The Unified Numbering System for Metals and Alloys (UNS) provides a means of correlating many internationally used metal and alloy numbering systems administered by societies, trade associations, and individual users and producers of metals and alloys. Jointly developed by SAE International and the American Society for Testing and Materials (ASTM), it provides the uniformity necessary for efficient indexing, record keeping, data storage and retrieval, and cross-referencing.

The 15th edition of UNS has been updated to include more than 5,736 designations, 12,183 representative specification cross references, and 18,300 trade names.

The Print Edition of UNS includes:

• Introduction to the Unified Numbering System
• Index to UNS Designations by Base Elements
• Listing of UNS Numbers assigned-to date, with a description of each material covered and references to documents in which the same or similar materials are described
• Cross-index of commonly known documents which describe materials which are the same as, or similar to, those covered by UNS numbers
• Index of Common Trade Designations
• Reprint of “Numbering Metals and Alloys” (SAE J1086 OCT2012) and “Standard Practice for Numbering Metals and Alloys in the Unified Numbering System (UNS) (ASTM E527-16)

Cross-references include specifications from these organizations:

• AA (Aluminum Association) Numbers
• ACI (Steel Founders of America) Numbers
• AISI (American Iron and Steel Institute) including SAE Numbers (Carbon and Low Alloy Steels)
• AMS (SAE Aerospace Materials Specifications) Numbers
• ASME (American Society of Mechanical Engineers) Numbers
• ASTM (American Society for Testing & Materials) Numbers
• AWS (American Welding Society) Numbers
• QQ (Federal Specification Numbers)
• MILS (Military Specification Numbers)
• SAE (Society of Automotive Engineers) “AMS” and "J" Numbers