Unified numbering system
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
Categories
Alloys