1、Rolled Shapes with Improved Notch ToughnessAPI SPECIFICATION 2MT2FIRST EDITION, JUNE 2002EFFECTIVE DATE: DECEMBER 1, 2002REAFFIRMED, JUNE 2015Rolled Shaped with Improved Notch ToughnessUpstream SegmentAPI SPECIFICATION 2MT2FIRST EDITION, JUNE 2002EFFECTIVE DATE: DECEMBER 1, 2002REAFFIRMED, JUNE 2015
2、SPECIAL NOTESAPI publications necessarily address problems of a general nature. With respect to partic-ular circumstances, local, state, and federal laws and regulations should be reviewed.API is not undertaking to meet the duties of employers, manufacturers, or suppliers towarn and properly train a
3、nd equip their employees, and others exposed, concerning healthand safety risks and precautions, nor undertaking their obligations under local, state, or fed-eral laws.Information concerning safety and health risks and proper precautions, with respect toparticular materials and conditions, should be
4、 obtained from the employer, the manufactureror supplier of that material, or the material safety data sheet.Nothing contained in any API publication is to be construed as granting any right, byimplication or otherwise, for the manufacture, sale, or use of any method, apparatus, or prod-uct covered
5、by letters patent. Neither should anything contained in the publication be con-strued as insuring anyone against liability for infringement of letters patent.Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at least everyfive years. Sometimes a one-time extension of up to
6、two years will be added to this reviewcycle. This publication will no longer be in effect five years after its publication date as anoperative API standard or, where an extension has been granted, upon republication. Statusof the publication can be ascertained from the API Upstream Segment telephone
7、 (202) 682-8000. A catalog of API publications and materials is published annually and updated quar-terly by API, 1220 L Street, N.W., Washington, D.C. 20005.This document was produced under API standardization procedures that ensure appropri-ate notification and participation in the developmental p
8、rocess and is designated as an APIstandard. Questions concerning the interpretation of the content of this standard or com-ments and questions concerning the procedures under which this standard was developedshould be directed in writing to the standardization manager, American Petroleum Institute,1
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10、practices. These standards are not intended to obviate the need for apply-ing sound engineering judgment regarding when and where these standards should beutilized. The formulation and publication of API standards is not intended in any way toinhibit anyone from using any other practices.Any manufac
11、turer marking equipment or materials in conformance with the markingrequirements of an API standard is solely responsible for complying with all the applicablerequirements of that standard. API does not represent, warrant, or guarantee that such prod-ucts do in fact conform to the applicable API sta
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13、eet, N.W., Washington, D.C. 20005.Copyright 2002 American Petroleum InstituteFOREWORDAPI publications may be used by anyone desiring to do so. Every effort has been made bythe Institute to assure the accuracy and reliability of the data contained in them; however, theInstitute makes no representatio
14、n, warranty, or guarantee in connection with this publicationand hereby expressly disclaims any liability or responsibility for loss or damage resultingfrom its use or for the violation of any federal, state, or municipal regulation with which thispublication may conflict.Suggested revisions are inv
15、ited and should be submitted to the standardization manager,American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005.iiiCONTENTSPage1 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 REFERENCED DOC
16、UMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.1 Normative. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.2 Informative. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17、. . . . . . . . . . . . . . . . . . . . . . 13 GENERAL REQUIREMENTS FOR DELIVERY . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 MANUFACTURING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 CHEMICAL COMPOSITION . . . . . . . . . .
18、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 MECHANICAL PROPERTIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 MARKING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19、. . . . 38 SUPPLEMENTARY REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38.1 S1Vacuum Treatment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38.2 S2Product Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20、 . . . . . . . . . . . . . . . . . . 38.3 S3Impact Tests at Lower Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38.4 S4Additional Tension Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38.5 S8Ultrasonic Examination. . . . . . . . . .
21、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38.6 S9Simulation of Thermal Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38.7 S19Additional Quality Control Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 38.8 S20Additional Surface Require
22、ments and Weld Repair. . . . . . . . . . . . . . . . . . 48.9 S44Through Thickness (Z-Direction) Testing . . . . . . . . . . . . . . . . . . . . . . . . . 48.10 S75Maximum Yield and Yield/Tensile Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . 58.11 S76Core Region Charpy Tests (For “W” Sha
23、pes Only) . . . . . . . . . . . . . . . . . . 58.12 S77Reduced Sulfur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58.13 S7850% Shear Fracture Appearance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58.14 S101Class AAZ Shapes. . . .
