ASTM_A_370-06.pdf

4A370-06E 18 Test Methods for Rockwell Hardness and RockwellSuperficial Hardness of Metallic MaterialsCONC TODINAL SPEC UENE23 Test Methods for Notched Bar Impact Testing ofMetallic MaterialsONGITUDINA.F AT TENS Ch TESTE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE 83 Practice for Verification and Classification of Exten-someter SystemsE 110 Test Method for Indentation Hardness of MetallicMaterials by Portable Hardness TestersE 190 Test Method for Guided Bend Test for Ductility ofWeldsE290 Test Methods for Bend Testing of Material forDuctilityE 1595 Practice for Evaluating the Performance of Me-chanical Testing Laboratories2.2 ASME Document:3给ASME Boiler and Pressure Vessel Code.Section VIlI.Division I,Part UG-8FIG.1 The Relation of Test Coupons and Test Specimens to3.General PrecautionsRolling Direction or Extension(Applicable to General WroughtProducts)3.1 Certain methods of fabrication,such as bending,form-ing,and welding,or operations involving heating,may affectduring rolling or forging.The stress applied to a transversethe properties of the material under test.Therefore,the producttension test specimen is at right angles to the greatest exten-specifications cover the stage of manufacture at which me-sion,and the axis of the fold of a transverse bend test specimenchanical testing is to be performed.The properties shown byis parallel to the greatest extension(Fig.1).testing prior to fabrication may not necessarily be representa-4.2 The termsradial testandtangential testare used intive of the product after it has been completely fabricated.material specifications for some wrought circular products and3.2 Improper machining or preparation of test specimensare not applicable to castings.When such reference is made tomay give erroneous results.Care should be exercised to assurea test coupon or test specimen,the following definitions apply:good workmanship in machining.Improperly machined speci-4.2.1 Radial Test,unless specifically defined otherwise,mens should be discarded and other specimens substituted.signifies that the lengthwise axis of the specimen is perpen-3.3 Flaws in the specimen may also affect results.If any testdicular to the axis of the product and coincident with one of thespecimen develops flaws,the retest provision of the applicableradii of a circle drawn with a point on the axis of the productproduct specification shall govern.as a center(Fig.2a).3.4 If any test specimen fails because of mechanical reasons4.2.2 Tangential Test,unless specifically defined otherwise,such as failure of testing equipment or improper specimensignifies that the lengthwise axis of the specimen is perpen-preparation,it may be discarded and another specimen taken.dicular to a plane containing the axis of the product and tangent4.Orientation of Test Specimensto a circle drawn with a point on the axis of the product as acenter(Fig.2a,2b,2c,and 2d).4.I The terms longitudinal test”and“transverse test”areused only in material specifications for wrought products andTENSION TESTare not applicable to castings.When such reference is made toa test coupon or test specimen,the following definitions apply:5.Description4.1.1 Longitudinal Test,unless specifically defined other-5.1 The tension test related to the mechanical testing of steelwise,signifies that the lengthwise axis of the specimen isproducts subjects a machined or full-section specimen of theparallel to the direction of the greatest extension of the steelmaterial under examination to a measured load sufficient toduring rolling or forging.The stress applied to a longitudinalcause rupture.The resulting properties sought are defined intension test specimen is in the direction of the greatestTerminology E6.extension,and the axis of the fold of a longitudinal bend test5.2 In general,the testing equipment and methods are givenspecimen is at right angles to the direction of greatest extensionin Test Methods E 8.However,there are certain exceptions to(Fig.1,Fig.2a,and 2b).Test Methods E 8 practices in the testing of steel,and these are4.1.2 Transverse Test,unless specifically defined otherwise,covered in these test methods.signifies that the lengthwise axis of the specimen is at rightangles to the direction of the greatest extension of the steel6.Terminology6.1 For definitions of terms pertaining to tension testing,including tensile strength,yield point,yield strength,elonga-3 Available from American Society of Mechanical Engineers(ASME).ASMEtion,and reduction of area,reference should be made toIntemational Headquarters.Three Park Ave.New York.NY 10016-5990.Terminology E 6.24A370-06TangentialProlongationTest.ProlongationLongitudinal Test(a)Shafta and RotorsProlongatlonJangential TestLongitudinal Test(b)Hollow ForgingsProlongationProlongotionTangential TestTongential Teste)D)isk ForgingnProlongationProlongationTongential TestTangential Test(d)Ring Forgings.FIG.2 Location of Longitudinal Tension Test Specimens in Rings Cut from Tubular Products7.Testing Apparatus and Operationsrecorders have a load measuring component entirely separate from the7.1 Loading Systems-There are two general types of load-load indicator of the testing machine.Such recorders are calibrateding systems,mechanical(screw power)and hydraulic.Theseseparately.differ chiefly in the variability of the rate of load application7.3 Loading-It is the function of the gripping or holdingThe older screw power machines are limited to a small numberdevice of the testing machine to transmit the load from theof fixed free running crosshead speeds.Some modern screwheads of the machine to the specimen under test.The essentialpower machines,and all hydraulic machines permit steplessrequirement is that the load shall be transmitted axially.Thisvariation throughout the range of speeds.implies that the centers of the action of the grips shall be in7.2 The tension testing machine shall be maintained in goodalignment,insofar as practicable,with the axis of the specimenoperating condition,used only in the proper loading range,andat the beginning and during the test and that bending orcalibrated periodically in accordance with the latest revision oftwisting be held to a minimum.For specimens with a reducedPractices E4.section,gripping of the specimen shall be restricted