ASTM E8/E8M-24

Standard Test Methods for Tension Testing of Metallic Materials

SIGNIFICANCE AND USE
4.1 Tension tests provide information on the strength and ductility of materials under uniaxial tensile stresses. This information may be useful in comparisons of materials, alloy development, quality control, and design under certain circumstances.  
4.2 The results of tension tests of specimens machined to standardized dimensions from selected portions of a part or material may not totally represent the strength and ductility properties of the entire end product or its in-service behavior in different environments.  
4.3 These test methods are considered satisfactory for acceptance testing of commercial shipments. The test methods have been used extensively in the trade for this purpose.
SCOPE
1.1 These test methods cover the tension testing of metallic materials in any form at room temperature, specifically, the methods of determination of yield strength, yield point elongation, tensile strength, elongation, and reduction of area.  
1.2 The gauge lengths for most round specimens are required to be 4D for E8 and 5D for E8M. The gauge length is the most significant difference between E8 and E8M test specimens. Test specimens made from powder metallurgy (P/M) materials are exempt from this requirement by industry-wide agreement to keep the pressing of the material to a specific projected area and density.  
1.3 Exceptions to the provisions of these test methods may need to be made in individual specifications or test methods for a particular material. For examples, see Test Methods and Definitions A370 and Test Methods B557, and B557M.  
1.4 Room temperature shall be considered to be 10 °C to 38 °C [50 °F to 100°F] unless otherwise specified.  
1.5 The values stated in SI units are to be regarded as separate from inch/pound units. The values stated in each system are not exact equivalents; therefore each system must be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.6 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 practices and determine the applicability of regulatory limitations prior to use.  
1.7 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: 31-Dec-2023
• ICS: 77.040.10 - Mechanical testing of metals
• Technical Committee: E28 - Mechanical Testing
• Drafting Committee: E28.04 - Uniaxial Testing

Relations

• Replaces: ASTM E8/E8M-22 - Standard Test Methods for Tension Testing of Metallic Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM A370-24 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Mar-2024
• Referred By: ASTM B903-15(2022) - Standard Specification for Seamless Copper Heat Exchanger Tubes With Internal Enhancement
• Effective Date: 01-Jan-2024
• Referred By: ASTM F2527-24 - Standard Specification for Wrought Seamless and Welded and Drawn Cobalt Alloy Small Diameter Tubing for Surgical Implants (UNS R30003, UNS R30008, UNS R30035, UNS R30605, and UNS R31537)
• Effective Date: 01-Jan-2024
• Referred By: ASTM F560-22 - Standard Specification for Unalloyed Tantalum for Surgical Implant Applications (UNS R05200, UNS R05400)
• Effective Date: 01-Jan-2024
• Referred By: ASTM B453/B453M-19 - Standard Specification for Copper-Zinc-Lead Alloy (Leaded-Brass) Rod, Bar, and Shapes
• Effective Date: 01-Jan-2024
• Referred By: ASTM F606/F606M-21 - Standard Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, Direct Tension Indicators, and Rivets
• Effective Date: 01-Jan-2024
• Referred By: ASTM B248M-22 - Standard Specification for General Requirements for Wrought Copper and Copper-Alloy Plate, Sheet, Strip, and Rolled Bar (Metric)
• Effective Date: 01-Jan-2024
• Referred By: ASTM F2581-12(2017) - Standard Specification for Wrought Nitrogen Strengthened 11Manganese-17Chromium-3Molybdenum Low-Nickel Stainless Steel Alloy Bar and Wire for Surgical Implants (UNS S29225)
• Effective Date: 01-Jan-2024
• Referred By: ASTM F2321-23 - Standard Specification for Flexible and Rigid Insulated Temporary By-Pass Jumpers
• Effective Date: 01-Jan-2024
• Referred By: ASTM B100-20 - Standard Specification for Wrought Copper-Alloy Bearing and Expansion Plates and Sheets for Bridge and Other Structural Use
• Effective Date: 01-Jan-2024
• Referred By: ASTM A834-95(2020) - Standard Specification for Common Requirements for Iron Castings for General Industrial Use
• Effective Date: 01-Jan-2024
• Referred By: ASTM A1056-20 - Standard Specification for Cast Iron Couplings Used for Joining Hubless Cast Iron Soil Pipe and Fittings
• Effective Date: 01-Jan-2024
• Referred By: ASTM A1077/A1077M-21 - Standard Specification for Structural Steel with Improved Yield Strength at High Temperature for Use in Buildings
• Effective Date: 01-Jan-2024
• Referred By: ASTM B570-22 - Standard Specification for Copper-Beryllium Alloy Forgings and Extrusions (UNS Nos. C17000 and C17200)
• Effective Date: 01-Jan-2024

Overview

ASTM E8/E8M-24 is the international reference standard for tension testing of metallic materials at room temperature. Issued by ASTM International, this standard specifies widely accepted test methods to determine key mechanical properties such as yield strength, yield point elongation, tensile strength, elongation, and reduction of area. The results from these methods are critical for material comparison, quality assurance, and supporting design and development activities in metals manufacturing and engineering. ASTM E8/E8M-24 is recognized globally, providing consistent methodologies for acceptance testing in trade and compliance with regulatory or procurement requirements.

Key Topics

• Scope and Applicability: Encompasses tension testing of metallic materials in various forms, including sheets, plates, rods, wires, and bars, at room temperature (10 °C to 38 °C or 50 °F to 100 °F).
• Test Specimens: Defines standardized specimen dimensions and preparation for different product shapes, including plate-type, sheet-type, and various round specimens. Special provisions are included for powder metallurgy (P/M) materials and for specimens when standard configurations are impractical.
• Measurement Parameters: Provides methods to accurately determine:
  • Yield strength
  • Yield point elongation
  • Tensile strength
  • Elongation at fracture
  • Reduction of area
• Testing Apparatus: Details requirements for testing machines, gripping devices, extensometers, and measurement instruments, ensuring reliable and reproducible results.
• Data Interpretation: Stresses the importance of properly interpreting test outcomes, understanding that properties measured from standardized specimens may not fully represent entire components or in-service behavior.
• Safety and Compliance: Reminds users of the necessity to implement appropriate safety, health, and environmental practices, and to respect unit system conventions by avoiding mixing SI and inch/pound values in a single test.

Applications

Tension testing as specified in ASTM E8/E8M-24 is foundational across the metals industry, metallurgy research, and engineering design:

• Material Selection and Comparison: Generates reliable mechanical data to compare different alloys, grades, or processing conditions, aiding in material selection for structural and pressure-containing applications.
• Product Qualification and Acceptance: Used extensively for acceptance testing in commercial transactions, meeting requirements in procurement specifications and regulatory standards.
• Quality Control: Supports ongoing monitoring of batch-to-batch consistency and process performance in fabrication and manufacturing.
• Alloy Development: Provides objective metrics for research and development, helping engineers optimize new metals and heat treatments.
• Design Validation: Supplies essential input for engineering analysis, finite element modeling, and validation of safety-critical designs.
• Regulatory Compliance: Aligns with international principles and can be referenced for regulatory submissions involving metallic material mechanical properties.

Related Standards

ASTM E8/E8M-24 is part of a comprehensive suite of ASTM and related international mechanical testing standards:

• ASTM A370: Test Methods and Definitions for Mechanical Testing of Steel Products
• ASTM B557 / B557M: Test Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products
• ASTM E4: Practices for Force Calibration and Verification of Testing Machines
• ASTM E83: Practice for Verification and Classification of Extensometer Systems
• ASTM E345: Test Methods of Tension Testing of Metallic Foil
• ISO/ASTM 52909:2024: Additive Manufacturing of Metals – Finished Part Properties

By adhering to ASTM E8/E8M-24, organizations can ensure uniformity, data integrity, and global comparability in the tension testing of metallic materials. This drives product reliability, cross-border trade, and engineering excellence.

