1.1 This practice covers a system originally adopted for designating light metals and alloys, cast and wrought, and later extended to certain heavier, base-metal die-casting alloys. Those designations, which are currently being used in specifications under the jurisdiction of Committees B02 on Nonferrous Metals and Alloys and B07 on Light Metals and Alloys, are listed in Tables X2.1.

1.1.1 The alloy designations now being used in Committee B07 specifications for aluminum and aluminum-alloy wrought and cast products conform to ANSI H35.1. Alloys formerly codified by this practice and the corresponding ANSI designations are shown in Tables X3.1 and X3.2.

1.2 This practice also provides a system for designating magnesium alloys that have been used commercially since 1952, and thus is intended to be the registration source for new magnesium alloys. A record of designations along with the established compositions is given in Table X4.1.

1.3 The equivalent Unified Numbering System (UNS) alloy designations shown in the appendixes are in accordance with Practice E 527.