ASTM D7269-06
(Test Method)Standard Test Methods for Tensile Testing of Aramid Yarns
Standard Test Methods for Tensile Testing of Aramid Yarns
SCOPE
1.1 These test methods cover the tensile testing of aramid yarns, cords twisted from such yarns, and fabrics woven from such cords. The yarn or cord may be wound on cones, tubes, bobbins, spools, or beams; may be woven into fabric; or may be in some other form. The methods include testing procedure only and include no specifications or tolerances.
1.2 These test methods show the values in both SI and inch-pound units. SI units is the technically correct name for the system of metric units known as the International System of Units. Inch-pound units is the technically correct name for the customary units used in the United States. The values stated in either acceptable metric units or other units shall be regarded separately as standard. The values expressed in each system may not be exact equivalents; therefore, each system must be used independently of each other, without combining values in any way.
1.3 This standard includes the following test methods:
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.
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Designation:D7269–06
Standard Test Methods for
Tensile Testing of Aramid Yarns
This standard is issued under the fixed designation D 7269; 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.
1. Scope D 885 Test Methods for Tire Cords, Tire Cord Fabrics, and
Industrial Filament Yarns Made from Manufactured
1.1 These test methods cover the tensile testing of aramid
Organic-Base Fibers
yarns, cords twisted from such yarns, and fabrics woven from
D 1907 Test Method for Linear Density of Yarn (Yarn
such cords. The yarn or cord may be wound on cones, tubes,
Number) by the Skein Method
bobbins, spools, or beams; may be woven into fabric; or may
D 1909 Standard Table of Commercial Moisture Regains
be in some other form. The methods include testing procedure
for Textile Fibers
only and include no specifications or tolerances.
D 2258 Practice for Sampling Yarn for Testing
1.2 These test methods show the values in both SI and
D 4848 Terminology of Force, Deformation and Related
inch-pound units. SI units is the technically correct name for
Properties of Textiles
thesystemofmetricunitsknownastheInternationalSystemof
D 6477 Terminology Relating to Tire Cord, Bead Wire,
Units. Inch-pound units is the technically correct name for the
Hose Reinforcing Wire, and Fabrics
customary units used in the United States. The values stated in
either acceptable metric units or other units shall be regarded
3. Terminology
separately as standard. The values expressed in each system
3.1 Definitions:
may not be exact equivalents; therefore, each system must be
3.1.1 For definitions of terms relating to tire cord and tire
used independently of each other, without combining values in
cord fabrics, refer to Terminology D 6477.
any way.
3.1.1.1 The following terms are relevant to this standard:
1.3 This standard includes the following test methods:
cord, cord twist, dip, dip pickup, in a textile cord or fabric,
Section
industrial yarn, moisture equilibrium for testing, for industrial
Breaking Strength (Force) 11
Breaking Tenacity 12
yarns and tire cords, pneumatic tire, single twist, standard
Breaking Toughness 17
atmosphere for testing textiles, tabby sample, tire, and tire cord
Elongation at Break 13
fabric.
Force at Specified Elongation (FASE) 14
Linear Density 10
3.1.2 For definitions of terms related to force and deforma-
Modulus 15
tion in textiles, refer to Terminology D 4848.
Work-to-Break 16
3.1.2.1 The following terms are relevant to this standard:
1.4 This standard does not purport to address all of the
breaking force, breaking strength, breaking tenacity. breaking
safety concerns, if any, associated with its use. It is the
toughness, chord modulus, in a stress-strain curve, elongation,
responsibility of the user of this standard to establish appro-
force at specified elongation (FASE), initial modulus, tensile
priate safety and health practices and determine the applica-
strength, and work-to-break.
bility of regulatory limitations prior to use.
3.1.3 For definitions of other terms related to textiles, refer
to Terminology D 123.
2. Referenced Documents
3.1.3.1 The following terms are relevant to this standard:
2.1 ASTM Standards:
fabric and growth.
D76 SpecificationforTensileTestingMachinesforTextiles
D 123 Terminology Relating to Textiles 4. Summary of Test Method
4.1 These test methods are used to determine the tensile
properties of aramid yarns or cords.
These test methods are under the jurisdiction of ASTM Committee D13 on
4.2 Aconditioned or oven-dried specimen of aramid yarn or
Textiles and are the direct responsibility of Subcommittee D13.19 on Tire Cord and
cord is clamped in a tensile testing machine and then stretched
Fabrics.
