ASTM E9-19

Standard Test Methods of Compression Testing of Metallic Materials at Room Temperature

SIGNIFICANCE AND USE
5.1 Significance—The data obtained from a compression test may include the yield strength, the upper yield strength, the Young's modulus, the stress-strain curve, and the compressive strength (see Terminology E6). In the case of a material that does not fail in compression by a shattering fracture, compressive strength is a value that depends on total strain and specimen geometry.  
5.2 Use—Compressive properties are of interest in the analyses of structures subject to compressive forces or bending moments or both and in the analyses of metal working and fabrication processes that involve large compressive deformation such as forging and rolling. For brittle or nonductile metals that fracture in tension at stresses below the yield strength, compression tests offer the possibility of extending the strain range of the stress-strain data. While the compression test is not complicated by necking as is the tension test for certain metallic materials, buckling and barreling (see Appendix X1) can complicate results and should be minimized.
SCOPE
1.1 These test methods cover the apparatus, specimens, and procedure for axial-force compression testing of metallic materials at room temperature (Note 1). For additional requirements pertaining to cemented carbides, see Annex A1.
Note 1: For compression tests at elevated temperatures, see Practice E209.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This 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 appropriate safety, health, and environmental health practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 14-Apr-2019
• ICS: 77.040.10 - Mechanical testing of metals
• Technical Committee: E28 - Mechanical Testing
• Drafting Committee: E28.04 - Uniaxial Testing

Relations

• Refers: ASTM E251-20a - Standard Test Methods for Performance Characteristics of Metallic Bonded Resistance Strain Gages
• Effective Date: 01-Jun-2020
• Refers: ASTM E251-20 - Standard Test Methods for Performance Characteristics of Metallic Bonded Resistance Strain Gages
• Effective Date: 01-May-2020
• Refers: ASTM E209-18 - Standard Practice for Compression Tests of Metallic Materials at Elevated Temperatures with Conventional or Rapid Heating Rates and Strain Rates
• Effective Date: 01-Feb-2018
• Refers: ASTM E4-14 - Standard Practices for Force Verification of Testing Machines
• Effective Date: 01-Jun-2014
• Refers: ASTM B557-14 - Standard Test Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products
• Effective Date: 15-May-2014
• Refers: ASTM E177-14 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2014
• Refers: ASTM E251-92(2014) - Standard Test Methods for Performance Characteristics of Metallic Bonded Resistance Strain Gages
• Effective Date: 15-Apr-2014
• Refers: ASTM E177-13 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2013
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM E691-11 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2011
• Refers: ASTM E2658-11 - Standard Practices for Verification of Speed for Material Testing Machines
• Effective Date: 01-Feb-2011
• Refers: ASTM E177-10 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Oct-2010
• Refers: ASTM E111-04(2010) - Standard Test Method for Young's Modulus, Tangent Modulus, and Chord Modulus
• Effective Date: 15-Sep-2010
• Refers: ASTM E209-00(2010) - Standard Practice for Compression Tests of Metallic Materials at Elevated Temperatures with Conventional or Rapid Heating Rates and Strain Rates
• Effective Date: 01-Sep-2010
• Refers: ASTM B557-10 - Standard Test Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products
• Effective Date: 01-Jul-2010

Overview

ASTM E9-19 specifies the Standard Test Methods of Compression Testing of Metallic Materials at Room Temperature. Developed by ASTM International, this widely adopted compression testing standard defines procedures, apparatus, and specimen requirements for accurately measuring the compressive properties of metals. The results, including yield strength, compressive strength, and stress-strain curve data, are crucial for structural analysis, quality control, and the development of materials and components subjected to compressive forces in various engineering fields.

By following ASTM E9-19, laboratories and industrial facilities ensure reproducibility, reliability, and comparability of test results across different testing environments. Adhering to this standard enhances confidence in the mechanical properties data used for construction, manufacturing, and materials research.

Key Topics

• Scope and Applicability: Addresses axial-force compression testing for metallic materials at room temperature. It is not intended for elevated temperature tests, which are covered by ASTM E209.
• Test Apparatus: Outlines requirements for testing machines (as per ASTM E4), alignment devices, bearing blocks, and anti-buckling fixtures to ensure accurate, axial loading.
• Specimen Preparation: Details correct geometries for both solid cylindrical and thin-sheet metal specimens, surface finish, flatness, and parallelism to produce valid and reproducible results.
• Testing Procedures: Provides step-by-step instructions, including measurement, cleaning, lubrication, alignment, load application, and use of strain measurement devices (in accordance with ASTM E83 and E251).
• Data Collection: Specifies how to develop stress-strain curves, calculate modulus of elasticity (referencing ASTM E111), yield strength, upper yield point, and compressive strength.
• Reporting Requirements: Lists the minimum information needed in test reports, enhancing traceability and transparency for commercial or research acceptance.

Applications

Compression testing of metals according to ASTM E9-19 is essential for:

• Structural Engineering: Determining compressive strength and yield properties of metals used in columns, beams, and load-bearing components.
• Metalworking and Fabrication: Analyzing performance during forging, rolling, or any process involving substantial compressive deformation.
• Material Research and Development: Obtaining comprehensive stress-strain data for brittle or non-ductile metals, where tensile tests may be insufficient.
• Quality Assurance: Ensuring that metallic products meet relevant mechanical specifications for safe application.
• Failure Analysis: Understanding modes of failure such as buckling or barreling in components under compressive loads.

Following these standardized methods improves product reliability, compliance with regulatory requirements, and international trade by ensuring consistent mechanical property evaluation.

Related Standards

Several ASTM standards are referenced in, or support, ASTM E9-19, including:

• ASTM E4: Practices for Force Verification of Testing Machines
• ASTM E6: Terminology Relating to Mechanical Testing
• ASTM E83: Verification and Classification of Extensometer Systems
• ASTM E111: Method for Modulus of Elasticity and Related Properties
• ASTM E177: Practice for Use of the Terms Precision and Bias
• ASTM E209: Compression Tests of Metallic Materials at Elevated Temperatures
• ASTM E251: Performance of Metallic Bonded Resistance Strain Gages
• ASTM B557: Tension Testing of Aluminum- and Magnesium-Alloy Products

These related ASTM standards help ensure accurate, repeatable, and reliable test results across diverse materials and applications, supporting the broader framework for mechanical testing of metals.

