ASTM D2524-95
(Test Method)Standard Test Method for Breaking Tenacity of Wool Fibers, Flat Bundle Method- 1/8-in. (3.2-mm) Gage Length
Standard Test Method for Breaking Tenacity of Wool Fibers, Flat Bundle Method- 1/8-in. (3.2-mm) Gage Length
SCOPE
1.1 This test method covers the determination of the breaking tenacity of wool fibers as a flat bundle with a 1/8-in. (3.2-mm) clamp separation.
1.2 This test method is especially adapted to the fiber bundle clamps and strength testing instruments specified, but may be used on other tensile testing machines when equipped with appropriate adapters to accommodate the prescribed clamps.
1.3 This test method is applicable to wool in any form which can be hand-combed into small bundles of parallelized fibers. Note 1-Other test methods for measuring breaking tenacity of fiber bundles include Test Methods D1294, D1445, and D540.
1.4 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.
1.5 The values stated in inch-pound units are to be regarded as the standard. The SI units in parentheses are provided for information only.
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Standards Content (Sample)
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Designation: D 2524 – 95
Standard Test Method for
Breaking Tenacity of Wool Fibers, Flat Bundle Method— ⁄8-
in. (3.2-mm) Gage Length
This standard is issued under the fixed designation D 2524; 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 3.1.1 breaking tenacity, n—the tenacity corresponding to
the breaking load.
1.1 This test method covers the determination of the break-
1 3.1.2 Discussion—Breaking tenacity is commonly ex-
ing tenacity of wool fibers as a flat bundle with a ⁄8-in.
pressed as grams-force per tex (gf/tex), grams-force per denier
(3.2-mm) clamp separation.
(gf/den), millinewtons per tex (mN/tex), or millinewtons per
1.2 This test method is especially adapted to the fiber bundle
denier (mN/den). Millinewtons are numerically equal to the
clamps and strength testing instruments specified, but may be
grams-force times 9.81.
used on other tensile testing machines when equipped with
3.1.3 constant-rate-of-extension (CRE) type tensile testing
appropriate adapters to accommodate the prescribed clamps.
machine, n—in tensile testing, an apparatus in which the
1.3 This test method is applicable to wool in any form
pulling clamp moves at a uniform rate, and the force-
which can be hand-combed into small bundles of parallelized
measuring mechanism moves a negligible distance with in-
fibers.
creasing force, less than 0.13 mm (0.005 in.).
NOTE 1—Other test methods for measuring breaking tenacity of fiber
3.1.4 constant-rate-of-loading (CRL) type tensile testing
bundles include Test Methods D 1294, D 1445, and D 540.
machine, n—in tensile testing, an apparatus in which the rate of
1.4 This standard does not purport to address all of the
increase of the force is uniform with time after the first3sand
safety concerns, if any, associated with its use. It is the
the specimen is free to elongate, this elongation being depen-
responsibility of the user of this standard to establish appro-
dent on the extension characteristics of the specimen at any
priate safety and health practices and determine the applica-
applied force.
bility of regulatory limitations prior to use.
3.1.5 constant-rate-of-traverse (CRT) type tensile testing
1.5 The values stated in inch-pound units are to be regarded
machine, n—in tensile testing, an apparatus in which the
as the standard. The SI units in parentheses are provided for
pulling clamp moves at a uniform rate and the force is applied
information only.
through the other clamp, which moves appreciably to actuate a
force-measuring mechanism, producing a rate of increase of
2. Referenced Documents
force or extension that is usually not constant and is dependent
2.1 ASTM Standards:
on the extension characteristics of the specimen.
D 123 Terminology Relating to Textiles
3.1.6 gage length, n—in tensile testing, the length of a
D 540 Testing Man-Made Staple Fibers
specimen measured between the points of attachment to clamps
D 1294 Test Method for Tensile Strengh and Breaking
while under uniform tension.
Tenacity of Wool Fiber Bundles—1-in. (25.4-mm). Gage
3.1.7 tenacity, n—in a tensile test, the force exerted on the
Length
specimens based on the linear density of the unstrained
D 1445 Test Method for Breaking Strength and Elongation
specimen.
of Cotton Fibers (Flat Bundle Method)
3.1.8 Discussion—In textiles, tenacity is considered a prop-
D 1776 Practice for Conditioning Textiles for Testing
erty of fabrics and yarns, and tensile strain is the complemen-
D 2525 Practice for Sampling Wool for Moisture
tary property of fabrics. In direct yarn numbering systems,
tenacity is force divided by linear density. In indirect yarn
3. Terminology
numbering systems, tenacity is force times the reciprocal linear
3.1 Definitions:
density.
3.1.9 wool, n—the fibrous covering of sheep, Ovis species.
