This specification covers the standard requirements for high-strength quenched and tempered alloy steel forgings for pressure vessels, isostatic presses, shock tubes, and similar components. These materials are not intended for welded construction. Three grades of nickel-chromium-molybdenum steels and six classes of increasing tensile strength are included. The strength class, section size, and configuration of the forging will largely dictate the applicable type of steel. Materials shall be manufactured by steel melting processes, rough machining, and final heat treatment, which shall consist of normalizing, reaustenitization, liquid quenching, and tempering. Conformance of the forging specimens to chemical composition requirements shall be analyzed by heat and product analyses. Proper sampling methods for mechanical properties testing shall be done by any of four possible ways, as judged appropriate. Steel specimens shall also undergo straight-beam and angle-beam ultrasonic examination, and magnetic particle examination procedures to evaluate nondestructive examination requirements. Repair welding of the forgings shall not be permitted.

1.1 This specification2 covers requirements for high-strength quenched and tempered alloy steel forgings for pressure vessels, isostatic presses, shock tubes, and similar components.

1.2 These materials are not intended for welded construction.

1.3 Three grades of nickel-chromium-molybdenum steels and six classes of increasing tensile strength are included. The strength class, section size, and configuration of the forging will largely dictate the applicable type(s) of steel.

1.4 The values stated in either inch-pound units or SI (metric) units are to be regarded separately as the standard. Within the text and tables, 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.

1.5 Unless the order specifies the applicable “M” specification designation, the material shall be furnished to the inch-pound units.

1.6 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.