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: E8/E8M − 24 American Association State
Highway and Transportation Officials Standard
AASHTO No.: T68
An American National Standard
Standard Test Methods for
Tension Testing of Metallic Materials
This standard is issued under the fixed designation E8/E8M; 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* mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 These test methods cover the tension testing of metallic
materials in any form at room temperature, specifically, the
2. Referenced Documents
methods of determination of yield strength, yield point
2.1 ASTM Standards:
elongation, tensile strength, elongation, and reduction of area.
A356/A356M Specification for Steel Castings, Carbon, Low
1.2 The gauge lengths for most round specimens are re-
Alloy, and Stainless Steel, Heavy-Walled for Steam Tur-
quired to be 4D for E8 and 5D for E8M. The gauge length is
bines
the most significant difference between E8 and E8M test
A370 Test Methods and Definitions for Mechanical Testing
specimens. Test specimens made from powder metallurgy
of Steel Products
(P/M) materials are exempt from this requirement by industry-
B557 Test Methods for Tension Testing Wrought and Cast
wide agreement to keep the pressing of the material to a
Aluminum- and Magnesium-Alloy Products
specific projected area and density.
B557M Test Methods for Tension Testing Wrought and Cast
1.3 Exceptions to the provisions of these test methods may
Aluminum- and Magnesium-Alloy Products (Metric)
need to be made in individual specifications or test methods for
E4 Practices for Force Calibration and Verification of Test-
a particular material. For examples, see Test Methods and
ing Machines
Definitions A370 and Test Methods B557, and B557M.
E6 Terminology Relating to Methods of Mechanical Testing
E29 Practice for Using Significant Digits in Test Data to
1.4 Room temperature shall be considered to be 10 °C to
Determine Conformance with Specifications
38 °C [50 °F to 100°F] unless otherwise specified.
E83 Practice for Verification and Classification of Exten-
1.5 The values stated in SI units are to be regarded as
someter Systems
separate from inch/pound units. The values stated in each
E345 Test Methods of Tension Testing of Metallic Foil
system are not exact equivalents; therefore each system must
E691 Practice for Conducting an Interlaboratory Study to
be used independently of the other. Combining values from the
Determine the Precision of a Test Method
two systems may result in non-conformance with the standard.
E1012 Practice for Verification of Testing Frame and Speci-
1.6 This standard does not purport to address all of the
men Alignment Under Tensile and Compressive Axial
safety concerns, if any, associated with its use. It is the
Force Application
responsibility of the user of this standard to establish appro-
D1566 Terminology Relating to Rubber
priate safety, health, and environmental practices and deter-
E1856 Guide for Evaluating Computerized Data Acquisition
mine the applicability of regulatory limitations prior to use.
Systems Used to Acquire Data from Universal Testing
1.7 This international standard was developed in accor-
Machines
dance with internationally recognized principles on standard-
E2658 Practices for Verification of Speed for Material Test-
ization established in the Decision on Principles for the
ing Machines
Development of International Standards, Guides and Recom-
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. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Jan. 1, 2024. Published March 2024. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1924. Last previous edition approved 2022 as E8/E8M – 22. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/E0008_E0008M-24. 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
E8/E8M − 24
2.2 ISO/ASTM Standard: 3.1.9.1 Discussion—Tensile strength is calculated from the
ISO/ASTM 52909:2024(en) Additive manufacturing of met- maximum force during a tension test carried to rupture and the
als — Finished part properties — Orientation and location original cross-sectional area of the specimen.
dependence of mechanical properties for metal parts
3.1.10 uniform elongation, El , [%]—the elongation deter-
u
mined at the maximum force sustained by the test specimen
3. Terminology
just prior to necking or fracture, or both.
3.1.10.1 Discussion—Uniform elongation includes both
3.1 Definitions of Terms Common to Mechanical Testing—
elastic and plastic elongation.
3.1.1 The definitions of mechanical testing terms that ap-
-2
pear in the Terminology E6 apply to this test method.
3.1.11 upper yield strength, UYS [FL ]—in a uniaxial test,
3.1.1.1 These terms include bending strain, constraint,
the first stress maximum (stress at first zero slope) associated
elongation, extensometer, force, gauge length, necking, re-
with discontinuous yielding at or near the onset of plastic
duced section, stress-strain diagram, testing machine, and
deformation.
modulus of elasticity.
3.1.12 yield point elongation, YPE, n—in a uniaxial test, the
3.1.2 In addition, the following common terms from Termi-
strain (expressed in percent) separating the stress-strain curve’s
nology E6 are defined:
first point of zero slope from the point of transition from
3.1.3 discontinuous yielding, n—in a uniaxial test, a hesita-
discontinuous yielding to uniform strain hardening.
tion or fluctuation of force observed at the onset of plastic
3.1.12.1 Discussion— If the transition occurs over a range
deformation, due to localized yielding.
of strain, the YPE end point is the intersection between (a) a
3.1.3.1 Discussion—The stress-strain curve need not appear
horizontal line drawn tangent to the curve at the last zero slope
to be discontinuous.
and (b) a line drawn tangent to the strain hardening portion of
3.1.4 elongation after fracture, n—the elongation measured
the stress-strain curve at the point of inflection. If there is no
by fitting the two halves of the broken specimen together.
point at or near the onset of yielding at which the slope reaches
zero, the material has 0 % YPE.
3.1.5 elongation at fracture, n—the elongation measured
–2
just prior to the sudden decrease in force associated with
3.1.13 yield strength, YS or S [FL ], n—the engineering
y
fracture.
stress at which, by convention, it is considered that plastic
-2
elongation of the material has commenced.
3.1.6 lower yield strength, LYS [FL ]—in a uniaxial test,
3.1.13.1 Discussion—This stress may be specified in terms
the minimum stress recorded during discontinuous yielding,
of (a) a specified deviation from a linear stress-strain
ignoring transient effects.
relationship, (b) a specified total extension attained, or (c)
3.1.7 reduced parallel section, A, n—the central portion of
maximum or minimum engineering stresses measured during
the specimen that has a nominally uniform cross section, with
discontinuous yielding.
an optional small taper toward the center, that is smaller than
that of the ends that are gripped, not including the fillets. 3.2 Definitions of Terms Specific to This Standard:
3.2.1 referee test, n—test made to settle a disagreement as to
3.1.7.1 Discussion—This term is often called the parallel
length in other standards. the conformance to specified requirements, or conducted by a
third party to arbitrate between conflicting results. D1566,
3.1.7.2 Discussion—Previous versions of E8/E8M defined
this term as “reduced section.” D11.08
3.1.8 reduction of area, n—the difference between the
4. Significance and Use
original cross-sectional area of a tension test specimen and the
area of its smallest cross section.
4.1 Tension tests provide information on the strength and
3.1.8.1 Discussion—The reduction of area is usually ex-
ductility of materials under uniaxial tensile stresses. This
pressed as a percentage of the original cross-sectional area of
information may be useful in comparisons of materials, alloy
the specimen.
development, quality control, and design under certain circum-
3.1.8.2 Discussion—The smallest cross section may be mea-
stances.
sured at or after fracture as specified for the material under test.
4.2 The results of tension tests of specimens machined to
3.1.8.3 Discussion—The term reduction of area when ap-
standardized dimensions from selected portions of a part or
plied to metals generally means measurement after fracture;
material may not totally represent the strength and ductility
when applied to plastics and elastomers, measurement at
properties of the entire end product or its in-service behavior in
fracture. Such interpretation is usually applicable to values for
different environments.
reduction of area reported in the literature when no further
4.3 These test methods are considered satisfactory for ac-
qualification is given. (E28.04)
ceptance testing of commercial shipments. The test methods
–2
3.1.9 tensile strength, S [FL ], n—the maximum tensile
u
have been used extensively in the trade for this purpose.
stress that a material is capable of sustaining.
5. Apparatus
5.1 Testing Machines—Machines used for tension testing
Available from International Organization for Standardization (ISO), ISO
shall conform to the requirements of Practices E4. The forces
Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, https://www.iso.org. used in determining tensile strength and yield strength shall be
E8/E8M − 24
within the verified force application range of the testing and precise to at least one half the smallest unit to which the
machine as defined in Practices E4. Where verification of the individual dimension is required to be measured.
testing machine speed is required, Practices E2658 shall be
5.4 Extensometers—Extensometers used in tension testing
used unless otherwise specified.
shall conform to the requirements of Practice E83 for the
classifications specified by the procedure section of this test
5.2 Gripping Devices:
method. Extensometers shall be used and verified to include
5.2.1 General—Various types of gripping devices may be
the strains corresponding to the yield strength and elongation at
used to transmit the measured force applied by the testing
fracture (if determined).
machine to the test specimens. To ensure axial tensile stress
5.4.1 Extensometers with gauge lengths equal to or shorter
within the gauge length, the axis of the test specimen should
than the nominal gauge length of the specimen (dimension
coincide with the center line of the heads of the testing
shown as “G-Gauge Length” in the accompanying figures) may
machine. Any departure from this requirement may introduce
be used to determine the yield behavior. For specimens without
bending stresses that are not included in the usual stress
a reduced section (for example, full cross sectional area