24、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58.15 S102Product Analysis without Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5APPENDIX A SUGGESTIONS FOR ORDERING API 2MT2 SHAPES. . . . . . . . . . . . 7Tables1 Chemical Requirements (Heat Analys
25、is %) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Charpy Test Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3v1Rolled Shapes with Improved Notch Toughness1 Scope1.1This specification covers rolled shapes (wide flangeshapes,
26、angles, etc.), having a specified minimum yieldstrength of 50 ksi (345 Mpa), intended for use in offshorestructures. Commonly available Class A, Class B, and ClassC beams refer to degrees of fracture criticality as described insection 8.1.3 of API RP 2A, with Class C being for the leastcritical appl
27、ications. For special critical applications, ClassAAZ shapes may be specified, by agreement, using supple-ment S101.1.2Supplementary requirements are provided for usewhere additional testing or additional restrictions are requiredby the purchaser. Such requirements apply only when speci-fied in the
28、purchase order.1.3When the steel is to be welded, a welding proceduresuitable for the grade of steel and intended use or service is tobe utilized. For the purposes of welding procedure qualifica-tion under AWS D1.1, until AWS cites this specification, usethe following:a. Matching filler metals (AWS
29、D1.1, Table 3.1) shall be asfor Group II.b. Preheats (AWS D1.1, Table 3.2) shall be as for Category B(or Category D for class A-QST herein).c. Matching weld toughness (AWS D1.1, Tables C4.2 andC4.3) shall correspond to Class A, B, or C herein.Alternative preheats (AWS D1.1, Annex XI) may also beused
30、 to advantage.1.4When heat straightening, hot or warm forming, or post-weld heat treatment above 1050F (565C) is anticipated forClass A shapes produced by methods other than hot rolling,controlled rolling, normalized rolling, or normalizing, supple-ment S9 should be invoked.1.5By agreement, this spe
31、cification may be used as a sup-plement to purchase rolled shapes to other international stan-dards, e.g., Euronorm, ISO, or JIS, in which case referencesto ASTM A6 may be replaced by the comparable interna-tional standard. Users should note that dimensions and designproperties might not be the same
32、 as A6 shape designations,and that “equivalent” sections could be heavier.2 Referenced Documents2.1 NORMATIVEASTM A6/A6M, Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet PilingASTM A370/A370M, Test Methods and Definitions for Mechanical Testing of S
33、teel ProductsASTM A673/A673M, Specification for Sampling Procedure for Impact Testing of Structural SteelASTM A898/A898M, Specification of Straight Beam Ultra-sonic Inspection of Rolled Steel Structural Shapes2.2 INFORMATIVEAPI RP2A-WSD, 21st Edition, Recommended Practice for Planning, Designing, an
34、d Constructing Fixed Offshore Plat-formsAPI Spec 2B, Specification for the Fabrication of Structural Steel PipeAPI Spec 2W, Specification for Steel Plates for Offshore Structures, Produced by Thermo-Mechanical Control Pro-cessing (TMCP)ASTM A913/A913M, High-Strength Low-Allow Shapes of Structural Qu
35、ality, Produced by Quenching and Self-Temper-ing Process (QST)ASTM A992/A992M, Standard Specification for Steel for Structural ShapesAWS D1.1-2000, Structural Welding CodeSteelHeat Straightening Repairs of Damaged Steel Bridges:A Technical Guide and Manual of Practice (with CD), U.S. Dept. of Transp
36、ortation Rep. No. FHWA-IF-99-004.3 General Requirements for Delivery3.1Material furnished to this specification shall conform toASTM A6/A6M, except as provided otherwise herein.3.2Visual examination for defects shall be performed onall surfaces.4 Manufacturing4.1The steel shall be made by basic oxyg
37、en or electricfurnace process. Additional refining by electroslag remelt-ing, vacuum arc remelting, or ladle metallurgy furnace ispermitted.4.2The steel shall be killed. Killed steel is confirmed by astatement of “killed steel” on the test report, or by reportingstrong deoxidizers.4.3The steel shall
