Designation:E23−16An American National Standard Standard Test Methods for

Notched Bar Impact Testing of Metallic Materials1

This standard is issued under thefixed designation E23;the number immediately following the designation indicates the year of original

adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript

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.


1.1These test methods 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 specimen configurations(see Annex A3),desig-nation of test specimen orientation(see Terminology E1823), and determining the percent of shear fracture on the surface of broken impact specimens(see Annex A4).In addition,infor-mation is provided on the significance of notched-bar impact testing(see Appendix X1),and methods of measuring the center of strike(see Appendix X2).

1.2These test methods do not address the problems associ-ated with impact testing at temperatures below–196°C(77K).

1.3The values stated in SI units are to be regarded as standard.No other units of measurement are included in this standard.

1.3.1Exception—Section8and Annex A4provide inch-pound units for information only.

1.4This standard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility 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.Specific precau-tionary statements are given in Section5.

2.Referenced Documents

2.1ASTM Standards:2

B925Practices for Production and Preparation of Powder Metallurgy(PM)Test Specimens

E177Practice for Use of the Terms Precision and Bias in ASTM Test Methods

E691Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

E1823Terminology Relating to Fatigue and Fracture Testing E2298Test Method for Instrumented Impact Testing of Metallic Materials

3.Summary of Test Method

3.1The essential features of an impact test are:a suitable specimen(specimens of several different types are recognized), a set of anvils,and specimen supports on which the test specimen is placed to receive the blow of the moving mass,a moving mass that has sufficient energy to break the specimen placed in its path,and a device for measuring the energy absorbed by the broken specimen.

4.Significance and Use

4.1These test methods of impact testing relate specifically to the behavior of metal when subjected to a single application of a force resulting in multi-axial stresses associated with a notch,coupled with high rates of loading and in some cases with high or low temperatures.For some materials and temperatures the results of impact tests on notched specimens, when correlated with service experience,have been found to predict the likelihood of brittle fracture accurately.Further information on significance appears in Appendix X1.

5.Precautions in Operation of Machine

5.1Safety precautions should be taken to protect personnel from the swinging pendulum,flying broken specimens,and hazards associated with specimen warming and cooling media.


6.1General Requirements:

6.1.1The testing machine shall be a pendulum type of rigid construction.

6.1.2The testing machine shall be designed and built to conform with the requirements given in Annex A1.

6.2Inspection and Verification:

6.2.1Inspection procedures to verify impact machines di-rectly are provided in A2.2and A2.3.The items listed in A2.2 must be inspected annually.

1These test methods are under the jurisdiction of ASTM Committee E28on

Mechanical Testing and are the direct responsibility of Subcommittee E28.07on

Impact Testing.

Current edition approved Jan.1,2016.Published May2016.Originally approved previous edition approved2012as E23–12c.DOI:10.1520/E0023-


2For referenced ASTM standards,visit the ASTM website,,or

contact ASTM Customer Service at service@ Annual Book of ASTM

Standards volume information,refer to the standard’s Document Summary page on

the ASTM website.

*A Summary of Changes section appears at the end of this standard Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959.United States