computation (force divided by cross-sectional area).
specimens of wire, rod, or bar), the extensometer gauge length
NOTE 1—The effect of this eccentric force application may be illus-
for the determination of yield behavior shall not exceed 80 %
trated by calculating the bending moment and stress thus added. For a
of the distance between grips. For measuring elongation at
standard 12.5 mm [0.500 in.] diameter specimen, the stress increase is 1.5
fracture with an appropriate extensometer, the gauge length of
percentage points for each 0.025 mm [0.001 in.] of eccentricity. This error
increases to 2.5 percentage points/ 0.025 mm [0.001 in.] for a 9 mm the extensometer shall be equal to the nominal gauge length
[0.350 in.] diameter specimen and to 3.2 percentage points/ 0.025 mm
required for the specimen being tested.
[0.001 in.] for a 6 mm [0.250 in.] diameter specimen.
NOTE 2—Alignment methods are given in Practice E1012.
6. Test Specimens
5.2.2 Wedge Grips—Testing machines usually are equipped
6.1 General:
with wedge grips. These wedge grips generally furnish a
6.1.1 Specimen Size—Test specimens shall be either sub-
satisfactory means of gripping long specimens of ductile metal
stantially full size or machined, as prescribed in the product
and flat plate test specimens such as those shown in Fig. 1. If,
specifications for the material being tested.
however, for any reason, one grip of a pair advances farther
6.1.2 Location—Unless otherwise specified, the axis of the
than the other as the grips tighten, an undesirable bending
test specimen shall be located within the parent material as
stress may be introduced. When liners are used behind the
follows:
wedges, they must be of the same thickness and their faces
6.1.2.1 At the center for products 40 mm [1.500 in.] or less
must be flat and parallel. For best results, the wedges should be
in thickness, diameter, or distance between flats.
supported over their entire lengths by the heads of the testing
6.1.2.2 Midway from the center to the surface for products
machine. This requires that liners of several thicknesses be
over 40 mm [1.500 in.] in thickness, diameter, or distance
available to cover the range of specimen thickness. For proper
between flats.
gripping, it is desirable that the entire length of the serrated
6.1.3 Specimen Machining—Improperly prepared test speci-
face of each wedge be in contact with the specimen. Proper
mens often are the reason for unsatisfactory and incorrect test
alignment of wedge grips and liners is illustrated in Fig. 2. For
results. It is important, therefore, that care be exercised in the
short specimens and for specimens of many materials it is
preparation of specimens, particularly in the machining, to
generally necessary to use machined test specimens and to use
maximize precision and minimize bias in test results.
a special means of gripping to ensure that the specimens, when
6.1.3.1 The reduced section including the fillets of prepared
under load, shall be as nearly as possible in uniformly
specimens should be free of cold work, notches, chatter marks,
distributed pure axial tension (see 5.2.3, 5.2.4, and 5.2.5).
grooves, gouges, burrs, rough surfaces or edges, overheating,
5.2.3 Grips for Threaded and Shouldered Specimens and
or any other condition which can deleteriously affect the
Brittle Materials—A schematic diagram of a gripping device
properties to be measured.
for threaded-end specimens is shown in Fig. 3, while Fig. 4
NOTE 3—Punching or blanking of the reduced section may produce
shows a device for gripping specimens with shouldered ends.
significant cold work or shear burrs, or both, along the edges which should
Both of these gripping devices should be attached to the heads
be removed by machining.
of the testing machine through properly lubricated spherical-
6.1.3.2 Within the reduced parallel section of rectangular
seated bearings. The distance between spherical bearings
specimens, edges or corners should not be ground or abraded in
should be as great as feasible.
a manner which could cause the actual cross-sectional area of
5.2.4 Grips for Sheet Materials—The self-adjusting grips
the specimen to be significantly different from the calculated
shown in Fig. 5 have proven satisfactory for testing sheet
area.
materials that cannot be tested satisfactorily in the usual type of
6.1.3.3 For brittle materials, large radius fillets at the ends of
wedge grips.
the reduced parallel section should be used.
5.2.5 Grips for Wire—Grips of either the wedge or snubbing
6.1.3.4 The cross-sectional area of the specimen should be
types as shown in Fig. 5 and Fig. 6 or flat wedge grips may be
smallest at the center of the reduced parallel section to ensure
used.
fracture within the gauge length. For this reason, a small taper
5.3 Dimension-Measuring Devices—Micrometers and other is permitted in the reduced parallel section of each of the
devices used for measuring linear dimensions shall be accurate specimens described in the following sections.
E8/E8M − 24
Dimensions
Standard Specimens Subsize Specimen
Plate-Type, 40 mm Sheet-Type, 12.5 mm 6 mm
[1.500 in.] Wide [0.500 in.] Wide [0.250 in.] Wide
mm [in.] mm [in.] mm [in.]
G—Gauge length (Note 1 and Note 2) 200.0 ± 0.2 50.0 ± 0.1 25.0 ± 0.1
[8.00 ± 0.01] [2.000 ± 0.005] [1.000 ± 0.003]
W—Width (Note 3 and Note 4) 40.0 ± 2.0 12.5 ± 0.2 6.0 ± 0.1
[1.500 + 0.125, -0.250] [0.500 ± 0.010] [0.250 ± 0.005]
T—Thickness (Note 5) thickness of material
R—Radius of fillet, min (Note 6) 25 [1] 12.5 [0.500] 6 [0.250]
L—Overall length, min (Note 2, Note 7, and Note 8) 450 [18] 200 [8] 100 [4]
A—Length of reduced parallel section, min 225 [9] 57 [2.25] 32 [1.25]
B—Length of grip section, min (Note 9) 75 [3] 50 [2] 30 [1.25]
C—Width of grip section, approximate (Note 4 and Note 9) 50 [2] 20 [0.750] 10 [0.375]
NOTE 1—For the 40 mm [1.500 in.] wide specimen, punch marks for measuring elongation after fracture shall be made on the flat or on the edge of
the specimen and within the reduced parallel section. Either a set of nine or more punch marks 25 mm [1 in.] apart, or one or more pairs of punch marks
200 mm [8 in.] apart may be used.
NOTE 2—When elongation measurements of 40 mm [1.500 in.] wide specimens are not required, a minimum length of reduced parallel section (A)
of 75 mm [2.25 in.] may be used with all other dimensions similar to those of the plate-type specimen.
NOTE 3—For the three sizes of specimens, the ends of the reduced parallel section shall not differ in width by more than 0.10 mm, 0.05 mm or 0.02
mm [0.004 in., 0.002 in. or 0.001 in.], respectively. Also, there may be a gradual decrease in width from the ends to the center, but the width at each end
shall not be more than 1 % larger than the width at the center.
NOTE 4—For each of the three sizes of specimens, narrower widths (W and C) may be used when necessary. In such cases the width of the reduced
parallel section should be as large as the width of the material being tested permits; however, unless stated specifically, the requirements for elongation
in a product specification shall not apply when these narrower specimens are used.
NOTE 5—The dimension T is the thickness of the test specimen as provided for in the applicable material specifications. Minimum thickness of 40 mm
[1.500 in.] wide specimens shall be 5 mm [0.188 in.]. Maximum thickness of 12.5 mm and 6 mm [0.500 in. and 0.250 in.] wide specimens shall be 19
and 6 mm [0.750 and 0.250 in.], respectively.
NOTE 6—For the 40 mm [1.500 in.] wide specimen, a 13 mm [0.500 in.] minimum radius at the ends of the reduced parallel section is permitted for
steel specimens under 690 MPa [100 000 psi] in tensile strength when a profile cutter is used to machine the reduced section.
NOTE 7—The dimension shown is suggested as a minimum. In determining the minimum length, the grips must not extend in to the transition section
between Dimensions A and B, see Note 9.
NOTE 8—To aid in obtaining axial force application during testing of 6 mm [0.250 in.] wide specimens, the overall length should be as large as the
material will permit, up to 200 mm [8.00 in.].
NOTE 9—It is desirable, if possible, to make the length of the grip section large enough to allow the specimen to extend into the grips a distance equal
to two thirds or more of the length of the grips. If the thickness of 12.5 mm [0.500 in.] wide specimens is over 10 mm [0.375 in.], longer grips and
correspondingly longer grip sections of the specimen may be necessary to prevent failure in the grip section.
NOTE 10—For the three sizes of specimens, the ends of the specimen shall be symmetrical in width with the center line of the reduced parallel section
within 2.5 mm, 1.25 mm and 0.13 mm [0.10 in., 0.05 in. and 0.005 in.], respectively. However, for referee testing and when required by product
specifications, the ends of the 12.5 mm [0.500 in.] wide specimen shall be symmetrical within 0.2 mm [0.01 in.].
NOTE 11—For each specimen type, the radii of all fillets shall be equal to each other within a tolerance of 1.25 mm [0.05 in.], and the centers of
curvature of the two fillets at a particular end shall be located across from each other (on a line perpendicular to the centerline) within a tolerance of 2.5
mm [0.10 in.].
NOTE 12—Specimens with sides parallel throughout their length are permitted, except for referee testing, provided: (a) the above tolerances are used;
(b) an adequate number of marks are provided for determination of elongation; and (c) when yield strength is determined, a suitable extensometer is used.
If the fracture occurs at a distance of less than 2 W from the edge of the gripping device, the tensile properties determined may not be representative of
the material. In acceptance testing, if the properties meet the minimum requirements specified, no further testing is required, but if they are less than the
minimum requirements, discard the test and retest.
FIG. 1 Rectangular Tension Test Specimens
E8/E8M − 24
FIG. 2 Wedge Grips with Liners for Flat Specimens
FIG. 4 Gripping Device for Shouldered-End Specimens
FIG. 3 Gripping Device for Threaded-End Specimens
6.1.4 Specimen Surface Finish—When materials are tested
with surface conditions other than as manufactured, the surface
finish of the test specimens should be as provided in the
applicable product specifications.
NOTE 4—Particular attention should be given to the uniformity and
quality of surface finish of specimens for high strength and very low
ductility materials since this has been shown to be a factor in the
variability of test results.
FIG. 5 Gripping Devices for Sheet and Wire Specimens
6.1.5 Specimen Grip Section Symmetry—Symmetry toler-
ances for grip sections of specimens (relative to centerlines of
reduced parallel sections) are given within Fig. 1 and Fig. 7.
the centerlines of reduced parallel sections can affect alignment, stress-