1 3.1.10 Discussion—For the purposes of this method, the
This test method is under the jurisdiction of ASTM Committee D-13 on Textiles
and is the direct responsibility of Subcommittee D13.13 on Wool and Wool Felt. word wool is used in the generic sense, and includes repro-
Current edition approved May 15, 1995. Published August 1995. Originally
cessed and reused wool as well as wool as defined in the Wool
published as D 2524 – 66 T. Last previous edition D 2524 – 94.
Products Labeling Act of 1939: “the fiber from the fleece of the
Annual Book of ASTM Standards, Vol 07.01.
sheep or lamb, or hair of the Angora goat or Cashmere goat
Discontinued—See 1973 Annual Book of ASTM Standards, Part 25.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 2524
(and may include the so called specialty fibers from the hair of clamps. For CRL testing machines, the rate of loading is
the camel, alpaca, llama, and vicuna) which has never been specified as 1 kgf/s (10 N/s). For CRE and CRT machines,
reclaimed from any woven or felted wool product.” select a rate of operation which will reach the breaking force in
3.1.11 For definitions of other textile terms used in this test an average time of 20 6 3s.
method, refer to Terminology D 123. 6.1.1 In case the CRE or CRT testing machine is not capable
of operating as specified in 6.1, select a rate so as to reach the
4. Summary of Test Method
breaking force in an average time as close to 20 s as possible
4.1 A bundle of fibers is combed until parallel, placed under
and report the average time to break.
a uniform tension sufficient to remove as much crimp as
NOTE 2—There may be no overall correlation between the results
possible without stretching the fibers, and secured in special
obtained with the CRE, CRT or CRL type testing machines. Consequently,
clamps. The fibers are then cut to a known length, broken in the
these three machines cannot be used interchangeably.
tensile testing machine, removed from the clamps, and
6.2 Balance, suitable for weighing 2 to 6 mg with a
weighed. Breaking tenacity is calculated from the ratio of
sensitivity of 0.02 mg.
breaking force to bundle linear density. The length measured
6.3 Flat Bundle Clamps and Accessories, including the
under the applied tension is the basis for computing linear
following components:
density from bundle mass.
NOTE 3—Pressley clamps and accessories have been found satisfactory
5. Significance and Uses
for this purpose. Adapters to fit the clamps to various tensile testing
5.1 Test Method D 2524 for testing wool fibers for tenacity
instruments are also available or can be fabricated.
is considered satisfactory for acceptance testing when the
6.3.1 Clamps, having a total thickness of 0.465 6 0.001 in.
participating laboratories, using a reference wool, have shown
(11.8 6 0.03 mm) and a 0.125 6 0.001-in. (3.2 6 0.03-mm)
acceptable between-laboratory precision. It is recommended
spacer.
that any program of acceptance testing be preceded by an
6.3.2 Clamp Vise, with a device to indicate approximately 8
interlaboratory check in the laboratory of the purchaser and the
lbf·in. (0.9 N·m) torque.
laboratory of the seller on replicate specimens of samples of
6.3.3 Clamp Wrench.
the material to be evaluated. In cases of dispute, the statistical
6.4 Coarse Comb, approximately 8 teeth per in. (3 per 10
bias, if any, between the laboratory of the purchaser and the
mm).
seller should be determined with each comparison being based
6.5 Fine Comb, approximately 50 teeth per in. (20 per 10
on testing randomized specimens from one sample of material
mm).
of the type being evaluated.
6.6 Black Paper, to hold bundles.
5.2 Values obtained from flat bundle tenacity show a good
6.7 Shearing Knife or Razor Blade.
correlation with values obtained from single fiber tests and
6.8 Tweezers.
require much less time.
6.9 Torque Wrench or Friction Disk Wrench, to indicate
5.3 The basic differences between the procedures described
approximately 8 lbf·in. (0.9 N·m) torque (optional).
in Test Method D 2524 and those described in Test Method
6.10 Standard Wool Top Sample , having an assigned break-
D 1294 lie in the manner of clamping the bundles and the
ing tenacity of 11.4 gf/tex (112 mN/tex).
shorter gage length employed. The special clamps used in this
method allow quicker and easier bundle preparation; however,
NOTE 4—The standard wool top sample, USDA Lot 58-27, has a
for Test Method D 1294 no special clamps are required. Closer breaking tenacity (based on single fiber tests) of 11.4 6 0.6 gf/tex, at the
95 % probability level.
agreement with single fiber tenacity is also obtained with Test
Method D 2524 than when using the procedure in Test Method
7. Sampling
D 1294.
