ASTM D2524-95(2003)
(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
SIGNIFICANCE AND USE
Test Method D 2524 for testing wool fibers for tenacity is considered satisfactory for acceptance testing when the participating laboratories, using a reference wool, have shown acceptable between-laboratory precision. It is recommended that any program of acceptance testing be preceded by an interlaboratory check in the laboratory of the purchaser and the laboratory of the seller on replicate specimens of samples of the material to be evaluated. In cases of dispute, the statistical bias, if any, between the laboratory of the purchaser and the seller should be determined with each comparison being based on testing randomized specimens from one sample of material of the type being evaluated.
Values obtained from flat bundle tenacity show a good correlation with values obtained from single fiber tests and require much less time.
The basic differences between the procedures described in Test Method D 2524 and those described in Test Method D 1294 lie in the manner of clamping the bundles and the shorter gage length employed. The special clamps used in this method allow quicker and easier bundle preparation; however, for Test Method D 1294 no special clamps are required. Closer agreement with single fiber tenacity is also obtained with Test Method D 2524 than when using the procedure in Test Method D 1294.
As the observed tenacity of fibers depends in part on the type of tensile testing machine used and the time required to break the specimen, results obtained with the different types of machines which may be used in this method will not necessarily agree. The machines specifically designed for bundle testing are CRL testers which operate at a loading rate of 1 kgf/s and therefore reach the breaking force at variable times in the order of 5 s. CRE and CRT type machines would be expected to produce somewhat different results not only because of the inherent difference in operation but because CRE and CRT type machines are to be operated at a rate to achieve the bre...
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 D 1294, D 1445, and D 540.
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.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D 2524 – 95 (Reapproved 2003)
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. Terminology
1.1 This test method covers the determination of the break- 3.1 Definitions:
ing tenacity of wool fibers as a flat bundle with a ⁄8-in. 3.1.1 breaking tenacity, n—the tenacity corresponding to
(3.2-mm) clamp separation. the breaking load.
1.2 Thistestmethodisespeciallyadaptedtothefiberbundle 3.1.1.1 Discussion—Breaking tenacity is commonly ex-
clamps and strength testing instruments specified, but may be pressed as grams-force per tex (gf/tex), grams-force per denier
used on other tensile testing machines when equipped with (gf/den), millinewtons per tex (mN/tex), or millinewtons per
appropriate adapters to accommodate the prescribed clamps. denier (mN/den). Millinewtons are numerically equal to the
1.3 This test method is applicable to wool in any form grams-force times 9.81.
which can be hand-combed into small bundles of parallelized 3.1.2 constant-rate-of-extension (CRE) type tensile testing
fibers. machine, n—in tensile testing, an apparatus in which the
pulling clamp moves at a uniform rate, and the force-
NOTE 1—Other test methods for measuring breaking tenacity of fiber
measuring mechanism moves a negligible distance with in-
bundles include Test Methods D 1294, D 1445, and D 540.
creasing force, less than 0.13 mm (0.005 in.).
1.4 This standard does not purport to address all of the
3.1.3 constant-rate-of-loading (CRL) type tensile testing
safety concerns, if any, associated with its use. It is the
machine, n—in tensile testing,anapparatusinwhichtherateof
responsibility of the user of this standard to establish appro-
increase of the force is uniform with time after the first3sand
priate safety and health practices and determine the applica-
the specimen is free to elongate, this elongation being depen-
bility of regulatory limitations prior to use.
dent on the extension characteristics of the specimen at any
1.5 The values stated in inch-pound units are to be regarded
applied force.
as the standard. The SI units in parentheses are provided for
3.1.4 constant-rate-of-traverse (CRT) type tensile testing
information only.
machine, n—in tensile testing, an apparatus in which the
pulling clamp moves at a uniform rate and the force is applied
2. Referenced Documents
through the other clamp, which moves appreciably to actuate a
2.1 ASTM Standards:
force-measuring mechanism, producing a rate of increase of
D 123 Terminology Relating to Textiles
force or extension that is usually not constant and is dependent
D 540 Testing Man-Made Staple Fibers
on the extension characteristics of the specimen.