NOTE 5—Symmetry of grip sections of machined specimens relative to strain curves, and test results, especially when the grip sections of
E8/E8M − 24
may be applied axially. Fig. 10 shows specimens with various
types of ends that have given satisfactory results.
6.5 Specimens for Sheet, Strip, Flat Wire, and Plate—In
testing sheet, strip, flat wire, and plate, use a specimen type
appropriate for the nominal thickness of the material, as
described in the following:
6.5.1 For material with a nominal thickness of 0.13 mm to
5 mm [0.005 in. to 0.1875 in.], use the sheet-type specimen
described in 6.3.
6.5.2 For material with a nominal thickness of 5 mm to
12.5 mm [0.1875 in. to 0.500 in.], use either the sheet-type
specimen of 6.3 or the plate-type specimen of 6.2.
6.5.3 For material with a nominal thickness of 12.5 mm to
FIG. 6 Snubbing Device for Testing Wire 19 mm [0.500 in. to 0.750 in.], use either the sheet-type
specimen of 6.3, the plate-type specimen of 6.2, or the largest
practical size of round specimen described in 6.4.
rectangular specimens are used to locate the specimens within the testing
machine. Tighter tolerances, such as those given by Note 10 of Fig. 1 for 6.5.4 For material with a nominal thickness of 19 mm
referee testing, can be used to maintain alignment where asymmetry of
[0.750 in.], or greater, use the plate-type specimen of 6.2 or the
specimen grip sections could otherwise result in the reduced parallel
largest practical size of round specimen described in 6.4.
section being offset, oriented at an angle, or both, relative to the axis of
6.5.4.1 If the product specifications permit, material of a
force application.
thickness of 19 mm [ 0.750 in.], or greater may be tested using
NOTE 6—Effects of specimen symmetry and misalignment errors can be
minimized by use of certain types of gripping systems or backstops.
a modified sheet-type specimen conforming to the configura-
tion shown by Fig. 1. The thickness of this modified specimen
6.2 Plate-Type Specimens—The standard plate-type test
must be machined to 10 mm 6 0.5 mm [0.400 in. 6 0.020 in.],
specimen is shown in Fig. 1. This specimen is used for testing
and must be uniform within 0.1 mm [0.004 in.] throughout the
metallic materials in the form of plate, shapes, and flat material
reduced parallel section. In the event of disagreement, a round
having a nominal thickness of 5 mm [0.188 in.] or over. When
specimen shall be used as the referee test (comparison)
product specifications so permit, other types of specimens may
specimen.
be used, as provided in 6.3, 6.4, and 6.5.
6.6 Specimens for Wire, Rod, and Bar:
6.3 Sheet-Type Specimens:
6.6.1 For round wire, rod, and bar, test specimens having the
6.3.1 The standard sheet-type test specimen is shown in Fig.
full cross-sectional area of the wire, rod, or bar shall be used
1. This specimen is used for testing metallic materials in the
wherever practicable. The gauge length for the measurement of
form of sheet, plate, flat wire, strip, band, hoop, rectangles, and
elongation of wire less than 4 mm [0.125 in.] in diameter shall
shapes ranging in nominal thickness from 0.13 mm to 19 mm
be as prescribed in product specifications. When testing wire,
[0.005 in. to 0.750 in.]. When product specifications so permit,
rod, or bar having a diameter of 4 mm [0.125 in.] or larger, a
other types of specimens may be used, as provided in 6.2, 6.4,
gauge length equal to four times the diameter shall be used
and 6.5.
when following E8 and a gauge length equal to five times the
NOTE 7—Test Methods E345 may be used for tension testing of
diameter shall be used when following E8M unless otherwise
materials in thicknesses up to 0.15 mm [0.0059 in.].
specified. The total length of the specimens shall be at least
6.3.2 Pin ends as shown in Fig. 8 may be used. In order to
equal to the gauge length plus the length of material required
avoid buckling in tests of thin and high-strength materials, it
for the full use of the grips employed.
may be necessary to use stiffening plates at the grip ends.
6.6.2 For wire of octagonal, hexagonal, or square cross
6.4 Round Specimens: section, for rod or bar of round cross section where the
6.4.1 The standard 12.5 mm [0.500 in.] diameter round test specimen required in 6.6.1 is not practicable, and for rod or bar
specimen shown in Fig. 9 is used quite generally for testing of octagonal, hexagonal, or square cross section, one of the
metallic materials, both cast and wrought. following types of specimens shall be used:
6.4.2 Fig. 9 also shows small-size specimens proportional to 6.6.2.1 Full Cross Section (Note 8)—It is permissible to
the standard specimen. These may be used when it is necessary reduce the test section slightly with abrasive cloth or paper, or
to test material from which the standard specimen or specimens machine it sufficiently to ensure fracture within the gauge
shown in Fig. 1 cannot be prepared. Other sizes of small round marks. For material not exceeding 5 mm [0.188 in.] in diameter
specimens may be used. In any such small-size specimen it is or distance between flats, the cross-sectional area may be
important that the gauge length for measurement of elongation reduced to not less than 90 % of the original area without
be four times the diameter of the specimen when following E8 changing the shape of the cross section. For material over
and five times the diameter of the specimen when following 5 mm [0.188 in.] in diameter or distance between flats, the
E8M. diameter or distance between flats may be reduced by not more
6.4.3 The shape of the ends of the specimen outside of the than 0.25 mm [0.010 in.] without changing the shape of the
gauge length shall be suitable to the material and of a shape to cross section. Square, hexagonal, or octagonal wire or rod not
fit the holders or grips of the testing machine so that the forces exceeding 5 mm [0.188 in.] between flats may be turned to a
E8/E8M − 24
Dimensions
Specimen 1 Specimen 2 Specimen 3 Specimen 4 Specimen 5 Specimen 6 Specimen 7
mm [in.] mm [in.] mm [in.] mm [in.] mm [in.] mm [in.] mm [in.]
G—Gauge length 50.0 ± 0.1 50.0 ± 0.1 200.0 ± 0.2 50.0 ± 0.1 100.0 ± 0.1 50.0 ± 0.1 100.0 ± 0.1
[2.000 ± 0.005] [2.000 ± 0.005] [8.00 ± 0.01] [2.000 ± 0.005] [4.000 ± 0.005] [2.000 ± 0.005] [4.000 ± 0.005]
W—Width (Note 1) 12.5 ± 0.2 40.0 ± 2.0 40.0 ± 2.0 20.0 ± 0.7 20.0 ± 0.7 25.0 ± 1.5 25.0 ± 1.5
[0.500 ± 0.010] [1.500 + 0.125, [1.500 + 0.125, [0.750 ± 0.031] [0.750 ± 0.031] [1.000 ± 0.062] [1.000 ± 0.062]
-0.250] -0.250]
T—Thickness measured thickness of specimen
R—Radius of fillet, 12.5 [0.5] 25 [1] 25 [1] 25 [1] 25 [1] 25 [1] 25 [1]
min
A—Length of re- 60 [2.25] 60 [2.25] 230 [9] 60 [2.25] 120 [4.5] 60 [2.25] 120 [4.5]
duced parallel
section,
min
B—Length of grip 75 [3] 75 [3] 75 [3] 75 [3] 75 [3] 75 [3] 75 [3]
section,
min (Note 2)
C—Width of grip 20 [0.75] 50 [2] 50 [2] 25 [1] 25 [1] 40 [1.5] 40 [1.5]
section,
approximate (Note
3)
NOTE 1—The ends of the reduced parallel section shall differ from each other in width by not more than 0.5 %. There may be a gradual taper in width
from the ends to the center, but the width at each end shall be not more than 1 % greater than the width at the center.
NOTE 2—It is desirable, if possible, to make the length of the grip section great enough to allow the specimen to extend into the grips a distance equal
to two thirds or more of the length of the grips.
NOTE 3—The ends of the specimen shall be symmetrical with the center line of the reduced parallel section within 1 mm [0.05 in.] for specimens 1,
4, and 5, and 2.5 mm [0.10 in.] for specimens 2, 3, 6, and 7.
NOTE 4—For each specimen type, the radii of all fillets shall be equal to each other within a tolerance of 1.25 mm [ 0.05 in.], and the centers of curvature
of the two fillets at a particular end shall be located across from each other (on a line perpendicular to the centerline) within a tolerance of 2.5 mm [0.10
in.].
NOTE 5—For circular segments, the cross-sectional area may be calculated by multiplying W and T. If the ratio of the dimension W to the diameter
of the tubular section is larger than about ⁄6 the error in using this method to calculate the cross-sectional area may be appreciable. In this case, the exact
equation (see 7.2.2.4) must be used to determine the area.
NOTE 6—Specimens with G/W less than 4 should not be used for determination of elongation.
NOTE 7—Specimens with sides parallel throughout their length are permitted, except for referee testing, provided: (a) the above tolerances are used;
(b) an adequate number of marks are provided for determination of elongation; and (c) when yield strength is determined, a suitable extensometer is used.
If the fracture occurs at a distance of less than 2 W from the edge of the gripping device, the tensile properties determined may not be representative of
the material. If the properties meet the minimum requirements specified, no further testing is required, but if they are less than the minimum requirements,
discard the test and retest.
FIG. 7 Tension Test Specimens for Large-Diameter Tubular Products
round having a cross-sectional area not smaller than 90 % of 6.6.2.2 For rod and bar, the largest practical size of round
the area of the maximum inscribed circle. Fillets, preferably specimen as described in 6.4 may be used in place of a test
with a radius of 10 mm [0.375 in.], but not less than 3 mm specimen of full cross section. Unless otherwise specified in
[0.125 in.], shall be used at the ends of the reduced parallel the product specification, specimens shall be parallel to the
sections. Square, hexagonal, or octagonal rod over 5 mm direction of rolling or extrusion.
[0.188 in.] between flats may be turned to a round having a
6.7 Specimens for Rectangular Bar—In testing rectangular
diameter no smaller than 0.25 mm [0.010 in.] less than the
bar one of the following types of specimens shall be used:
original distance between flats.
6.7.1 Full Cross Section—It is permissible to reduce the
NOTE 8—The ends of copper or copper alloy specimens may be width of the specimen throughout the test section with abrasive
flattened 10 % to 50 % from the original dimension in a jig similar to that
cloth or paper, or by machining sufficiently to facilitate fracture
shown in Fig. 11, to facilitate fracture within the gauge marks. In
within the gauge marks, but in no case shall the reduced width
flattening the opposite ends of the test specimen, care shall be taken to
be less than 90 % of the original. The edges of the midlength
ensure that the four flattened surfaces are parallel and that the two parallel
of the reduced parallel section not less than 20 mm [ ⁄4 in.] in
surfaces on the same side of the axis of the test specimen lie in the same
plane. length shall be parallel to each other and to the longitudinal
