Coverage. This specification covers four grades of intermediate 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. Grades 42@ 50@ and 50T are covered in thicknesses up to 6 in. [150 mm] inclusive@ and Grade 60 is covered in Uiicknesses up to 4 in. [100 mm] inclusive. It is intended that steel produced to Grades 42 and 50T of the basic API Spec 2Y@ without Supplementary Requirements@ 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 and API Spec 2W. API 2Y 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 quenched-and-tempered steels@ users may want to consider welding consumables which avoid undermatched weld metal. Conversely@ the steels should be amenable to fabrication and welding under shipyard and offshore conditions.