This specification covers hot-finished or cold-finished precipitation hardening iron base superalloy bars, forgings, and forging stock for high-temperature service. The mechanical properties of these alloys are developed by suitable solution treating and precipitation hardening treatments. Two grades of iron base alloy are covered; Grade 660 and Grade 662 (bars and forgings). The material shall meet the requirements as to stress rupture properties specified. The material shall conform to the chemical, mechanical, and metallurgical properties requirements specified.