E8/E8M − 24
Dimensions, mm [in.]
G—Gauge length 50.0 ± 0.1 [2.000 ± 0.005]
W—Width (Note 1) 12.5 ± 0.2 [0.500 ± 0.010]
T—Thickness, max (Note 2) 16 [0.625]
R—Radius of fillet, min (Note 3) 13 [0.5]
L—Overall length, min 200 [8]
A—Length of reduced parallel section, min 57 [2.25]
B—Length of grip section, min 50 [2]
C—Width of grip section, approximate 50 [2]
D—Diameter of hole for pin, min (Note 4) 13 [0.5]
E—Edge distance from pin, approximate 40 [1.5]
F—Distance from hole to fillet, min 13 [0.5]
NOTE 1—The ends of the reduced parallel section shall differ in width by not more than 0.1 mm [0.002 in.]. There may be a gradual taper in width
from the ends to the center, but the width at each end shall be not more than 1 % greater than the width at the center.
NOTE 2—The dimension T is the thickness of the test specimen as stated in the applicable product specifications.
NOTE 3—For some materials, a fillet radius R larger than 13 mm [0.500 in.] may be needed.
NOTE 4—Holes must be on center line of reduced parallel section within 6 0.05 mm [0.002 in].
NOTE 5—Variations of dimensions C, D, E, F, and L may be used that will permit failure within the gauge length.
FIG. 8 Pin-Loaded Tension Test Specimen with 50 mm [2 in.] Gauge Length
E8/E8M − 24
Dimensions, mm [in.]
For Test Specimens with Gauge Length Four times the Diameter [E8]
Standard Small-Size Specimens Proportional to Standard
Specimen
Specimen 1 Specimen 2 Specimen 3 Specimen 4 Specimen 5
G—Gauge length 50.0 ± 0.1 36.0 ± 0.1 24.0 ± 0.1 16.0 ± 0.1 10.0 ±0.1
[2.000 ± 0.005] [1.400 ± 0.005] [1.000 ± 0.005] [0.640 ± 0.005] [0.450 ± 0.005]
D—Diameter (Note 1) 12.5 ± 0.2 9.0 ±0.1 6.0 ± 0.1 4.0 ± 0.1 2.5 ± 0.1
[0.500 ± 0.010] [0.350 ± 0.007] [0.250 ± 0.005] [0.160 ± 0.003] [0.113 ± 0.002]
R—Radius of fillet, min 10 [0.375] 8 [0.25] 6 [0.188] 4 [0.156] 2 [0.094]
A—Length of reduced parallel section, min 56 [2.25] 45 [1.75] 30 [1.25] 20 [0.75] 16 [0.625]
(Note 2)
Dimensions, mm [in.]
For Test Specimens with Gauge Length Five times the Diameter [E8M]
Standard Specimen Small-Size Specimens Proportional to Standard
Specimen 1 Specimen 2 Specimen 3 Specimen 4 Specimen 5
G—Gauge length 62.5 ± 0.1 45.0 ± 0.1 30.0 ± 0.1 20.0 ± 0.1 12.5 ± 0.1
[2.500 ± 0.005] [1.750 ± 0.005] [1.250 ± 0.005] [0.800 ± 0.005] [0.565 ± 0.005]
D—Diameter (Note 1) 12.5 ± 0.2 9.0 ± 0.1 6.0 ± 0.1 4.0 ± 0.1 2.5 ± 0.1
[0.500 ± 0.010] [0.350 ± 0.007] [0.250 ± 0.005] [0.160 ± 0.003] [0.113 ± 0.002]
R—Radius of fillet, min 10 [0.375] 8 [0.25] 6 [0.188] 4 [0.156] 2 [0.094]
A—Length of reduced parallel section, min 75 [3.0] 54 [2.0] 36 [1.4] 24 [1.0] 20 [0.75]
(Note 2)
NOTE 1—The reduced parallel section may have a gradual taper from the ends toward the center, with the ends not more than 1 % larger in diameter
than the center (controlling dimension).
NOTE 2—If desired, the length of the reduced parallel section may be increased to accommodate an extensometer of any convenient gauge length.
Reference marks for the measurement of elongation should, nevertheless, be spaced at the indicated gauge length.
NOTE 3—The gauge length and fillets may be as shown, but the ends may be of any form to fit the holders of the testing machine in such a way that
the force shall be axial (see Fig. 10). If the ends are to be held in wedge grips it is desirable, if possible, to make the length of the grip section great enough
to allow the specimen to extend into the grips a distance equal to two thirds or more of the length of the grips.
NOTE 4—On the round specimens in Figs. 9 and 10, the gauge lengths are equal to four [E8] or five times [E8M] the nominal diameter. In some product
specifications other specimens may be provided for, but unless the 4-to-1 [E8] or 5-to-1 [E8M] ratio is maintained within dimensional tolerances, the
elongation values may not be comparable with those obtained from the standard test specimen.
NOTE 5—The use of specimens smaller than 6 mm [0.250 in.] diameter shall be restricted to cases when the material to be tested is of insufficient size
to obtain larger specimens or when all parties agree to their use for acceptance testing. Smaller specimens require suitable equipment and greater skill
in both machining and testing.
NOTE 6—For inch/pound units only: Five sizes of specimens often used have diameters of approximately 0.505 in., 0.357 in., 0.252 in., 0.160 in., and
0.113 in., the reason being to permit easy calculations of stress from loads, since the corresponding cross-sectional areas are equal or close to 0.200 in. ,
2 2 2 2
0.100 in. , 0.0500 in. , 0.0200 in. , and 0.0100 in. , respectively. Thus, when the actual diameters agree with these values, the stresses (or strengths) may
be computed using the simple multiplying factors 5, 10, 20, 50, and 100, respectively. (The metric equivalents of these five diameters do not result in
correspondingly convenient cross-sectional areas and multiplying factors.)
FIG. 9 Standard 12.5 mm [0.500 in.] Round Tension Test Specimen and Examples of Small-Size Specimens
Proportional to the Standard Specimen
E8/E8M − 24
Dimensions, mm [in.]
For Test Specimens with Gauge Length Four times the Diameter [E8]
Specimen 1 Specimen 2 Specimen 3 Specimen 4 Specimen 5
G—Gauge length 50 ± 0.1 50 ± 0.1 50 ± 0.1 50 ± 0.1 50 ± 0.1
[2.000 ± 0.005] [2.000 ± 0.005] [2.000 ± 0.005] [2.000 ± 0.005] [2.000 ± 0.005]
D—Diameter (Note 1) 12.5 ± 0.2 12.5 ± 0.2 12.5 ± 0.2 12.5 ± 0.2 12.5 ± 0.2
[0.500 ± 0.010] [0.500 ± 0.010] [0.500 ± 0.010] [0.500 ± 0.010] [0.500 ± 0.010]
R—Radius of fillet, min 10 [0.375] 10 [0.375] 2 [0.0625] 10 [0.375] 10 [0.375]
A—Length of reduced parallel section 56 [2.25] 56 [2.25] 100 [4] 56 [2.25] 56 [2.25]
min min approximate min min
L—Overall length, approximate 145 [5] 155 [5.5] 155 [5.5] 140 [4.75] 255 [9.5]
B—Length of end section (Note 3) 35 [1.375] 25 [1] 20 [0.75] 15 [0.5] 75 [3]
approximate approximate approximate approximate min
C—Diameter of end section 20 [0.75] 20 [0.75] 20 [0.75] 22 [0.875] 20 [0.75]
E—Length of shoulder and fillet section, approximate 15 [0.625] 20 [0.75] 15 [0.625]
F—Diameter of shoulder 15 [0.625] 15 [0.625] 15 [0.625]
Dimensions, mm [in.]
For Test Specimens with Gauge Length Five times the Diameter [E8M]
Specimen 1 Specimen 2 Specimen 3 Specimen 4 Specimen 5
G—Gauge length 62.5 ± 0.1 62.5 ± 0.1 62.5 ± 0.1 62.5 ± 0.1 62.5 ± 0.1
[2.500 ± 0.005] [2.500 ± 0.005] [2.500 ± 0.005] [2.500 ± 0.005] [2.500 ± 0.005]
D—Diameter (Note 1) 12.5 ± 0.2 12.5 ± 0.2 12.5 ± 0.2 12.5 ± 0.2 12.5 ± 0.2
[0.500 ± 0.010] [0.500 ± 0.010] [0.500 ± 0.010] [0.500 ± 0.010] [0.500 ± 0.010]
R—Radius of fillet, min 10 [0.375] 10 [0.375] 2 [0.0625] 10 [0.375] 10 [0.375]
A—Length of reduced parallel section 75 [3] 75 [3] 75 [3] 75 [3] 75 [3]
min min approximate min min
L—Overall length, approximate 145 [5] 155 [5.5] 155 [5.5] 140 [4.75] 255 [9.5]
B—Length of end section (Note 3) 35 [1.375] 25 [1] 20 [0.75] 15 [0.5] 75 [3]
approximate approximate approximate approximate min
C—Diameter of end section 20 [0.75] 20 [0.75] 20 [0.75] 22 [0.875] 20 [0.75]
E—Length of shoulder and fillet section, approximate 15 [0.625] 20 [0.75] 15 [0.625]
F—Diameter of shoulder 15 [0.625] 15 [0.625] 15 [0.625]
NOTE 1—The reduced parallel section may have a gradual taper from the ends toward the center with the ends not more than 1 %. larger in diameter
than the center.
NOTE 2—On Specimens 1 and 2, any standard thread is permissible that provides for proper alignment and aids in assuring that the specimen will break
within the reduced parallel section.
NOTE 3—On Specimen 5 it is desirable, if possible, to make the length of the grip section great enough to allow the specimen to extend into the grips
a distance equal to two thirds or more of the length of the grips.
NOTE 4—The values stated in SI units in the table for Fig. 10 are to be regarded as separate from the inch/pound units. The values stated in each system
are not exact equivalents; therefore each system must be used independently of the other.
FIG. 10 Various Types of Ends for Standard Round Tension Test Specimens
E8/E8M − 24
FIG. 11 Squeezing Jig for Flattening Ends of Full-Size Tension
NOTE 1—The diameter of the plug shall have a slight taper from the line
Test Specimens
limiting the test machine jaws to the curved section.
FIG. 12 Metal Plugs for Testing Tubular Specimens, Proper Loca-
tion of Plugs in Specimen and of Specimen in Heads of Testing
axis of the specimen within 0.05 mm [0.002 in.]. Fillets,
Machine
preferably with a radius of 10 mm [ ⁄8 in.] but not less than 3
mm [ ⁄8 in.] shall be used at the ends of the reduced parallel
sections.
6.7.2 Rectangular bar of thickness small enough to fit the
grips of the testing machine but of too great width may be
reduced in width by cutting to fit the grips, after which the cut
surfaces shall be machined or cut and smoothed to ensure
failure within the desired section. The reduced width shall not
be less than the original bar thickness. Also, one of the types of
specimens described in 6.2, 6.3, and 6.4 may be used.
6.8 Shapes, Structural and Other—In testing shapes other
than those covered by the preceding sections, one of the types
NOTE 1—The edges of the blank for the specimen shall be cut parallel
of specimens described in 6.2, 6.3, and 6.4 shall be used.
to each other.
6.9 Specimens for Pipe and Tube (Note 9): FIG. 13 Location from Which Longitudinal Tension Test Speci-
mens Are to be Cut from Large-Diameter Tube
6.9.1 For all small tube (Note 9), particularly sizes 25 mm
[1 in.] and under in nominal outside diameter, and frequently
for larger sizes, except as limited by the testing equipment, it is
grips having a surface contour corresponding to the curvature
standard practice to use tension test specimens of full-size
of the tube. When grips with curved faces are not available, the
tubular sections. Snug-fitting metal plugs shall be inserted far
ends of the specimens may be flattened without heating. If the
enough into the ends of such tubular specimens to permit the
tube-wall thickness is 20 mm [0.750 in.] or over, the standard
testing machine jaws to grip the specimens properly. The plugs
specimen shown in Fig. 9 shall be used.
shall not extend into that part of the specimen on which the
elongation is measured. Elongation is measured over a length NOTE 10—In clamping of specimens from pipe and tube (as may be
done during machining) or in flattening specimen ends (for gripping), care
of four times the diameter when following E8 or five times the
must be taken so as not to subject the reduced section including the fillets
diameter when following E8M unless otherwise stated in the
to any deformation or cold work, as this would alter the mechanical
product specification. Fig. 12 shows a suitable form of plug,
properties.
the location of the plugs in the specimen, and the location of
6.9.3
...

