The most widely accepted alloy and temper designation system for aluminum and its alloys is maintained by the Aluminum Association and recognized by the American National Standards Institute (ANSI) as the American National Standard Alloy and Temper Designation Systems for Aluminum (ANSI H35.1). This article provides a detailed discussion on the alloy and temper designation system for aluminum and its alloys. The Aluminum Association alloy designations are grouped as wrought and cast alloys. Lengthy tables provide information on alloying elements in wrought aluminum and aluminum alloys; nominal composition of aluminum alloy castings; typical mechanical properties of wrought and cast aluminum alloys in various temper conditions; and cross references to former and current cast aluminum alloy designations.

Commercial aluminum alloys are classified based on how they are made and what they contain. This article describes the ANSI H35.1 designation system, which is widely used to classify wrought and cast aluminum alloys. The ANSI standard uses a four-digit numbering system to identify alloying elements, compositional modifications, purity levels, and product types. It also uses a multicharacter code to convey process-related details on heat treating, hardening, cooling, cold working, and other stabilization treatments. The article includes several large tables that provide extensive information on aluminum alloy and temper designations and how they correspond to critical mechanical properties as well as other designation systems.