ASTM D4975-04(2010)
(Test Method)Standard Test Methods for Single-Filament Tire Bead Wire Made from Steel
Standard Test Methods for Single-Filament Tire Bead Wire Made from Steel
SIGNIFICANCE AND USE
The procedures for the determination of properties of single-filament bead wire made from steel are considered satisfactory for acceptance testing of commercial shipments of this product because the procedures are the best available and have been used extensively in the trade.
In case of a dispute arising from differences in reported test results when using these test methods for acceptance testing of commercial shipments, the purchaser and supplier should conduct comparative test to determine if there is a statistical bias between their laboratories. Competent statistical assistance is recommended for the investigation of bias. As a minimum, the two parties should take a group of test specimens which are as homogeneous as possible and which are from a lot of material of the type in question. The test specimens then should be randomly assigned in equal number to each laboratory for testing. The average results from the two laboratories should be compared using Student's t-test for unpaired data and an acceptable probability level chosen by the two parties before testing is begun. If a bias is found, either its cause must be determined and corrected or the purchaser and the supplier must agree to interpret future test results with consideration to the known bias.
SCOPE
1.1 These test methods cover testing of single-filament steel wires that are components of tire beads used in the manufacture of pneumatic tires. By agreement, these test methods may be applied to similar filaments used for reinforcing other rubber products.
1.2 These test methods describe test procedures only and do not establish specifications and tolerances.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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Standards Content (Sample)
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Designation:D4975–04 (Reapproved 2010)
Standard Test Methods for
Single-Filament Tire Bead Wire Made from Steel
This standard is issued under the fixed designation D4975; 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.
1. Scope 3. Terminology
1.1 These test methods cover testing of single-filament steel 3.1 Definitions:
wiresthatarecomponentsoftirebeadsusedinthemanufacture 3.1.1 Fordefinitionsoftermsrelatingtotirecord,beadwire,
of pneumatic tires. By agreement, these test methods may be hose wire, and tire cord fabrics, refer to Terminology D6477.
applied to similar filaments used for reinforcing other rubber 3.1.1.1 The following terms are relevant to this standard:
products. percent elongation, tire bead, tire bead wire, torsion resistance,
1.2 These test methods describe test procedures only and do in tire bead wire, yield strength.
not establish specifications and tolerances. 3.1.2 For definitions of terms related to force and deforma-
1.3 The values stated in SI units are to be regarded as tion in textiles, refer to Terminology D4848
standard. No other units of measurement are included in this 3.1.2.1 The following terms are relevant to this standard:
standard. breaking force.
1.4 These test methods cover the determination of the 3.1.3 For definitions of other textile terms, refer to Termi-
mechanical properties listed below: nology D123.
Property Section
4. Summary of Test Methods
Breaking Force (Strength) 7-13
4.1 A summary of the procedures prescribed for the deter-
Yield Strength 7-13
mination of specific properties of tire bead wire is stated in the
Elongation 7-13
Torsion Resistance 14-20
appropriate sections of the specific test methods that follow.
Diameter (Gage) 21-27
5. Significance and Use
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 5.1 The procedures for the determination of properties of
responsibility of the user of this standard to establish appro- single-filament bead wire made from steel are considered
satisfactory for acceptance testing of commercial shipments of
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. this product because the procedures are the best available and
have been used extensively in the trade.
2. Referenced Documents
5.1.1 In case of a dispute arising from differences in
2.1 ASTM Standards: reported test results when using these test methods for accep-
D76 Specification for Tensile Testing Machines for Textiles tance testing of commercial shipments, the purchaser and
D123 Terminology Relating to Textiles supplier should conduct comparative test to determine if there
D4848 Terminology Related to Force, Deformation and is a statistical bias between their laboratories. Competent
Related Properties of Textiles statistical assistance is recommended for the investigation of
D6477 Terminology Relating to Tire Cord, Bead Wire,
bias.As a minimum, the two parties should take a group of test
Hose Reinforcing Wire, and Fabrics specimens which are as homogeneous as possible and which
are from a lot of material of the type in question. The test
specimens then should be randomly assigned in equal number
These test methods are under the jurisdiction of ASTM Committee D13 on
to each laboratory for testing.The average results from the two
Textiles and are the direct responsibility of Subcommittee D13.19 on Industrial
laboratories should be compared using Student’s t-test for
Fibers and Metallic Reinforcements.