Keywords: ASTM E9-19, compression testing, metallic materials, yield strength, compressive strength, stress-strain curve, modulus of elasticity, quality control, mechanical testing standards.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E9 − 19
Standard Test Methods of
Compression Testing of Metallic Materials at Room
Temperature
This standard is issued under the fixed designation E9; the number immediately following the designation indicates the year of original
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
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. Scope* E4Practices for Force Verification of Testing Machines
E6Terminology Relating to Methods of Mechanical Testing
1.1 These test methods cover the apparatus, specimens, and
E83Practice for Verification and Classification of Exten-
procedure for axial-force compression testing of metallic
someter Systems
materialsatroomtemperature(Note1).Foradditionalrequire-
E111Test Method for Young’s Modulus, Tangent Modulus,
ments pertaining to cemented carbides, see Annex A1.
and Chord Modulus
NOTE 1—For compression tests at elevated temperatures, see Practice
E177Practice for Use of the Terms Precision and Bias in
E209.
ASTM Test Methods
1.2 The values stated in inch-pound units are to be regarded
E209PracticeforCompressionTestsofMetallicMaterialsat
as standard. The values given in parentheses are mathematical
Elevated Temperatures with Conventional or Rapid Heat-
conversions to SI units that are provided for information only
ing Rates and Strain Rates
and are not considered standard.
E251Test Methods for Performance Characteristics of Me-
tallic Bonded Resistance Strain Gages
1.3 This standard does not purport to address all of the
E691Practice for Conducting an Interlaboratory Study to
safety concerns, if any, associated with its use. It is the
Determine the Precision of a Test Method
responsibility of the user of this standard to establish appro-
E2658Practices for Verification of Speed for Material Test-
priate safety, health, and environmental health practices and
ing Machines
determine the applicability of regulatory limitations prior to
use.
3. Terminology
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3.1 Definitions: The definitions of terms in Terminology E6
ization established in the Decision on Principles for the
shall apply to these test methods. These terms include com-
Development of International Standards, Guides and Recom-
pressive strength, extensometer system, modulus of elasticity,
mendations issued by the World Trade Organization Technical
necking, proportional limit, stress-strain curve, stress-strain
Barriers to Trade (TBT) Committee.
diagram, tangent modulus, testing machine, upper yield
strength, yield strength, and Young’s modulus. The terms
2. Referenced Documents
precision, bias, coefficient of variation, repeatability,
2.1 ASTM Standards:
reproducibility, and accuracy are used as defined in Practice
B557Test Methods for Tension Testing Wrought and Cast
E177.
Aluminum- and Magnesium-Alloy Products
3.2 Definitions of Terms Specific to This Standard:
3.2.1 alignment device—a fixture for compression testing in
These test methods are under the jurisdiction of ASTM Committee E28 on
a testing machine that is an integral part of the load train and
Mechanical Testing and are the direct responsibility of Subcommittee E28.04 on
that aids in achieving and maintaining axial forces.
Uniaxial Testing.
Current edition approved April 15, 2019. Published June 2019. Originally
3.2.2 anti-buckling fixture, n—a device that applies lateral
published in 1924. Last previous edition approved in 2018 as E9-09(2018). DOI:
support to a thin-sheet specimen to prevent it from buckling,
10.1520/E0009-19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or but does not interfere with axial deformation.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3.2.3 solid cylindrical specimen, n—a specimen with solid
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. cylindrical cross section that does not require lateral support to
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E9−19
prevent buckling, but can require testing with an alignment (m/m). Lack of initial parallelism may be overcome by using
device or subpress to ensure that compressive forces are axial. adjustable bearing blocks (Note 3). The blocks shall be made
of, or faced with, hard material. The specimen shall be
3.2.4 subpress, n—a fixture for compression testing in a
carefully centered with respect to the testing machine heads,
testing machine that is designed to be easily inserted into and
alignment device, or subpress if used (see 6.3, Alignment
removed from the load train and that aids in achieving and
Device or Subpress).
maintaining axial forces.
3.2.5 thin-sheet specimen, n—a specimen that requires lat- NOTE 3—The purpose of an adjustable bearing block is to give the
specimen as even a distribution of initial force as possible.An adjustable
eral support from an anti-buckling fixture to prevent buckling
bearing block cannot be relied on to compensate for any tilting of the
during a compression test.
heads that can occur during the test. Tungsten carbide bearing blocks are
suitable for testing steel. Hardened steel bearing blocks (55 HRC or
4. Summary of Test Methods
greater)aresuitablefortestingnonferrousmaterialssuchasaluminumand
copper.
4.1 The specimen is subjected to an increasing axial com-
NOTE 4—Appendix X2 describes some bearing blocks that have been
pressive force; both force and strain may be monitored either
used successfully.
continuously or in finite increments, and the mechanical
6.2.2 The bearing faces of adjustable bearing blocks that
properties in compression determined.
contact the specimen shall be made parallel before the force is
appliedtothespecimen.Ifabearingblockwithasphericalseat
5. Significance and Use
is used, the spherical surface of the block shall be defined by a
5.1 Significance—The data obtained from a compression
radiushavingitspointoforiginintheflatsurfacethatbearson
testmayincludetheyieldstrength,theupperyieldstrength,the
the specimen.
Young’s modulus, the stress-strain curve, and the compressive
6.3 Alignment Device or Subpress:
strength (see Terminology E6). In the case of a material that
6.3.1 Alignment devices and subpresses shall apply the
does not fail in compression by a shattering fracture, compres-
force axially, uniformly, and with negligible “slip-stick” fric-
sive strength is a value that depends on total strain and
tion.
specimen geometry.
5.2 Use—Compressive properties are of interest in the NOTE5—Itisusuallynecessarytouseanalignmentdeviceorsubpress,
unless the testing machine has been designed specifically for axial
