API Spec 2H-2006 pdf free download

API Spec 2H-2006 pdf free download.Specification for Carbon Manganese Steel Plate for Offshore Structures.
1 Scope 1.1 This specification covers two grades of intermediate strength steel plates up to 4 in. thick for use in welded construction of offshore structures, in selected critical portions which must resist impact, plastic fatigue loading, and lamellar tearing. These steels are intended for fabrication primarily by cold forming and welding as per API Spec 2B. The welding procedure is of funda- mental importance and it is presumed that procedures will be suitable for the steels and their intended service. Conversely, the steels should be amenable to fabrication and welding under shipyard and offshore conditions. API Specifications 2W and 2Y cover companion steels providing similar mechanical properties but with the advantage of potentially lower preheats, and the availability of API RP 2Z prequalification of HAZ toughness. This improvement results from a reduction in the maximum allowed chemical composition and is made possible by changes in the method of heat treatment and/or processing. 1.2 The primary use of these steels is in tubular joints, stiffened plate construction, and other intersections where portions of the plates will be subjected to tension in the thickness direction (Z-direction). Supplementary Requirement S4 provides for through- thickness (Z-direction) testing of the plates by the material manufacturer and specified limits for acceptance. Supplementary Requirement S1 provides for ultrasonic examination of the plates by the material manufacturer and specifies limits for accep- tance. For applications where through-thickness properties are desirable but the expense of extra testing is not considered neces- sary, Supplementary Requirement S5 provides a low-sulfur chemistry intended to reduce the size and number of sulfide inclusions in the plate. Supplementary requirement S5 is neither a substitute for S4 Through-Thickness Testing nor a guarantee of a minimum level of through-thickness ductility.
1.3 The notch toughness requirements specified in Section 7 or S12 are suitable for application below water or above water in areas of temperate climate [14°F (–10°C) minimum service temperature]. Cold-formed materials have less toughness due to straining than that of the original flat plate, especially in those areas aged by the attachment welding of stubs or braces. The requirements for plates in Section 7 include a moderate adjustment for losses in toughness due to straining and aging; however, differences in composition or fabrication practices may result in significantly greater degradation than that included. Supplemen- tary Requirements S7 and S8 deal with the strain-aging problem, and consideration should be given to invoking S7 and/or S8 when the strain exceeds 5% or when (Nitrogen x % strain) exceeds 0.040. Supplementary Requirement S8 provides for testing at the specific temperatures and strain levels of interest and is recommended for all material purchases which exceed the purchaser’s experience base. For applications with lower service temperatures, lower test temperatures should be considered. Supplementary Requirement S2 provides for impact tests at temperatures other than those specified in Section 6 or S12. S2.1 provides for Drop Weight or Charpy V-notch testing at –76°F (–60°C). S2.2 provides for such testing at temperatures less than –40°F (–40°C) but other than –76°F (–60°C).
S1 Ultrasonic Examination S1.1 Pulse Echo ultrasonic examination shall be performed on each plate in accordance with ASTM A578/A578M. Accep- tance Standard—Level A shall be used. Any area where one or more discontinuities produce a continuous total loss of backwall reflection accompanied by continuous indications on the same plane that cannot be encompassed within a circle whose diameter is 3 in. (75mm) shall be cause for rejection. S1.2 Examination reports shall be furnished for each plate, the areas with more than 50% loss of back reflection shall be located on the sketch. S2 Notch Toughness Test at Lower Temperature S2.1 Notch toughness tests shall be made in accordance with the requirements of Section 7 or S12 and shall meet the require- ments of Table S2-1 in lieu of the requirements of Table 3 or S12.2. S2.2 Impact tests may be made at temperatures lower than those specified in Table 3 or S12.2 and other than those specified in Table S2-1. The testing temperature shall be specified by the purchaser and agreed to by the material manufacturer. S2.3 If the design condition requires a higher energy value, energy values higher than those stated in Table S2-1 may be speci- fied subject to agreement between the purchaser and the material manufacturer.