ASTM A931-96
(Test Method)Standard Test Method for Tension Testing of Wire Ropes and Strand
Standard Test Method for Tension Testing of Wire Ropes and Strand
SCOPE
1.1 This test method covers the tension testing of wire ropes and strand at room temperature, specifically to determine the minimum acceptance strength or nominal strength, yield strength, elongation, and modulus of elasticity.
1.2 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are for information only.
1.3 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. Specific precautionary statements are given in Note 1, Note 2, Note 3, and Note 5.
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An American National Standard
Designation: A 931 – 96
Standard Test Method for
Tension Testing of Wire Ropes and Strand
This standard is issued under the fixed designation A 931; 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 3.2.3 aggregate strength—the strength derived by totalling
the individual breaking strengths of the elements of the strand
1.1 This test method covers the tension testing of wire ropes
or rope. This strength does not give recognition to the
and strand at room temperature, specifically to determine the
reduction in strength resulting from the angularity of the
minimum acceptance strength or nominal strength, yield
elements in the rope, or other factors that may affect efficiency.
strength, elongation, and modulus of elasticity.
3.2.4 area, metallic—sum of the cross-sectional areas of all
1.2 The values stated in inch-pound units are to be regarded
wires either in a wire rope or in a strand.
as the standard. The SI units given in parentheses are for
3.2.5 breaking strength—the ultimate load at which a tensile
information only.
failure occurs in the sample of wire rope being tested.
1.3 This standard does not purport to address all of the
3.2.6 Discussion—The term breaking strength is synony-
safety concerns, if any, associated with its use. It is the
mous with actual strength.
responsibility of the user of this standard to establish appro-
3.2.7 cable—a term loosely applied to wire rope, wire
priate safety and health practices and determine the applica-
strand, and electrical conductors.
bility of regulatory limitations prior to use. Specific precau-
3.2.8 center—the axial member of a strand about which the
tionary statements are given in Note 1, Note 2, Note 3, and
wires are laid.
Note 5.
3.2.9 classification—group or family designation based on
2. Referenced Documents
wire rope constructions with common strengths and weights
listed under the broad designation.
2.1 ASTM Standards:
3.2.10 construction—geometric design description of the
A 586 Specification for Zinc-Coated Parallel and Helical
wire rope’s cross section. This includes the number of strands,
Steel Wire Structural Strand
the number of wires per strand, and the pattern of wire
A 603 Specification for Zinc-Coated Steel Structural Wire
arrangement in each strand.
Rope
3.2.11 core—the axial member of a wire rope about which
B 6 Specification for Zinc
the strands are laid.
E 4 Practices for Force Verification of Test Machines
3.2.12 fiber core—cord or rope of vegetable or synthetic
E 6 Terminology Relating to Methods of Mechanical Test-
fiber used as the core of a rope.
ing
3.2.13 galvanized rope—wire rope made up of galvanized
E 8 Test Methods for Tension Testing of Metallic Materials
wire.
3. Terminology
3.2.14 galvanized strand—strand made up of galvanized
wire.
3.1 The terminology relating to tensile testing in Terminol-
3.2.15 grade—wire rope or strand classification by strength
ogy E 6 applies to this test method. In addition, the following
or type of material, that is, Class 3, Type 302 stainless,
definitions for wire rope will apply:
phosphor bronze, etc. It does not apply to strength of the
3.2 Definitions:
individual wires used to manufacture the rope or strand.
3.2.1 abrasion—frictional surface wear on the wires of a
3.2.16 independent wire rope core (IWRC)—a wire rope
wire rope.
used as the core of a larger wire rope.
3.2.2 aggregate area—see area, metallic.
3.2.17 inner wires—all wires of a strand except the outer or
cover wires.
3.2.18 lay—(a) the manner in which the wires in a strand or
This test method is under the jurisdiction of ASTM Committee A-1 on Steel,
the strands in a rope are helically laid, or (b) the distance
Stainless Steel, and Related Alloys and is the direct responsibility of Subcommittee
A01.03 on Steel Rod and Wire. measured parallel to the axis of the rope (or strand) in which a
Current edition approved March 10, 1996. Published May 1996. Originally
strand (or wire) makes one complete helical convolution about
published as A 931 – 94. Last previous edition A 931 – 94.
the core (or center). In this connection, lay is also referred to as
Annual Book of ASTM Standards, Vol 01.06.
lay length or pitch.
Annual Book of ASTM Standards, Vol 02.04.
Annual Book of ASTM Standards, Vol 03.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
A 931
3.2.19 minimum acceptance strength—that strength that is 2 length of the test specimen shall be at least 20 times the rope
1 2 % lower than the catalog or nominal strength. This diameter.