analysesofstructuressubjecttocompressiveforcesorbending
alignment. Appendix X2 shows some examples of alignment devices and
moments or both and in the analyses of metal working and
subpresses that have been used successfully
fabrication processes that involve large compressive deforma-
6.3.2 The bearing blocks of the alignment device or sub-
tionsuchasforgingandrolling.Forbrittleornonductilemetals
press shall have the same requirements for parallelism and
that fracture in tension at stresses below the yield strength,
flatness as given in 6.2.1
compression tests offer the possibility of extending the strain
rangeofthestress-straindata.Whilethecompressiontestisnot
6.4 An anti-buckling fixture may be used to prevent thin-
complicated by necking as is the tension test for certain
sheet specimens from buckling.
metallic materials, buckling and barreling (see Appendix X1)
NOTE 6—Appendix X2 describes some anti-buckling fixtures and
can complicate results and should be minimized.
thin-sheet specimens that have been used successfully.
6.5 Strain Measurements:
6. Apparatus
6.5.1 Extensometer systems shall comply with the require-
6.1 Testing Machines—Machinesusedforcompressiontest-
ments for the applicable class described in Practice E83 and
ingshallconformtotherequirementsofPracticesE4andshall
shall be verified in compression.
be calibrated in compression.
6.1.1 The bearing surfaces of the heads of the testing
NOTE 7—In using these methods, a Class B-2 extensometer, as
machine shall be parallel at all times with 0.0002 in./in. (m/m) described in Practice E83, is sufficiently sensitive for most materials.
unlessanalignmentdeviceorsubpressofthetypedescribedin
6.5.2 Automaticdevicesthatdetermineoffsetyieldstrength
6.3 is used.
without plotting a stress-strain curve may be used if their
6.1.2 The dynamic response of the force-measuring system
accuracy has been demonstrated to be satisfactory.
shall be sufficient to accurately measure the rate of force
6.5.3 Electrical-resistance strain gages (or other single-use
change on the specimen.
devices) may be used provided the measuring system has been
NOTE 2—This requirement is of particular importance when testing verified and found to be accurate to the degree specified in
short specimens of materials with high modulus of elasticity.
Practice E83. Electrical resistance strain gages shall have
performance characteristics established by the manufacturer in
6.1.3 Where verification of the testing machine speed is
accordance with Test Methods E251.
required, unless otherwise specified, Practices E2658 shall be
used, and the testing machine shall meet Class E.
6.6 Qualification of Test Apparatus—The complete
6.2 Bearing Blocks: compression-test apparatus, which consists of the testing ma-
6.2.1 Iftheaxialforceistransmittedthroughtheendsofthe chine and when applicable, the alignment device or subpress,
solid cylindrical or thin-sheet specimen, they shall bear on the anti-buckling fixture and the extensometer system, shall be
blocks with surfaces flat and parallel within 0.0002 in./in. qualified by the procedure in 6.6.1-6.6.2.
E9−19
dimensions and examples of anti-buckling fixtures that have been used
6.6.1 Conduct tests to establish the elastic modulus of five
successfully.
replicate thin-sheet specimens of 2024-T3 aluminum alloy
sheet or five replicate solid cylindrical specimens of 2024-T4 7.3 Preparation of Solid Cylindrical and Thin-Sheet
aluminum alloy bar in accordance with Test Method E111. Specimens—Lateral surfaces in the gauge length shall not vary
These qualification specimens shall be machined from sheet or in diameter, width, or thickness by more than 1% or 0.002 in.
bar in the location specified in Test Methods B557. The (0.05 mm), whichever is less. If a reduced section is used, this
thickness of the sheet or diameter of the bar may be machined requirement applies only to the surface of the reduced section.
to the desired thickness or diameter.The extensometer shall be The centerlines of all lateral surfaces of the specimens shall be
properly seated on the specimen when this test is performed. coaxial within 0.01 in. (0.25 mm).
When the qualification specimens each provide a modulus 7.3.1 Surface Roughness—Machined surfaces of solid cy-
value of 10.7×10 psi (73.8 GPa) 65%, the apparatus lindrical and thin-sheet specimens shall have a surface rough-
qualifies. nessof63µin.(1.6µm)Raorbetter.Machinedlateralsurfaces
6.6.2 The qualification procedure shall be performed using to which lateral support is applied shall have a surface
the thinnest thin-sheet specimen or smallest diameter solid roughness of 40 µin. (1.0 µm) Ra or better
cylindrical specimen to be tested in the apparatus. 7.3.2 Flatness and Parallelism—The ends of solid cylindri-
cal specimens from Table 2 and of thin-sheet specimens where
7. Test Specimens
the force is applied through the ends of the specimen shall be
flat and parallel within 0.0005 in./in. (mm/mm) and perpen-
7.1 Specimens in Solid Cylindrical Form—Where feasible,
compression test specimens should be in the form of solid dicular to the lateral surfaces to within 3' of arc.
circular cylinders. Three forms of solid cylindrical specimens
NOTE11—Inmostcasesmeetingthisrequirementcanonlybeachieved
for metallic materials are recognized, and designated as short,
by machining or grinding of the ends of the specimen.
medium, and long (Note 8). Suggested dimensions for solid
7.3.3 Edges of thin-sheet Specimens—A width of material
cylindrical specimens for general use are given in Table 1.
equal to at least the thickness of the thin-sheet specimen shall
NOTE 8—Short specimens typically are used for compression tests of be machined from all sheared or stamped edges in order to
such materials as bearing metals, which in service are used in the form of
remove material with potentially altered properties. If a re-
thin plates to carry load perpendicular to the surface. Medium-length
duced section is used, this requirement applies only to the
specimens typically are used for determining the general compressive
edges of the reduced section. Thin-sheet specimens shall be
strengthpropertiesofmetallicmaterials.Longspecimensarebestadapted
finished so that the surfaces are free of nicks, grooves, and
for determining the modulus of elasticity in compression of metallic
materials. The specimen dimensions given in Table 1 have been used
burrs.
successfully. Specimens with a L/D (length/diameter ratio) of 1.5 or 2.0
7.4 Gauge Length Location—The ends of the gauge length
arebestadaptedfordeterminingthecompressivestrengthofhigh-strength
materials. shall not be closer to the ends of the solid cylindrical or
thinsheetspecimenortheendsofthereducedsection,thanone
7.2 Thin-sheet Specimens—Test specimens shall be flat and
