1、Designation: E 23 07ae1An American National StandardStandard Test Methods forNotched Bar Impact Testing of Metallic Materials1This standard is issued under the fixed designation E 23; the number immediately following the designation indicates the year of originaladoption or, in the case of revision,
2、 the year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon (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.e1NOTEEditorial changes made throug
3、hout in September 2007.1. Scope1.1 These test methods describe notched-bar impact testingof metallic materials by the Charpy (simple-beam) test and theIzod (cantilever-beam) test. They give the requirements for:test specimens, test procedures, test reports, test machines (seeAnnexA1) verifying Charp
4、y impact machines (seeAnnexA2),optional test specimen configurations (see Annex A3), pre-cracking Charpy V-notch specimens (see Annex A4), designa-tion of test specimen orientation (see Annex A5), and deter-mining the percent of shear fracture on the surface of brokenimpact specimens (see Annex A6).
5、 In addition, information isprovided on the significance of notched-bar impact testing (seeAppendix X1), methods of measuring the center of strike (seeAppendix X2).1.2 These test methods do not address the problems associ-ated with impact testing at temperatures below 196 C (320F, 77 K).1.3 The valu
6、es stated in SI units are to be regarded as thestandard. Inch-pound units are provided for information only.1.4 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
7、and health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in Section 5.2. Referenced Documents2.1 ASTM Standards:2B 925 Practices for Production and Preparation of PowderMetallurgy (P/M) Test SpecimensE 177 Practice for
8、 Use of the Terms Precision and Bias inASTM Test MethodsE 399 Test Method for Linear-Elastic Plane-Strain FractureToughness KIcof Metallic MaterialsE 604 Test Method for Dynamic Tear Testing of MetallicMaterialsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Tes
9、t MethodE 1313 Guide for Recommended Formats for Data RecordsUsed in the Computerization of Mechanical Test Data forMetals3. Summary of Test Method3.1 The essential features of an impact test are: a suitablespecimen (specimens of several different types are recognized),a set of anvils, and specimen
10、supports on which the testspecimen is placed to receive the blow of the moving mass, amoving mass that has sufficient energy to break the specimenplaced in its path, and a device for measuring the energyabsorbed by the broken specimen.4. Significance and Use4.1 These test methods of impact testing r
11、elate specificallyto the behavior of metal when subjected to a single applicationof a force resulting in multi-axial stresses associated with anotch, coupled with high rates of loading and in some caseswith high or low temperatures. For some materials andtemperatures the results of impact tests on n
12、otched specimens,when correlated with service experience, have been found topredict the likelihood of brittle fracture accurately. Furtherinformation on significance appears in Appendix X1.5. Precautions in Operation of Machine5.1 Safety precautions should be taken to protect personnelfrom the swing
13、ing pendulum, flying broken specimens, andhazards associated with specimen warming and cooling media.1These test methods are under the jurisdiction of ASTM Committee E28 onMechanical Testing and are the direct responsibility of Subcommittee E28.07 onImpact Testing.Current edition approved June 1, 20
14、07. Published July 2007. Originally approvedin 1933. Last previous edition approved 2007 as E 23 07.2For 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 Do
15、cument Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Apparatus6.1 General Requirements:6.1.1 The testing machine shall be a pendulum type of rigidconstruction.6.1.2 The testing machine shall be de
16、signed and built toconform with the requirements given in Annex A1.6.2 Inspection and Verification6.2.1 Inspection procedures to verify impact machines di-rectly are provided in A2.2 and A2.3. The items listed in A2.2must be inspected annually.6.2.2 The procedures to verify Charpy V-notch machinesin
