API 2W-2000 pdf free download

API 2W-2000 pdf free download.Specification for Steel Plates for Offshore Structures, Produced by Thermo-Mechanical Control Processing (TMCP).
1 Scope 1.1 COVERAGE This specification covers four grades of intermediate strength steel plates for use in welded construction of off- shore structures, in selected critical portions which must resist impact, plastic fatigue loading, and lamellar tearing. Grades 42, 50, and 50T are 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 42 and 50T of the basic API Spec 2W, without Supplementary Requirements, although produced in a different manner and of somewhat different chemical compositions, be at least equivalent in minimum performance and, therefore, in service application, to the corresponding grades listed in Sections 4 through 6 of API Spec 2H. Higher performance (i.e., notch toughness at lower temperatures, or enhanced weldability) typically available with TMCP steel may be achieved by specification of Supplementary Requirements. 1.1.2 API 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 their 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 MANUFACTURING 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 1100°F (595°C) without some risk of sustaining irreversible and significant losses in strength and toughness. If warm-forming is to be required during subsequent fabrication, the tensile and notch toughness properties of the finished component shall be veri- fied and the properties shall conform to the requirements of this specification.
1.2.3 For applications where through-thickness properties are important but Z-direction testing has not been specified, Supplementary Requirement S5 provides a low-sulfur chem- istry intended to reduce the size and number of sulfide inclu- sions in the plate. Supplement S5 is neither a substitute for S4 Through-Thickness Testing nor a guarantee of a minimum level of through-thickness ductility. 1.2.4 The notch toughness requirements specified in Sec- tion 7 are suitable for applications below water, or above water in areas of temperature climate (14°F [– 10°C] mini- mum service temperature). Cold-formed materials have less toughness due to straining than that of the original flat plates, especially in those areas aged by the attachment welding of stubs and braces. The requirements in Section 7 take into con- sideration typical losses in toughness due to straining and aging. Supplementary Requirements S7 and S8 deal with the strain-aging problem, and consideration should be given to invoking S1 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 S.2 provides for impact tests at temperatures other than specified in Section 7. S2.1 provides for Drop- Weight or Charpy V-notch testing at – 60°C. S2.2 provides for such testing at temperatures less than – 40°C but other than – 60°C. 1.3 PREPRODUCTION QUALIFICATION Supplementary Requirement S.11 and Section 4 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.
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 con- trol processing (TMCP). 4.2.1 TMCP is a rolling method in which both reduction and rolling temperatures are strictly controlled, and acceler- ated cooling may be carried out through strict control of tem- perature 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.