ASTM D638-99

Standard Test Method for Tensile Properties of Plastics

SCOPE
1.1 This test method covers the determination of the tensile properties of unreinforced and reinforced plastics in the form of standard dumbbell-shaped test specimens when tested under defined conditions of pretreatment, temperature, humidity, and testing machine speed.
1.2 This test method can be used for testing materials of any thickness up to 14 mm (0.55 in.). However, for testing specimens in the form of thin sheeting, including film less than 1.0 mm (0.04 in.) in thickness, Test Methods D882 is the preferred test method. Materials with a thickness greater than 14 mm (0.55 in.) must be reduced by machining.
1.3 This test method includes the option of determining Poisson's ratio at room temperature.
Note 1—This test method and ISO 527-1 are technically equivalent.
Note 2—This test method is not intended to cover precise physical procedures. It is recognized that the constant rate of crosshead movement type of test leaves much to be desired from a theoretical standpoint, that wide differences may exist between rate of crosshead movement and rate of strain between gage marks on the specimen, and that the testing speeds specified disguise important effects characteristic of materials in the plastic state. Further, it is realized that variations in the thicknesses of test specimens, which are permitted by these procedures, produce variations in the surface-volume ratios of such specimens, and that these variations may influence the test results. Hence, where directly comparable results are desired, all samples should be of equal thickness. Special additional tests should be used where more precise physical data are needed.
Note 3—This test method may be used for testing phenolic molded resin or laminated materials. However, where these materials are used as electrical insulation, such materials should be tested in accordance with Test Methods D229 and Test Method 651.
Note 4—For tensile properties of resin-matrix composites reinforced with oriented continuous or discontinuous high modulus >20-GPa (>3.0 106-psi) fibers, tests shall be made in accordance with Test Method D3039/D3039M.
1.4 Test data obtained by this test method are relevant and appropriate for use in engineering design.
1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Apr-2002
• ICS: 83.080.01 - Plastics in general
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.10 - Mechanical Properties

Relations

• Replaced By: ASTM D638-00 - Standard Test Method for Tensile Properties of Plastics
• Effective Date: 10-Apr-2002
• Referred By: ASTM D5138-23 - Standard Classification System and Basis for Specification for Liquid Crystal Polymers Molding and Extrusion Materials (LCP)
• Effective Date: 10-Apr-2002
• Referred By: ASTM D4066-13(2019) - Standard Classification System for Nylon Injection and Extrusion Materials (PA)
• Effective Date: 10-Apr-2002
• Referred By: ASTM F3378/F3378M-22 - Standard Specification for Crosslinkable Polyethylene (CX-PE) Pipe
• Effective Date: 10-Apr-2002
• Referred By: ASTM F1743-22 - Standard Practice for Rehabilitation of Existing Pipelines and Conduits by Pulled-in-Place Installation of Cured-in-Place Thermosetting Resin Pipe (CIPP)
• Effective Date: 10-Apr-2002
• Referred By: ASTM D3308-12(2022) - Standard Specification for PTFE Resin Skived Tape
• Effective Date: 10-Apr-2002
• Referred By: ASTM F3430-20 - Standard Specification for Closed-Cell Cellular Polypropylene (PP) Corrugated Wall Stormwater Collection Chambers
• Effective Date: 10-Apr-2002
• Referred By: ASTM D4349-22 - Classification System and Basis for Specification for Polyphenylene Ether (PPE) Materials
• Effective Date: 10-Apr-2002
• Referred By: ASTM F1867-22 - Standard Practice for Installation of Folded/Formed Poly (Vinyl Chloride) (PVC) Pipe Type A for Existing Sewer and Conduit Rehabilitation
• Effective Date: 10-Apr-2002
• Referred By: ASTM D787-18 - Standard Specification for Ethyl Cellulose Molding and Extrusion Compounds
• Effective Date: 10-Apr-2002
• Referred By: ASTM D707-15(2023) - Standard Classification System and Basis for Specification for Cellulose Acetate Butyrate Molding and Extrusion Compounds (CAB)
• Effective Date: 10-Apr-2002
• Referred By: ASTM F3373-21 - Standard Specification for Polyethylene (PE) Electrofusion Fittings for Outside Diameter Controlled Crosslinked Polyethylene (PEX) Pipe
• Effective Date: 10-Apr-2002
• Referred By: ASTM D7292-18 - Standard Specification for Extruded, Compression-Molded, and Injection-Molded Basic Shapes of Polyamide-Imide (PAI)
• Effective Date: 10-Apr-2002
• Referred By: ASTM D4067-23 - Standard Classification System and Basis for Specification for Reinforced and Filled Poly(Phenylene Sulfide) (PPS) Injection Molding and Extrusion Materials Using ASTM Methods
• Effective Date: 10-Apr-2002
• Referred By: ASTM F450-13(2019) - Standard Test Methods for Vacuum Cleaner Hose—Durability and Reliability (Plastic)
• Effective Date: 10-Apr-2002

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 638 – 99 An American National Standard
Standard Test Method for
Tensile Properties of Plastics
This standard is issued under the fixed designation D 638; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope * safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
1.1 This test method covers the determination of the tensile
priate safety and health practices and determine the applica-
properties of unreinforced and reinforced plastics in the form
bility of regulatory limitations prior to use.
