1、Standard Specification for Structural Steel for Bridges AASHTO Designation: M 270M/M 270-15 ASTM Designation: A709/A709M-13a American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-4f M 270M/M 270-1 AASHTO Standard Specifi
2、cation for Structural Steel for Bridges AASHTO Designation: M 270M/M 270-15 ASTM Designation: A709/A709M-13a 1. SCOPE 1.1. This specification covers carbon and high-strength low-alloy steel structural shapes, plates, and bars and quenched and tempered alloy steel for structural plates intended for u
3、se in bridges. Seven grades are available in four yield strength levels as follows: Table 1Yield Strength Levels Grade SI U.S. Yield Strength, MPa ksi 250 36 250 36 345 50 345 50 345S 50S 345 50 345W 50W 345 50 HPS 345W HPS 50W 345 50 HPS 485W HPS 70W 485 70 HPS 690W HPS 100W 690 100 1.1.1. Grades 2
4、50 36, 345 50, 345S 50S, or 345W 50W are also included in ASTM A36/A36M, A572/A572M, A992/A992M, A588/A588M, and A514/A514M. When the supplementary requirements of this specification are specified, they exceed the requirements of A36/A36M, A572/A572M, A992/A992M, A588/A588M, and A514/A514M. 1.1.2. G
5、rades 345W 50W, HPS 345W HPS 50W, HPS 485W HPS 70W, and HPS 690W HPS 100W have enhanced atmospheric corrosion resistance (Section 13.1.2). Product availability is shown in Table 2. 1.2. Grade HPS 485W HPS 70W or HPS 690W HPS 100W shall not be substituted for Grade 250 36, 345 50, 345S 50S, 345W 50W,
6、 or HPS 345W HPS 50W. Grade 345W 50W or HPS 345W HPS 50W shall not be substituted for Grade 250 36, 345 50, or 345S 50S without agreement between the purchaser and supplier. 1.3. When the steel is to be welded, it is presupposed that a welding procedure suitable for the grade of steel and intended u
7、se or service will be utilized. See Appendix X3 of ASTM A6/A6M for information on weldability. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.Table 2Tensile and Hardness Requirementsa Grade Plate Thick-
8、 ness, mm in. Structural Shape Flange or Leg Thickness, mm in. Yield Point or Yield Strength,bMPa ksi Tensile Strength, MPa ksi Minimum Elongation, % Reduction of Areac,dMin, % Plates and Bars c,eShapese200 mm or 8 in. 50 mm or 2 in. 200 mm or 8 in. 50 mm or 2 in. 250 36 To 100 4, incl to 75 3, incl
9、 250 36 min 400550 5880 20 23 20 21 over 75 3. 250 36 min 400 58 min 20 19 345 50 To 100 4, incl All 345 50 min 450 65 min 18 21 18 21f 345S 50S g All 345450 5065h,i450 65 h 18 21 345W 50W and HPS 345W HPS 50W To 100 4, incl All 345 50 min 485 70 min 18 21 18 21j HPS 485W HPS 70W To 100 4, incl g 48
10、5 70bmin 585760 85110 19k HPS 690W HPS 100W To 65 21/2, incl g 690 100bmin 760895 110130 18k l over 65 to 100 21/2to 4mg 620 90b690895 100130 16k l aSee “Orientation” and “Preparation” under “Tension Tests” in ASTM A6/A6M. bMeasure at 0.2 percent offset or 0.5 percent extension under load as describ
11、ed in Section 13 of T 244. c Elongation and reduction of area not required to be determined for floor plates. dFor plates wider than 600 mm 24 in., the reduction of area requirement, where applicable, is reduced five percentage points. eFor plates wider than 600 mm 24 in., the elongation requirement
12、 is reduced two percentage points. See elongation requirement adjustments under the Tension Tests section of ASTM A6/A6M. fElongation in 50 mm 2 in., 19 percent minimum for shapes with flange thickness over 75 mm 3 in. gNot applicable. h The yield-to-tensile ratio shall be 0.87 or less for shapes th
13、at are tested from the web location; for all other shapes, the requirement is 0.85. iA maximum yield strength of 70 ksi 480 MPa is permitted for structural shapes that are required to be tested from the web location. j For wide flange shapes with flange thickness greater than 75 mm 3 in., elongation
14、 in 50 mm 2 in. of 18 percent minimum applies. k If measured on the Figure 3 (T 244) 40-mm 11/2-in. wide specimen, the elongation is determined in a 50-mm 2-in. gauge length that includes the fracture and shows the greatest elongation. l40 percent minimum applies if measured on the Figure 3 (T 244)
15、40-mm 11/2-in. wide specimen, 50 percent minimum applies if measured on the Figure 4 (T 244) 12.5-mm 1/2-in. round specimen. mNot applicable to fracture critical Tension Components. (See Table 10.) Note: Where “” appears in this table, there is no requirement. TS-4fM 270M/M 270-2AASHTO 2015 by the A
16、merican Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4f M 270M/M 270-3 AASHTO 1.4. For structural products to be used as tension components requiring notch toughness testing, standardized requirements are provided in t