Current edition approved Jan. 1, 2010. Published August 2010. Originally
unpaireddataandanacceptableprobabilitylevelchosenbythe
approved in 1989. Last previous edition approved in 2004 as D4975–04. DOI:
two parties before testing is begun. If a bias is found, either its
10.1520/D4975-04R10.
cause must be determined and corrected or the purchaser and
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4975–04 (2010)
the supplier must agree to interpret future test results with and print the results for each of these desired properties.
consideration to the known bias. Because of the variety of electronic equipment available and
the various possibilities for recording test data, use of this type
6. Sampling
of equipment is not covered in this test method.
6.1 Lot Sample—As a lot sample for acceptance testing,
9.3 Grips, of such design that failure of the specimen does
take at random the number of reels, coils, spools, or other
not occur at the gripping point, and slippage of the specimen
shipping units of wire directed in an applicable material
within the jaws (grips) is prevented.
specification or other agreement between the purchaser and the
supplier.Considerreels,coils,spools,orothershippingunitsof
10. Procedure
wire to be the primary sampling units.
10.1 Thermally age the specimen by placing it in an oven
NOTE 1—A realistic specification or other agreement between the
for 60 6 1 min, at 150 6 3°C. Allow specimens to cool to
purchaser and the supplier requires taking into account the variability
room temperature before testing.
between and within primary sampling units so as to provide a sampling
10.2 Select the proper force scale range on the tensile
plan which at the specified level of the property of interest has a
testing machine based on the estimated breaking force of the
meaningful producer’s risk, consumer’s risk, acceptable quality level, and
specimen being tested.
desired limiting quality level.
10.3 Adjust the distance between the grips of the testing
6.2 Laboratory Sample—Use the primary sampling units in
machine, nip to nip, to a gage length of 250 mm.
the lot sample as a laboratory sample.
10.4 Secure the specimen in the top clamp, exerting enough
6.3 Test Specimens—For each test procedure, take the
pressure to prevent the specimen from slipping when loaded.
number of lengths of tire bead wire of the specified lengths
Place the other end of the specimen between the jaws of the
from each laboratory sample as directed in the test procedure.
bottom clamp.
BREAKING FORCE, YIELD STRENGTH, AND 10.5 Apply a pretension of 1 % of full scale to keep the
ELONGATION specimen taut.
10.6 After setting the cross head speed at 25 mm/min and
7. Summary of Test Method
recorder chart speed at 250 mm/min, start the testing machine
7.1 The two ends of a specimen are clamped in a tensile
and record the force-extension curve generated.
testing machine; an increasing force is applied until the
10.6.1 Ifthespecimenfractureswithin5mmofthegripping
specimen breaks. The change in force is measured versus the
point, discard the result and test another specimen. If such jaw
increase in separation of the specimen clamps to form a
breaks continue to occur, insert a jaw liner such as an abrasive
force-extension curve. Breaking force is read directly from the
cloth between the gripping surface and the specimen in a
curve and is expressed in newtons. Percent elongation at break
manner so that the liner extends beyond the grip edge where it
is the extension at break divided by the original specimen
comes in contact with the specimen.
length, 3 100. The yield strength, the intersection of the
10.7 Conduct this test procedure on two specimens from
force-extension curve with a line at 0.2 % elongation offset, is
each laboratory sampling unit.
read from the force-extension curve and is expressed in
10.8 Elongation, the increase in gage length of a tensile
newtons.
specimen, is usually expressed as a percentage of the original
gage length and can be determined from the force-extension
8. Significance and Use
curve.
8.1 The load-bearing ability of a reinforced rubber product
10.8.1 When a greater degree of accuracy is required in the
such as a tire bead is related to the strength of the single-
determination of elongation, an extensometer can be attached
filament wire used as the reinforcing material. The breaking
to the specimen.
force and yield strength of tire bead wire is used in engineering
10.9 Yield strength is the stress at which a material exhibits
calculations when designing this type of reinforced product.
a specified limiting deviation from the proportionality of stress
8.2 Elongation of tire bead wire is taken into consideration
to strain. Determine the yield strength by the 0.2 % offset
in the design and engineering of tire beads because of its effect
elongation method.
on uniformity and dimensional stability during service.
10.9.1 On the force-extension curve (Fig. 1) that has been
generated (see 10.6) mark off Om equal to the specified value
9. Apparatus
of the offset (0.2 % elongation); draw mn parallel to OA and
9.1 Tensile Testing Machine, CRE (Constant-Rate-of-
locate r.This intersection of mn with the force-extension curve
Extension) tensile testing machine of such capacity that the
corresponds to force R which is the yield strength. Should the
maximum force required to fracture the wire shall not exceed
force-extension curve exhibit an initial nonlinear portion,
90 % nor be of less than 10 % of the selected force measure-
extrapolate from the straight line portion to the base line. The
ment range. The specifications and methods of calibration and
intersection is point O used in this section.
verification for tensile testing machines shall conform to
Specification D76.