Current edition approved June 1, 2006. Published July 2006.
or loaded until broken. Breaking force, elongation, and force at
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
specified elongation (FASE) are determined directly. Modulus
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
and work-to-break are calculated from the force-elongation
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. curve.Theoutputofaconstant-rate-of-extension(CRE)tensile
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7269–06
testingmachinecanbeconnectedwithelectronicrecordingand therefore, to evaluate the performance of a textile reinforced
computing equipment, which may be programmed to calculate product in terms of the reinforcing material alone.
and print the test results of tensile properties of interest.
5.8 If there are differences of practical significance between
reported test results for two laboratories (or more), compara-
5. Significance and Use
tive tests should be performed to determine if there is a
5.1 The levels of tensile properties obtained when testing
statistical bias between them, using competent statistical assis-
aramid yarns and tire cords are dependent on the age and
tance. As a minimum, test samples should be used that are as
history of the specimen and on the specific conditions used
homogeneous as possible, that are drawn from the material
during the test. Among these conditions are rate of stretching,
from which the disparate test results were obtained, and that
type of clamps, gage length of specimen, temperature and
are randomly assigned in equal numbers to each laboratory for
humidity of the atmosphere, rate of airflow across the speci-
testing. Other materials with established test values may be
men, and temperature and moisture content of the specimen.
used for this purpose.The test results from the two laboratories
Testing conditions accordingly are specified precisely to obtain
should be compared using a statistical test for unpaired data, at
reproducible test results on a specific sample.
a probability level chosen prior to the testing series. If a bias is
5.2 Because the force-bearing ability of a reinforced rubber
found, either its cause must be found and corrected, or future
product is related to the strength of the yarn or cord used as a
test results must be adjusted in consideration of the known
reinforcing material, breaking strength is used in engineering
bias.
calculations when designing various types of textile reinforced
rubber products. When needed to compare intrinsic strength
6. Apparatus
characteristics of yarns or cords of different sizes or different
6.1 Tensile Testing Machine—Asingle-strand tensile testing
types of fiber, breaking tenacity is very useful because, for a
machine of the constant rate of extension (CRE) type. The
given type of fiber, breaking force is approximately propor-
specifications and methods of calibration and verification of
tional to linear density.
these machines shall conform to Specification D76. The
5.3 Elongation of yarn or cord is taken into consideration in
testingmachineshallbeequippedwithanautographicrecorder
the design and engineering of reinforced rubber products
(rectilinear coordinates preferred). It is permissible to use
because of its effect on uniformity of the finished product and
tensile testing machines that have a means for calculating and
its dimensional stability during service.
displaying the required results without the use of an auto-
5.4 The FASE is used to monitor changes in characteristics
graphic recorder. It is also permissible to use automated tensile
of the textile material during the various stages involved in the
testing equipment.
processing and incorporation of yarn or cord into a rubber
6.1.1 Clamps—Bollard type clamps, in which the specimen
product.
is gripped between plane-faced jaws and then makes a partial
5.5 Modulusisameasureoftheresistanceofyarnorcordto
turn (wrap angle) around a curved extension (or other type of
extension as a force is applied. It is useful for estimating the
snubbing device) of one jaw before passing to the other similar
response of a textile reinforced structure to the application of
clamp (see Fig. 1). Clamps with a wrap angle of 3.14 rad
varying forces and rates of stretching. Although modulus may
(180°) is recommended for yarns with a linear density up to
be determined at any specified force, initial modulus is the
10 000decitex(9000denier).Forlineardensitiesabove10 000
value most commonly used.
decitex (9000 denier), clamps with a wrap angle of 4.71 rad
5.6 Work-to-break is dependent on the relationship of force
(270°) is required to prevent slippage.
to elongation. It is a measure of the ability of a textile structure
to absorb mechanical energy. Breaking toughness is work-to- 6.1.1.1 Clampsshallgripthetestspecimenwithoutspurious
break per unit mass. slippageordamagetothetestspecimenwhichcanresultinjaw
5.7 It should be emphasized that, although the preceding breaks.The clamps shall maintain constant gripping conditions
parameters are related to the performance of a textile- duringthetestbymeansofpneumaticorhydraulicclamps.The
reinforced product, the actual configuration of the product is surface of the jaws in contact with the specimen shall be of a
significant. Shape, size, and internal construction also can have material and configuration that minimizes slippage and/or
appreciable effect on product performance. It is not possible, specimen failure in the clamping zone.