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: E8/E8M − 22 E8/E8M − 24 American Association State
Highway and Transportation Officials Standard
AASHTO No.: T68
An American National Standard
Standard Test Methods for
Tension Testing of Metallic Materials
This standard is issued under the fixed designation E8/E8M; 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*
1.1 These test methods cover the tension testing of metallic materials in any form at room temperature, specifically, the methods
of determination of yield strength, yield point elongation, tensile strength, elongation, and reduction of area.
1.2 The gauge lengths for most round specimens are required to be 4D for E8 and 5D for E8M. The gauge length is the most
significant difference between E8 and E8M test specimens. Test specimens made from powder metallurgy (P/M) materials are
exempt from this requirement by industry-wide agreement to keep the pressing of the material to a specific projected area and
density.
1.3 Exceptions to the provisions of these test methods may need to be made in individual specifications or test methods for a
particular material. For examples, see Test Methods and Definitions A370 and Test Methods B557, and B557M.
1.4 Room temperature shall be considered to be 10 °C to 38 °C [50 °F to 100°F] unless otherwise specified.
1.5 The values stated in SI units are to be regarded as separate from inch/pound units. The values stated in each system are not
exact equivalents; therefore each system must be used independently of the other. Combining values from the two systems may
result in non-conformance with the standard.
1.6 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 practices and determine the applicability of
regulatory limitations prior to use.
1.7 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:
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 May 1, 2022Jan. 1, 2024. Published July 2022March 2024. Originally approved in 1924. Last previous edition approved 20212022 as
E8/E8M – 21.E8/E8M – 22.
DOI: 10.1520/E0008_E0008M-22.10.1520/E0008_E0008M-24.
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
E8/E8M − 24
A356/A356M Specification for Steel Castings, Carbon, Low Alloy, and Stainless Steel, Heavy-Walled for Steam Turbines
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
B557 Test Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products
B557M Test Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products (Metric)
E4 Practices for Force Calibration and Verification of Testing Machines
E6 Terminology Relating to Methods of Mechanical Testing
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E83 Practice for Verification and Classification of Extensometer Systems
E345 Test Methods of Tension Testing of Metallic Foil
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E1012 Practice for Verification of Testing Frame and Specimen Alignment Under Tensile and Compressive Axial Force
Application
D1566 Terminology Relating to Rubber
E1856 Guide for Evaluating Computerized Data Acquisition Systems Used to Acquire Data from Universal Testing Machines
E2658 Practices for Verification of Speed for Material Testing Machines
2.2 ISO/ASTM Standard:
ISO/ASTM 52909:2024(en) Additive manufacturing of metals — Finished part properties — Orientation and location
dependence of mechanical properties for metal parts
3. Terminology
3.1 Definitions of Terms Common to Mechanical Testing—
3.1.1 The definitions of mechanical testing terms that appear in the Terminology E6 apply to this test method.
3.1.1.1 These terms include bending strain, constraint, elongation, extensometer, force, gauge length, necking, reduced section,
stress-strain diagram, testing machine, and modulus of elasticity.
3.1.2 In addition, the following common terms from Terminology E6 are defined:
3.1.3 discontinuous yielding, n—in a uniaxial test, a hesitation or fluctuation of force observed at the onset of plastic deformation,
due to localized yielding.
3.1.3.1 Discussion—
The stress-strain curve need not appear to be discontinuous.
3.1.4 elongation after fracture, n—the elongation measured by fitting the two halves of the broken specimen together.
3.1.5 elongation at fracture, n—the elongation measured just prior to the sudden decrease in force associated with fracture.
-2
3.1.6 lower yield strength, LYS [FL ]—in a uniaxial test, the minimum stress recorded during discontinuous yielding, ignoring
transient effects.
3.1.7 reduced parallel section, A, n—the central portion of the specimen that has a nominally uniform cross section, with an
optional small taper toward the center, that is smaller than that of the ends that are gripped, not including the fillets.
3.1.7.1 Discussion—
This term is often called the parallel length in other standards.
3.1.7.2 Discussion—
Previous versions of E8/E8M defined this term as “reduced section.”
3.1.8 reduction of area, n—the difference between the original cross-sectional area of a tension test specimen and the area of its
smallest cross section.
3.1.8.1 Discussion—
The reduction of area is usually expressed as a percentage of the original cross-sectional area of the specimen.
3.1.8.2 Discussion—
The smallest cross section may be measured at or after fracture as specified for the material under test.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland,
https://www.iso.org.
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3.1.8.3 Discussion—
The term reduction of area when applied to metals generally means measurement after fracture; when applied to plastics and
elastomers, measurement at fracture. Such interpretation is usually applicable to values for reduction of area reported in the
literature when no further qualification is given. (E28.04)
–2
3.1.9 tensile strength, S [FL ],n—the maximum tensile stress that a material is capable of sustaining.
u
3.1.9.1 Discussion—
Tensile strength is calculated from the maximum force during a tension test carried to rupture and the original cross-sectional area
of the specimen.
3.1.10 uniform elongation, El , [%]—the elongation determined at the maximum force sustained by the test specimen just prior
u
to necking or fracture, or both.
3.1.10.1 Discussion—
Uniform elongation includes both elastic and plastic elongation.
-2
3.1.11 upper yield strength, UYS [FL ]—in a uniaxial test, the first stress maximum (stress at first zero slope) associated with
discontinuous yielding at or near the onset of plastic deformation.
3.1.12 yield point elongation, YPE, n—in a uniaxial test, the strain (expressed in percent) separating the stress-strain curve’s first
point of zero slope from the point of transition from discontinuous yielding to uniform strain hardening.
3.1.12.1 Discussion—
If the transition occurs over a range of strain, the YPE end point is the intersection between (a) a horizontal line drawn tangent
to the curve at the last zero slope and (b) a line drawn tangent to the strain hardening portion of the stress-strain curve at the point
of inflection. If there is no point at or near the onset of yielding at which the slope reaches zero, the material has 0 % YPE.
–2
3.1.13 yield strength, YSorS [FL ],n—the engineering stress at which, by convention, it is considered that plastic elongation of
y
the material has commenced.
3.1.13.1 Discussion—
This stress may be specified in terms of (a) a specified deviation from a linear stress-strain relationship, (b) a specified total
extension attained, or (c) maximum or minimum engineering stresses measured during discontinuous yielding.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 referee test, n—test made to settle a disagreement as to the conformance to specified requirements, or conducted by a third
party to arbitrate between conflicting results. D1566, D11.08
4. Significance and Use
4.1 Tension tests provide information on the strength and ductility of materials under uniaxial tensile stresses. This information
may be useful in comparisons of materials, alloy development, quality control, and design under certain circumstances.
4.2 The results of tension tests of specimens machined to standardized dimensions from selected portions of a part or material may
not totally represent the strength and ductility properties of the entire end product or its in-service behavior in different
environments.
4.3 These test methods are considered satisfactory for acceptance testing of commercial shipments. The test methods have been
used extensively in the trade for this purpose.
5. Apparatus
5.1 Testing Machines—Machines used for tension testing shall conform to the requirements of Practices E4. The forces used in
determining tensile strength and yield strength shall be within the verified force application range of the testing machine as defined
in Practices E4. Where verification of the testing machine speed is required, Practices E2658 shall be used unless otherwise
specified.
5.2 Gripping Devices:
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5.2.1 General—Various types of gripping devices may be used to transmit the measured force applied by the testing machine to
the test specimens. To ensure axial tensile stress within the gauge length, the axis of the test specimen should coincide with the
center line of the heads of the testing machine. Any departure from this requirement may introduce bending stresses that are not
included in the usual stress computation (force divided by cross-sectional area).
NOTE 1—The effect of this eccentric force application may be illustrated by calculating the bending moment and stress thus added. For a standard 12.5 mm
[0.500 in.] diameter specimen, the stress increase is 1.5 percentage points for each 0.025 mm [0.001 in.] of eccentricity. This error increases to 2.5
percentage points/ 0.025 mm [0.001 in.] for a 9 mm [0.350 in.] diameter specimen and to 3.2 percentage points/ 0.025 mm [0.001 in.] for a 6 mm
[0.250 in.] diameter specimen.
NOTE 2—Alignment methods are given in Practice E1012.
5.2.2 Wedge Grips—Testing machines usually are equipped with wedge grips. These wedge grips generally furnish a satisfactory
means of gripping long specimens of ductile metal and flat plate test specimens such as those shown in Fig. 1. If, however, for
any reason, one grip of a pair advances farther than the other as the grips tighten, an undesirable bending stress may be introduced.
When liners are used behind the wedges, they must be of the same thickness and their faces must be flat and parallel. For best
results, the wedges should be supported over their entire lengths by the heads of the testing machine. This requires that liners of
several thicknesses be available to cover the range of specimen thickness. For proper gripping, it is desirable that the entire length
of the serrated face of each wedge be in contact with the specimen. Proper alignment of wedge grips and liners is illustrated in
Fig. 2. For short specimens and for specimens of many materials it is generally necessary to use machined test specimens and to
use a special means of gripping to ensure that the specimens, when under load, shall be as nearly as possible in uniformly
distributed pure axial tension (see 5.2.3, 5.2.4, and 5.2.5).
5.2.3 Grips for Threaded and Shouldered Specimens and Brittle Materials—A schematic diagram of a gripping device for
threaded-end specimens is shown in Fig. 3, while Fig. 4 shows a device for gripping specimens with shouldered ends. Both of these
gripping devices should be attached to the heads of the testing machine through properly lubricated spherical-seated bearings. The
distance between spherical bearings should be as great as feasible.
5.2.4 Grips for Sheet Materials—The self-adjusting grips shown in Fig. 5 have proven satisfactory for testing sheet materials that
cannot be tested satisfactorily in the usual type of wedge grips.
5.2.5 Grips for Wire—Grips of either the wedge or snubbing types as shown in Fig. 5 and Fig. 6 or flat wedge grips may be used.
5.3 Dimension-Measuring Devices—Micrometers and other devices used for measuring linear dimensions shall be accurate and
precise to at least one half the smallest unit to which the individual dimension is required to be measured.
5.4 Extensometers—Extensometers used in tension testing shall conform to the requirements of Practice E83 for the classifications
specified by the procedure section of this test method. Extensometers shall be used and verified to include the strains corresponding
to the yield strength and elongation at fracture (if determined).
5.4.1 Extensometers with gauge lengths equal to or shorter than the nominal gauge length of the specimen (dimension shown as
“G-Gauge Length” in the accompanying figures) may be used to determine the yield behavior. For specimens without a reduced
section (for example, full cross sectional area specimens of wire, rod, or bar), the extensometer gauge length for the determination
of yield behavior shall not exceed 80 % of the distance between grips. For measuring elongation at fracture with an appropriate
extensometer, the gauge length of the extensometer shall be equal to the nominal gauge length required for the specimen being
tested.
6. Test Specimens
6.1 General:
6.1.1 Specimen Size—Test specimens shall be either substantially full size or machined, as prescribed in the product specifications
for the material being tested.
6.1.2 Location—Unless otherwise specified, the axis of the test specimen shall be located within the parent material as follows:
6.1.2.1 At the center for products 40 mm [1.500 in.] or less in thickness, diameter, or distance between flats.
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Dimensions
Standard Specimens Subsize Specimen
Plate-Type, 40 mm Sheet-Type, 12.5 mm 6 mm
[1.500 in.] Wide [0.500 in.] Wide [0.250 in.] Wide
mm [in.] mm [in.] mm [in.]
G—Gauge length (Note 1 and Note 2) 200.0 ± 0.2 50.0 ± 0.1 25.0 ± 0.1
[8.00 ± 0.01] [2.000 ± 0.005] [1.000 ± 0.003]
W—Width (Note 3 and Note 4) 40.0 ± 2.0 12.5 ± 0.2 6.0 ± 0.1
[1.500 + 0.125, -0.250] [0.500 ± 0.010] [0.250 ± 0.005]
T—Thickness (Note 5) thickness of material
R—Radius of fillet, min (Note 6) 25 [1] 12.5 [0.500] 6 [0.250]
