1、 Standard Specification for Uncoated Stress-Relieved Steel Wire for Prestressed Concrete AASHTO Designation: M 204M/M 204-141ASTM Designation: A421/A421M-10 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-4g M 204M
2、/M 204-1 AASHTO Standard Specification for Uncoated Stress-Relieved Steel Wire for Prestressed Concrete AASHTO Designation: M 204M/M 204-141ASTM Designation: A421/A421M-10 1. SCOPE 1.1. This specification covers two types of uncoated stress-relieved, round, high-carbon steel wire commonly used in pr
3、estressed 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 applications in which the ends are anchored by wedges, and no cold-end deformation of
4、the wire is involved (Wedge Anchorage). 1.2. Supplement 1 describes low-relaxation wire and relaxation testing for that product. 1.3. This specification is applicable for orders in either SI units (M 204M) or in inch-pound units (M 204). SI units and inch-pound units are not necessarily equivalent.
5、Inch-pound units are shown in brackets in the text for clarity, but they are the applicable values when the material is ordered to M 204. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standard: T 244, Mechanical Testing of Steel Products 2.2. ASTM Standards: A751, Standard Test Methods, Practices, and Termino
6、logy for Chemical Analysis of Steel Products E328, Standard Test Methods for Stress Relaxation Tests for Materials and Structures 2.3. IEEE/ASTM Standard: SI 10, American National Standard for Metric Practice 2.4. Military Standards: MIL-STD-129, Marking for Shipment and Storage 2.5. Federal Standar
7、d: Fed. Std. No. 123, Marking for Shipments (Civil Agencies) 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4g M 204M/M 204-2 AASHTO 3. ORDERING INFORMATION 3.1. It shall be the responsibility of the
8、 purchaser to specify all requirements that are necessary for material ordered to this specification. Such requirements shall include, but are not limited to, the following: 3.1.1. Quantity (kg) lb; 3.1.2. Diameter; 3.1.3. Type of anchorage (BA or WA); 3.1.4. Packaging; 3.1.5. AASHTO designation and
9、 date of issue; and 3.1.6. Special requirements, if any. Note 1A typical ordering description is as follows: 10,000-kg, 6.35-mm-diameter wire, Type BA in approximately 450-kg, 1.5-m-diameter coils, to M 204M-_. 22,000-lb, 0.250-in.-diameter wire, Type BA in approximately 1000-lb, 60-in.-diameter coi
10、ls, to M 204-_. 4. MANUFACTURE 4.1. ProcessThe steel shall be made by the basic-oxygen, open-hearth, or electric-furnace process. 4.2. Internal SoundnessA sufficient discard shall be made to ensure freedom from injurious piping and undue segregation. 4.3. WireThe wire shall be cold-drawn to size and
11、 suitably stress relieved after cold drawing by a continuous heat treatment to produce the prescribed mechanical properties. 5. PHYSICAL REQUIREMENTS 5.1. Tensile StrengthThe tensile strength of Type BA wire and Type WA wire shall conform to the requirements prescribed in Table 1 and shall be determ
12、ined as prescribed in T 244. Table 1Tensile Strength Requirements Nominal Diameter, mm in. Minimum Tensile Strength, MPa psi Type BA Type WA 4.88 0.192 a 1725 250,000 4.98 0.196 1655 240,000 1725 250,000 6.35 0.250 1655 240,000 1655 240,000 7.01 0.276 1620 235,000 1620 235,000 aThis size is not comm
13、only furnished in Type BA wire. 5.2. Yield Strength: 5.2.1. The minimum yield strength for all wire, measured by the 1 percent extension under load method, shall not be less than 85 percent of the specified minimum tensile strength. 5.2.2. The extension under load shall be measured by an extensomete
14、r calibrated with the smallest division not larger than 0.0001 mm/mm 0.0001 in./in. of gauge length. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4g M 204M/M 204-3 AASHTO 5.2.3. The initial load co
15、rresponding to the initial stress prescribed in Table 2 shall be applied to the specimen, at which time the extensometer is attached and adjusted to a reading of 0.001 mm/mm 0.001 in./in. of gauge length. The load shall then be increased until the extensometer indicates an extension of 1 percent. Th
16、e load for this extension shall be recorded. The stress corresponding to this load shall meet the requirements for stress at 1 percent extension prescribed in Table 2. Table 2Yield Strength Requirements Nominal Diameter, mm in. Initial Stress, MPa psi Minimum Stress at 1% Extension, MPa psi Type BA
17、Type WA 4.88 0.192 200 29,000 a 1465 212,500 4.98 0.196 200 29,000 1407 204,000 1465 212,500 6.35 0.250 200 29,000 1407 204,000 1407 204,000 7.01 0.276 200 29,000 1377 199,750 1377 199,750 aThis size is not commonly furnished in Type BA wire. 5.3. ElongationThe total elongation under load of all wir
18、e shall not be less than 4 percent when measured in a gauge length of 250 mm 10 in. The elongation shall be determined by an extensometer which is placed on the test specimen after a load corresponding to the initial stress prescribed in Table 2 is applied. If the fracture takes place outside of the