17、directly, using verification specimens, are given in A2.4.Charpy impact machines must be verified directly and indi-rectly annually.7. Test Specimens7.1 Configuration and Orientation:7.1.1 Specimens shall be taken from the material as speci-fied by the applicable specification. Specimen orientations
18、hould be designated according to the terminology given inAnnex A5.7.1.2 The type of specimen chosen depends largely upon thecharacteristics of the material to be tested. A given specimenmay not be equally satisfactory for soft nonferrous metals andhardened steels; therefore, many types of specimens
19、arerecognized. In general, sharper and deeper notches are requiredto distinguish differences in very ductile materials or whenusing low testing velocities.7.1.3 The specimens shown in Figs. 1 and 2 are those mostwidely used and most generally satisfactory. They are particu-larly suitable for ferrous
20、 metals, excepting cast iron.37.1.4 The specimen commonly found suitable for die-castalloys is shown in Fig. 3.7.1.5 The specimens commonly found suitable for PowderMetallurgy (P/M) materials are shown in Figs. 4 and 5. P/Mimpact test specimens shall be produced following the proce-dure in Practice
21、B 925. The impact test results of thesematerials are affected by specimen orientation. Therefore,3Report of Subcommittee XV on Impact Testing of CommitteeA-3 on Cast Iron,Proceedings, ASTM, Vol 33 Part 1, 1933.Notch length to edge 90 62Adjacent sides shall be at 90 6 10 minCross-section dimensions 6
22、 0.075 mmLength of specimen (L) +0, 2.5 mmCentering of notch (L/2) 6 1mmAngel of notch 61Radius of notch 60.025 mmLigament Length: 60.025 mmType A specimen 60.025 mmType B and C specimen 60.075 mmFinish requirements 2 m on notched surface and opposite face; 4 m on other two surfacesFIG. 1 Charpy (Si
23、mple-Beam) Impact Test Specimens, Types A, B, and CE2307ae12NOTE 1Permissible variations shall be as follows:Notch length to edge 90 62Cross-section dimensions 60.025 mmLength of specimen +0, 2.5 mmAngle of notch 61Radius of notch 60.025 mmLigament Length 60.025 mmAdjacent sides shall be at 90 6 10
24、minFinish requirements 2 m on notched surface and opposite face; 4 m on other two surfacesFIG. 2 Izod (Cantilever-Beam) Impact Test Specimen, Type DNOTE 1Two Izod specimens may be cut from this bar.NOTE 2Blow shall be struck on narrowest face.FIG. 3 Izod Impact Test Bar for Die Castings AlloysE2307a
25、e13unless otherwise specified, the position of the specimen inthe machine shall be such that the pendulum will strike asurface that is parallel to the compacting direction. For P/Mmaterials the impact test results are reported as unnotchedabsorbed impact energy.7.1.6 Sub-size and supplementary speci
26、men recommenda-tions are given in Annex A3.7.2 Specimen Machining:7.2.1 When heat-treated materials are being evaluated, thespecimen shall be finish machined, including notching, afterthe final heat treatment, unless it can be demonstrated that theimpact properties of specimens machined before heat
27、treatmentare identical to those machined after heat treatment.7.2.2 Notches shall be smoothly machined but polishing hasproven generally unnecessary. However, since variations innotch dimensions will seriously affect the results of the tests,adhering to the tolerances given in Fig. 1 is necessary (A
28、ppen-dix X1.2 illustrates the effects from varying notch dimensionson Type A specimens). In keyhole specimens, the round holeshall be carefully drilled with a slow feed rate. The slot may becut by any feasible method, but care must be exercised incutting the slot to ensure that the surface of the dr
29、illed holeopposite the slot is not damaged.7.2.3 Identification marks shall only be placed in the fol-lowing locations on specimens: either of the 10-mm squareends; the side of the specimen that faces up when the specimenDimensionsmm in.L- Overall Length 55.0 6 1.0 2.16 6 0.04W-Width 10.00 6 0.13 0.
