Unified numbering system

From Wikipedia, the free encyclopedia

The Unified Numbering System (UNS) is an alloy designation system widely accepted in North America. It consists of a prefix letter and five digits. A prefix of S indicates steel alloys, C for copper, brass, or bronze alloys, T for tool steels, etc. The first three digits often match older three-digit numberins systems, while the last two digits indicate more modern variations. For example, Copper Alloy No. 377 (forging brass) in the original three-digit system became C37700 in the UNS System. The UNS is managed jointly by the American Society for Testing and Materials and the Society of Automotive Engineers.

Some common materials and translations to other standards:

• UNS K11547 is T2 tool steel
• UNS S17400 is ASTM grade 630, Cr-Ni 17-4PH precipitation hardening stainless steel
• UNS S30400 is AISI 304, Cr/Ni 18/10, Euronorm 1.4301 stainless steel
• UNS S31600 is AISI 316
• UNS S31603 is 316L, a low carbon version of 316
• UNS C95400 is Ampco 18 aluminum bronze

The table below indicates the general categories

    UNS Series             Metal 
 A00001 to A99999 Aluminum and aluminum alloys 
 C00001 to C99999 Copper and copper alloys 
 D00001 to D99999 Specified mechanical property steels 
 E00001 to E99999 Rare earth and rare earthlike metals and alloys 
 F00001 to F99999 Cast irons 
 G00001 to G99999 AISI and SAE carbon and alloy steels (except tool steels) 
 H00001 to H99999 AISI and SAE H-steels 
 J00001 to J99999 Cast steels (except tool steels) 
 K00001 to K99999 Miscellaneous steels and ferrous alloys 
 L00001 to L99999 Low-melting metals and alloys 
 M00001 to M99999 Miscellaneous nonferrous metals and alloys 
 N00001 to N99999 Nickel and nickel alloys 
 P00001 to P99999 Precious metals and alloys 
 R00001 to R99999 Reactive and refractory metals and alloys 
 S00001 to S99999 Heat and corrosion resistant (stainless) steels 
 T00001 to T99999 Tool steels, wrought and cast 
 W00001 to W99999 Welding filler metals 
 Z00001 to Z99999 Zinc and zinc alloys