half of the diameter or one half of the width of the specimen.
shouldbethefullthicknessofthematerial.Thelengthshallbe
sufficienttoallowthespecimentoshortentheamountrequired
8. Procedure
to define the yield strength, or upper yield strength, but not
8.1 Specimen Measurement—Measure the width and
long enough to permit buckling in the unsupported portion.
thickness, or the diameter of the specimen along the gauge
NOTE 9—Where lateral support is necessary, the width and length
section. Specimen dimensions greater than or equal to 0.10 in.
depend upon the dimensions of the anti-buckling fixture used to support
(2.5 mm) should be measured to the nearest 0.001 in. (0.02
the specimen.
mm),andthoselessthan0.10in.(2.5mm)shouldbemeasured
NOTE 10—Appendix X2 describes dimensions of thin-sheet specimen
to the nearest 1% of the dimension being measured. Calculate
A theaveragecross-sectionalareaofthespecimengaugesection.
TABLE 1 Suggested Solid Cylindrical Specimens
8.2 Cleaning—Clean the ends of the specimen and fixture
NOTE 1—Metric units represent converted specimen dimensions close
to, but not the exact conversion from inch-pound units. bearing blocks with acetone or another suitable solvent to
remove all traces of grease and oil.
Diameter Length Approx
Speci- L/
8.3 Lubrication—Bearing surfaces, including the ends of
mens D Ra-
in. mm in. mm
tio solidcylindricalspecimensandtheendsandfacesofthin-sheet
Short 1.12 ± 0.01 30.0 ± 0.2 1.00 ± 0.05 25±1 0.8 specimens may be lubricated.
0.50 ± 0.01 13.0 ± 0.2 1.00 ± 0.05 25±1 2.0
NOTE 12—Bearing surface friction can affect test results (see Fig.
Medium 0.50 ± 0.01 13.0 ± 0.2 1.50 ± 0.05 38 ± 1 3.0
X1.2). Friction has been successfully reduced by lubricating the bearing
0.80±0.01 20.0±0.2 2.38±0.12 60±3 3.0
surfaces with TFE-fluorocarbon sheet, molybdenum disulfide, and other
1.00±0.01 25.0±0.2 3.00±0.12 75±3 3.0
materials summarized in (1).
1.12±0.01 30.0±0.2 3.38±0.12 85±3 3.0
8.4 Specimen Installation—Place the specimen in the test
Long 0.80 ± 0.01 20.0 ± 0.2 6.38 ± 0.12 160±3 8.0
fixture and carefully align the specimen to the fixture to ensure
1.25 ± 0.01 32.0 ± 0.2 12.50 min 320 min 10.0
A
Other length-to-diameter ratios may be used when the test is for compressive
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
yield strength.
this standard.
E9−19
TABLE 2 Precision
95 % 95 %
Reproducibility standard Repeatability Reproducibility
Material YS(0.02% offset) Repeatability standard deviation
deviation limit (within a limit (between
laboratory) laboratories)
s s rR
x¯ r R
MPa MPa MPa MPa MPa
AA2024–T351 346.2 3.8 6.8 10.7 19.1
Repeatability coefficient Reproducibility coefficient rR
of variation of variation
s s
%%
r R
CV5 CV 5
r R
x¯ x¯
AA2024–T351 1.1 % 2.0 % 3.1 % 5.5 %
The table was calculated using the relationship limit = 2.8 × standard deviation. The quantity 1.96=2 rounds to 2.77 or 2.8.
coaxial loading. Check that the specimen loading/reaction 8.6.2 Whatever the method, the specimen should be tested
surfaces mate with the respective surfaces of the fixture. If the at a uniform rate without reversals or sudden changes.
fixture has lateral supports, the sides of thin-sheet specimens
8.7 Test Conduct—After the specimen has been installed
should contact the supports with the clamping pressure recom-
and aligned, and the strain- or deflection-measuring transducer
mended by the anti-buckling fixture manufacturer, or as deter-
installed,activatetherecordingdevice(s)andinitiatethetestat
mined during the fixture-qualification tests. If screws are used
the prescribed rate. Continue the test at a uniform rate until the
to adjust lateral support pressure, a torque wrench should be
test has been completed as stated below.
used to ensure consistent pressure.
8.7.1 Ductile Materials—For ductile materials, if allowed
8.4.1 Transducer Attachment—If required, attach the exten-
by the material specification, the test may be halted after the
someter or other transducers, or both, to the specimen gauge
strain is large enough to determine the yield strength or upper
section. The gauge length of solid cylindrical specimens shall
yield strength, or the strength at a strain greater than the yield
be at least one half diameter away from the ends of the
strain. For materials that exhibit a sharp-kneed stress-strain
specimen, and should be a full diameter away from the ends of
curve or a distinctive yield point, the test may be terminated
the specimen. The gauge length of the thin-sheet specimen
either after a sharp knee or after the drop in force is observed.
shall be at least one half the width away from the ends of the
NOTE 14—For materials without sharp-kneed stress-strain diagrams, it
specimen or ends of the reduced section, and should be at least
is useful to estimate the strain or deflection at yield and test the specimen
full width away. See 7.4.
sufficiently beyond this estimate to ensure that the yield strength can be
8.5 Force-Strain Range Selection—Set the force range of
determined after the test (see 9.3).
the testing machine so the maximum expected force is at least
8.7.2 Brittle Materials—Brittle materials that fail by crush-
one third of the range selected. If an autographic recorder is
ing or shattering may be tested to failure.
used, select the strain or deflection scale so that the elastic
8.8 Number of Specimens—Specimen blanks shall be taken
portion of the force-versus-strain or force-versus-deflection, is
frombulkmaterialsaccordingtoapplicablespecifications.The
between 30° and 60° to the force axis.
number of specimens to be tested should be sufficient to meet
8.6 Testing Speed—For testing machines equipped with
the requirements as determined by the test purpose, or as
strain-rate control, set the machine to strain the specimen at a
agreed upon between the parties involved.
nominalrateof0.005in./in./min(m/m/min).Formachinewith
NOTE 15—The larger the sample, the greater the confidence that the
force control or with crosshead speed control, set the nominal
samplerepresentsthetotalpopulation.Inmostcases,betweenfiveandten
rate so the specimen is tested at a rate equivalent to 0.005
specimens are sufficient to determine the compressive properties of a
in./in.·min (m/m·min) strain-rate in the elastic portion. A
sample with reasonable confidence.
nominalrateof0.003in./in./min(m/m/min)maybeusedifthe
8.9 Precautions:
material is strain-rate sensitive.
8.9.1 Buckling—Long, slender specimens that are not later-
8.6.1 For machines without automatic feedback control
allysupportedcanbuckleelasticallyandflyfromthetestsetup.
systems, maintain a constant crosshead speed to obtain the
A protective device should be in place to prevent injury.
desired average strain-rate from the start of loading to the end