38、 be made to fine grain practice. For ClassA and B, the fine grain definition in Section 8.3 of ASTM A6shall apply.2 API SPECIFICATION2MT24.4Steel may be cast in ingots or may be strand cast. Whensteels of different specifications are sequentially strand cast,the producer shall identify and remove th
39、e transition material.4.5Class A shapes shall be produced by any of the follow-ing processes. The process used shall be identified on the millcertificate.a. AR: as-rolled (hot rolled).b. CR: controlled rolling, with final rolling at a reducedtemperature.c. NR: normalized rolling, with final rolling
40、of the shape per-formed in the upper recrystallization range, without the extracycle of cooling and reheating.d. N: normalizing, with reheating and cooling performed offline (see 4.7).e. QST: quenching and self-tempering process, as describedin Appendix X1 of ASTM A913. Self-tempering temperaturesha
41、ll be a minimum of 1100F (600C), and the self-temper-ing temperature for the material represented shall be reportedon the mill certificate. f. QT: conventional quenching and tempering, off line (see4.7).g. TMCP: thermo-mechanical control processing, by agree-ment. TMCP is defined in Appendix B of AP
42、I Spec 2W. Themanufacturers process shall be identified with a code numberor designation for ready reference, sufficient to provide trace-ability of process variables.4.6Class B and Class C shapes may be produced by AR,CR, or NR. Shapes which fail to meet the minimum specifiedmechanical requirements
43、 in the as-produced condition maybe heat treated by normalizing, provided the delivered beamsmeet the grain size, tensile, and impact mechanical propertiesof this specification, and dimensional tolerances and surfacefinish requirements of ASTM A6 (see 4.7). Test frequencyshall be per heat, per heat
44、treat batch. Heat treatment shall benoted on the mill certificate.4.7By agreement, straightening and surface dressing tomeet the dimensional tolerances and surface finish require-ments of ASTM A6 may be performed by a third party reme-diation shop or fabricator. Heat straightening, if used, shallcon
45、form to agreed procedures. Reference may be made to theprinciples and precautions described in U.S. Dept. of Trans-portation Report No. FHWA-IF-99-004, Heat StraighteningRepairs of Damaged Steel Bridges:A Technical Guide andManual of Practice.5 Chemical Composition5.1Chemical analysis shall be perfo
46、rmed in accordancewith ASTM A6, and comply with the heat requirements pre-scribed in Table 1. Elements shown without a range are max-ima. Any element knowingly added shall be reported.5.2The carbon equivalents CE and PCM on heat analysisshall not exceed the limits prescribed in Table 1, using the fo
47、l-lowing formulae: CE = C + Mn/6 + (Cr + Mo + V)/5 + (Cu + Ni)/15PCM = C + Si/30 + (Mn + Cu + Cr)/20 + Ni/60 + Mo/15 + V/10 + 5BThe chemical analysis (heat analysis) of all the elementsthat appear in the carbon equivalent formulae shall bereported. For thickness over 1.5-in. (38-mm), the CE may be0.
48、02 higher, and the PCM may be 0.01 higher.6 Mechanical Properties6.1Tensile properties of the steel as represented by testspecimens taken according to ASTM A6 shall meet the fol-lowing requirements: yield strength 50 ksi (345 MPa) min. tensile strength 65-90 ksi (450-620 MPa) elongation 18% in 8-in.
49、 (200 mm) gage length21% in 2-in. (50 mm) gage length6.2Charpy V-Notch (CVN) tests shall be made in accor-dance with ASTM A673, Frequency H (i.e., 50 tons per sec-tion, footweight and grade, continuously produced).Specimens with orientation L-T shall be removed from theflange or thickest outstand as shown in Figure 2 of ASTMA673. Test temperature and minimum average energy valuefor full size specimens shall be as prescribed in Table 2. Table 1Chemical Requirements (Heat Analysis %)Element Class A Class B Class CCarbon 0.14 0.16 0.23Manganese 1.60 1.60 0.50 1.50Ph
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