1、Specification for Steel Plates for Offshore Structures, Produced by Thermo-Mechanical Control Processing (TMCP)API SPECIFICATION 2WFIFTH EDITION, DECEMBER 2006EFFECTIVE DATE: JUNE 1, 2007REAFFIRMED, JANUARY 2012Specification for Steel Plates for Offshore Structures, Produced by Thermo-Mechanical Con
2、trol Processing (TMCP)Upstream SegmentAPI SPECIFICATION 2WFIFTH EDITION, DECEMBER 2006EFFECTIVE DATE: JUNE 1, 2007REAFFIRMED, JANUARY 2012ii SPECIAL NOTES API publications necessarily address problems of a general nature. With respect to particular circumstances, local, state, and federal laws and r
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10、vices, 1220 L Street, N.W., Washington, D.C. 20005. Copyright 2006 American Petroleum Institute iii FOREWORD This specification is under the jurisdiction of the API Subcommittee on Standardization of Offshore Structures. The purpose of this specification is to provide standards for the purchase of q
11、uenched-and-tempered steel plate suitable for use in welded offshore structures. Nothing in this specification should be interpreted as indicating a preference by the committee for any material or process. In the selection of materials and processes, the purchaser must be guided by his experience an
12、d by the service for which the plate is intended. Changes from the previous edition are noted by bars in the margins. Shall: As used in a standard, “shall” denotes a minimum requirement in order to conform to the specification. Should: As used in a standard, “should” denotes a recommendation or that
13、 which is advised but not required in order to conform to the specification. Suggested revisions are invited and should be submitted to the Director of the Standards, American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005. v TABLE OF CONTENTS 1 SCOPE1 1.1 Coverage.1 1.2 Post Manuf
14、acturing Heating 1 1.3 Preproduction Qualification .2 2 REFERENCED DOCUMENTS2 3 GENERAL REQUIREMENTS FOR DELIVERY 2 4 MANUFACTURING.3 4.1 Melting3 4.2 Rolling 3 5 CHEMICAL REQUIREMENTS.3 6 MECHANICAL REQUIREMENTS.4 7 NOTCH TOUGHNESS REQUIREMENTS 5 8 MARKING.6 APPENDIX A SUPPLEMENTARY REQUIREMENTS7 A
15、PPENDIX B DESCRIPTION OF THERMO-MECHANICAL CONTROL PROCESS.11 APPENDIX C SUGGESTIONS FOR ORDERING API SPEC 2W STEEL PLATE 13 APPENDIX D API MONOGRAM .15 Figures B-1 Schematic Diagrams of Conventional and Thermo-Mechanical Control Process of Steel Plate 11 Tables 1 Chemical Requirements .4 2 Carbon E
16、quivalent Maximums .4 3 Tensile Requirements.5 4 Notch Toughness Requirements Charpy V-Notch Testing.5 S2-1 Notch Toughness Requirements at Lower Temperatures Drop-Weight TestingNo-Break at 67F (55C) or Charpy Impact Testing .8 1 Specification for Steel Plates for Offshore Structures, Produced by Th
17、ermo-Mechanical Control Processing (TMCP) 1 Scope 1.1 COVERAGE This specification covers two grades of high strength steel plates for use in welded construction of offshore structures, in selected critical portions which must resist impact, plastic fatigue loading, and lamellar tearing. Grade 50 is
18、covered in thicknesses up to 6 in. (150 mm) inclusive, and Grade 60 is covered in thicknesses up to 4 in. (100 mm) inclusive. 1.1.1 It is intended that steel produced to Grades 50 of the basic API Spec 2W, without Supplementary Requirements, although produced in a different manner and of somewhat di
19、fferent chemical compositions, be at least equivalent in minimum performance and, therefore, in service application, to the corresponding grades listed in Sections 5 through 7 of API Spec 2H. Higher performance (i.e., notch toughness at lower temperatures, or enhanced weldability) typically availabl
20、e with TMCP steel may be achieved by specification of Supplementary Requirements. 1.1.2 API Spec 2W steels are intended for fabrication primarily by cold forming and welding. The welding procedure is of fundamental importance and it is presumed that procedures will be suitable for the steels and the
21、ir intended service. Because of the characteristic high YS/TS ratio of TMCP steels, users may want to consider welding consumables which avoid under-matched weld metal. Conversely, the steels should be amendable to fabrication and welding under shipyard and offshore conditions. 1.2 POST MANUFACTURIN
22、G HEATING 1.2.1 Due to the inherent characteristics of the TMCP method, plates manufactured to this spec cannot be formed or postweld heat treated at temperatures above 1100F (595C) without some risk of sustaining irreversible and significant losses in strength and toughness. If warm-forming is to b
23、e required during subsequent fabrication, the tensile and notch toughness properties of the finished component shall be verified and the properties shall conform to the requirements of this specification. The procedure for verification shall be subject to mutual agreement. The plates may be post-wel