8.9.2 Shattering Fracture—Some materials fail by
point of the test.
shattering, which will cause pieces to be expelled from the test
NOTE 13—The average strain rate can be determined from a time-
setup.Aprotective device should be in place to prevent injury.
interval-marked force-strain record, a time-strain graph, or from the time
of the start of loading to the end point of test as determined from a
9. Calculations
time-measuring device, for example a stopwatch. Constant rate of
crossheadmovementdoesnotensureconstantstrainratethroughoutatest.
9.1 Determine the properties of the material from the
Thefre
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E9 − 09 (Reapproved 2018) E9 − 19
Standard Test Methods of
Compression Testing of Metallic Materials at Room
Temperature
This standard is issued under the fixed designation E9; 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. Scope Scope*
1.1 These test methods cover the apparatus, specimens, and procedure for axial-loadaxial-force compression testing of metallic
materials at room temperature (Note 1). For additional requirements pertaining to cemented carbides, see Annex A1.
NOTE 1—For compression tests at elevated temperatures, see Practice E209.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.3 This 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 appropriate safety, health, and environmental health practices and determine the
applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
B557 Test Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products
E4 Practices for Force Verification of Testing Machines
E6 Terminology Relating to Methods of Mechanical Testing
E83 Practice for Verification and Classification of Extensometer Systems
E111 Test Method for Young’s Modulus, Tangent Modulus, and Chord Modulus
E171/E171M Practice for Conditioning and Testing Flexible Barrier Packaging
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E209 Practice for Compression Tests of Metallic Materials at Elevated Temperatures with Conventional or Rapid Heating Rates
and Strain Rates
E251 Test Methods for Performance Characteristics of Metallic Bonded Resistance Strain Gages
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E2658 Practices for Verification of Speed for Material Testing Machines
3. Terminology
3.1 Definitions: The definitions of terms relating to compression testing and room temperature in Terminology E6 and Practice
E171/E171M, respectively, shall apply to these test methods. These terms include compressive strength, extensometer system,
modulus of elasticity, necking, proportional limit, stress-strain curve, stress-strain diagram, tangent modulus, testing machine,
upper yield strength, yield strength, and Young’s modulus. The terms precision, bias, coefficient of variation, repeatability,
reproducibility, and accuracy are used as defined in Practice E177.
These test methods are under the jurisdiction of ASTM Committee E28 on Mechanical Testing and are the direct responsibility of Subcommittee E28.04 on Uniaxial
Testing.
Current edition approved Jan. 1, 2018April 15, 2019. Published January 2018June 2019. Originally published in 1924. Last previous edition approved in 20092018 as
E9E9-09(2018).-09. DOI: 10.1520/E0009-09R18.10.1520/E0009-19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For 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, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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3.2 Definitions of Terms Specific to This Standard:
3.2.1 buckling—In addition to compressive failure by crushing of the material, compressive failure may occur by (1) elastic
instability over the length of a column specimen due to nonaxiality of loading, (2) inelastic instability over the length of a column
specimen, (3) a local instability, either elastic or inelastic, over a small portion of the gage length, or (4) a twisting or torsional
failure in which cross sections rotate over each other about the longitudinal specimen axis. These types of failures are all termed
buckling.
3.2.1 column—alignment device—a compression member that is axially loaded and that may fail by buckling.fixture for
compression testing in a testing machine that is an integral part of the load train and that aids in achieving and maintaining axial
forces.
3.2.3 radius of gyration—the square root of the ratio of the moment of inertia of the cross section about the centroidal axis to
the cross-sectional area:
1/2
ρ5 I/A (1)
~ !
where:
ρ = radius of gyration,
I = moment of inertia of the cross section about centroidal axis (for specimens without lateral support, the smaller value of I
is the critical value), and
A = cross-sectional area.
3.2.4 critical stress—the axial uniform stress that causes a column to be on the verge of buckling. The critical load is calculated
by multiplying the critical stress by the cross-section area.
3.2.2 buckling equations—anti-buckling fixture, n—If the buckling stress is less than or equal to the proportional limit of the
material its value may be calculated using the Euler equation: a device that applies lateral support to a thin-sheet specimen to
prevent it from buckling, but does not interfere with axial deformation.
2 2
S 5 Cπ E/~L/ρ! (2)
cr
If the buckling stress is greater than the proportional limit of the material its value may be calculated from the modified
Euler equation:
2 2
S 5 Cπ E / L/ρ (3)
~ !
cr t
where:
S = critical buckling stress,
cr
E = Young’s modulus,
E = tangent modulus at the buckling stress,
t
L = column length, and
C = end-fixity coefficient.
Methods of calculating the critical stress using Eq 3 are given in Ref (1).
3.2.3 end-fixity coeffıcient—solid cylindrical specimen, n—There are certain ideal specimen end-fixity conditions for which
theory will define the value of the constanta specimen with solid cylindrical cross section that does not require lateral support to
Cprevent (seebuckling, Fig. 1). These values are:but can require testing
Freely rotating ends (pinned or hinged) C = 1 (a)
One end fixed, the other free to rotate C = 2 (b)
Both ends fixed C = 4 (c)
with an alignment device or subpress to ensure that compressive forces are axial.
NOTE 2—For flat-end specimens tested between flat rigid anvils, it was shown in Ref (1) that a value of C = 3.75 is appropriate.
3.2.4 barreling—subpress, n—restricted deformation of the end regions of a test specimen under compressive load due to
friction at the specimen end sections and the resulting nonuniform transverse deformation as shown schematically and in the
photograph ina fixture for compression testing in a testing machine Fig. 2. Additional theoretical and experimental information on