of standard dumbbell-shaped test specimens when tested under
defined conditions of pretreatment, temperature, humidity, and
2. Referenced Documents
testing machine speed.
2.1 ASTM Standards:
1.2 This test method can be used for testing materials of any
D 229 Test Methods for Rigid Sheet and Plate Materials
thickness up to 14 mm (0.55 in.). However, for testing
Used for Electrical Insulation
specimens in the form of thin sheeting, including film less than
D 412 Test Methods for Vulcanized Rubber and Thermo-
1.0 mm (0.04 in.) in thickness, Test Methods D 882 is the
plastic Rubbers and Thermoplastic Elastomers— Tension
preferred test method. Materials with a thickness greater than
D 618 Practice for Conditioning Plastics for Testing
14 mm (0.55 in.) must be reduced by machining.
D 651 Test Method for Tensile Strength of Molded Electri-
1.3 This test method includes the option of determining
cal Insulating Materials
Poisson’s ratio at room temperature.
D 882 Test Methods for Tensile Properties of Thin Plastic
NOTE 1—This test method and ISO 527-1 are technically equivalent.
Sheeting
NOTE 2—This test method is not intended to cover precise physical
D 883 Terminology Relating to Plastics
procedures. It is recognized that the constant rate of crosshead movement
D 1822 Test Method for Tensile-Impact Energy to Break
type of test leaves much to be desired from a theoretical standpoint, that
Plastics and Electrical Insulating Materials
wide differences may exist between rate of crosshead movement and rate
D 3039/D 3039M Test Method for Tensile Properties of
of strain between gage marks on the specimen, and that the testing speeds
specified disguise important effects characteristic of materials in the Polymer Matrix Composite Materials
plastic state. Further, it is realized that variations in the thicknesses of test
D 4000 Classification System for Specifying Plastic Mate-
specimens, which are permitted by these procedures, produce variations in
rials
the surface-volume ratios of such specimens, and that these variations may
D 4066 Specification for Nylon Injection and Extrusion
influence the test results. Hence, where directly comparable results are
Materials
desired, all samples should be of equal thickness. Special additional tests
D 5947 Test Methods for Physical Dimensions of Solid
should be used where more precise physical data are needed.
Plastic Specimens
NOTE 3—This test method may be used for testing phenolic molded
resin or laminated materials. However, where these materials are used as
E 4 Practices for Force Verification of Testing Machines
electrical insulation, such materials should be tested in accordance with
E 83 Practice for Verification and Classification of Exten-
Test Methods D 229 and Test Method D 651.
someters
NOTE 4—For tensile properties of resin-matrix composites reinforced
E 132 Test Method for Poisson’s Ratio at Room Tempera-
with oriented continuous or discontinuous high modulus >20-GPa
6 ture
(>3.0 3 10 -psi) fibers, tests shall be made in accordance with Test
E 691 Practice for Conducting an Interlaboratory Study to
Method D 3039/D 3039M.
Determine the Precision of a Test Method
1.4 Test data obtained by this test method are relevant and
2.2 ISO Standard:
appropriate for use in engineering design.
1.5 The values stated in SI units are to be regarded as the
Annual Book of ASTM Standards, Vol 10.01.
standard. The values given in parentheses are for information
Annual Book of ASTM Standards, Vol 09.01.
only.
Annual Book of ASTM Standards, Vol 08.01.
