C05_03_-_J_4__QQ-S-681b-Federal_Specifications.pdf

This is a Federal Specification for Steel Castings (QQ-S-681b), originally dated November 6, 1941, with Amendment-1 effective August 24, 1943, and Amendment-2 dated July 18, 1952.

The specification establishes requirements for steel castings across multiple classes (X, O, 1, 2, 3, and 4 with subclasses 4A1, 4A2, 4B1, 4B2, 4B3, 4C1, 4C2, 4C3, and 4C4) for use by all federal government departments and agencies. Class X and O castings require no heat treatment or physical testing and are intended for non-structural applications. Classes 1 through 3 specify increasing levels of strength and heat treatment (annealing), with Class 1 suited for welding and Class 3 for high-stress applications. Class 4 castings are designed for applications requiring specific physical properties and are normally manufactured from alloy steel. Steel castings must be produced using electric (arc or induction) or open hearth processes and meet specified chemical composition limits for carbon, manganese, phosphorus, sulphur, and other elements. Physical property requirements vary by class, including tensile strength ranging from 60,000 to 150,000 pounds per square inch, yield point from 30,000 to 125,000 pounds per square inch, elongation from 10 to 24 percent, and reduction of area from 10 to 45 percent. The specification requires surface inspection by a Government inspector, cleanliness standards, specific heat treatment procedures, welding authorization with restrictions for high-carbon steels, test coupon sampling, tension and bend testing protocols, and proper packaging and marking for shipment. Navy Department purchases are made under Military Specification MIL-S-15083, except Bureau of Yards and Docks uses this Federal specification for 4C2 castings.