19、 gauge length and the elongation so measured meets the minimum requirements, no further testing shall be required. If the elongation is less than the minimum requirements, the test shall be considered an invalid test and a retest made. 6. DIAMETER AND PERMISSIBLE VARIATIONS 6.1. Wire meeting the req
20、uirements of this specification is normally ordered in the diameters shown in Table 1. 6.2. The diameter of the wire shall not vary from the nominal diameter specified by more than 0.05 mm 0.002 in. 6.3. The wire shall not be out-of-round by more than 0.05 mm 0.002 in. 7. WORKMANSHIP AND FINISH 7.1.
21、 CastA wire sample having a chord length of 1524 mm 60 in. shall have an offset at the center of the chord of not more than 76 mm 3 in. This is equivalent to a chord of an arc of a circle not less than 7.6 m 25 ft in diameter. 7.2. Type BA WireType BA wire shall be of suitable quality to permit cold
22、 forming of buttons for anchorage. Splitting shall not be considered a cause for rejection if the button anchorage is capable of developing the minimum required tensile strength of the wire. 7.3. The wire shall be free of kinks. 7.4. The wire shall be furnished in firmly tied coils having a minimum
23、inside diameter of 1219 mm 48 in. Each coil shall be of one continuous length. 7.5. There shall be no welds or joints in the finished wire. Any welds or joints made during manufacture to promote continuity of operations shall be removed. 2015 by the American Association of State Highway and Transpor
24、tation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4g M 204M/M 204-4 AASHTO 7.6. The wire shall not be oiled or greased. Slight rusting, provided it is not sufficient to cause pits visible to a person with normal or corrected vision, shall not be cause for rejectio
25、n. 7.7. Temper colors, which may result from the stress-relieving operations, are considered normal for the finished appearance of this strand. 8. CHEMICAL REQUIREMENTS 8.1. Variations in manufacturing processes and equipment among wire manufacturers necessitate the individual selection of an approp
26、riate chemical composition at the discretion of the manufacturer. 8.2. Phosphorus and sulfur values shall not exceed the following: Phosphorus 0.040% Sulfur 0.050% 8.3. The purchaser shall have the right to make an analysis from finished wire representing each heat of steel. Samples for analysis sha
27、ll be obtained by milling the wire in such a manner as to obtain a sample representative of the entire cross section. Prior to milling, the surface shall be cleaned to remove all foreign matter. All such individual determinations shall not vary from the limits shown in Section 8.2 by more than 0.008
28、 percent. 8.4. For referee purposes, ASTM A751 shall be applied. 9. SAMPLING 9.1. Unless otherwise agreed upon between the manufacturer and the purchaser, one test specimen shall be taken from each of ten or fewer coils in a lot (Note 2) and tested to determine compliance with Sections 5.1, 5.2, 5.3
29、, 6, and 7.1. Note 2The term “lot” means all the coils of wire of the same nominal wire size contained in an individual shipping release or shipping order. 10. INSPECTION 10.1. The purchaser shall state at the time of order whether outside inspection is required or waived. If outside inspection is r
30、equired, the manufacturer shall afford the inspector representing the purchaser all reasonable facilities to satisfy him or her that the material is being furnished in accordance with this specification. All tests and inspections shall be made at the place of manufacture prior to shipment, unless ot
31、herwise agreed upon at the time of purchase, and shall be so conducted as not to interfere unnecessarily with the operation of the work. 11. REJECTION 11.1. Unless otherwise specified, any rejection based on tests made in accordance with this specification shall be reported to the manufacturer withi
32、n a reasonable length of time. 12. CERTIFICATION 12.1. If outside inspection is waived, a manufacturers certification that the material has been tested in accordance with and meets the requirements of this specification shall be the basis of acceptance of the material. 2015 by the American Associati
33、on of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4g M 204M/M 204-5 AASHTO 12.2. A material test report, certificate of inspection, or similar document printed from or used in electronic form from an electronic data interchange (EDI
34、) transmission shall be regarded as having the same validity as a counterpart printed in the certifiers facility. The content of the EDI-transmitted document must meet the requirements of the invoked AASHTO standard(s) and conform to any existing EDI agreement between the purchaser and the supplier.