barreling as illustrated that is designed to be easily inserted into and removed from the load train and that aids in Fig. 2 is given
in Ref achieving and maintaining axial forces.(2).
3.2.5 thin-sheet specimen, n—a specimen that requires lateral support from an anti-buckling fixture to prevent buckling during
a compression test.
4. Summary of Test Methods
4.1 The specimen is subjected to an increasing axial compressive load;force; both loadforce and strain may be monitored either
continuously or in finite increments, and the mechanical properties in compression determined.
The boldface numbers in parentheses refer to the list of references at the end of this standard.
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5. Significance and Use
5.1 Significance—The data obtained from a compression test may include the yield strength, the upper yield point, strength, the
Young’s modulus, the stress-strain curve, and the compressive strength (see Terminology E6). In the case of a material that does
not fail in compression by a shattering fracture, compressive strength is a value that is dependent depends on total strain and
specimen geometry.
5.2 Use—Compressive properties are of interest in the analyses of structures subject to compressive forces or bending
loadsmoments or both and in the analyses of metal working and fabrication processes that involve large compressive deformation
such as forging and rolling. For brittle or nonductile metals that fracture in tension at stresses below the yield strength, compression
tests offer the possibility of extending the strain range of the stress-strain data. While the compression test is not complicated by
necking as is the tension test for certain metallic materials, buckling and barreling (see Section 3Appendix X1) can complicate
results and should be minimized.
6. Apparatus
6.1 Testing Machines—Machines used for compression testing shall conform to the requirements of Practices E4. For universal
machines with a common test space, calibration shall be performed and shall be calibrated in compression.
6.1.1 The bearing surfaces of the heads of the testing machine shall be parallel at all times with 0.0002 in./in. (m/m) unless an
alignment device or subpress of the type described in 6.3 is used.
6.1.2 The dynamic response of the force-measuring system shall be sufficient to accurately measure the rate of force change on
the specimen.
NOTE 2—This requirement is of particular importance when testing short specimens of materials with high modulus of elasticity.
6.1.3 Where verification of the testing machine speed is required, unless otherwise specified, Practices E2658 shall be used, and
the testing machine shall meet Class E.
6.2 Bearing Blocks:
6.2.1 Both If the axial force is transmitted through the ends of the compression specimen solid cylindrical or thin-sheet
specimen, they shall bear on blocks with surfaces flat and parallel within 0.0002 in./in. (m/m). Lack of initial parallelism canmay
be overcome by the use of using adjustable bearing blocks (Note 3). The blocks shall be made of, or faced with, hard material.
Current laboratory practice suggests the use of tungsten carbide when testing steel and hardened steel blocks (55 HRC or greater)
and when testing nonferrous materials such as aluminum, copper, etc. The specimen mustThe specimen shall be carefully centered
with respect to the testing machine heads or the heads, alignment device, or subpress if used (see 6.3, Alignment
Device/Subpress).Device or Subpress).
NOTE 3—The purpose of an adjustable bearing block is to give the specimen as even a distribution of initial loadforce as possible. An adjustable bearing
block cannot be relied on to compensate for any tilting of the heads that maycan occur during the test. Tungsten carbide bearing blocks are suitable for
testing steel. Hardened steel bearing blocks (55 HRC or greater) are suitable for testing nonferrous materials such as aluminum and copper.
NOTE 4—Appendix X2 describes some bearing blocks that have been used successfully.
6.2.2 The bearing faces of adjustable bearing blocks that contact the specimen shall be made parallel before the loadforce is
applied to the specimen. One type of adjustable bearing block that has proven satisfactory is illustrated in If Fig. 3. Another
arrangement involving the use of a spherical-seated bearing block that has been found satisfactory for testing material other than
in sheet form is shown in a bearing block Fig. 4. It is desirable that the spherical-seated bearing block be at the upper end of the
test specimen (for specimens tested with the load axis vertical). The with a spherical seat is used, the spherical surface of the block
shall be defined by a radius having its point of origin in the flat surface that bears on the specimen.
6.3 Alignment Device/Subpress: Device or Subpress:
6.3.1 It is usually necessary to use an alignment device, unless the testing machine has been designed specifically for axial
alignment. The design of the device or subpress depends on the size and strength of the specimen. It must be designed so that the
ram (or other moving parts) does not jam or tilt the device or the frame of the machine as a result of loading. The bearing blocks
of the device shall have the same requirements for parallelism and flatness as given in Alignment devices and subpresses shall
apply the force axially, uniformly, and with negligible “slip-stick” friction.6.2.1.
NOTE 5— It is usually necessary to use an alignment device or subpress, unless the testing machine has been designed specifically for axial alignment.
Appendix X2 shows some examples of alignment devices and subpresses that have been used successfully
6.3.2 The primary requirements of all alignment devices are that the load is applied axially, uniformly, and with negligible
“slip-stick” friction. An alignment device that has been found suitable is shown inbearing blocks of the alignment device or
subpress shall have the same requirements for Fig. 5 and described in Ref.parallelism and flatness as given in 6.2.1(3). Other
devices of the subpress type have also been used successfully.
6.4 Compression Testing Jigs—In testing thin specimens, such as sheet material, some means should be adopted to prevent the
specimen from buckling during loading. This may be accomplished by using a jig containing side-support plates that bear against
the wide sides of the specimen. The jig must afford a suitable combination of lateral-support pressure and spring constant to prevent
E9 − 19
buckling, but without interfering with axial deformation of the specimen. Although suitable combinations vary somewhat with
variations in specimen material and thickness, testing temperatures, and accuracy of alignment, acceptable results can be obtained
