"This recommended practice describes a unified numbering system (UNS) for metals and alloys which have a ""commercial standing"" and covers the procedure by which such numbers are assigned. Section 2 describes the system of alphanumeric designations or ""numbers"" established for each family of metals and alloys. Section 3 outlines the organization established for administering the system. Section 4 describes the procedure for requesting number assignment to metals and alloys for which UNS numbers have not previously been assigned. The UNS provides a means of correlating many nationally used numbering systems currently administered by societies@ trade associations@ and individual users and producers of metals and alloys@ thereby avoiding confusion caused by use of more than one identification number for the assigned to two or more entirely different materials. It provides@ also@ the uniformity necessary for efficient indexing@ record keeping@ data storage and retrieval@ and cross referencing. A UNS number is not in itself a specification@ since it establishes no requirements for form@ condition@ quality@ etc. It is a unified identification of metals and alloys for which controlling limits have been established in specifications published elsewher"