35、 Notwithstanding the absence of a signature, the organization submitting the EDI transmission is responsible for the content of the report. Note 3The industry definition as invoked here is: EDI is the computer-to-computer exchange of business information in a standard format such as ANSI ASC X12. 13
36、. PACKAGING AND MARKING 13.1. The size of the wire, AASHTO specification number, heat number, type of wire, and name or mark of the manufacturer shall be marked on a tag securely attached to each bundle of wire. 13.2. For Government Procurement OnlyWhen specified in the contract or order, and for di
37、rect procurement by or direct shipment to the government, marking for shipment shall be in accordance with Fed. Std. No. 123 for civil agencies and MIL-STD-129 for military agencies. 14. KEYWORDS 14.1. Cold-drawn wire; prestressed concrete; steel wire (tendon); stress-relieved wire. SUPPLEMENTARY RE
38、QUIREMENTSLOW-RELAXATION WIRE S1. SCOPE S1.1. This supplement delineates only those details that are peculiar to low-relaxation wire and to the method of relaxation testing related to single wire tendons having properties generally as described in M 204M/M 204. S2. REFERENCED DOCUMENTS S2.1. ASTM St
39、andard: E328, Standard Test Methods for Stress Relaxation Tests for Materials and Structures S3. TEST METHOD S3.1. Low-relaxation strand shall be tested as prescribed in ASTM E328. S4. RELAXATION PROPERTIES S4.1. Low-relaxation wire shall meet the physical requirements of this specification, with th
40、e added requirement that relaxation after 1000 hours under the conditions of Section S6 shall not be more than 2.5 percent when initially loaded to 70 percent of specified minimum tensile strength or not more than 3.5 percent when loaded to 80 percent of specified minimum tensile strength of the wir
41、e. S5. YIELD STRENGTH S5.1. Yield strength of low-relaxation wire as described in Section 5.2 shall not be less than 90 percent of the specified minimum tensile strength of the wire. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a
42、violation of applicable law.TS-4g M 204M/M 204-6 AASHTO S6. CONDITIONS OF RELAXATION TEST S6.1. If required, relaxation evidence shall be provided from the manufacturers records of tests on similarly dimensioned wire of the same grade. S6.2. The temperature of the test specimen shall be maintained a
43、t 20 2C 68 3.5F. S6.3. The test specimen shall not be subjected to any loading prior to relaxation test. S6.4. The initial load shall be applied uniformly over a period of not less than 180 s and not more than 300 s, and the gauge length shall be maintained constant; load-relaxation readings shall c
44、ommence 60 s after application of the total load. S6.5. Overstressing of the test specimen during the loading operation shall not be permitted. S6.6. The duration of the test shall be 1000 h or a shorter computed period extrapolated to 1000 h that can be shown by records to provide similar relaxatio
45、n values. S6.7. The test gauge length shall be at least 60 times the nominal diameter. 1Agrees technically with ASTM A421/A421M-10 except for minor differences in wording. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
