1、Designation: E209 18Standard Practice forCompression Tests of Metallic Materials at ElevatedTemperatures with Conventional or Rapid Heating Ratesand Strain Rates1This standard is issued under the fixed designation E209; the number immediately following the designation indicates the year oforiginal a
2、doption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers compression test in which thespecimen is heated
3、to a constant and uniform temperature andheld at temperature while an axial force is applied at acontrolled rate of strain.1.2 In metals with extremely high proportional limit or lowmodulus of elasticity, 1.5 % total strain under load could bereached before the 0.2 %-offset yield strength is reached
4、. Inthis event the end point of the test may be reported as the 0.2percent-offset yield strength unless rupture occurs before thatpoint.1.3 For acceptable compression tests it is imperative that thespecimens not buckle before the end point is reached. For thisreason the equipment and procedures shal
5、l be designed tomaintain uniform loading and axial alignment.1.4 Preferred conditions of testing are recommended so thatdata from different sources conducting the tests will becomparable.1.5 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are math
6、ematicalconversions to SI units that are provided for information onlyand are not considered standard.1.6 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, healt
7、h, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of Internati
8、onal Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE9 Test Methods of C
9、ompression Testing of Metallic Mate-rials at Room TemperatureE21 Test Methods for ElevatedTemperatureTensionTests ofMetallic MaterialsE83 Practice for Verification and Classification of Exten-someter Systems3. Apparatus3.1 Testing MachinesMachines used for compression test-ing shall conform to the r
10、equirements of Practices E4.3.2 Bearing Blocks and Loading AdaptersLoad both endsof the compression specimens through bearing blocks orthrough pin-type adapters that are part of the compression-testing assembly. Bearing blocks may be designed with flatbearing faces for sheet- or bar-type specimens.
11、Sheet speci-mens may also be loaded through pin-type adapters that areclamped rigidly to the grip sections of specimens designed forthese adapters (1).3The main requirement is that the method ofapplying the force be consistent with maintaining axial align-ment and uniform loading on the specimen thr
12、oughout the test.When bearing blocks with flat faces are used, the load-bearingsurfaces should be smooth and parallel within very close limits.The tolerance for parallelism for these surfaces should be equalto or closer than that specified for the loaded ends of thespecimens. The design of the equip
13、ment should provideadequate rigidity so that parallelism is maintained duringheating and loading. The bearing blocks or pin-type adaptersshould be made of a material that is sufficiently hard at thetesting temperature to resist plastic indentation at maximumforce. They should also be of a material o
14、r coated with amaterial that is sufficiently oxidation resistant at the maximum1This practice is under the jurisdiction ofASTM Committee E28 on MechanicalTesting and is the direct responsibility of Subcommittee E28.04 on Uniaxial Testing.Current edition approved Feb. 1, 2018 Published March 2018. Or
15、iginallyapproved in 1963. Last previous edition, approved in 2010 as E209 00(2010). DOI:10.1520/E0209-18.2For 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 standar
16、ds Document Summary page onthe ASTM website.3Boldface numbers in parentheses refer to references at the end of this practice.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with i
17、nternationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1testing temperature to prevent the formation
18、 of an oxidecoating that would cause misalignment. In any compressiontest it is important that the specimen be carefully centered withrespect to the bearing blocks, which in turn should be centeredwith respect to the testing machine heads.NOTE 1Bearing blocks with straight cylindrical or threaded ho
19、lesdepending on specimen design may be used for bar-type specimensproviding the apparatus qualifies in accordance with Section 10.NOTE 2Bearing blocks of an adjustable type to provide parallelloading surfaces are discussed in Test Methods E9. Bearing blocks with aspherical seat for the upper block a
20、re also shown.3.3 SubpressesA subpress or other alignment device isnecessary in order to maintain suitable alignment when testingspecimens that are not laterally supported, unless the testingmachine has been designed specifically for axial alignment anduniform application of force in elevated-temper
21、ature compres-sion testing. A subpress for room-temperature testing is shownin Test Methods E9. For elevated-temperature compressiontesting, the subpress must accommodate the heating andloading devices and the temperature-sensing elements. Thedesign of the subpress is largely dependent on the size a
22、ndstrength of the specimens, the temperatures to be used, theenvironment, and other factors. It must be designed so the ramdoes not jam or tilt the frame as a result of heating orapplication of force. If the bearing faces of the subpress, theopposite faces of both bearing blocks, and the ends of the
23、specimen are respectively plane and parallel within very closelimits, it is unnecessary to use adjustable or spherical seats. Inany case, the specimen should be properly centered in thesubpress.3.4 Compression Testing JigsWhen testing sheet material,buckling of the specimen during application of com
24、pessiveforces must be prevented. This may be accomplished by usinga jig containing side-support plates that bear against the facesof the specimen. The jig must afford a suitable combination oflateral-support pressure and spring constant to prevent buck-ling without interfering with axial deformation
25、 of the specimen(1). Although suitable combinations vary somewhat withvariations in specimen material and thickness, testingtemperature, and accuracy of alignment, acceptable results canbe obtained with rather wide ranges of lateral-support pressureand spring constant for any given test conditions.
