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 StrengthGrades A, B, D, CS, and E with a specified minimum yield point of 34 ksi [235 MPa], and 1.2.2 Higher StrengthGrades AH, DH, EH, and FH with specified minimum yield points of either 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, or AH36. Other grades may be furnished by agreement between the purchaser and the manufacturer. 1.4 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 A 6/A 6M for information on weldability. 1.5 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.