/
tolerance is used to offset variables that occur during sample
6. Apparatus
preparation and actual physical test of a wire rope.
6.1 Testing Machines—Machines used for tension testing
3.2.20 modulus of elasticity—the slope of the elastic portion
shall conform to the requirements of Practices E 4. The loads
of the stress-strain curve. The ratio of stress to corresponding
used in determining tensile strength and yield strength shall be
strain below the proportional limit. This value is generally
within loading range of the tensile machine as defined in
taken between 20 and 50 % of the nominal strength.
Practices E 4.
3.2.21 nominal strength—the published (catalog) strength
6.2 Gripping Devices:
calculated by a standard procedure that is accepted by the wire
6.2.1 General—Various types of gripping devices may be
rope industry. The wire rope manufacturer designs wire rope to
used to transmit the measured load applied by the testing
this strength, and the user should consider this strength when
machine to test specimens. To ensure axial tensile stress within
making design calculations.
the gage length, the axis of the test specimen should coincide
3.2.22 socket—generic name for a type of wire rope fitting.
with the center line of the heads of the machine. Any departure
3.2.23 strand—a plurality of round or shaped wires heli-
from this requirement may introduce bending stresses that are
cally laid about a center.
not included in the usual stress computation.
3.2.24 wire rope—strands helically laid around a core.
6.2.2 Wedge Grips—Testing machines usually are equipped
3.2.25 wire strand core (WSC)—a wire strand used as the
with wedge grips. These wedge grips generally furnish a
core of a wire rope.
satisfactory means of gripping long specimens of ductile metal.
If, however, for any reason, one grip of a pair advances farther
4. Significance and Use
than the other as the grips tighten, an undesirable bending
4.1 Wire rope tests are generally to be performed on new
stress may be introduced. When liners are used behind the
rope. The use of wire rope in any application can reduce
wedges, they must be of the same thickness and their faces
individual wire strengths due to abrasion and nicking that will
must be flat and parallel. For best results, the wedges should be
result in the wire rope strength being reduced. Damage to the
supported over their entire lengths by the heads of the testing
outer wires will also lower the maximum strength achieved
machine. This requires that liners of several thicknesses be
during tension testing.
available to cover the range of specimen thickness. For proper
4.2 The modulus of elasticity of wire rope is not considered
gripping, it is desirable that the entire length of the serrated
to be a standard requirement at this time. The determination of
face of each wedge be in contact with the specimen. Specially-
this material property requires specialized equipment and
designed round-shaped grips may have to be used for testing
techniques.
rope or strand. It is essential that all wires in the rope or strand
4.3 Rope to be tested should be thoroughly examined to
are uniformly gripped when the load is applied.
verify that no external wire damage is present. If present, it
6.2.3 Conical Grips—Conical grips are constructed so that
should be noted. When possible, a new undamaged sample
when they are fitted together, a conical-shaped cavity exists
should be obtained for testing.
which will hold a cone socket wire rope or strand and
4.4 End attachments and their installation can directly affect
attachment (fitting).
breaking strength achieved during testing. Any attachment that
can be used to directly achieve the required rope breaking 7. Sample Preparation and Preparation of End
strength can be used. Standard testing with a poured socket,
Attachments
using zinc, white metal or thermoset resin, has been considered
7.1 Poured sockets are considered to be the most efficient
the most efficient. Proficiency in attachment of any fitting can
and should be used due to their ability to distribute the load
have a direct effect on the final test results.
evenly in the wire rope when installed properly. Procedures for
the proper installation of poured end attachments can be found
5. Interferences
in socketing procedures.
5.1 Visual examination of the sample for any damage to
7.2 Other end attachments such as grips may be used
outer wires should be done. If any damage is evident, the
provided the required loading is achieved.
sample should not be used. The purpose of this test method is
7.3 Sample Preparation Procedures: —
to verify the nominal or maximum strength the wire rope or
7.3.1 Socketing
strand can achieve.
Zinc-Poured Socketing:
5.2 Measurement of the rope or strand sample is necessary 7.3.1.1 Measuring the Rope Ends to be Socketed—The rope
to document the size, length between end attachments, and end should be of sufficient length so that the ends of the unlaid
length of lay of the rope if necessary. Further details regarding wires (from the strands) will be at the top of the socket basket
this will be discussed in test results. (see Fig. 1(a)).
5.3 The length of test specimen shall not be less than 3 ft, 7.3.1.2 Apply Serving at Base of Socket—Apply a tight wire
(0.91 m) between sockets for wire ropes up to 1 in. (25.4 mm) serving band at the point where the socket base will be for a
di
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