26、Generally,the higher the spring constant of the jig, the lower thelateral-support pressure that is required. Proper adjustment ofthese test variables may be established in preliminary verifi-cation tests for the equipment (Section 10).3.4.1 This practice does not intend to designate specificcompress
27、ion jigs for testing sheet metals, but merely to providea few illustrations and references to jigs that have been usedsuccessfully. Many other jigs are acceptable provided theyprevent buckling and pass the qualification tests set forth inSection 10. Satisfactory results have been obtained in room-te
28、mperature testing using the jigs illustrated in Test MethodsE9. These jigs usually require that the specimen be lubricatedto permit normal compression on loading. For elevated-temperature testing, modified jigs that accommodate the heat-ing and strain-measuring equipment as well as the temperature-s
29、ensing elements must be used. A number of compression-testing jigs have been evaluated specifically for performance inelevated-temperature tests (2, 3). The preferred type dependson the material, its thickness, and the temperatures involved.For moderately elevated temperatures, one of the room-tempe
30、rature designs may be used in an oven in which the air iscirculated to provide uniform heating. One design for side-support plates that has been found satisfactory for use attemperatures up to 1000 F (538 C) when lubricated withgraphite is shown in Fig. 1(a) (4). Longitudinal grooves are cutin each
31、plate with the grooves offset across the thickness of thespecimen. These plates are made of titanium carbide.Atype ofside-support plate that has been used in compression jigs to1800 F (982 C) is shown in Fig. 1(b) (4). This is an assemblyof small titanium carbide balls backed up by a titanium carbid
32、eplate. The balls protrude through holes in the front retainingplate. The holes for the balls are large enough to allow rotationand translation of each ball while at the same time retaining theballs in the plate assembly. The spacing of the balls, which isnormally about18 in. (3.2 mm), determines th
33、e minimumspecimen thickness that can be tested without buckling be-tween the balls. Rational values of the ball spacing can beobtained from calculations based upon the plastic buckling ofsimply supported plates where the plate width can be taken asthe ball spacing. Another type of jig has a number o
34、f leaf-spring supports on each side of the specimen (3, 5). This designis limited to a temperature range in which the metal leaf-springelements can support the specimen satisfactorily. Jigs for usewith specimens that are heated by self resistance are discussedin (1, 6) and (7), which also provide qu
35、antitative informationon the effects of lubrication, lateral-support pressure, springconstant, and misalignment.3.4.2 The side-support plates are assembled in a frame thatis part of the jig. A typical frame and jig assembly is shown inFig. 2.Afurnace is placed around the jig after the specimen andex
36、tensometer are assembled in the jig. The holes in the supportblocks are for auxiliary cartridge-type heaters.4. Significance and Use4.1 SignificanceThe data obtained from a compressiontest may include the yield strength, the yield point, Youngsmodulus, the stress-strain curve, and the compressive st
37、rength(see Terminology E6). In the case of a material that does notFIG. 1 Specimen Side Support Plates (4)E209 182fail in compression by a shattering fracture, compressivestrength is a value that is dependent on total strain andspecimen geometry.4.2 UseCompressive properties are of interest in thean
