ASTM A421/A421M-98a
(Specification)Standard Specification for Uncoated Stress-Relieved Steel Wire for Prestressed Concrete
Standard Specification for Uncoated Stress-Relieved Steel Wire for Prestressed Concrete
SCOPE
1.1 This specification covers two types of uncoated stress-relieved round high-carbon steel wire commonly used in prestressed linear concrete construction, as follows:
1.1.1 Type BA wire is used for applications in which cold-end deformation is used for anchoring purposes (Button Anchorage), and
1.1.2 Type WA wire is used for application in which the ends are anchored by wedges, and no cold-end deformation of the wire is involved (Wedge Anchorage).
1.2 Supplement I describes low relaxation wire and relaxation testing for that product.
1.3 The values stated in inch-pound units are to be regarded as the standard.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.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.
American Association State
Designation: A 421/A 421M – 98a Highway and Transportation Officials Standard
AASHTO No.: M 204
Standard Specification for
Uncoated Stress-Relieved Steel Wire for Prestressed
Concrete
This standard is issued under the fixed designation A 421/A 421M; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 2.3 Federal Standard:
Fed. Std. No. 123 Marking for Shipments (Civil Agencies)
1.1 This specification covers two types of uncoated stress-
relieved round high-carbon steel wire commonly used in
3. Ordering Information
prestressed linear concrete construction, as follows:
3.1 Orders for stress-relieved wire under this specification
1.1.1 Type BA wire is used for applications in which cold-
should include the following information:
end deformation is used for anchoring purposes (Button
3.1.1 Quantity (kg [lb]),
Anchorage), and
3.1.2 Diameter,
1.1.2 Type WA wire is used for application in which the
3.1.3 Type of anchorage (BA or WA),
ends are anchored by wedges, and no cold-end deformation of
3.1.4 Packaging,
the wire is involved (Wedge Anchorage).
3.1.5 ASTM designation and date of issue, and
1.2 Supplement I describes low relaxation wire and relax-
3.1.6 Special requirements, if any.
ation testing for that product.
1.3 The values stated in either inch-pound or SI units are to
NOTE 1—A typical ordering description is as follows: 10 000 kg of
be regarded as standard. Within the text, the inch-pound units 6.35-mm diameter wire, Type BA in approximately 450 kg 1.5-m diameter
coils to ASTM A 421/A 421M– _______(22 000 lb 0.250-in. diameter
are shown in parentheses. The values stated in each system are
wire, Type BA in approximately 1000 lb 60-in. diameter coils to ASTM
not exact equivalents; therefore, each system shall be used
A 421/A 421M–_______).
independently of the other, without combining values in any
way.
4. Manufacture
4.1 Process—The steel shall be made by the basic-oxygen,
2. Referenced Documents
open-hearth, or electric-furnace process.
2.1 ASTM Standards:
4.2 Internal Soundness—A sufficient discard shall be made
A 370 Test Methods and Definitions for Mechanical Testing
to ensure freedom from injurious piping and undue segrega-
of Steel Products
tion.
E 30 Test Methods for Chemical Analysis of Steel, Cast
4.3 Wire—The wire shall be cold-drawn to size and suitably
Iron, Open-Hearth Iron, and Wrought Iron
stress relieved after cold drawing by a continuous heat treat-
E 328 Methods for Stess Relaxation Tests for Materials and
ment to produce the prescribed mechanical properties.
Structures
2.2 Military Standards:
5. Physical Requirements
MIL-STD-129 Marking for Shipment and Storage
5.1 Tensile Strength—The tensile strength of Type BA wire
MIL-STD-163 Steel Mill Products, Preparation for Ship-
and Type WA wire shall conform to the requirements pre-
ment and Storage
scribed in Table 1, and shall be determined as prescribed in
Test Methods and Definitions A 370, including Annex A4.
5.2 Yield Strength:
This specification is under the jurisdiction of ASTM Committee A-1 on Steel,
Stainless Steel and Related Alloys, and is the direct responsibility of Subcommittee 5.2.1 The minimum yield strength for all wire, measured by
A01.05 on Steel Reinforcement.
the 1.0 % extension under load method, shall not be less than
Current edition approved Sept. 10, 1998. Published December 1998. Originally
85 % of the specified minimum breaking strength.
published as A 421 – 58 T. Last previous edition A 421 – 98.
5.2.2 The extension under load shall be measured by an
Annual Book of ASTM Standards, Vol 01.03.
Discontinued. See 1995 Annual Book of ASTM Standards, Vol 03.05.
extensometer calibrated with the smallest division not larger
Annual Book of ASTM Standards, Vol 03.01.
than 0.0001 mm/mm (0.0001 in./in.) of gage length.
Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, 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.
A 421/A 421M – 98a
TABLE 1 Tensile Strength Requirements
7.4 The wire shall be furnished in firmly tied coils having a
Tensile Strength, min, MPa (psi) minimum inside diameter of 1219 mm (48 in.). Each coil shall
Nominal Diameter, mm
(in.) be of one continuous length.
Type BA Type WA
A 7.5 There shall be no welds or joints in the finished wire.
4.88 (0.192) 1725 (250 000)
Any welds or joints made during manufacture to promote
4.98 (0.196) 1655 (240 000) 1725 (250 000)
6.35 (0.250) 1655 (240 000) 1655 (240 000)
continuity of operations shall be removed.
7.01 (0.276) 1620 (235 000) 1620 (235 000)
7.6 The wire shall not be oiled or greased. Slight rusting,
A
This size is not commonly furnished in Type BA wire.
provided it is not sufficient to cause pits visible to the naked
eye, shall not be cause for rejection.
7.7 Temper colors which result from the stress-relieving
5.2.3 The initial load corresponding to the initial stress
operation are considered normal for the finished appearance of
prescribed in Table 2 shall be applied to the specimen, at which
this strand.
time the extensometer is attached and adjusted to a reading of
0.001 mm/mm (0.001 in./in.) of gage length. The load shall
8. Chemical Requirements
then be increased until the extensometer indicates an extension
8.1 Variations in manufacturing processes and equipment
of 1 %. The load for this extension shall be recorded. The stress
among wire manufacturers necessitate the individual selection
corresponding to this load shall meet the requirements for
of an appropriate chemical composition at the discretion of the
stress at 1 % extension prescribed in Table 2.
manufacturer.
5.3 Elongation—The total elongation under load of all wire
8.2 Phosphorus and sulfur values shall not exceed the
shall not be less than 4.0 % when measured in a gage length of
following:
250 mm (10 in.). The elongation shall be determined by an
Phosphorus 0.040%
extensometer which is placed on the test specimen after a load
Sulfur 0.050%
corresponding to the initial stress prescribed in Table 2 is
applied. If the fracture takes place outside of the gage length,
8.3 An analysis may be made by the purchaser from finished
the elongation value obtained may not be representative of the
wire representing each heat of steel. Samples for analysis shall
material. If the elongation so measured meets the minimum
be obtained by milling the wire in such a manner as to obtain
requirements specified, no further testing is indicated; but if the
a sample representative of the entire cross section. Prior to
elongation is less tha
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