17、his standard. These requirements are based upon American Association of State Highway and Transportation Officials (AASHTO) requirements for both fracture-critical and non-fracture-critical members. 1.5. Supplementary requirements are available but shall apply only if specified in the purchase order
18、. 1.6. The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system is to be used independently of the other, without
19、 combining values in any way. 1.7. For structural products cut from coiled product and furnished without heat treatment or with stress relieving only, the additional requirements of ASTM A6/A6M, including additional testing requirements and the reporting of additional tests, apply. 2. REFERENCED DOC
20、UMENTS 2.1. AASHTO Standards: T 243M/T 243, Sampling Procedure for Impact Testing of Structural Steel T 244, Mechanical Testing of Steel Products 2.2. ASTM Standards: A6/A6M, Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling A36/A36M,
21、Standard Specification for Carbon Structural Steel A514/A514M, Standard Specification for High-Yield-Strength, Quenched and Tempered Alloy Steel Plate, Suitable for Welding A572/A572M, Standard Specification for High-Strength Low-Alloy Columbium-Vanadium Structural Steel A588/A588M, Standard Specifi
22、cation for High-Strength Low-Alloy Structural Steel, up to 50 ksi 345 MPa Minimum Yield Point, with Atmospheric Corrosion Resistance A992/A992M, Standard Specification for Structural Steel Shapes G101, Standard Guide for Estimating the Atmospheric Corrosion Resistance of Low-Alloy Steels 3. TERMINOL
23、OGY 3.1. Definitions of Terms Specific to This Standard: 3.1.1. fracture-critical membera main loadcarrying member or tension component of a bending member the failure of which would be expected to cause collapse of a structure or bridge without multiple, redundant load paths. 3.1.2. main loadcarryi
24、ng membera steel member designed to carry primary design loads, including dead, live, impact, and other loads. 3.1.3. non-fracture-critical membera main loadcarrying member the failure of which would not be expected to cause collapse of a structure or bridge with multiple, redundant load paths. 2015
25、 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4f M 270M/M 270-4 AASHTO 3.1.4. nontension componenta steel member that is not in tension under any design loading. 3.1.5. secondary membera steel member us
26、ed for aligning and bracing of main loadcarrying members or for attaching utilities, signs, or other items to them, but not to directly support primary design loads. 3.1.6. tension componenta part or element of a fracture-critical or non-fracture-critical member that is in tension under various desi
27、gn loadings. 4. ORDERING REQUIREMENTS 4.1. In addition to the items listed in the ordering information section of ASTM A6/A6M, the following items should be considered if applicable: 4.1.1. Type of component (tension or nontension, fracture-critical or non-fracture-critical) (see Section 10). 4.1.2.
28、 Impact testing temperature zone (see Table 3). Table 3Relationship between Impact Testing Temperature Zones and Minimum Service Temperatures Zone Minimum Service Temperature, C F 1 18 0 2 Below 18 to 34 0 to 30 3 Below 34 to 51 30 to 60 5. GENERAL REQUIREMENTS FOR DELIVERY 5.1. Material furnished u
29、nder this specification shall conform to the requirements of the current edition of ASTM A6/A6M for the specific structural product unless a conflict exists, in which case this specification shall prevail. 5.2. Coils are excluded from qualification to this specification until they are processed into
30、 a finished structural product. “Structural products produced from coil” means structural products that have been cut to individual lengths from a coil. The processor controls, or is responsible for, the operations involved in the processing of a coil into a finished structural product. Such operati
31、ons include decoiling, leveling or straightening, hot forming or cold forming (if applicable), cutting to length, testing, inspection, conditioning, heat treatment (if applicable), packaging, marking, loading for shipment, and certification. (See Note 1.) Note 1For structural products produced from
32、coil and finished without heat treatment or with stress relieving only, two test results are to be reported for each qualifying coil. Additional requirements regarding structural products from coil are described in ASTM A6/A6M. 6. MATERIALS AND MANUFACTURE 6.1. For Grades 250 36 and 345 50, the stee
33、l shall be semi-killed or killed. 6.2. For Grades 345W 50W, HPS 345W HPS 50W, and HPS 485W HPS 70W, the steel shall be made to fine grain practice. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4f M