L—Overall length, min (Note 2, Note 7, and Note 8) 450 [18] 200 [8] 100 [4]
A—Length of reduced parallel section, min 225 [9] 57 [2.25] 32 [1.25]
B—Length of grip section, min (Note 9) 75 [3] 50 [2] 30 [1.25]
C—Width of grip section, approximate (Note 4 and Note 9) 50 [2] 20 [0.750] 10 [0.375]
NOTE 1—For the 40 mm [1.500 in.] wide specimen, punch marks for measuring elongation after fracture shall be made on the flat or on the edge of
the specimen and within the reduced parallel section. Either a set of nine or more punch marks 25 mm [1 in.] apart, or one or more pairs of punch marks
200 mm [8 in.] apart may be used.
NOTE 2—When elongation measurements of 40 mm [1.500 in.] wide specimens are not required, a minimum length of reduced parallel section (A)
of 75 mm [2.25 in.] may be used with all other dimensions similar to those of the plate-type specimen.
NOTE 3—For the three sizes of specimens, the ends of the reduced parallel section shall not differ in width by more than 0.10 mm, 0.05 mm or 0.02
mm [0.004 in., 0.002 in. or 0.001 in.], respectively. Also, there may be a gradual decrease in width from the ends to the center, but the width at each end
shall not be more than 1 % larger than the width at the center.
NOTE 4—For each of the three sizes of specimens, narrower widths (W and C) may be used when necessary. In such cases the width of the reduced
parallel section should be as large as the width of the material being tested permits; however, unless stated specifically, the requirements for elongation
in a product specification shall not apply when these narrower specimens are used.
NOTE 5—The dimension T is the thickness of the test specimen as provided for in the applicable material specifications. Minimum thickness of 40 mm
[1.500 in.] wide specimens shall be 5 mm [0.188 in.]. Maximum thickness of 12.5 mm and 6 mm [0.500 in. and 0.250 in.] wide specimens shall be 19
and 6 mm [0.750 and 0.250 in.], respectively.
NOTE 6—For the 40 mm [1.500 in.] wide specimen, a 13 mm [0.500 in.] minimum radius at the ends of the reduced parallel section is permitted for
steel specimens under 690 MPa [100 000 psi] in tensile strength when a profile cutter is used to machine the reduced section.
NOTE 7—The dimension shown is suggested as a minimum. In determining the minimum length, the grips must not extend in to the transition section
between Dimensions A and B, see Note 9.
NOTE 8—To aid in obtaining axial force application during testing of 6 mm [0.250 in.] wide specimens, the overall length should be as large as the
material will permit, up to 200 mm [8.00 in.].
NOTE 9—It is desirable, if possible, to make the length of the grip section large enough to allow the specimen to extend into the grips a distance equal
to two thirds or more of the length of the grips. If the thickness of 12.5 mm [0.500 in.] wide specimens is over 10 mm [0.375 in.], longer grips and
correspondingly longer grip sections of the specimen may be necessary to prevent failure in the grip section.
NOTE 10—For the three sizes of specimens, the ends of the specimen shall be symmetrical in width with the center line of the reduced parallel section
within 2.5 mm, 1.25 mm and 0.13 mm [0.10 in., 0.05 in. and 0.005 in.], respectively. However, for referee testing and when required by product
specifications, the ends of the 12.5 mm [0.500 in.] wide specimen shall be symmetrical within 0.2 mm [0.01 in.].
NOTE 11—For each specimen type, the radii of all fillets shall be equal to each other within a tolerance of 1.25 mm [0.05 in.], and the centers of
curvature of the two fillets at a particular end shall be located across from each other (on a line perpendicular to the centerline) within a tolerance of 2.5
mm [0.10 in.].
NOTE 12—Specimens with sides parallel throughout their length are permitted, except for referee testing, provided: (a) the above tolerances are used;
(b) an adequate number of marks are provided for determination of elongation; and (c) when yield strength is determined, a suitable extensometer is used.
If the fracture occurs at a distance of less than 2 W from the edge of the gripping device, the tensile properties determined may not be representative of
the material. In acceptance testing, if the properties meet the minimum requirements specified, no further testing is required, but if they are less than the
minimum requirements, discard the test and retest.
FIG. 1 Rectangular Tension Test Specimens
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FIG. 2 Wedge Grips with Liners for Flat Specimens
FIG. 3 Gripping Device for Threaded-End Specimens
6.1.2.2 Midway from the center to the surface for products over 40 mm [1.500 in.] in thickness, diameter, or distance between flats.
6.1.3 Specimen Machining—Improperly prepared test specimens often are the reason for unsatisfactory and incorrect test results.
It is important, therefore, that care be exercised in the preparation of specimens, particularly in the machining, to maximize
precision and minimize bias in test results.
6.1.3.1 The reduced section including the fillets of prepared specimens should be free of cold work, notches, chatter marks,
grooves, gouges, burrs, rough surfaces or edges, overheating, or any other condition which can deleteriously affect the properties
to be measured.
NOTE 3—Punching or blanking of the reduced section may produce significant cold work or shear burrs, or both, along the edges which should be removed
by machining.
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FIG. 4 Gripping Device for Shouldered-End Specimens
FIG. 5 Gripping Devices for Sheet and Wire Specimens
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FIG. 6 Snubbing Device for Testing Wire
6.1.3.2 Within the reduced parallel section of rectangular specimens, edges or corners should not be ground or abraded in a manner
which could cause the actual cross-sectional area of the specimen to be significantly different from the calculated area.
6.1.3.3 For brittle materials, large radius fillets at the ends of the reduced parallel section should be used.
6.1.3.4 The cross-sectional area of the specimen should be smallest at the center of the reduced parallel section to ensure fracture
within the gauge length. For this reason, a small taper is permitted in the reduced parallel section of each of the specimens
described in the following sections.
6.1.4 Specimen Surface Finish—When materials are tested with surface conditions other than as manufactured, the surface finish
of the test specimens should be as provided in the applicable product specifications.
NOTE 4—Particular attention should be given to the uniformity and quality of surface finish of specimens for high strength and very low ductility materials
since this has been shown to be a factor in the variability of test results.
6.1.5 Specimen Grip Section Symmetry—Symmetry tolerances for grip sections of specimens (relative to centerlines of reduced
parallel sections) are given within Fig. 1 and Fig. 7.
NOTE 5—Symmetry of grip sections of machined specimens relative to the centerlines of reduced parallel sections can affect alignment, stress-strain
curves, and test results, especially when the grip sections of rectangular specimens are used to locate the specimens within the testing machine. Tighter
tolerances, such as those given by Note 10 of Fig. 1 for referee testing, can be used to maintain alignment where asymmetry of specimen grip sections
could otherwise result in the reduced parallel section being offset, oriented at an angle, or both, relative to the axis of force application.
NOTE 6—Effects of specimen symmetry and misalignment errors can be minimized by use of certain types of gripping systems or backstops.
6.2 Plate-Type Specimens—The standard plate-type test specimen is shown in Fig. 1. This specimen is used for testing metallic
materials in the form of plate, shapes, and flat material having a nominal thickness of 5 mm [0.188 in.] or over. When product
specifications so permit, other types of specimens may be used, as provided in 6.3, 6.4, and 6.5.
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Dimensions
Specimen 1 Specimen 2 Specimen 3 Specimen 4 Specimen 5 Specimen 6 Specimen 7
mm [in.] mm [in.] mm [in.] mm [in.] mm [in.] mm [in.] mm [in.]
G—Gauge length 50.0 ± 0.1 50.0 ± 0.1 200.0 ± 0.2 50.0 ± 0.1 100.0 ± 0.1 50.0 ± 0.1 100.0 ± 0.1
[2.000 ± 0.005] [2.000 ± 0.005] [8.00 ± 0.01] [2.000 ± 0.005] [4.000 ± 0.005] [2.000 ± 0.005] [4.000 ± 0.005]
W—Width (Note 1) 12.5 ± 0.2 40.0 ± 2.0 40.0 ± 2.0 20.0 ± 0.7 20.0 ± 0.7 25.0 ± 1.5 25.0 ± 1.5
[0.500 ± 0.010] [1.500 + 0.125, [1.500 + 0.125, [0.750 ± 0.031] [0.750 ± 0.031] [1.000 ± 0.062] [1.000 ± 0.062]
-0.250] -0.250]
T—Thickness measured thickness of specimen
R—Radius of fillet, 12.5 [0.5] 25 [1] 25 [1] 25 [1] 25 [1] 25 [1] 25 [1]
min
A—Length of re- 60 [2.25] 60 [2.25] 230 [9] 60 [2.25] 120 [4.5] 60 [2.25] 120 [4.5]
duced parallel
section,
min
B—Length of grip 75 [3] 75 [3] 75 [3] 75 [3] 75 [3] 75 [3] 75 [3]
section,
min (Note 2)
C—Width of grip 20 [0.75] 50 [2] 50 [2] 25 [1] 25 [1] 40 [1.5] 40 [1.5]
section,
approximate (Note
3)
NOTE 1—The ends of the reduced parallel section shall differ from each other in width by not more than 0.5 %. There may be a gradual taper in width
from the ends to the center, but the width at each end shall be not more than 1 % greater than the width at the center.
NOTE 2—It is desirable, if possible, to make the length of the grip section great enough to allow the specimen to extend into the grips a distance equal
to two thirds or more of the length of the grips.
NOTE 3—The ends of the specimen shall be symmetrical with the center line of the reduced parallel section within 1 mm [0.05 in.] for specimens 1,
4, and 5, and 2.5 mm [0.10 in.] for specimens 2, 3, 6, and 7.
NOTE 4—For each specimen type, the radii of all fillets shall be equal to each other within a tolerance of 1.25 mm [ 0.05 in.], and the centers of curvature
of the two fillets at a particular end shall be located across from each other (on a line perpendicular to the centerline) within a tolerance of 2.5 mm [0.10
in.].
NOTE 5—For circular segments, the cross-sectional area may be calculated by multiplying W and T. If the ratio of the dimension W to the diameter
of the tubular section is larger than about ⁄6 the error in using this method to calculate the cross-sectional area may be appreciable. In this case, the exact
equation (see 7.2.2.4) must be used to determine the area.
NOTE 6—Specimens with G/W less than 4 should not be used for determination of elongation.
NOTE 7—Specimens with sides parallel throughout their length are permitted, except for referee testing, provided: (a) the above tolerances are used;
(b) an adequate number of marks are provided for determination of elongation; and (c) when yield strength is determined, a suitable extensometer is used.
If the fracture occurs at a distance of less than 2 W from the edge of the gripping device, the tensile properties determined may not be representative of
the material. If the properties meet the minimum requirements specified, no further testing is required, but if they are less than the minimum requirements,
discard the test and retest.
FIG. 7 Tension Test Specimens for Large-Diameter Tubular Products
6.3 Sheet-Type Specimens:
6.3.1 The standard sheet-type test specimen is shown in Fig. 1. This specimen is used for testing metallic materials in the form
of sheet, plate, flat wire, strip, band, hoop, rectangles, and shapes ranging in nominal thickness from 0.13 mm to 19 mm [0.005 in.
to 0.750 in.]. When product specifications so permit, other types of specimens may be used, as provided in 6.2, 6.4, and 6.5.
NOTE 7—Test Methods E345 may be used for tension testing of materials in thicknesses up to 0.15 mm [0.0059 in.].
6.3.2 Pin ends as shown in Fig. 8 may be used. In order to avoid buckling in tests of thin and high-strength materials, it may be
necessary to use stiffening plates at the grip ends.
6.4 Round Specimens:
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Dimensions, mm [in.]
G—Gauge length 50.0 ± 0.1 [2.000 ± 0.005]
W—Width (Note 1) 12.5 ± 0.2 [0.500 ± 0.010]
T—Thickness, max (Note 2) 16 [0.625]
R—Radius of fillet, min (Note 3) 13 [0.5]
L—Overall length, min 200 [8]
A—Length of reduced parallel section, min 57 [2.25]
B—Length of grip section, min 50 [2]
C—Width of grip section, approximate 50 [2]
D—Diameter of hole for pin, min (Note 4) 13 [0.5]
E—Edge distance from pin, approximate 40 [1.5]
F—Distance from hole to fillet, min 13 [0.5]
NOTE 1—The ends of the reduced parallel section shall differ in width by not more than 0.1 mm [0.002 in.]. There may be a gradual taper in width
from the ends to the center, but the width at each end shall be not more than 1 % greater than the width at the center.
NOTE 2—The dimension T is the thickness of the test specimen as stated in the applicable product specifications.
NOTE 3—For some materials, a fillet radius R larger than 13 mm [0.500 in.] may be needed.
NOTE 4—Holes must be on center line of reduced parallel section within 6 0.05 mm [0.002 in].
NOTE 5—Variations of dimensions C,D,E,F, and L may be used that will permit failure within the gauge length.
FIG. 8 Pin-Loaded Tension Test Specimen with 50 mm [2 in.] Gauge Length
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6.4.1 The standard 12.5 mm [0.500 in.] diameter round test specimen shown in Fig. 9 is used quite generally for testing metallic
materials, both cast and wrought.
6.4.2 Fig. 9 also shows small-size specimens proportional to the standard specimen. These may be used when it is necessary to
test material from which the standard specimen or specimens shown in Fig. 1 cannot be prepared. Other sizes of small round
specimens may be used. In any such small-size specimen it is important that the gauge length for measurement of elongation be
four times the diameter of the specimen when following E8 and five times the diameter of the specimen when following E8M.
6.4.3 The shape of the ends of the specimen outside of the gauge length shall be suitable to the material and of a shape to fit the
holders or grips of the testing machine so that the forces may be applied axially. Fig. 10 shows specimens with various types of
