NotchedBarImpactTesting ofMetallicMaterials Standard TestMethodsfor
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1. Scopea
2. Referenced Documents
1.1Thee tst methods describe othed-barmpact testingIzod (cantilever-beam） test. They give the requirements fo: of metallic materials by the Charpy (simple-beam) test and thetest specimens test procedures test reports test machines (see Annex A1) verifying Charpy impact machines (see Annex A2).nation of test specimen orientation (see Terminology E1823). optional test specimen configurations (see Annex A3) desig-In adition.infomation is provided on the significance of and determining the shear fracture appearance (see Annex A4).measuring the center of strike (see Appendix X2）. notched-bar impact testing (se Appendix X1) and methods of
2.1 ASTM Standards
B925 Practices for Production and Preparation of Powder Metallurgy (PM) Test SpecimensE6 Terminology Relating to Methods of Mechanical Testing E29 Practice for Using Significan Digits in Test Data toE177 Practice for Use of the Terms Precision and Bias in Determine Conformance with SpecifieationsASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE1823 Terminology Relating to Fatigue and Fracture Testing E229s Test Method for Instrumented Impaet Testing ofMetallic Materials
1.2 These test methods do not address the problems associ-ated with impact testing at temperatures below 196 °C (77 K).
standard. No other units of measurement are included in this 1.3 The values stated in SI units are to be regarded asstandard.
3. Terminology
from Terminology E6: 3.1 Definitions of Terms Common to Mechanical Testing
1.3.1 ExceprionSection 9 and Annex A4 provide inch-pound units for information only.
specimen in a single pendulum swing as measured by a 3.1.1 absorbed energx [FL] n-work spem to fracture apensated indicating device.
1.4 This standard does not purport to address all of thesafety concerns if any. associated with its use. lt is theresponsibiliy of the user of this standard to establish appro- priate sofety. health and environmental practices and deter.mine theapplicabiliry ofregulatory limiations priortouse. Specific precautionary statements are given in Section 6.
distance between the free-hanging position and the latched 3.1.2 drop height h [L] nthe center of strike verticalposition.
3.2 Definitions of Terms Specijfic to This Standard:
dance with intermationally recognied principles on standand- 1.5 This intermational standard was developed in accor-ization established in the Decision on Principles for the Development of Internarional Standards Guides cnd Re-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Commitee.
3.2.1 direct verifcation process that ensures all partsthat may affect measured absorbed energy are within specified dimensional tolerances.
3.2.2 free-hanging position nposition of the pendulumafter oscilatin tops chtht th ptetialan kinetic eney is zero.
pendulum swing from the latched position as recorded by the 3.2.3 free swing unintruptod (without a test specimen)indicating device (see A2.3.8.1).
age absorbed energy from testing a set of verification speci- 3.2.4indiret verificton process that ensures theavspecified tolerance (see A2.4.1). mens corresponds to the certified absorbed energy within a
3.2.5 latched position nposition of the pendulum on therelease mechanism prior to being released to perform a test.
3.2.6 lateral expansion [L] n-the maximum increase in thethickness of the specimen as a result of the impact test expressed in mm.
3.2.6.1 DiscassionLateral expansion is used as a measureof ductility.
3.2.7 range capacirs nmaximum available energy for aspecific pendulum setting.
3.2.7.1 DiscassonOn single range machines this corresponds to the machine capacity.
fracture sufacein th ecimen that filed in ahear (stable) 3.2.8 shear fracture appearance. SFA nthe amount ofmode cxpressed in percent.
4. Summary of Test Method
4.1 The essential features of an impact test are: a suitablespecimen speiens of several diffent types areregizeda set of anvils and specimen supports on which the test specimen is placed to receive the blow of the moving mass aplaced in its path and an indicating device for measuring theabsorbed energy of the broken specimen.
5. Significance and Use
5.1 These test methods of impact testing relate specificallyto the behavior of metal when subjeted to a ingle applicationnotch coupled with high rates of loading and in some cases of a force resuling in multi-axial stresses associated with awith 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 britle fracture accurately. Furtherinformation on significance appears in Appendix X1.
6. Precautions in Operation of Machine
s d ms 6.1Safety precautions should be taken to protect personelhazards associated with specimen warming and cooling media.
7. Apparatus
7.1 General Requirements:
7.1.1 The testing machine shall be a pendulum type of rigidconstruction.
7.1.2 The testing machine shall be designed and built toconform with the requirements given in Annex A1.
7.2 Inspection and Verification:
are provided in A2.2 and A2.3. The items listed in A2.2 require 7.2.1 Procedures for direct verification of impact machinesdirect verification annually.
machines using verification specimens are given in A2.4. 7.2.2 Procedures for indirect verification of CharpyCharpy impact machines require direct and indirect verificationannually.