24、d heat treated at elevated temperatures not exceeding 1100F (595C) providing test coupons are subjected to a thermal cycle to stimulate such fabrication operations, as described in Supplementary Requirement S9. Verification or simulation is not necessary for heating at temperatures not exceeding 400
25、F (205C). 1.2.2 The primary use of these steels is in tubular joints, stiffened plate construction, and other intersections where portions of the plates will be subject to tension in the thickness direction (Z-direction). Supplementary Requirement S4 provides for through-thickness (Z-direction) test
26、ing of plates by the manufacturer and specifies limits for acceptance. Supplementary Requirement S1 provides for ultrasonic examination of the plates by the manufacturer and specifies limits for acceptance. 1.2.3 For applications where through-thickness properties are important but Z-direction testi
27、ng has not been specified, Supplementary Requirement S5 provides low-sulfur chemistry intended to reduce the size and number of sulfide inclusions in the plate. Supplement Requirement S5 is neither a substitute for S4, Through-Thickness Testing, nor a guarantee of a minimum level of through-thicknes
28、s ductility. 1.2.4 The notch toughness requirements specified in Section 7 are suitable for applications below water, or above water in areas of temperature climate (14F 10C minimum service temperature). Cold-formed materials have less toughness due to straining than that of the original flat plates
29、, especially in those areas aged by the attachment welding of stubs and braces. The requirements in Section 7 take into consideration typical losses in toughness due to straining and aging. Supplementary Requirements S7 and S8 deal with the strain-aging problem, 2 API SPECIFICATION 2W and considerat
30、ion should be given to invoking Supplementary Requirement S7 and/or S8 when the strain exceeds 5% or when (Nitrogen % strain) exceeds 0.040. 1.2.4.1 For applications with lower service temperatures, lower test temperatures should be considered. Supplementary Requirement S2 provides for impact tests
31、at temperatures other than specified in Section 7 or Supplementary Requirement S12. Supplementary Requirement S2.1 provides for Drop-Weight or Charpy V-notch testing at 60C. Supplementary Requirement S2.2 provides for such testing at temperatures less than 40C but other than 60C. 1.3 PREPRODUCTION Q
32、UALIFICATION Supplementary Requirement S11 and Section 3 of API RP 2Z, dealing with CTOD testing of the weld heat-affected zone and with resistance to hydrogen cracking, respectively, address problems which are not normally dealt with in a “commodity grade” steel specification. These problems are no
33、t unique to TMCP steels, but arise because: a. Users may be expecting higher performance from TMCP steels than is available with conventional steels (e.g., welding with no preheat, or welding with very high heat inputs while retaining the superior notch toughness), and b. This is a performance speci
34、fication which accommodates a variety of different steelmaking practices, rather than a recipe which completely describes all particulars of chemistry, process, and quality control (essential variables). It is intended that Supplementary Requirement S11 shall apply only when specified in advance by
35、the purchaser. In many cases it may be possible to rely on prior data assembled by the steelmaker, provided no essential variables of the process have been changed. 2 Referenced Documents The applicable editions of standards referenced herein are as follows: API RP 2A-WSD Planning, Designing and Con
36、structing Fixed Offshore PlatformsWorking Stress Design Spec 2H Carbon Manganese Steel Plate for Offshore Platform Tubular Joints RP 2Z Preproduction Qualification for Steel Plates for Offshore Structures ASTM1A 6/A 6M Standard Specification for General Requirements for Rolled Structural Steel Bars,
37、 Plates, Shapes and Sheet Piling A 370 Standard Test Methods and Definitions for Mechanical Testing of Steel Products A 578/A 578M Standard Specification for Straight-Beam Ultrasonic Examination of Plain and Clad Steel Plates for Special Applications A 673/A 673M Standard Specification for Sampling
38、Procedure for Impact Testing of Structural Steel E 10 Standard Test Method for Brinell Hardness of Metallic Materials E 23 Standard Test Methods for Notched Bar Impact Testing of Metallic Materials E 208 Standard Test Method for Conducting Drop-Weight Test to Determine Nil-Ductility Transition Tempe
39、rature of Ferritic Steels 3 General Requirements for Delivery 3.1 Material furnished to this specification shall conform to the applicable requirements of ASTM A 6/A 6M, as modified herein. 3.2 Plates not ordered to Supplementary Requirement 11 may be weld repaired in accordance with ASTM A 6/A 6M.