D 1294 Test Method for Tensile Strengh and Breaking
3.1.5 gage length, n—in tensile testing, the length of a
Tenacity of Wool Fiber Bundles—1-in. (25.4-mm). Gage
specimenmeasuredbetweenthepointsofattachmenttoclamps
Length
while under uniform tension.
D 1445 Test Method for Breaking Strength and Elongation
3.1.6 tenacity, n—in a tensile test, the force exerted on the
of Cotton Fibers (Flat Bundle Method)
specimens based on the linear density of the unstrained
D 1776 Practice for Conditioning Textiles for Testing
specimen.
D 2525 Practice for Sampling Wool for Moisture
3.1.6.1 Discussion—In textiles, tenacity is considered a
property of fabrics and yarns, and tensile strain is the comple-
mentary property of fabrics. In direct yarn numbering systems,
This test method is under the jurisdiction ofASTM Committee D13 onTextiles
and is the direct responsibility of Subcommittee D13.13 on Wool and Felt.
tenacity is force divided by linear density. In indirect yarn
Current edition approved April 10, 2003. Published August 1995. Originally
numbering systems, tenacity is force times the reciprocal linear
published as D 2524 – 66 T. Last previous edition D 2524 – 94.
2 density.
Annual Book of ASTM Standards, Vol 07.01.
Discontinued—See 1973 Annual Book of ASTM Standards , Part 25. 3.1.7 wool, n—the fibrous covering of sheep, Ovis species.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 2524 – 95 (2003)
3.1.7.1 Discussion—For the purposes of this method, the 6. Apparatus and Materials
word wool is used in the generic sense, and includes repro-
6.1 Tensile Testing Machine, having a capacity of at least 7
cessed and reused wool as well as wool as defined in the Wool
kgf (70 N), equipped to accommodate the specified flat bundle
Products LabelingAct of 1939: “the fiber from the fleece of the
clamps. For CRL testing machines, the rate of loading is
sheep or lamb, or hair of the Angora goat or Cashmere goat
specified as 1 kgf/s (10 N/s). For CRE and CRT machines,
(and may include the so called specialty fibers from the hair of
select a rate of operation which will reach the breaking force in
the camel, alpaca, llama, and vicuna) which has never been
an average time of 20 63s.
reclaimed from any woven or felted wool product.”
6.1.1 IncasetheCREorCRTtestingmachineisnotcapable
3.1.8 For definitions of other textile terms used in this test
of operating as specified in 6.1, select a rate so as to reach the
method, refer to Terminology D 123.
breaking force in an average time as close to 20 s as possible
and report the average time to break.
4. Summary of Test Method
NOTE 2—There may be no overall correlation between the results
4.1 Abundle of fibers is combed until parallel, placed under
obtainedwiththeCRE,CRTorCRLtypetestingmachines.Consequently,
a uniform tension sufficient to remove as much crimp as
these three machines cannot be used interchangeably.
possible without stretching the fibers, and secured in special
6.2 Balance, suitable for weighing 2 to 6 mg with a
clamps.Thefibersarethencuttoaknownlength,brokeninthe
sensitivity of 0.02 mg.
tensile testing machine, removed from the clamps, and
6.3 Flat Bundle Clamps and Accessories, including the
weighed. Breaking tenacity is calculated from the ratio of
following components:
breaking force to bundle linear density. The length measured
under the applied tension is the basis for computing linear
NOTE 3—Pressley clamps and accessories have been found satisfactory
density from bundle mass.
for this purpose. Adapters to fit the clamps to various tensile testing
instruments are also available or can be fabricated.