30、394 6 0.005T-Thickness 10.00 6 0.13 0.394 6 0.005NOTE 1Adjacent sides shall be 906 10 min.FIG. 4 Unnotched Charpy (Simple Beam) Impact Test Specimen for P/M Structural MaterialsDimensionsmm in.L- Overall Length 75.0 6 1.5 2.95 6 0.06W-Width 10.00 6 0.13 0.394 6 0.005T-Thickness 10.00 6 0.13 0.394 6
31、0.005NOTE 1Adjacent sides shall be 906 10 min. Editorially corrected in August 2007.FIG. 5 Izod (Cantilever-Beam) Impact Test Specimen for P/M Structural MaterialsE2307ae14is positioned in the anvils (see Note 1); or the side of thespecimen opposite the notch. No markings, on any side of thespecimen
32、, shall be within 15 mm of the center line of the notch.An electrostatic pencil may be used for identification purposes,but caution must be taken to avoid excessive heat.NOTE 1Careful consideration should be given before placing identi-fication marks on the side of the specimen to be placed up when
33、positionedin the anvils. If the test operator is not careful, the specimen may be placedin the machine with the identification marking resting on the specimensupports. Under these circumstances, the absorbed energy value obtainedmay be unreliable.8. Procedure8.1 Preparation of the Apparatus:8.1.1 Pe
34、rform a routine procedure for checking impactmachines at the beginning of each day, each shift, or just priorto testing on a machine used intermittently. It is recommendedthat the results of these routine checks be kept in a log book forthe machine. After the testing machine has been ascertained toc
35、omply with Annex A1 and Annex A2, carry out the routinecheck as follows:8.1.1.1 Visually examine the striker and anvils for obviousdamage and wear.8.1.1.2 Check the zero position of the machine by using thefollowing procedure: raise the pendulum to the latched posi-tion, move the pointer to near the
36、 maximum capacity of therange being used, release the pendulum, and read the indicatedvalue. The pointer should indicate zero on machines readingdirectly in energy. On machines reading in degrees, the readingshould correspond to zero on the conversion chart furnished bythe machine manufacturer.NOTE
37、2On machines that do not compensate for windage and frictionlosses, the pointer will not indicate zero. In this case, the indicated values,when converted to energy, shall be corrected for frictional losses that areassumed to be proportional to the arc of swing.8.1.1.3 To ensure that friction and win
38、dage losses are withinallowable tolerances, the following procedure is recom-mended: raise the pendulum to the latched position, move thepointer to the negative side of zero, release the pendulum andallow it to cycle five times (a forward and a backward swingtogether count as one swing), prior to th
39、e sixth forward swing,set the pointer to between 5 and 10 % of the scale capacity ofthe dial, after the sixth forward swing (eleven half swings),record the value indicated by the pointer, convert the reading toenergy (if necessary), divide it by 11 (half swings), then divideby the maximum scale valu
40、e being used and multiply it by 100to get the percent friction. The result, friction and windage loss,shall not exceed 0.4 % of scale range capacity being tested andshould not change by more than 10 % of friction measurementspreviously made on the machine. If the friction and windageloss value does
41、exceed 0.4 % or is significantly different fromprevious measurements, check the indicating mechanism, thelatch height, and the bearings for wear and damage. However,if the machine has not been used recently, let the pendulumswing for 50 to 100 cycles, and repeat the friction test beforeundertaking r
42、epairs to the machine.8.2 Test Temperature Considerations:8.2.1 The temperature of testing affects the impact proper-ties of most materials. For materials with a body centered cubicstructure, a transition in fracture mode occurs over a tempera-ture range that depends on the chemical composition andm
43、icrostructure of the material. Test temperatures may bechosen to characterize material behavior at fixed values, orover a range of temperatures to characterize the transitionregion, lower shelf, or upper shelf behavior, or all of these. Thechoice of test temperature is the responsibility of the user
44、 ofthis test method and will depend on the specific application.For tests performed at room temperature, a temperature of 206 5C (68 6 9F) is recommended.8.2.2 The temperature of a specimen can change signifi-cantly during the interval it is removed from the temperatureconditioning environment, tran
45、sferred to the impact machine,and the fracture event is completed (see Note 5). When usinga heating or cooling medium near its boiling point, use datafrom the references in Note 5 or calibration data with thermo-couples to confirm that the specimen is within the statedtemperature tolerances when the
46、 striker contacts the specimen.If excessive adiabatic heating is expected, monitor the speci-men temperature near the notch during fracture.8.2.3 Verify temperature-measuring equipment at least ev-ery six months. If liquid-in-glass thermometers are used, aninitial verification shall be sufficient, h
47、owever, the device shallbe inspected for problems, such as the separation of liquid, atleast twice annually.8.2.4 Hold the specimen at the desired temperature within 61C(6 2 F) in the temperature conditioning environment(see 8.2.4.1 and 8.2.4.2). Any method of heating or cooling ortransferring the s
48、pecimen to the anvils may be used providedthe temperature of the specimen immediately prior to fractureis essentially the same as the holding temperature (see Note 5).The maximum change in the temperature of the specimenallowed for the interval between the temperature conditioningtreatment and impac
49、t is not specified here, because it isdependent on the material being tested and the application. Theuser of nontraditional or lesser used temperature conditioningand transfer methods (or sample sizes) shall show that thetemperature change for the specimen prior to impact iscomparable to or less than the temperature change for astandard size specimen of the same material that has beenthermally conditioned in a commonly used medium (oil, air,nitrogen, acetone, methanol), and transferred for impact within5 seconds (see Note 5). Three temperature conditi