with rather wide ranges of lateral-support pressure and spring constant. Generally, the higher the spring constant of the jig, the
lower the lateral-support pressure that is required. Proper adjustments of these variables should be established during the
qualification of the equipment (see An anti-buckling fixture may be used to prevent thin-sheet specimens from buckling.6.6).
6.4.1 It is not the intent of these methods to designate specific jigs for testing sheet materials, but merely to provide a few
illustrations and references to jigs that have been used successfully, some of which are cited in Table 1. Other jigs are acceptable
provided they prevent buckling and pass the qualification test set forth in 6.6. Compression jigs generally require that the specimen
be lubricated on the supported sides to prevent extraneous friction forces from occurring at the support points.
NOTE 6—Appendix X2 describes some anti-buckling fixtures and thin-sheet specimens that have been used successfully.
6.5 Strain Measurements:
6.5.1 Mechanical or electromechanical devices used for measuring strain Extensometer systems shall comply with the
requirements for the applicable class described in Practice E83. The device and shall be verified in compression.
NOTE 7—In using these methods, a Class B-2 extensometer, as described in Practice E83, is sufficiently sensitive for most materials.
6.5.2 Automatic devices that determine offset yield strength without plotting a stress-strain curve may be used if their accuracy
has been demonstrated to be satisfactory.
6.5.3 Electrical-resistance strain gages (or other single-use devices) may be used provided the measuring system has been
verified and found to be accurate to the degree specified in Practice E83. The characteristics of electrical Electrical resistance strain
gages have been determined from shall have performance characteristics established by the manufacturer in accordance with Test
Methods E251.
6.6 Qualification of Test Apparatus—The complete compression-test apparatus, which consists of the testing machine and when
applicable, one or more of the following; the alignment device, the jig and the strain-measurementthe alignment device or subpress,
the anti-buckling fixture and the extensometer system, shall be qualified as follows:by the procedure in 6.6.1-6.6.2.
6.6.1 Conduct tests to establish the elastic modulus of five replicate thin-sheet specimens of 2024-T3 aluminum alloy sheet or
five replicate solid cylindrical specimens of 2024-T4 aluminum alloy bar in accordance with Test Method E111. These qualification
specimens shall be machined from sheet or bar in the location specified in Test Methods B557. The thickness of the sheet or
diameter of the bar may be machined to the desired thickness or diameter. It is essential that the extensometer The extensometer
shall be properly seated on the specimensspecimen when this test is performed. When the qualification specimens each provide
a modulus value of 10.7 × 10 psi (73.8 GPa) 65 %, the apparatus qualifies.
6.6.2 The qualification procedure shall be performed using the thinnest rectangularthin-sheet specimen or smallest diameter
round solid cylindrical specimen to be tested in the apparatus.
7. Test Specimens
7.1 Specimens in Solid Cylindrical Form—It is recommended that, where Where feasible, compression test specimens should
be in the form of solid circular cylinders. Three forms of solid cylindrical test specimens for metallic materials are recognized, and
designated as short, medium-length,medium, and long (Note 48). Suggested dimensions for solid compression test cylindrical
specimens for general use are given in Table 21.
NOTE 8—Short specimens typically are used for compression tests of such materials as bearing metals, which in service are used in the form of thin
plates to carry load perpendicular to the surface. Medium-length specimens typically are used for determining the general compressive strength properties
A
TABLE 21 Suggested Solid Cylindrical Specimens
NOTE 1—Metric units represent converted specimen dimensions close
to, but not the exact conversion from inch-pound units.
Diameter Length Approx
Speci- L/
mens D Ra-
in. mm in. mm
tio
Short 1.12 ± 0.01 30.0 ± 0.2 1.00 ± 0.05 25 ± 1 0.8
0.50 ± 0.01 13.0 ± 0.2 1.00 ± 0.05 25 ± 1 2.0
Medium 0.50 ± 0.01 13.0 ± 0.2 1.50 ± 0.05 38 ± 1 3.0
0.80 ± 0.01 20.0 ± 0.2 2.38 ± 0.12 60 ± 3 3.0
1.00 ± 0.01 25.0 ± 0.2 3.00 ± 0.12 75 ± 3 3.0
1.12 ± 0.01 30.0 ± 0.2 3.38 ± 0.12 85 ± 3 3.0
Long 0.80 ± 0.01 20.0 ± 0.2 6.38 ± 0.12 160 ± 3 8.0
1.25 ± 0.01 32.0 ± 0.2 12.50 min 320 min 10.0
A
Other length-to-diameter ratios may be used when the test is for compressive
yield strength.
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of metallic materials. Long specimens are best adapted for determining the modulus of elasticity in compression of metallic materials. The specimen
dimensions given in Table 21 have been used successfully. Specimens with a L/D (length/diameter ratio) of 1.5 or 2.0 are best adapted for determining
the compressive strength of high-strength materials.
7.2 Rectangular or Sheet-Type Thin-sheet Specimens—Test specimens shall be flat and preferably ofshould be the full thickness
of the material. Where lateral support is necessary, the width and length are dependent upon the dimensions of the jig used to
support the specimen. The length shall be sufficient to allow the specimen to shorten the amount required to define the yield
strength, or upper yield point,strength, but not long enough to permit buckling in the unsupported portion. Specimen dimensions
and the various types of jigs are given in Table 1.
NOTE 9—Where lateral support is necessary, the width and length depend upon the dimensions of the anti-buckling fixture used to support the specimen.
NOTE 10—Appendix X2 describes dimensions of thin-sheet specimen dimensions and examples of anti-buckling fixtures that have been used
successfully.
7.3 Preparation of Solid Cylindrical and Thin-Sheet Specimens—Lateral surfaces in the gagegauge length shall not vary in
diameter, width, or thickness by more than 1 % or 0.002 in. (0.05 mm), whichever is less. (IfIf a reduced section is used, this
requirement applies only to the surface of the reduced section.) Also, the centerline section. The centerlines of all lateral surfaces
of the specimens shall be coaxial within 0.01 in. (0.25 mm).
7.3.1 Surface Finish—Roughness—Machined surfaces of solid cylindrical and thin-sheet specimens shall have a surface
finishroughness of 63 μin. (1.6 μm) Ra or better. Machined lateral surfaces to which lateral support is to be applied shall be finished
to at least 40 microinches (1.0 μm) arithmetic average.have a surface roughness of 40 μin. (1.0 μm) Ra or better
