ANSI H35.1/H35.1(M)-2024, Alloy and Temper Designation Systems for Aluminum, is the 2024 revision of the 2017 edition, issued as an American National Standard with The Aluminum Association as secretariat. It defines the designation system by which aluminum and aluminum alloys are named: the four-digit system for wrought alloys, the three-digit-plus-decimal system for castings and ingot, and the temper designations that record strain-hardened (H), annealed (O) and thermally treated (T) conditions and their subdivisions. The standard explains how new designations are registered and maintained, so that producers, purchasers and specifiers refer to the same alloy and temper by the same name. It is the reference behind the designations used in Aluminum Standards and Data and in the Association's registration record sheets, and is applied wherever an alloy or temper is specified on a drawing, purchase order or material certificate.