, excepting cast iron.3 The Charpy specimen designations are V-notch and U-notch.NOTE 1Keyhole notch s

27、pecimen is similar to U-notch, except the notch width is 1.6 mm or less.8.1.4 The specimens commonly found suitable for powder metallurgy materials are shown in Figs. 3 and 4Fig. 3 and Fig. 4.Powder metallurgy impact test specimens shall be produced following the procedure in Practices B925. The imp

28、act test results ofthese materials are affected by specimen orientation. Therefore, unless otherwise specified, the position of the specimen in themachine shall be such that the pendulum will strike a surface that is parallel to the compacting direction. For powder metallurgymaterials the impact tes

29、t results are reported as unnotched absorbed impact energy.8.1.5 Sub-size and supplementary specimen recommendations are given in Annex A3.8.2 Specimen Machining:8.2.1 When heat-treated materials are being evaluated, the specimen shall be finish machined, including notching, after the finalheat trea

30、tment, unless it can be demonstrated that the impact properties of specimens machined before heat treatment are identicalto those machined after heat treatment.8.2.2 Notches shall be smoothly machined, but polishing has proven generally unnecessary. However, since variations in notchdimensions will

31、seriously affect the results of the tests, adhering to the tolerances given in Fig. 1 is necessary (Appendix X1.2illustrates the effects from varying notch dimensions on V-notch specimens).NOTE 2Variations in notch dimensions will affect the results of the tests. Appendix X1.2 illustrates the effect

32、s from varying notch dimensions onV-notch specimens.NOTE 3In keyhole notch specimens, carefully drill the round hole shall be carefully drilled with a slow feed rate. The slot may be cut by any feasible3 Report of Subcommittee XV on Impact Testing of Committee A-3A03 on Cast Iron, Proceedings, ASTM,

33、 Vol 33 Part 1, 1933.E23 183ID Number Description Dimension Tolerance1 Length of specimen 55 mm +0/-2.5 mm2 Centering of notch 1 mm3 Notch length to edge 90 24 Adjacent sides angle 90 0.175 Width 10 mm 0.075 mm6 Thickness 10 mm 0.075 mm7V Ligament length, Type V 8 mm 0.025 mm7U Ligament length, Type

34、 U 5 mm 0.075 mm8V Radius of notch, Type V 0.25 mm 0.025 mm8U Radius of notch, Type U 1 mm 0.025 mm9 Angle of notch 45 1A Surface finish requirements 2 m (Ra) #B Surface finish requirements 4 m (Ra) #FIG. 1 Charpy (Simple-Beam) Impact Test Specimens, V-Notch and U-NotchID Number Description Dimensio

35、n Tolerance1 Length of specimen 75 mm +0/-2.5 mm2 Notch to top 28 mm3 Notch length to edge 90 24 Adjacent sides angle 90 0.175 Width 10 mm 0.025 mm6 Thickness 10 mm 0.025 mm7 Ligament length 8 mm 0.025 mm8 Radius of notch 0.25 mm 0.025 mm9 Angle of notch 45 1A Surface finish requirement 2 m (Ra) #B

36、Surface finish requirement 4 m (Ra) #FIG. 2 Izod (Cantilever-Beam) Impact Test SpecimenE23 184method, but care shall be exercised Exercise care in cutting the slot to ensure that the surface of the drilled hole opposite the slot is not damaged.8.2.3 Identification marks shall only be placed in the f

37、ollowing locations on specimens: either of the 10-mm square ends; theside of the specimen that faces up when the specimen is positioned in the anvils (see Note 34); or the side of the specimen oppositethe notch. No markings, on any side of the specimen, shall be within 10 mm of the center line of th

38、e notch. Permanent markers,laser engraving, scribes, electrostatic pencils, and other reasonable marking methods may be used for identification purposes.However, some marking methods can result in damage to the specimens if not used correctly. For example, excessive heat fromelectrostatic pencils or

39、 deformation to the specimen from stamping can change the mechanical properties of the specimen.Therefore, care shall always be taken to avoid damage to the specimen. Stamping and other marking processes that result indeformation of the specimen should only be used on the ends of the specimens, prio

40、r to notching.NOTE 4Careful consideration should be given before placing identification marks on the side of the specimen to be placed up when positioned inthe anvils. If the test operator is not careful, the specimen can be placed in the machine with the identification marking resting on the specim

41、en supports(that is, facing down). Under these circumstances, the absorbed energy value obtained may be unreliable.8.2.4 Test specimens shall conform to the dimensions and tolerances shown in Fig. 1 or any other applicable figure in this testmethod.DimensionsmmL- Overall Length 55.0 1.0W-Width 10.00

42、 0.13T-Thickness 10.00 0.13NOTE 1Adjacent sides shall be at 906 10 min.FIG. 3 Unnotched Charpy (Simple Beam) Impact Test Specimenfor Metal Powder Structural MaterialsDimensionsmmL- Overall Length 75.0 1.5W-Width 10.00 0.13T-Thickness 10.00 0.13NOTE 1Adjacent sides shall be at 906 10 min.FIG. 4 Izod

43、(Cantilever-Beam) Impact Test Specimen for P/MStructural MaterialsE23 1859. Procedure9.1 Preparation of the Apparatus:9.1.1 Perform a routine procedure for checking impact machines at the beginning of each day, each shift, or just prior to testingon a machine used intermittently. It is recommended t

44、hat the The results of these routine checks should be kept in a log book forthe machine. After the testing machine has been ascertained to comply with Annex A1 and Annex A2Annex A1 and Annex A2,carry out the routine check as follows:9.1.1.1 Visually examine the striker and anvils for obvious damage

45、and wear.9.1.1.2 Check the zero position of the machine by using the following procedure: raise the pendulum to the latched position,move the pointer to near the maximum capacity of the range being used, release the pendulum, and read the indicated value. Thepointer should machine with a free swing.

46、 The indicating device shall indicate zero on machines reading directly in absorbedenergy. On machines reading in degrees, the reading shouldshall correspond to zero absorbed energy on the conversion chartfurnished by the machine manufacturer. On machines that do not compensate for total frictional

47、losses, the analog scale will notindicate zero. In this case, the indicated values, when converted to absorbed energy, shall be corrected for total frictional lossesthat are assumed to be proportional to the arc of the swing.NOTE 4On machines that do not compensate for windage and friction losses, t

48、he pointer will not indicate zero. In this case, the indicated values, whenconverted to energy, shall be corrected for frictional losses that are assumed to be proportional to the arc of swing.9.1.1.3 The percent friction and windage loss shall not exceed 0.4 % of the scale range capacity being test

49、ed and should notchange by more than 10 % of the percent friction and windage loss measurements previously recorded on the machine. If thepercent friction and windage loss does exceed 0.4 % or is significantly different from previous measurements, check the indicatingmechanism,device, the latch height, and the bearings for wear and damage. However, if the machine has not been used recently,let the pendulum swing for 50 to 100 cycles, and repeat the percent friction and windage loss test before undertaking