ends that have given satisfactory results.
6.5 Specimens for Sheet, Strip, Flat Wire, and Plate—In testing sheet, strip, flat wire, and plate, use a specimen type appropriate
for the nominal thickness of the material, as described in the following:
6.5.1 For material with a nominal thickness of 0.13 mm to 5 mm [0.005 in. to 0.1875 in.], use the sheet-type specimen described
in 6.3.
6.5.2 For material with a nominal thickness of 5 mm to 12.5 mm [0.1875 in. to 0.500 in.], use either the sheet-type specimen of
6.3 or the plate-type specimen of 6.2.
6.5.3 For material with a nominal thickness of 12.5 mm to 19 mm [0.500 in. to 0.750 in.], use either the sheet-type specimen of
6.3, the plate-type specimen of 6.2, or the largest practical size of round specimen described in 6.4.
6.5.4 For material with a nominal thickness of 19 mm [0.750 in.], or greater, use the plate-type specimen of 6.2 or the largest
practical size of round specimen described in 6.4.
6.5.4.1 If the product specifications permit, material of a thickness of 19 mm [ 0.750 in.], or greater may be tested using a modified
sheet-type specimen conforming to the configuration shown by Fig. 1. The thickness of this modified specimen must be machined
to 10 mm 6 0.5 mm [0.400 in. 6 0.020 in.], and must be uniform within 0.1 mm [0.004 in.] throughout the reduced parallel
section. In the event of disagreement, a round specimen shall be used as the referee test (comparison) specimen.
6.6 Specimens for Wire, Rod, and Bar:
6.6.1 For round wire, rod, and bar, test specimens having the full cross-sectional area of the wire, rod, or bar shall be used
wherever practicable. The gauge length for the measurement of elongation of wire less than 4 mm [0.125 in.] in diameter shall
be as prescribed in product specifications. When testing wire, rod, or bar having a diameter of 4 mm [0.125 in.] or larger, a gauge
length equal to four times the diameter shall be used when following E8 and a gauge length equal to five times the diameter shall
be used when following E8M unless otherwise specified. The total length of the specimens shall be at least equal to the gauge
length plus the length of material required for the full use of the grips employed.
6.6.2 For wire of octagonal, hexagonal, or square cross section, for rod or bar of round cross section where the specimen required
in 6.6.1 is not practicable, and for rod or bar of octagonal, hexagonal, or square cross section, one of the following types of
specimens shall be used:
6.6.2.1 Full Cross Section (Note 8)—It is permissible to reduce the test section slightly with abrasive cloth or paper, or machine
it sufficiently to ensure fracture within the gauge marks. For material not exceeding 5 mm [0.188 in.] in diameter or distance
between flats, the cross-sectional area may be reduced to not less than 90 % of the original area without changing the shape of the
cross section. For material over 5 mm [0.188 in.] in diameter or distance between flats, the diameter or distance between flats may
be reduced by not more than 0.25 mm [0.010 in.] without changing the shape of the cross section. Square, hexagonal, or octagonal
wire or rod not exceeding 5 mm [0.188 in.] between flats may be turned to a round having a cross-sectional area not smaller than
90 % of the area of the maximum inscribed circle. Fillets, preferably with a radius of 10 mm [0.375 in.], but not less than 3 mm
[0.125 in.], shall be used at the ends of the reduced parallel sections. Square, hexagonal, or octagonal rod over 5 mm [0.188 in.]
between flats may be turned to a round having a diameter no smaller than 0.25 mm [0.010 in.] less than the original distance
between flats.
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Dimensions, mm [in.]
For Test Specimens with Gauge Length Four times the Diameter [E8]
Standard Small-Size Specimens Proportional to Standard
Specimen
Specimen 1 Specimen 2 Specimen 3 Specimen 4 Specimen 5
G—Gauge length 50.0 ± 0.1 36.0 ± 0.1 24.0 ± 0.1 16.0 ± 0.1 10.0 ±0.1
[2.000 ± 0.005] [1.400 ± 0.005] [1.000 ± 0.005] [0.640 ± 0.005] [0.450 ± 0.005]
D—Diameter (Note 1) 12.5 ± 0.2 9.0 ±0.1 6.0 ± 0.1 4.0 ± 0.1 2.5 ± 0.1
[0.500 ± 0.010] [0.350 ± 0.007] [0.250 ± 0.005] [0.160 ± 0.003] [0.113 ± 0.002]
R—Radius of fillet, min 10 [0.375] 8 [0.25] 6 [0.188] 4 [0.156] 2 [0.094]
A—Length of reduced parallel section, min 56 [2.25] 45 [1.75] 30 [1.25] 20 [0.75] 16 [0.625]
(Note 2)
Dimensions, mm [in.]
For Test Specimens with Gauge Length Five times the Diameter [E8M]
Standard Specimen Small-Size Specimens Proportional to Standard
Specimen 1 Specimen 2 Specimen 3 Specimen 4 Specimen 5
G—Gauge length 62.5 ± 0.1 45.0 ± 0.1 30.0 ± 0.1 20.0 ± 0.1 12.5 ± 0.1
[2.500 ± 0.005] [1.750 ± 0.005] [1.250 ± 0.005] [0.800 ± 0.005] [0.565 ± 0.005]
D—Diameter (Note 1) 12.5 ± 0.2 9.0 ± 0.1 6.0 ± 0.1 4.0 ± 0.1 2.5 ± 0.1
[0.500 ± 0.010] [0.350 ± 0.007] [0.250 ± 0.005] [0.160 ± 0.003] [0.113 ± 0.002]
R—Radius of fillet, min 10 [0.375] 8 [0.25] 6 [0.188] 4 [0.156] 2 [0.094]
A—Length of reduced parallel section, min 75 [3.0] 54 [2.0] 36 [1.4] 24 [1.0] 20 [0.75]
(Note 2)
NOTE 1—The reduced parallel section may have a gradual taper from the ends toward the center, with the ends not more than 1 % larger in diameter
than the center (controlling dimension).
NOTE 2—If desired, the length of the reduced parallel section may be increased to accommodate an extensometer of any convenient gauge length.
Reference marks for the measurement of elongation should, nevertheless, be spaced at the indicated gauge length.
NOTE 3—The gauge length and fillets may be as shown, but the ends may be of any form to fit the holders of the testing machine in such a way that
the force shall be axial (see Fig. 10). If the ends are to be held in wedge grips it is desirable, if possible, to make the length of the grip section great enough
to allow the specimen to extend into the grips a distance equal to two thirds or more of the length of the grips.
NOTE 4—On the round specimens in Figs. 9 and 10, the gauge lengths are equal to four [E8] or five times [E8M] the nominal diameter. In some product
specifications other specimens may be provided for, but unless the 4-to-1 [E8] or 5-to-1 [E8M] ratio is maintained within dimensional tolerances, the
elongation values may not be comparable with those obtained from the standard test specimen.
NOTE 5—The use of specimens smaller than 6 mm [0.250 in.] diameter shall be restricted to cases when the material to be tested is of insufficient size
to obtain larger specimens or when all parties agree to their use for acceptance testing. Smaller specimens require suitable equipment and greater skill
in both machining and testing.
NOTE 6—For inch/pound units only: Five sizes of specimens often used have diameters of approximately 0.505 in., 0.357 in., 0.252 in., 0.160 in., and
0.113 in., the reason being to permit easy calculations of stress from loads, since the corresponding cross-sectional areas are equal or close to 0.200 in. ,
2 2 2 2
0.100 in. , 0.0500 in. , 0.0200 in. , and 0.0100 in. , respectively. Thus, when the actual diameters agree with these values, the stresses (or strengths) may
be computed using the simple multiplying factors 5, 10, 20, 50, and 100, respectively. (The metric equivalents of these five diameters do not result in
correspondingly convenient cross-sectional areas and multiplying factors.)
FIG. 9 Standard 12.5 mm [0.500 in.] Round Tension Test Specimen and Examples of Small-Size Specimens
Proportional to the Standard Specimen
E8/E8M − 24
Dimensions, mm [in.]
For Test Specimens with Gauge Length Four times the Diameter [E8]
Specimen 1 Specimen 2 Specimen 3 Specimen 4 Specimen 5
G—Gauge length 50 ± 0.1 50 ± 0.1 50 ± 0.1 50 ± 0.1 50 ± 0.1
[2.000 ± 0.005] [2.000 ± 0.005] [2.000 ± 0.005] [2.000 ± 0.005] [2.000 ± 0.005]
D—Diameter (Note 1) 12.5 ± 0.2 12.5 ± 0.2 12.5 ± 0.2 12.5 ± 0.2 12.5 ± 0.2
[0.500 ± 0.010] [0.500 ± 0.010] [0.500 ± 0.010] [0.500 ± 0.010] [0.500 ± 0.010]
R—Radius of fillet, min 10 [0.375] 10 [0.375] 2 [0.0625] 10 [0.375] 10 [0.375]
A—Length of reduced parallel section 56 [2.25] 56 [2.25] 100 [4] 56 [2.25] 56 [2.25]
min min approximate min min
L—Overall length, approximate 145 [5] 155 [5.5] 155 [5.5] 140 [4.75] 255 [9.5]
B—Length of end section (Note 3) 35 [1.375] 25 [1] 20 [0.75] 15 [0.5] 75 [3]
approximate approximate approximate approximate min
C—Diameter of end section 20 [0.75] 20 [0.75] 20 [0.75] 22 [0.875] 20 [0.75]
E—Length of shoulder and fillet section, approximate 15 [0.625] 20 [0.75] 15 [0.625]
F—Diameter of shoulder 15 [0.625] 15 [0.625] 15 [0.625]
Dimensions, mm [in.]
For Test Specimens with Gauge Length Five times the Diameter [E8M]
Specimen 1 Specimen 2 Specimen 3 Specimen 4 Specimen 5
G—Gauge length 62.5 ± 0.1 62.5 ± 0.1 62.5 ± 0.1 62.5 ± 0.1 62.5 ± 0.1
[2.500 ± 0.005] [2.500 ± 0.005] [2.500 ± 0.005] [2.500 ± 0.005] [2.500 ± 0.005]
D—Diameter (Note 1) 12.5 ± 0.2 12.5 ± 0.2 12.5 ± 0.2 12.5 ± 0.2 12.5 ± 0.2
[0.500 ± 0.010] [0.500 ± 0.010] [0.500 ± 0.010] [0.500 ± 0.010] [0.500 ± 0.010]
R—Radius of fillet, min 10 [0.375] 10 [0.375] 2 [0.0625] 10 [0.375] 10 [0.375]
A—Length of reduced parallel section 75 [3] 75 [3] 75 [3] 75 [3] 75 [3]
min min approximate min min
L—Overall length, approximate 145 [5] 155 [5.5] 155 [5.5] 140 [4.75] 255 [9.5]
B—Length of end section (Note 3) 35 [1.375] 25 [1] 20 [0.75] 15 [0.5] 75 [3]
approximate approximate approximate approximate min
C—Diameter of end section 20 [0.75] 20 [0.75] 20 [0.75] 22 [0.875] 20 [0.75]
E—Length of shoulder and fillet section, approximate 15 [0.625] 20 [0.75] 15 [0.625]
F—Diameter of shoulder 15 [0.625] 15 [0.625] 15 [0.625]
NOTE 1—The reduced parallel section may have a gradual taper from the ends toward the center with the ends not more than 1 %. larger in diameter
than the center.
NOTE 2—On Specimens 1 and 2, any standard thread is permissible that provides for proper alignment and aids in assuring that the specimen will break
within the reduced parallel section.
NOTE 3—On Specimen 5 it is desirable, if possible, to make the length of the grip section great enough to allow the specimen to extend into the grips
a distance equal to two thirds or more of the length of the grips.
NOTE 4—The values stated in SI units in the table for Fig. 10 are to be regarded as separate from the inch/pound units. The values stated in each system
are not exact equivalents; therefore each system must be used independently of the other.
FIG. 10 Various Types of Ends for Standard Round Tension Test Specimens
E8/E8M − 24
NOTE 8—The ends of copper or copper alloy specimens may be flattened 10 % to 50 % from the original dimension in a jig similar to that shown in Fig.
11, to facilitate fracture within the gauge marks. In flattening the opposite ends of the test specimen, care shall be taken to ensure that the four flattened
surfaces are parallel and that the two parallel surfaces on the same side of the axis of the test specimen lie in the same plane.
6.6.2.2 For rod and bar, the largest practical size of round specimen as described in 6.4 may be used in place of a test specimen
of full cross section. Unless otherwise specified in the product specification, specimens shall be parallel to the direction of rolling
or extrusion.
6.7 Specimens for Rectangular Bar—In testing rectangular bar one of the following types of specimens shall be used:
6.7.1 Full Cross Section—It is permissible to reduce the width of the specimen throughout the test section with abrasive cloth or
paper, or by machining sufficiently to facilitate fracture within the gauge marks, but in no case shall the reduced width be less than
90 % of the original. The edges of the midlength of the reduced parallel section not less than 20 mm [ ⁄4 in.] in length shall be
parallel to each other and to the longitudinal axis of the specimen within 0.05 mm [0.002 in.]. Fillets, preferably with a radius of
3 1
10 mm [ ⁄8 in.] but not less than 3 mm [ ⁄8 in.] shall be used at the ends of the reduced parallel sections.
6.7.2 Rectangular bar of thickness small enough to fit the grips of the testing machine but of too great width may be reduced in
width by cutting to fit the grips, after which the cut surfaces shall be machined or cut and smoothed to ensure failure within the
desired section. The reduced width shall not be less than the original bar thickness. Also, one of the types of specimens described
in 6.2, 6.3, and 6.4 may be used.
FIG. 11 Squeezing Jig for Flattening Ends of Full-Size Tension Test Specimens
E8/E8M − 24
6.8 Shapes, Structural and Other—In testing shapes other than those covered by the preceding sections, one of the types of
specimens described in 6.2, 6.3, and 6.4 shall be used.
6.9 Specimens for Pipe and Tube (Note 9):
6.9.1 For all small tube (Note 9), particularly sizes 25 mm [1 in.] and under in nominal outside diameter, and frequently for larger
sizes, except as limited by the testing equipment, it is standard practice to use tension test specimens of full-size tubular sections.
Snug-fitting metal plugs shall be inserted far enough into the ends of such tubular specimens to permit the testing machine jaws
to grip the specimens properly. The plugs shall not extend into that part of the specimen on which the elongation is measured.
Elongation is measured over a length of four times the diameter when following E8 or five times the diameter when following E8M
unless otherwise stated in the product specification. Fig. 12 shows a suitable form of plug, the location of the plugs in the specimen,
and the location of the specimen in the grips of the testing machine.
NOTE 9—The term “tube” is used to indicate tubular products in general, and includes pipe, tube, and tubing.
6.9.2 For large-diameter tube that cannot be tested in full section, longitudinal tension test specimens shall be cut as indicated in
Fig. 13. Specimens from welded tube shall be located approximately 90° from the weld. If the tube-wall thickness is under 20 mm
[0.750 in.], either a specimen of the form and dimensions shown in Fig. 7 or one of the small-size specimens proportional to the
standard 12.5 mm [0.500 in.] specimen, as mentioned in
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