This specification covers standard requirements for three grades of carbon-manganese-silicon steel, designated Grades A, B, and C. Grade C may be produced with a boron addition. The plates shall be quenched and tempered and shall be intended for welded-layered pressure vessels. The steel shall be killed and shall conform to the fine austenitic grain size requirement. Heat and product analyses shall be performed wherein the material shall conform to the required chemical composition for carbon, manganese, phosphorus, sulfur, silicon, copper, nickel, chromium, molybdenum, vanadium, and boron. The steel plate shall undergo tension test and shall conform to tensile requirements such as tensile strength, yield strength, and elongation.

1.1 This specification2 covers three grades of carbon-manganese-silicon steel, designated Grades A, B, and C. Grade C may be produced with a boron addition. The plates are quenched and tempered and are intended for welded-layered pressure vessels.

1.2 The maximum thickness of plates supplied under this specification is limited only by the capability of the chemical composition to meet the specified mechanical requirements. However, current practice normally limits the maximum thickness to ⁷/₈ in. [22 mm] for Grades A and B, and to 2 in. [50 mm] for Grade C.

1.3 The values stated in either inch-pound units or SI units are to be regarded separately as 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 the specification.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.