This specification covers structural steel plates, shapes, bars, and rivets for use in ship construction. Materials under this specification can be categorized as ordinary strength and higher strength. Plates in all thicknesses shall be normalized or thermo-mechanical control processed while shapes and bars in all thicknesses shall be heat treated and rolled. Heat analysis of ordinary strength structural steel shall be used to determine the required chemical composition for carbon, manganese, phosphorus, sulfur, nickel, chromium, molybdenum, silicon, and copper. Same analysis shall be used to higher strength structural steel to determine the required chemical composition for carbon, manganese, phosphorus, sulfur, silicon, vanadium, aluminum, titanium, nickel, chromium, molybdenum, silicon, copper, nickel, and niobium. Materials shall conform to the required metallurgical structure which shall be evaluated by determining the average grain size. Mechanical properties such as elongation and toughness shall be evaluated using tension test and Charpy V-notch impact test.

1.1 This specification covers structural steel plates, shapes, bars, and rivets intended primarily for use in ship construction.

1.2 Material under this specification is available in the following categories:

1.2.1 Ordinary Strength—Grades A, B, D, and E with a specified minimum yield point of 34 ksi [235 MPa], and

1.2.2 Higher Strength—Grades AH, DH, EH, and FH with a specified minimum yield point of 46 ksi [315 MPa], 51 ksi [350 MPa], or 57 ksi [390 MPa].

1.3 Shapes and bars are normally available as Grades A, AH32, and AH36. Other grades may be furnished by agreement between the purchaser and the manufacturer.

1.4 The maximum thickness of products furnished under this specification is 4 in. [100 mm] for plates and 2 in. [50 mm] for shapes and bars.

1.5 When the steel is to be welded, it is presupposed that a welding procedure suitable for the grade of steel and intended use or service will be utilized. See Appendix X3 of Specification A6/A6M for information on weldability.

1.6 The values stated in either inch-pound units or SI units are to be regarded separately as the standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with this specification.