34、 270M/M 270-5 AASHTO 6.3. For Grade 345S 50S, the steel shall be killed. Killed steel is confirmed on the test report by a statement of killed steel, a value of 0.10 percent or more for the silicon content, or a value of 0.015 percent or more for the total aluminum content. 6.4. For Grade 345S 50S,
35、the steelmaking practice used shall be one that produces steel having a nitrogen content not greater than 0.015 percent and includes the addition of one or more nitrogen-binding elements, or one that produces steel having a nitrogen content of not greater than 0.012 percent (with or without the addi
36、tion of nitrogen-binding elements). The nitrogen content need not be reported, regardless of which steelmaking practice was used. 6.5. For Grades HPS 345W HPS 50W, HPS 485W HPS 70W, and HPS 690W HPS 100W, the steel shall be made using a low-hydrogen practice, such as vacuum degassing during steel ma
37、king; controlled soaking of the ingots or slabs; controlled slow cooling of the ingots, slabs, or plates; or a combination thereof. 6.6. For Grade HPS 690W HPS 100W the requirements for fine austenitic grain size in ASTM A6/A6M shall be met. 6.7. Grades HPS 345W HPS 50W and HPS 485W HPS 70W shall be
38、 furnished in one of the following conditions: as-rolled, control-rolled, thermomechanical control processed (TMCP) with or without accelerated cooling, or quenched and tempered. 7. HEAT TREATMENT 7.1. For quenched and tempered Grades HPS 345W HPS 50W and HPS 485W HPS 70W, the heat treatment shall b
39、e performed by the manufacturer and shall consist of heating the steel to not less than 900C 1650F, quenching it in water or oil, and tempering it at not less than 590C 1100F. The heat-treating temperatures shall be reported on the test certificates. 7.2. For Grade HPS 690W HPS 100W, the heat treatm
40、ent shall be performed by the manufacturer and shall consist of heating the steel to a temperature in the range from 870 to 925C 1600 to 1700F, quenching it in water, and tempering it at not less than 565C 1050F for a time to be determined by the manufacturer. The heat-treating temperatures shall be
41、 reported on the test certificates. 8. CHEMICAL REQUIREMENTS 8.1. The heat analysis shall conform to the requirements of the specified grade, as given in Tables 4 through 9. 8.2. For Grade 345S 50S, in addition to the elements listed in Table 6, test reports shall include, for information, the chemi
42、cal analysis for tin. Where the amount of tin is less than 0.02 percent, it shall be permissible for the analysis to be reported as 0.02 percent. 8.3. The maximum permissible carbon equivalent value shall be 0.47 percent for structural shapes with flange thickness over 50 mm 2 in., and 0.45 percent
43、for other structural shapes. The carbon equivalent shall be based on heat analysis. The required chemical analysis as well as the carbon equivalent shall be reported. The carbon equivalent (CE) shall be calculated using the following formula: %Mn %(Cr + Mo + V) %(Ni + Cu)CE %C6 5 15=+ + (1) 2015 by
44、the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4f M 270M/M 270-6 AASHTO Table 4Grade 250 36 Chemical Requirements (Heat Analysis) PlatesaBars Product Thickness, mm in. Shapes,ball To 20 3/4, incl. Over 20 to
45、 40 3/4to 11/2, incl. Over 40 to 65 11/2to 21/2, incl. Over 65 to 100 21/2to 4, incl. To 20 3/4, incl. Over 20 to 40 3/4to 11/2, incl. Over 40 to 100 11/2to 4, incl. Carbon, max % 0.26 0.25 0.25 0.26 0.27 0.26 0.27 0.28 Manganese, % 0.801.20 0.801.20 0.851.20 0.600.90 0.600.90 Phosphorus, max % 0.04
46、 0.04 0.04 0.04 0.04 0.04 0.04 0.04 Sulfur, max % 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Silicon, % 0.40 max 0.40 max 0.40 max 0.150.40 0.0150.40 0.40 max 0.40 max 0.40 max Copper, min % when copper steel is specified 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 aFor each reduction of 0.01 percentage po
47、ints below the specified carbon maximum, an increase of 0.06 percentage points manganese above the specified maximum will be permitted up to the maximum of 1.35 percent. bManganese content of 0.85 to 1.35 percent and silicon content of 0.15 to 0.40 percent are required for shapes over 634 kg/m 426 l
48、b/ft. Note: Where “” appears in this table, there is no requirement. The heat analysis for manganese shall be determined and reported as described in the Heat Analysis section of ASTM A6/A6M. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.Table 5Grade 345 50 Chemical Requirements (Heat Analysis)a Max Diameter, Thickness, or Distance Between Parallel Faces, mm in. Carbon, Max % Manganese,cMax % Phosphorus, Max % Sulfur, Max % Sili