Discontinued; see 1994 Annual Book of ASTM Standards, Vol 10.01.
1.6 This standard does not purport to address all of the
Annual Book of ASTM Standards, Vol 15.03.
Annual Book of ASTM Standards, Vol 08.02.
Annual Book of ASTM Standards, Vol 08.03.
This test method is under the jurisdiction of ASTM Committee D-20 on Plastics 9
Annual Book of ASTM Standards, Vol 03.01.
and is the direct responsibility of Subcommittee D 20.10 on Mechanical Properties. 10
Annual Book of ASTM Standards, Vol 14.02.
Current edition approved Nov. 10, 1999. Published February 2000. Originally
published as D 638 – 41 T. Last previous edition D 638 – 98.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 638
ISO 527-1 Determination of Tensile Properties 4.4 Poisson’s Ratio—When uniaxial tensile force is applied
to a solid, the solid stretches in the direction of the applied
3. Terminology
force (axially), but it also contracts in both dimensions lateral
to the applied force. If the solid is homogeneous and isotropic,
3.1 Definitions—Definitions of terms applying to this test
and the material remains elastic under the action of the applied
method appear in Terminology D 883 and Annex A2.
force, the lateral strain bears a constant relationship to the axial
4. Significance and Use
strain. This constant, called Poisson’s ratio, is defined as the
negative ratio of the transverse (negative) to axial strain under
4.1 This test method is designed to produce tensile property
uniaxial stress.
data for the control and specification of plastic materials. These
4.4.1 Poisson’s ratio is used for the design of structures in
data are also useful for qualitative characterization and for
which all dimensional changes resulting from the application
research and development. For many materials, there may be a
of force need to be taken into account and in the application of
specification that requires the use of this test method, but with
the generalized theory of elasticity to structural analysis.
some procedural modifications that take precedence when
adhering to the specification. Therefore, it is advisable to refer
NOTE 6—The accuracy of the determination of Poisson’s ratio is
to that material specification before using this test method.
usually limited by the accuracy of the transverse strain measurements
Table 1 in Classification D 4000 lists the ASTM materials
because the percentage errors in these measurements are usually greater
than in the axial strain measurements. Since a ratio rather than an absolute
standards that currently exist.
quantity is measured, it is only necessary to know accurately the relative
4.2 Tensile properties may vary with specimen preparation
value of the calibration factors of the extensometers. Also, in general, the
and with speed and environment of testing. Consequently,
value of the applied loads need not be known accurately.
where precise comparative results are desired, these factors
must be carefully controlled.
5. Apparatus
4.2.1 It is realized that a material cannot be tested without
5.1 Testing Machine—A testing machine of the constant-
also testing the method of preparation of that material. Hence,
rate-of-crosshead-movement type and comprising essentially
when comparative tests of materials per se are desired, the
the following:
greatest care must be exercised to ensure that all samples are
5.1.1 Fixed Member—A fixed or essentially stationary
prepared in exactly the same way, unless the test is to include
member carrying one grip.
the effects of sample preparation. Similarly, for referee pur-
5.1.2 Movable Member—A movable member carrying a
poses or comparisons within any given series of specimens,
second grip.
care must be taken to secure the maximum degree of unifor-
5.1.3 Grips—Grips for holding the test specimen between
mity in details of preparation, treatment, and handling.
the fixed member and the movable member of the testing
4.3 Tensile properties may provide useful data for plastics
machine can be either the fixed or self-aligning type.
engineering design purposes. However, because of the high
5.1.3.1 Fixed grips are rigidly attached to the fixed and
degree of sensitivity exhibited by many plastics to rate of
movable members of the testing machine. When this type of
straining and environmental conditions, data obtained by this
grip is used extreme care should be taken to ensure that the test
test method cannot be considered valid for applications involv-
specimen is inserted and clamped so that the long axis of the
ing load-time scales or environments widely different from
test specimen coincides with the direction of pull through the
those of this test method. In cases of such dissimilarity, no
center line of the grip assembly.
reliable estimation of the limit of usefulness can be made for
5.1.3.2 Self-aligning grips are attached to the fixed and
most plastics. This sensitivity to rate of straining and environ-
movable members of the testing machine in such a manner that
ment necessitates testing over a broad load-time scale (includ-
they will move freely into alignment as soon as any load is
ing impact and creep) and range of environmental conditions if
applied so that the long axis of the test specimen will coincide
tensile properties are to suffice for engineering design pur-
with the direction of the applied pull through the center line of
poses.