to the gripNorE 1-Many machines are equipped with stress-strain recorders forautographic plotting of stress-strain curves.It should be noted that some3A370-06section.In the case of certain sections tested in full size.representative bar or the destruction of a production part fornonaxial loading is unavoidable and in such cases shall betest purposes.For ring or disk-like forgings test metal ispermissible.provided by increasing the diameter,thickness,or length of the7.4 Speed of Testing-The speed of testing shall not beforging.Upset disk or ring forgings,which are worked orgreater than that at which load and strain readings can be madeextended by forging in a direction perpendicular to the axis ofaccurately.In production testing,speed of testing is commonlythe forging,usually have their principal extension alongexpressed:(/in terms of free running crosshead speed(rate ofconcentric circles and for such forgings tangential tensionmovement of the crosshead of the testing machine when notspecimens are obtained from extra metal on the periphery orunder load),(2)in terms of rate of separation of the two headsof the testing machine under load,(3)in terms of rate ofend of the forging.For some forgings,such as rotors,radialtension tests are required.In such cases the specimens are cutstressing the specimen,or(4)in terms of rate of straining thespecimen.The following limitations on the speed of testing areor trepanned from specified locations.recommended as adequate for most steel products:8.1.3 Cast Steels-Test coupons for castings from whichNorE 2-Tension tests using closed-loop machines(with feedbacktension test specimens are prepared shall be in accordance withthe requirements of Specifications A 703/A 703M or A 781/control of rate)should not be performed using load control,as this modeof testing will result in acceleration of the crosshead upon yielding andA 781M,as applicable.elevation of the measured yield strength.8.2 Size and Tolerances-Test specimens shall be the full7.4.1 Any convenient speed of testing may be used up tothickness or section of material as-rolled,or may be machinedone half the specified yield point or yield strength.When thisto the form and dimensions shown in Figs.3-6,inclusive.Thepoint is reached,the free-running rate of separation of theselection of size and type of specimen is prescribed by thecrossheads shall be adjusted so as not to exceed Vi in.per minapplicable product specification.Full section specimens shallper inch of reduced section,or the distance between the gripsbe tested in 8-in.(200-mm)gage length unless otherwisefor test specimens not having reduced sections.This speedspecified in the product specification.shall be maintained through the yield point or yield strength.In8.3 Procurement of Test Specimens-Specimens shall bedetermining the tensile strength,the free-running rate ofsheared,blanked,sawed,trepanned,or oxygen-cut from por-separation of the heads shall not exceed in.per min per inchtions of the material.They are usually machined so as to haveof reduced section,or the distance between the grips for testa reduced cross section at mid-length in order to obtain uniformspecimens not having reduced sections.In any event,thedistribution of the stress over the cross section and to localizeminimum speed of testing shall not be less than Vo thethe zone of fracture.When test coupons are sheared,blanked,specified maximum rates for determining yield point or yieldsawed,or oxygen-cut,care shall be taken to remove bystrength and tensile strength.7.4.2 It shall be permissible to set the speed of the testingmachining all distorted,cold-worked,or heat-affected areasfrom the edges of the section used in evaluating the test.machine by adjusting the free running crosshead speed to theabove specified values,inasmuch as the rate of separation of8.4 Aging of Test Specimens-Unless otherwise specified,itheads under load at these machine settings is less than theshall be permissible to age tension test specimens.The time-specified values of free running crosshead speed.temperature cycle employed must be such that the effects of7.4.3 As an alternative,if the machine is equipped with aprevious processing will not be materially changed.It may bedevice to indicate the rate of loading,the speed of the machineaccomplished by aging at room temperature 24 to 48 h,or infrom half the specified yield point or yield strength through theshorter time at moderately elevated temperatures by boiling inyield point or yield strength may be adjusted so that the rate ofwater,heating in oil or in an oven.stressing does not exceed 100 000 psi(690 MPa)/min.How-8.5 Measurement of Dimensions of Test Specimens:ever,the minimum rate of stressing shall not be less than8.5.1 Standard Rectangular Tension Test Specimens-These10 000 psi(70 MPa)/min.forms of specimens are shown in Fig.3.To determine thecross-sectional area,the center width dimension shall be8.Test Specimen Parametersmeasured to the nearest 0.005 in.(0.13 mm)for the 8-in.8.1 Selection-Test coupons shall be selected in accordance(200-mm)gage length specimen and 0.001 in.(0.025 mm)forwith the applicable product specifications.the 2-in.(50-mm)gage length specimen in Fig.3.The center8.1.1 Wrought Steels-Wrought steel products are usuallythickness dimension shall be measured to the nearest 0.001 intested in the longitudinal direction,but in some cases,wherefor both specimens.size permits and the service justifies it,testing is in thetransverse,radial,or tangential directions(see Fig.I and Fig.8.5.2 Standard Round Tension Test Specimens-These2).forms of specimens are shown in Fig.4 and Fig.5.To8.1.2 Forged Steels-For open die forgings,the metal fordetermine the cross-sectional area,the diameter shall betension testing is usually provided by allowing extensions ormeasured at the center of the gage length to the nearest 0.001prolongations on one or both ends of the forgings,either on allin.(0.025 mm)(see Table 1).or a representative number as provided by the applicable8.6 General-Test specimens shall be either substantiallyproduct specifications.Test specimens are normally taken atfull size or machined,as prescribed in the product specifica-mid-radius.Certain product specifications permit the use of ations for the material being tested.