8. Test Specimens
8.1 Confguration and Orienation:
fidby the appliable specifiaton. 8.1.1 Specimens shallbe taken from the material as speci-
8.1.2 The specimens shown in Fig. 1 and Fig. 2 are thoseparicularly suitable forfeousmetalsxting cast ion. most widely used andmost generally satisfactory. They areThe Charpy specimen designations are V-notch and U-notch.
notch width is 1.6 mm or less. Nore 1Keyhole notch specimen is similar to U-notch cxcept the
metallurgy materials is shown in Fig. 3. Powder metallurgy 8.1.3 The specimens monly found suitable for powderimpact est specimens shallbe poducedfollowing theproce dure in Practices B925. The impact test results of thesematerials are affeted by specimen orientation. Therefore unless otherwise specified the position of the specimen in themachine shall be such that the pendulum will strike a surfacethat is parallel to the pasting direction.For powder metallurgy materials the impact test results are reported asunnotched absorbed energy.
8.1.4 Sub-size and supplementary specimen remenda-tions are given in Annex A3.
8.2 Specimen Machining:
sthe final heat treatment unless it can be demonstrated that the specimen shall be finish machined including notching afterimpact properties of specimens machined efore heat treatment are identical to those machined after heat treatment.
has proven generally unnecessary. d
NonE 2Variations in noh dimensions willaffct the results of thetests Appendix X1.2 illustrates the effcts from varying notch dimesions
with a slow feed rate. Exercise care im cutting the slot to ensure that the Nore 3In keyhole motch specimens carefully drill the round holesurface of the drilled hole opposite the slot is not damagod.
8.2.3 Identification marks shall only be placed in the fol-lowing locations on specimens: either of the 10 mm square cnds; the side of the specimen that faces up when the specimenis positioned in the anvils (see Note 4); or the side of thc o pis ue o s o ou sodo udsspecimen shall be within 10 mm of the center line of the notch.Permanent markers laser engraving. scribes electrostatic pencils and other reasonable marking methods may be usedfor identification purposes. However some marking methods can result in damage to the specimens if not used correctly. Forcxample excessive heat from clectrostatic pencils or deforma- tion to the specimen from stamping can change the mechanicalproperties of the specimen. Therefore. care shall always be
FIG. 1 Charpy (Simple-Beam) Impact Test Specimens V-Notch and U-Notch
FIG. 2 Izod (Cantilever-Beam) Impact Test Specimen
FIG. 3 Powder Metallurgy (PMI) Unnotched Charpy and Izod Impact Test Specimens
marking processes that result in deformation of the specimen taken to avoid damage to the specimen. Stamping and othershoeld only be used on the ends of the specimens prior to notching.
Non: 4Careful consideration should be given before placing identi-fication marks on theside of th spein obe pladup whenpositiond in the anvils If the test operator is not careful the specimen can be placedsupports (tht is facing down) Under these circumstances the aborbed energy value obtained may be unreliable. in the machine with the identification marking resting on the specimen
specifications standard test specimens shall conform to the dimensions and tolerances shown in Fig. 1 or any otherapplicable figure in this test method.
characteristies of the material to be tested. Ofen a given spvimn is not Nore 5The type of specimen choen dpends langely upon theequally satisfactory for soft nonferrousmetals and hadened steels; therefore many types of specimens ar reoognized. In eeral. shaper and deeper notches are required to distinguish differences in very ductilematerials or when using low testing velocities. Side-grooved specimens have been ed to minimize absorbed energy variability for high-strengthand ductile materials.
9.Procedure
9.1 Preparation of the Apparatus:
9.1.1 Perform a routine procedure for checking impastmachines at the beginning of each day each shift or just prior to testing on a machine used intermitently. The results of theseroutine checks should be kept in a log book for the machine.
After the testing machine has been ascertained to ply with Annex A1 and Annex A2. carry out the routine check asfollows:
9.1.1.1 Visually examine the striker and anvils for obviousdamage and wear.
9.1.1.2 Check the machine with a free swing. The indicatingdevice shall indicate zero on machines reading directly inshall correspond to zero absorbed energy on the conversion absorbed energy. On machines reading in degrees the readingformula or table fumished by the machine manufacturer. On machines that do not pensate for total frictional losses theanalog scale will not indicate zero. In this case the indicated values when converted to absorbed energy. shall be correctedthe arc of the swing. for total frictional losses that are assumed to be proportional to
9.1.1.3 The percent friction and windage loss shall notexceed 0.4 % of the range capacity being tested and should not change by more than 10 % of the percem friction and windageloss measurements previously recorded on the machine. If the percet fiction and windage loss does exceed 0.4 % or issignificantly differemt from previous measurements check the indicating device the release mechanism and the bearings forrecently. let the pendulum swing for 50 to 100 cycles and wear and damage. However if the machine has not been usedrepeat the percent friction and windage loss test beforefriction and windage loss is within allowable tolerance use oneof the following evaluation procedures:
as the holding temperature (sce Note 9). The maximum change in the temperature of the specimen allowed for the intervalbetween the temperature conditioning treatment and impact isnot specified here because it is dependent on the material being tested and the application. The user of nontraditional orlesser used temperature conditioning and transfer methods (or specimen sizes) shall show that the temperature change for thees o jo us zis pps a dmaterial that has been thermally conditioned in a monly used medium (oil. air nitrogen acetone. methanol).andtransferred for impact within 5 s (see Note 9). Three tempera-ture conditioning and transfer methods used in the past are: liquid bath thermal conditioning and transfer to the specimenand robotic transfer to the specimen supports: placement of thepue 3ueaq mis u Xq pomooy suoddns oq uo uzujds cooling.