11. Calculation
9.2 In some laboratories, the output of CRE type of tensile
testing machine is connected with electronic recording and 11.1 Calculate the average breaking force of the laboratory
computing equipment which may be programmed to calculate sample to the nearest 5 N.
D4975–04 (2010)
13.2 Precision—For the property of interest, two averages
of observed values should be considered significantly different
at the 95 % probability level if the difference equals or exceeds
the critical differences given in Table 1.
NOTE 3—The tabulated values of the critical differences should be
considered to be a general statement, particularly with respect to between
laboratory precision. Before a meaningful statement can be made con-
cerning any two specific laboratories, the amount of statistical bias, if any,
between them must be established, with each comparison being based on
recent data obtained on specimens taken from a lot of material of the type
being evaluated so as to be as nearly homogeneous as possible and then
assigned randomly in equal numbers to each of the laboratories.
13.3 Bias—The procedures in this test method for measur-
ing breaking force, elongation, and yield strength have no
known bias because the value of these properties can be
defined only in terms of a test method.
TORSION RESISTANCE
FIG. 1 Force-Extension Curve for Determination of Yield
14. Summary of Test Method
Strength by the Offset Method
14.1 A single-filament of wire is tested in torsion by either
holding one end of the wire fixed while rotating the other or by
11.2 Calculate the elongation to break from the force-
rotating both ends in opposite directions at the same time until
extension curve to the nearest 0.1 %. Should the force-
fracture occurs.
extension curve exhibit an initial nonlinear portion, extrapolate
15. Significance and Use
from the straight line portion of the curve to the base line. This
intersection is the point of origin for the elongation determi-
15.1 Complex stress and strain conditions, sensitive to
nation. The extension from this point to the force at the point
variations in materials, occur in a wire specimen during torsion
of break is the total elongation.
testing. The torsion test is a useful tool in assessing wire
11.3 Calculate the average yield strength of each laboratory
ductility under torsional loading. Defective wire lowers torsion
sample as directed in 10.9.1 to the nearest 5 N.
resistance.
12. Report
16. Apparatus
12.1 State that the tests were performed as directed in Test
16.1 Torsion Test Machine, an automated drive apparatus
Methods D4975, describe the material or product tested, and
that allows a single-filament wire under light tension to be
report the following:
tested in torsion. A counter is provided that registers the
12.1.1 The test results of each specimen and the laboratory
number of wire rotations to wire fracture.
sample average. Calculate and report any other data agreed to
between the purchaser and the supplier,
17. Procedure
12.1.2 Date of test,
17.1 Thermally age the specimen by placing it in a suitable
12.1.3 Type of tensile test machine and rate of extension,
oven for 60 6 1 min. at 150 6 3°C. Allow specimens to cool
and
to room temperature before testing.
12.1.4 Any deviation from the standard test procedure.
17.2 Cut the test specimen to the appropriate length so that
a gage length of 200 mm between chuck or jaw edges is
13. Precision and Bias
obtained.
13.1 Interlaboratory Test Data—Aninterlaboratorytestwas
17.3 Certain test equipment requires that a 90° bend be put
run in 1990 in which randomly drawn samples of four
in each end of the test specimen; if that is required, measure
materials were tested in 13 laboratories. Each laboratory used
approximately 25 mm from each end and bend the wire 90°
two operators, each of whom tested two specimens of each
with both bends in the same direction.
material on two separate days.
17.4 Placethespecimenintheclampingfixturesandtighten
the jaws while keeping the wire in a straight alignment. A
NOTE 2—The bead wire products used in the interlaboratory evaluation
pretension 25 6 5 N shall be applied to the specimen in the
were of the following diameter and strength levels:
longitudinal direction to aid in keeping the wire straight during
TABLE
testing.
Material Diameter Strength 17.5 Set the rotation counter to zero.
17.6 Start the equipment and run until the specimen frac-
1 0.965 mm regular
tures. For wire sizes below 1.40 mm, use a rotation speed of 60
2 0.965 mm high
3 1.295 mm regular 6 15 r/min. For wire sizes greater than 1.40 mm, use a rotation
4 1.295 mm high
speed of 45 6 15 r/min.
D4975–04 (2010)
TABLE 1 Critical Differences for Conditions Noted
Number of Within-Laboratory
Name of Property Single Operator Precision Between-Laboratory Precisi
...
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