7.3.2 Flatness and Parallelism—The ends of a solid cylindrical specimens from Table 2 and of thin-sheet specimens where the
force is applied through the ends of the specimen shall be flat and parallel within 0.0005 in./in. (mm/mm) and perpendicular to
the lateral surfaces to within 3' of arc. In most cases this requirement necessitates the machining or grinding of the ends of the
specimen.
NOTE 11—In most cases meeting this requirement can only be achieved by machining or grinding of the ends of the specimen.
7.3.3 Edges of Rectangularthin-sheet Specimens—A width of material equal to at least the thickness of the thin-sheet specimen
shall be machined from all sheared or stamped edges in order to remove material whose properties may have been altered. with
potentially altered properties. If a reduced section is used, this requirement applies only to the edges of the reduced section.
Specimens Thin-sheet specimens shall be finished so that the surfaces are free of nicks, grooves, and burrs.
7.4 GageGauge Length Location—The ends of the gagegauge length shall not be closer to the ends of the solid cylindrical or
thinsheet specimen or the ends of the reduced section, than one half of the widthdiameter or diameter one half of the width of the
specimen.
8. Procedure
8.1 Specimen Measurement—Measure the width and thickness, or the diameter of the specimen with a micrometer along the
gagegauge section. Specimen dimensions greater than or equal to 0.10 in. (2.5 mm) should be measured to the nearest 0.001 in.
(0.02 mm), and those less than 0.10 in. (2.5 mm) should be determinedmeasured to the nearest 1 % of the dimension being
measured. Calculate the average cross-sectional area of the specimen gagegauge section.
8.2 Cleaning—Clean the ends of the specimen and fixture bearing blocks with acetone or another suitable solvent to remove
all traces of grease and oil.
8.3 Lubrication—Bearing surface friction can affect test results (see section surfaces, including 5.2 and Fig. 2). Friction has been
successfully reduced by lubricating the bearing surfaces with TFE-fluorocarbon sheet, molybdenum disulfide, and other materials
summarized in Ref.the ends of solid cylindrical specimens and the ends and faces of (thin-sheet3). specimens may be lubricated.
NOTE 12—Bearing surface friction can affect test results (see Fig. X1.2). Friction has been successfully reduced by lubricating the bearing surfaces
TABLE 32 Precision
95 % 95 %
Reproducibility standard Repeatability Reproducibility
Material YS(0.02% offset) Repeatability standard deviation
deviation limit (within a limit (between
laboratory) laboratories)
s s r R
x¯ r R
MPa MPa MPa MPa MPa
AA2024–T351 346.2 3.8 6.8 10.7 19.1
Repeatability coefficient Reproducibility coefficient r R
of variation of variation
s s
% %
r R
CV 5 CV 5
r R
x¯ x¯
AA2024–T351 1.1 % 2.0 % 3.1 % 5.5 %
The table was calculated using the relationship limit = 2.8 × standard deviation. The quantity 1.96=2 rounds to 2.77 or 2.8.
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with TFE-fluorocarbon sheet, molybdenum disulfide, and other materials summarized in (1).
8.4 Specimen Installation—Place the specimen in the test fixture and carefully align the specimen to the fixture to ensure
concentriccoaxial loading. Also, check Check that the specimen loading/reaction surfaces mate with the respective surfaces of the
fixture. If the fixture has sidelateral supports, the specimen sides sides of thin-sheet specimens should contact the support
mechanism supports with the clamping pressure recommended by the anti-buckling fixture manufacturer, or as determined during
the fixture verification fixture-qualification tests. If screws are used to adjust sidelateral support pressure, it is recommended that
a torque wrench should be utilizedused to ensure consistent pressure.
8.4.1 Transducer Attachment—If required, attach the extensometer or other transducers, or both, to the specimen gagegauge
section. The gage length must gauge length of solid cylindrical specimens shall be at least one half or preferably one diameter away
from the ends of the specimen (see specimen, and should be a full diameter away from the ends of the specimen. The gauge length
of the thin-sheet specimen shall be at least one half the width away from the ends of the specimen or ends of the reduced section,
and should be at least full width away. See 7.4).
8.5 Load-StrainForce-Strain Range Selection—Set the loadforce range of the testing machine so the maximum expected
loadforce is at least one third of the range selected. Select If an autographic recorder is used, select the strain or deflection scale
so that the elastic portion of the load-versus-strain or load-versus-deflection plot on the autographic record, force-versus-strain or
force-versus-deflection, is between 30° and 60° to the loadforce axis.
8.6 Strain Measurements—Devices used for measuring strain shall comply with the requirements for the applicable class of
extensometer described in Practice E83. Electrical strain gages, if used, shall have performance characteristics established by the
manufacturer in accordance with Test Methods E251.
8.6 Testing Speed—For testing machines equipped with strain-rate pacers,control, set the machine to strain the specimen at a
nominal rate of 0.005 in./in.·min (m/m·min).in./in./min (m/m/min). For machine with loadforce control or with crosshead speed
control, set the nominal rate so the specimen is tested at a rate equivalent to 0.005 in./in.·min (m/m·min) strain-rate in the elastic
portion. A nominal rate of 0.003 in./in.·min (m/m·min) canin./in./min (m/m/min) may be used if the material is strain-rate sensitive.
8.6.1 For machines without strain-pacing equipment or automatic feedback control systems, maintain a constant crosshead
speed to obtain the desired average strain-rate from the start of loading to the end point of the test. The average strain-rate can be
determined from a time-interval-marked load-strain record, a time-strain graph, or from the time of the start of loading to the end
point of test as determined from a time-measuring device (for example, stopwatch). It should be recognized that the use of
machines with constant rate of crosshead movement does not ensure constant strain rate throughout a test.
NOTE 13—The average strain rate can be determined from a time-interval-marked force-strain record, a time-strain graph, or from the time of the start
of loading to the end point of test as determined from a time-measuring device, for example a stopwatch. Constant rate of crosshead movement does not
ensure constant strain rate throughout a test. The free-running crosshead speed can differ from the speed under load for the same machine setting.
Spe
...