5. Significance and Uses
6.3.1 Clamps, having a total thickness of 0.465 6 0.001 in.
5.1 Test Method D 2524 for testing wool fibers for tenacity
(11.8 6 0.03 mm) and a 0.125 6 0.001-in. (3.2 6 0.03-mm)
is considered satisfactory for acceptance testing when the
spacer.
participating laboratories, using a reference wool, have shown
6.3.2 Clamp Vise, with a device to indicate approximately 8
acceptable between-laboratory precision. It is recommended
lbf·in. (0.9 N·m) torque.
that any program of acceptance testing be preceded by an
6.3.3 Clamp Wrench.
interlaboratory check in the laboratory of the purchaser and the
6.4 Coarse Comb, approximately 8 teeth per in. (3 per 10
laboratory of the seller on replicate specimens of samples of
mm).
the material to be evaluated. In cases of dispute, the statistical
6.5 Fine Comb, approximately 50 teeth per in. (20 per 10
bias, if any, between the laboratory of the purchaser and the
mm).
seller should be determined with each comparison being based
6.6 Black Paper, to hold bundles.
on testing randomized specimens from one sample of material
6.7 Shearing Knife or Razor Blade.
of the type being evaluated.
6.8 Tweezers.
5.2 Values obtained from flat bundle tenacity show a good
6.9 Torque Wrench or Friction Disk Wrench, to indicate
correlation with values obtained from single fiber tests and
approximately 8 lbf·in. (0.9 N·m) torque (optional).
require much less time.
6.10 Standard Wool Top Sample , having an assigned break-
5.3 The basic differences between the procedures described
ing tenacity of 11.4 gf/tex (112 mN/tex).
in Test Method D 2524 and those described in Test Method
NOTE 4—The standard wool top sample, USDA Lot 58-27, has a
D 1294 lie in the manner of clamping the bundles and the
breaking tenacity (based on single fiber tests) of 11.4 6 0.6 gf/tex, at the
shorter gage length employed. The special clamps used in this
95 % probability level.
method allow quicker and easier bundle preparation; however,
for Test Method D 1294 no special clamps are required. Closer
7. Sampling
agreement with single fiber tenacity is also obtained with Test
7.1 Division into Lots—Treat a single shipment of a single
Method D 2524 than when using the procedure in Test Method
fiber type as a lot.
D 1294.
7.2 Lot Sample—As a lot sample for acceptance testing,
5.4 As the observed tenacity of fibers depends in part on the
take at random the number of shipment containers directed in
type of tensile testing machine used and the time required to
an applicable material specification or other agreement be-
break the specimen, results obtained with the different types of
tween the purchaser and the supplier, such as an agreement to
machines which may be used in this method will not neces-
use Practice D 2525. Consider shipping containers to be the
sarily agree. The machines specifically designed for bundle
primary sampling units.
testing are CRL testers which operate at a loading rate of 1
kgf/sandthereforereachthebreakingforceatvariabletimesin
the order of 5 s. CRE and CRT type machines would be
The Stelometer, manufactured by the Special Instruments Laboratory, Inc., 312
W. Vine St., Knoxville, TN 37901; and the Clemson Tester (no longer available)
expected to produce somewhat different results not only
have been found satisfactory for this purpose.
because of the inherent difference in operation but because
Available from J. M. Doebrich and Co., P. O. Box 2789, Tucson, AZ 85702.
CRE and CRT type machines are to be operated at a rate to
Available from the Wool and Mohair Laboratory, Livestock and Seed Division,
achieve the breaking load in 20 s. AMS, U.S. Department of Agriculture, 711 “O” Street, Greeley, CO 80631.
D 2524 – 95 (2003)
7.3 Laboratory Sample—For acceptance testing, take a side with the tip of the comb to obtain the correct specimen
laboratory sample from each shipping container in the lot size. The specimen is now ready to be placed in the clamps.
sample as follows:
7.3.1 For loose fiber, grease, and scoured wool, reduce the 11. Procedure
mass of clean fiber submitted for testing to approximately 15 g
11.1 Test the conditioned specimens in the standard atmo-
by randomly selecting pieces throughout the
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