40、Separate welding procedure qualifications shall be made for each nominal chemical composition of the plate material and filler metal to be used. Low hydrogen electrodes and welding processes shall be used. 1American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, Pennsyl
41、vania 19428-2959, www.astm.org SPECIFICATION FOR STEEL PLATES FOR OFFSHORE STRUCTURES, PRODUCED BY THERMO-MECHANICAL CONTROL PROCESSING 3 3.3 Welding procedures for repairing plates ordered to Supplementary Requirement S11.3, CTOD Testing of Weld Heat Affected Zone, shall be subject to approval by t
42、he purchaser. 4 Manufacturing 4.1 MELTING The steel shall be made by the open hearth, basic oxygen, or electric furnace process. 4.2 ROLLING The plates shall be produced by thermo-mechanical control processing (TMCP). 4.2.1 TMCP is a rolling method in which both reduction and rolling temperatures ar
43、e strictly controlled, and accelerated cooling may be carried out through strict control of temperature immediately after the end of rolling in order to provide the specified mechanical properties. A description of the TMCP method is given in Appendix B. 4.2.2 The particular process used shall be id
44、entified. The process shall be identified as to whether thermo-mechanical rolling (TMR) alone, or TMR and accelerated cooling (AC) were used. The manufacturers process shall be identified with a code number or designation for ready reference, sufficient to provide traceability of process variables.
45、It is not the intent, however, to require the disclosure of confidential information. 5 Chemical Requirements 5.1 The steels shall conform to the requirements for chemical composition, as determined by heat analysis, prescribed in Table 1 and to the requirements of 5.2 through 5.5. 5.2 The Carbon Eq
46、uivalent (CE) of the heat analysis shall be calculated by both of the following equations: CE = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15 Pcm = C + Si/30 + (Mn + Cu + Cr)/20 + Ni/60 + Mo/15 + V/10 + 5B 5.3 The maximum Carbon Equivalent shall be as prescribed in Table 2. 5.4 Any element intentionally
47、 added or which appears in the carbon equivalent calculation shall be reported. 5.5 Vanadium, zirconium, cerium and other rare earth metals shall not be intentionally added without the specific approval of the purchaser. 5.5.1 If any of the above elements are added, the plate must have additional ma
48、rkings per 8.1.c. 4 API SPECIFICATION 2W Table 1Chemical Requirements (Heat Analysis, %)aElement Grade 50 Grade 60 Carbon, max. 0.16 0.16 Manganesebto 11/2in. (40 mm) incl. 1.15 1.60 1.15 1.60 over 11/2in. (40 mm) 1.15 1.60 1.15 1.60 Phosphorus, max. 0.03 0.03 Sulfur, max. 0.010 0.010 Silicon 0.05 0
49、.50 0.05 0.50 Nickel, max. 0.75 1.0 Chromium, max. 0.25 0.25 Molybdenum, max. 0.08 0.15 Copper, max. 0.35 0.35 Titanium N 0.005 0.003 0.02 0.003 0.02 N 0.005 0.007 0.02 0.007 0.02 Columbium (Niobium), max. 0.03 0.03 Nitrogen, max.c,d0.012 0.012 Boron, max.c0.0005 0.0005 Aluminum Acid soluble or 0.015 0.055 0.015 0.055 total 0.02 0.06 0.02 0.06 aSee 5.2, 5.3, 5.4, and 5.5. bManganese up to 1.65 (heat analysis) is permitted at the option of the material manufacturer. cNitrogen and boron shall not be intentionally added. dNitr