FIG. 1 Principle of Bollard Type Clamps
D7269–06
6.1.2 Gauge Length—The gauge length shall be the total 7.2 Cord:
length of yarn measured between the clamping point A of the
7.2.1 Number of Samples and Specimens—The size of an
first clamp and the point B of the second clamp in the starting
acceptance sampling lot of tire cord shall be not more than one
position (see Fig. 2).
truck or rail car load or as determined by agreement between
6.1.3 Use a crosshead travel rate in mm/min (in./min) of
the purchaser and the supplier. Take samples at random from
50 %ofthenominalgaugelengthinmillimeters(inches)ofthe
each of a number of cones, tubes, bobbins, or spools within a
specimen for para-aramids; 100 % of the nominal gauge length
lot to be as representative as possible within practical limita-
in millimeters (inches) of the specimen for meta-aramids.
tions. Make only one observation on an individual package for
each physical property determination. Take the number of
7. Sampling
samples, therefore, that will be sufficient to cover the total
7.1 Yarn:
number of specimens required for the determination of all
7.1.1 Packages—For acceptance testing, sample each lot as
physical properties of the tire cord. The recommended number
directed in Practice D 2258. Place each laboratory sampling
of specimens is included in the appropriate sections of specific
unit in a moisture-proof polyethylene bag or other moisture-
test methods covered in this standard. Where such is not
proof container to protect the samples from atmospheric
specified, the number of specimens is as agreed upon between
changes until ready to condition the samples in the atmosphere
buyer and supplier.
for testing industrial yarns and tire cords. Take the number of
7.2.2 Preparation of Samples—Remove and discard a mini-
specimens for testing specified for the specific property mea-
mum of 25 m (25 yd) from the outside of the package before
surement to be made.
taking the sample or any specimens. If specimens are not taken
7.1.2 Beams—For acceptance testing, sample by winding
directly from the original package, preferably wind the sample
yarns on a tube or spool by means of a winder using a tension
on a tube or spool by means of a winder using a tension of 5
of 5 6 1 mN/tex (0.05 6 0.01 gf/den). Take the yarn from the
6 1 mN/tex (0.05 6 0.01 gf/den). If the sample is collected as
outside beam layers unless there is a question or disagreement
a loosely wound package, or in the form of a skein, some
regarding the shipment; in this case, take the sample only after
shrinkage invariably will occur, in which case, report that the
removing yarn from the beam to a radial depth of 6 mm ( ⁄4 in.)
observed results were determined on a relaxed sample. Use
or more to minimize the effects of handling and atmospheric
care in handling the sample. Discard any sample subjected to
changes that may have occurred during shipment or storage.
any change of twist, kinking, or making any bend with a
Place each laboratory sampling unit in a moisture-proof
diameter less than 10 times the yarn/cord thickness (or diam-
polyethylene bag or other moisture-proof container to protect
eter). Place the sample in a moisture-proof polyethylene bag or
the samples from atmospheric changes until ready to condition
the samples in the atmosphere for testing industrial yarns and other moisture-proof container to protect it from atmospheric
changes until ready to condition the sample in the test
tire cords. Take the number of specimens for testing specified
for the specific property measurement to be made. atmosphere for industrial yarns and tire cords.
FIG. 2 Principle of Specimen Fixing in Bollard Type Jaws
D7269–06
7.3 Tire Cord Fabric: the tire from bead to bead following the cord path. Discard
7.3.1 Number of Samples and Specimens—The sizes of an these initial cords. After initial cords are removed, remove
acceptance sampling lot of tire cord fabric shall be one loom bands of cords for testing by cutting near the bead through Ply
creel of cord. Take a sample from at least one roll of fabric per 1 cords adjacent to the trough formed in initial cord removal.
lot. From each roll of tire cord fabric, take the number of Carefully pull several cord bands approximately 2 cm ( ⁄4 in.)
specimens as specified in the test method for each property to in width from the tire. Identify bands, fully including tire
be measured. number and ply number. Remove the remainder of Ply 1 to
7.3.2 Size of Sample—Take a sample equal to the length of uncover Ply 2. Proceed with Ply 2 or additional plies as
cord between the regular tabby woven at the end of the roll and directed for Ply 1. If the cords to be removed are from a tire
a special tabby woven a short distance from the end when the havingonlyoneplyofreinforcementintheareatobesampled,
roll of fabric is manufactured. For rolls that do not have a for example, carcass ply of many radial tires reinforced with
special woven tabby, improvise a tabby by the use of gummed glass, aramid, or steel, it is preferable to remove cords for
tape or strips of cemente
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