1.1 This specification covers quenched and tempered vacuum-treated carbon and alloy steel forgings for pressure vessels such as those used in reactor systems. Specifically, it covers forgings for vessel closures, shells, flanges, tube s This specification covers quenched and tempered vacuum-treated carbon and alloy steel forgings for pressure vessels, such as those used in reactor systems, specifically, vessel closures, shells, flanges, tube sheets, rings, heads, and similar parts. St