38、alyses of structures subject to compressive or bending loadsor both and in the analyses of metal working and fabricationprocesses that involve large compressive deformation such asforging and rolling. For brittle or nonductile metals thatfracture in tension at stresses below the yield strength, com-
39、pression tests offer the possibility of extending the strain rangeof the stress-strain data. While the compression test is notcomplicated by necking as is the tension test for certainmetallic materials, buckling and barreling can complicateresults and should be minimized5. Heating Apparatus5.1 The a
40、pparatus and method for heating the specimens arenot specified, but in present practice the following are mainlyused.5.1.1 The resistance of the specimen gage length to thepassage of an electric current,5.1.2 Resistance heating supplemented by radiant heating,5.1.3 Radiant heating,5.1.4 Induction he
41、ating, or5.1.5 Convection heating with circulating-air furnace.5.2 The apparatus must be suitable for heating the specimenunder the conditions specified in Section 6.6. Test Specimen6.1 The size and shape of the test specimen should be basedon three requirements as follows:6.1.1 The specimen should
42、be representative of the materialbeing investigated and should be taken from the materialproduced in the form and condition in which it will be used,6.1.2 The specimen should be adapted to meet the require-ments on temperature control and rates of heating andstraining, and6.1.3 The specimen should b
43、e conducive to the maintenanceof axial alignment uniform application of force, and freedomfrom buckling when loaded to the end point in the apparatusused.6.2 The specimens are divided into two general classifica-tions: those with rectangular cross sections and those withround cross sections. The dim
44、ensions of the specimens areoptional. The specimen must be long enough to be compressedto the required deformation without interference from a sup-porting jig but not long enough to permit buckling where it isunsupported. The end allowance (dimension between the gagepoints and the adjacent end of th
45、e uniform section) should bea minimum of one half the width of rectangular specimens orone half the diameter of round specimens. Typical acceptablespecimens are illustrated in Fig. 3 and Fig. 4.FIG. 2 Typical Compression Testing Jig for Sheet SpecimensMounted on Support Jig (3)DimensionsSpecimen 1 S
46、pecimen 2 Specimen 3G.L.Gage Length, in. (mm) 1.000 0.005(25.4 0.13)2.000 0.005(50.8 0.13)2.000 0.005(50.8 0.13)LUniform Section, in. (mm) 2.500 0.005(63.5 0.13)3.000 0.005(76.2 0.13)2.50 min(63.5)WWidth, in. (mm) 0.625 0.010(15.9 0.25)1.000 0.010(25.4 0.25)0.500 0.010(12.7 0.25)E.A.End Allowance, i
47、n. (mm) 0.75 (19) 0.50 (12.7) 0.25 min (6.35)FIG. 3 Dimensions of Typical Rectangular SpecimensE209 1836.3 When the dimensions of the test material permit, roundspecimens should be used. Round specimens should be de-signed to be free from buckling up to the end point of the testwithout lateral suppo
48、rt. Rectangular specimens up to 0.250 in.(6.35 mm) thick normally require lateral support; with greaterthicknesses lateral support may not be required in well-alignedequipment. The methods covered by this specification arenormally satisfactory for testing sheet specimens down to0.020 in. (0.51 mm) t
49、hick. With smaller thicknesses inaccura-cies resulting from buckling and nonuniform straining tend toincrease; consequently, extra care in the design, construction,and use of the test equipment is required to obtain valid resultsfor specimens in this thickness range. All compression speci-mens should be examined after they are tested; any evidence ofbuckling invalidates the results for that specimen.6.4 The width and thickness of rectangular specimens anddiameter of round specimens at any point in the gage lengthshould not vary from