7.1 Division into Lots—Treat a single shipment of a single
5.4 As the observed tenacity of fibers depends in part on the
fiber type as a lot.
type of tensile testing machine used and the time required to
7.2 Lot Sample—As a lot sample for acceptance testing,
break the specimen, results obtained with the different types of
take at random the number of shipment containers directed in
machines which may be used in this method will not neces-
an applicable material specification or other agreement be-
sarily agree. The machines specifically designed for bundle
tween the purchaser and the supplier, such as an agreement to
testing are CRL testers which operate at a loading rate of 1
use Practice D 2525. Consider shipping containers to be the
kgf/s and therefore reach the breaking force at variable times in
primary sampling units.
the order of 5 s. CRE and CRT type machines would be
7.3 Laboratory Sample—For acceptance testing, take a
expected to produce somewhat different results not only
laboratory sample from each shipping container in the lot
because of the inherent difference in operation but because
sample as follows:
CRE and CRT type machines are to be operated at a rate to
achieve the breaking load in 20 s.
6. Apparatus and Materials 4
The Stelometer, manufactured by the Special Instruments Laboratory, Inc., 312
W. Vine St., Knoxville, TN 37901; and the Clemson Tester (no longer available)
6.1 Tensile Testing Machine, having a capacity of at least 7
have been found satisfactory for this purpose.
kgf (70 N), equipped to accommodate the specified flat bundle
Available from J. M. Doebrich and Co., P. O. Box 2789, Tucson, AZ 85702.
Available from the Wool and Mohair Laboratory, Livestock and Seed Division,
AMS, U.S. Department of Agriculture, 711 “O” Street, Greeley, CO 80631.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 2524
7.3.1 For loose fiber, grease, and scoured wool, reduce the 11.2 Inspect the leather faces of the clamps frequently to
mass of clean fiber submitted for testing to approximately 15 g ensure that they are in good condition. Keep the inner edges of
by randomly selecting pieces throughout the mass. Form into a the leathers trimmed flush with the metal surfaces and replace
loose sliver by hand. the leathers as soon as grooves become evident to the touch.
7.3.2 For card sliver and top, cut a length of sliver about 20
11.3 Place the parallelized specimen (10.3) in the clamps in
in. (500 mm) long from each ball submitted for testing. the following manner: Using a Pressley type vise, lock the
7.3.3 For roving, cut a length about 20 in. (500 mm) long
clamps with a ⁄8-in. (3.2-mm) spacer separating the clamps of
from each spool submitted for testing and include all ends. the vise and open the jaws of the clamps. Hold both ends of the
7.4 Test Specimens—Scour or solvent-extract the laboratory
specimen as directed in 10.3, keeping the specimen approxi-
sample until residual contamination is 1 % or less of the mately ⁄4 in. (6 mm) wide, and place it in the central part of the
laboratory mass, as established by further cleaning of a part of
open clamps. Maintain sufficient tension on the specimen to
the laboratory sample. From each unit in the laboratory sample, hold the fibers straight while the jaws of the clamps are
prepare five test specimens as directed in 10.1.
lowered and tightened in place by applying an 8 lbf·in. (0.9
N·m) torque. The torque may be controlled by either a
8. Preparation, Calibration, and Verification of
vise-mounted, torque-indicating instrument or by a friction
Apparatus
disk wrench.
8.1 Tensile Testing Machine—Check the calibration of the
11.4 Remove the clamps from the vise. Shear off the
instrument according to the manufacturer’s instruction.
protruding ends of the specimen with the shearing knife or
8.2 Balance—Check the zero reading and the sensitivity in
razor blade, cutting downward and away from the leather face
the range to be used.
of the clamps and flush with the surface.
11.5 Insert the loaded clamps in the tensile testing machine
9. Preconditioning and Conditioning
and break the test specimen in accordance with the manufac-
9.1 Bring the laboratory sample to moisture equilibrium for
turer’s instructions. For other than the special instruments
testing in the standard atmosphere for testing as directed in
designed specifically for flat bundle testing, operate the test
Practice D 1776.
instrument as directed in 6.1.
10. Preparation of Specimens
11.6 After the specimen has been broken, record the break-
ing force to the nearest scale or chart reading. Remove the
10.1 Prepare each specimen by drawing small groups of
clamps from the instrument and place the clamps in the vise.
fibers from at least five locations in a unit of the laboratory
Check to see that all fibers are broken. If all the fibers are not
sample. Parallelize and combine them in a bundle which may
broken, are broken irregularly indicating some slippage of
be held conveniently between the thumb and forefinger. De-
fibers in the clamps, or if the breaking force is less than the
pending on fiber entanglement, take a sufficient number of
required minimum for the instrument used, discard the speci-
fibers so that, after combining, an aligned specimen of 2 to 6
men and make a new test. If the break is acceptable, open the
mg is available for testing.
clamps, collect all the broken fibers with tweezers, and weigh
10.2 Grasp the tuft about one-fourth the distance from the
to the nearest 0.02 mg (Note 5). To avoid gain in weight from
end of the tuft with the thumb and forefinger or a fiber hand
moisture pickup, do not touch the fibers with the finger
...
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