(1) For a machine equipped with an analog scale:
Moenascalinsthrncapitybeingse Relasee pendlu (tha secininthmachine): Raise the pendulum to the latched positisn:swingtgitheruntase cyle): Allow the pendulum to cycle five times (a forwardl and a backwandPriortthsihfrdinsethgscalei bewen5%n10fthngecaty bing useDivide h ner reaing by 10: Aer thesith tomard sing reord the vlu inic by analog scale pcinter (cmert to absorbed energy if necessary):Divide by the range capacity being used. and 0
Determine the percent friction and windage loss per mamufac- (2) A machine equipped with a digital display:pad s
(3) For machine equipped with both an analog scale anddigital display:
Detemin th prcefictionand windagelossusingthsame indicating device used to report absorbed energy (11.1.6 and A2.4).
9.2.4.1 For liquid bath cooling or heating use a suitablepositioning fixture. Cover the specimems when immersed withat least 25 mm (1 in.) of the liquid and position so that the notch area is not closer than 25 mm to the sides or bottom ofthe container and no part of the specimen is in contact with the container. Place the device used to measure the temperature ofthe bath in the center of a group of the specimens Agitate the bath and hold at the desired temperature within ± 1 °C (±2 °F).Thermally condition the specimens for at least 5 min before testing unless a shorter thermal conditioning time can bethe devie ngfr examleued thndl th seimsn shown to be valid by mcasurements with thermocouples. Leavethe bath for at least 5 min before testing and retum the deviceto the bath between tests.
No 6Por t2012enion t frician inengadsinwpdfitwi los was based on 11 (half swings and the analog scale pointer was notThe difrence is that the frietion windge and analog sale pointer mechanism losses associated with the first swing are no longer assumed ofollowing 10 (half) swings. be zero. On the firt swing the pointer shoud go to 0.00 so any frictin and windage losses that will be rocorded will only show up on the
9.2 Test Temperature Considerations:
ties of most materials. For materials with a body centered cubic 9.2.1 The temperature of testing affects the impact proper-structure a transition in fracture mode occurs over a tempera- ture range that depends on the chemical position andmicrostructure of the material. Test temperatures may bechosen to characterize material behavior at fixed values or over a range of temperatures to characterize the transitionregion lower shelf orupper shelf behavior or allof these. The choice of test temperature is the responsibility of the user ofthis test method and will depend on the specific application. For tests performed at room temperature the temperatureshould be 20 °C ± 5 °℃.
9.2.4.2 When using a gas medium position the specimensdesired temperature within ±1 °C (±2 °F) for at least 30 min. so that the gas circulates round them and hold thegas at theLeave the device used to remove the specimen from the medium in the medium except when handling the specimens.
Nore 7-Temperatares up to 260 °C may be cbtained with certainpuqo na q pnqs smudu _uod-qstg. nq so
9.2.2 The temperature of a specimen can change signifi-cantly during the inteal it is removed from the temperatureand the fracture event is pleted (sce Note 9）. When using conditioning environment transferred to the impact machine a heating or cooling medium near its boiling point use data from the references in Note 9 or calibration data with thermo-couples to confirm that the specimen is within the stated temperature tolerances when the striker contacts the specimen.If excessive adiabatic heating is expected monitor the speci- men temperature near the notch during fracture.
Nome SFor testing at temperatures dowm to196 °C (77 “K) standardtesting peocedures have been found to be adequate for most metals.
6can cool 10 °C in the 5 s allowed for ransfer to the secimen supports.d eseroom temperature have also shown large changes n specimen temperature during the transfer of secimes to the machine anvilsIn adlition soe malerials change temperature dramatically during impact testing atcryogenic temperatures due to adiabatic heating.*
9.3 Charpy Test Procedure:
9.2.3 Verify temperature-measuring oquipment at least ev-ery six months. If liquid-in-glass thermometers are used an initial verification shall be sufficient however the device shallbe inspected for problems such as the separation of liquid at least every six months.
9.3.1 The Charpy test proodure may be summarized asfollows: the test specimen is themally conditioned and posi- tioned on the specimen supports against the anvils; the pendu-lum is released without vibration and the specimen is impacted
± 1 °C (±2 °F) in the temperature conditioning environment. 9.2.4 Hold the specimen at the desired temperature withinto the anvils may be used provided the temperature of the ads uno uooujo pouyspecimen immediately prior to fracture is essentially the same