the grip assembly. The specimens should be aligned as per-
NOTE 5—Since the existence of a true elastic limit in plastics (as in
fectly as possible with the direction of pull so that no rotary
many other organic materials and in many metals) is debatable, the
motion that may induce slippage will occur in the grips; there
propriety of applying the term “elastic modulus” in its quoted, generally
is a limit to the amount of misalignment self-aligning grips will
accepted definition to describe the “stiffness” or “rigidity” of a plastic has
accommodate.
been seriously questioned. The exact stress-strain characteristics of plastic
5.1.3.3 The test specimen shall be held in such a way that
materials are highly dependent on such factors as rate of application of
stress, temperature, previous history of specimen, etc. However, stress-
slippage relative to the grips is prevented insofar as possible.
strain curves for plastics, determined as described in this test method,
Grip surfaces that are deeply scored or serrated with a pattern
almost always show a linear region at low stresses, and a straight line
similar to those of a coarse single-cut file, serrations about 2.4
drawn tangent to this portion of the curve permits calculation of an elastic
mm (0.09 in.) apart and about 1.6 mm (0.06 in.) deep, have
modulus of the usually defined type. Such a constant is useful if its
been found satisfactory for most thermoplastics. Finer serra-
arbitrary nature and dependence on time, temperature, and similar factors
tions have been found to be more satisfactory for harder
are realized.
plastics, such as the thermosetting materials. The serrations
should be kept clean and sharp. Breaking in the grips may
occur at times, even when deep serrations or abraded specimen
Available from American National Standards Institute, 11 W. 42nd St., 13th
Floor, New York, NY 10036. surfaces are used; other techniques must be used in these cases.
D 638
Other techniques that have been found useful, particularly with less), the same above extensometer, attenuated to 20 % exten-
smooth-faced grips, are abrading that portion of the surface of sion, may be used. In any case, the extensometer system must
the specimen that will be in the grips, and interposing thin meet at least Class C (Practice E 83) requirements, which
pieces of abrasive cloth, abrasive paper, or plastic, or rubber- include a fixed strain error of 0.001 strain or 61.0 % of the
coated fabric, commonly called hospital sheeting, between the indicated strain, whichever is greater.
specimen and the grip surface. No. 80 double-sided abrasive 5.2.3 High-Extension Measurements—For making mea-
paper has been found effective in many cases. An open-mesh surements at elongations greater than 20 %, measuring tech-
fabric, in which the threads are coated with abrasive, has also niques with error no greater than 610 % of the measured value
been effective. Reducing the cross-sectional area of the speci- are acceptable.
men may also be effective. The use of special types of grips is 5.2.4 Poisson’s Ratio—Bi-axial extensometer or axial and
sometimes necessary to eliminate slippage and breakage in the transverse extensometers capable of recording axial strain and
grips. transverse strain simultaneously. The extensometers shall be
capable of measuring the change in strains with an accuracy of
5.1.4 Drive Mechanism—A drive mechanism for imparting
1 % of the relevant value or better.
to the movable member a uniform, controlled velocity with
respect to the stationary member, with this velocity to be
NOTE 8—Strain gages can be used as an alternative method to measure
regulated as specified in Section 8.
axial and transverse strain; however, proper techniques for mounting
5.1.5 Load Indicator—A suitable load-indicating mecha- strain gages are crucial to obtaining accurate data. Consult strain gage
suppliers for instruction and training in these special techniques.
nism capable of showing the total tensile load carried by the
test specimen when held by the grips. This mechanism shall be
5.3 Micrometers—Suitable micrometers for measuring the
essentially free of inertia lag at the specified rate of testing and
width and thickness of the test specimen to an incremental
shall indicate the load with an accuracy of 61 % of the
discrimination of at least 0.025 mm (0.001 in.) should be used.
indicated value, or better. The accuracy of the testing machine
All width and thickness measurements of rigid and semirigid
shall be verified in accordance with Practices E 4.
plastics may be measured with a hand micrometer with ratchet.
A suitable instrument for measuring the thickness of nonrigid
NOTE 7—Experience has shown that many testing machines now in use
test specimens shall have: (1) a contact m
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