The Unified Numbering System for Metals and Alloys (UNS) provides means of correlating many internationally used metal and alloy numbering systems currently administered by societies, trade associations, and those individual users and producers of metals and alloys. This system avoids the confusion caused by the use of more than one identification number for the same metal or alloy, and the opposite situation of having the same number assigned to two or more different metals or alloys.
The UNS establishes 9 series of designations for ferrous metals and alloys. Each UNS designation consists of a single-letter prefix followed by five digits.
CA UNS designation is not, in itself, a specification, because it establishes no requirements for form, condition, property, or quality. It is a unified identifier of a metal or an alloy for which controlling limits have been established in specifications published elsewhere.
The UNS establishes 9 series of designations for ferrous metals and alloys. Each UNS designation consists of a single-letter prefix followed by five digits. In most cases the letter is suggestive of the family of metals identified: for example, F for cast irons, T for tool steel, S for stainless steels.
Although some of the digits in certain UNS designation groups have special assigned meanings, each series of UNS designations is independent of the others in regard to the significance of digits, thus permitting greater flexibility and avoiding complicated and lengthy UNS designations.
Wherever feasible, and for the convenience of the user, identification "numbers" from existing systems are incorporated into the UNS designations. For example, carbon steel presently identified by the American Iron and Steel Institute as "AISI 1020" is covered by the UNS designation "G10200".
The UNS designation assignments for certain metals and alloys are established by the relevant trade associations which in the past have administered their own numbering systems; for other metals and alloys, UNS designation assignments are administered by the Society of Automotive Engineers (SAE). Each of these assigners has the responsibility for administering a specific UNS series of designations. Each considers requests for the assignment of new UNS designations, and informs the applicants of the action taken. UNS designation assigners report immediately to the office of the Unified Numbering System for Metals and Alloys the details of each new assignment for inclusion into the system.
The listed cross-referenced specifications are representative only and are not necessarily a complete list of specifications applicable to a particular UNS designation.
D00001-D99999 | Steels with specified mechanical properties |
D40450-D40900 | Carbon Steels |
D50400-D52101 | Alloy Steels Casting |
F00001-F99999 | Cast irons |
F 10001-F15501 | Cast Iron, Gray |
F 10090-F10920 | Cast Iron Welding Filler Metal |
F 20000-F22400 | Cast Iron, Malleable |
F 22830-F26230 | Cast Iron, Pearlitic Malleable |
F 30000-F36200 | Cast Iron, Ductile (Nodular) |
F 41000-F41007 | Cast Iron, Gray, Austenitic |
F 43000- F43030 | Cast Iron, Ductile (Nodular), Austenitic |
F45000 F 45009 | Cast Iron, White |
F47001-F47006 | Cast Iron, Corrosion |
G00001-G99999 | AISI and SAE carbon and alloy steels (except tool steels) |
G10050-G10950 | Carbon Steel |
G15130-G15900 | Carbon Steel |
G11080-G11510 | Resulfurized Carbon Steel |
G12110-G12150 | Rephosphorized and Resulfurized Carbon Steel |
G13300-G13450 | Mn Alloy Steel |
G40120-G48200 | Mo Alloy Steel, Cr-Mo Alloy Steel, Ni-Cr-Mo Alloy Steel, Ni-Mo Alloy Steel |
G81150-G88220 | Ni-Cr-Mo Alloy Steel |
G50150-G52986 | Cr Alloy Steel, Cr-B Alloy Steel |
G61180-G61500 | Cr-V Alloy Steel |
G92540-G98500 | Cr-Si Alloy Steel, Si-Mn Alloy Steel, Cr-S-Mn Alloy Steel, Ni-Cr-Mo Alloy Steel, Ni-Cr-Mo-B Alloy Steel |
H00001-H99999 | AISI and SAE H-steels |
H10380-H15621 | H-Carbon Steel, C-Mn H-Alloy Steel, C-B H Carbon Steel, Mn H-Carbon Steel, B- Mn H -Carbon Steel |
H40270-H48200 | C-Mo H-Alloy Steel, Cr-Mo H-Alloy Steel Ni-Mo H-Alloy Steel |
H50401-H51601 | C-Cr-B H-Alloy Steel, C-Cr H-Alloy Steel |
H61180-H61500 | Cr-V H-Alloy Steel |
H81451-H94301 | Ni-Cr-Mo H-Alloy Steel |
J00001-J99999 | Cast steels (except tool steels) |
J01700-J05003 | Carbon Steel Casting |
J11442-J84090 | Alloy Steel Casting |
J91100-J92001 | Austenitic Manganese Steel Casting, Alloy Steel Casting |
J92110-J93000 | Alloy Steel Casting Precipitation Hardening, Alloy Steel Casting, Cast Cr-Ni-Mo Stainless Steel, Cast Cr-Ni Stainless Steel, Cast Cr-Mn-Ni-Si-N Stainless Steel |
J93001-J95705 | Stainless Steel Casting, Cast Cr-Ni-Mo Stainless Steel, Alloy Steel Casting, Maraging Cast Ferritic-Austenic Stainless Steel, Duplex Alloy Steel Casting, Alloy Steel Casting |
K00001-K99999 | Miscellaneous steels and ferrous alloys |
K00040-K08500 | Carbon Steel, Carbon Steel with Special Magnetic Properties, Steel Welding Rod, Enameling Steel |
K10614-K52440 | Alloy Steel, Alloy Steel Electrode and Welding Wire, High-Strength Low-Alloy Steel |
K90901-K95000 | Alloy Steel, Superstrength; Ferritic Cr-Mo-V Steel; Manganese Steel, Nonmagnetic; Ni-Co Steel Welding Wire; Iron, Electrical Heating Element Alloy; Iron Thermostat Alloy; Martensitic Age-Hardenable Alloy; Maraging Alloy; Fe-Co Soft Magnetic Alloy; Nickel Steel; Invar; Iron, Nickel Sealing Alloy; etc. |
S00001-S99999 | Heat and corrosion resistant steels (stainless), valve steels, iron-base "super alloys" |
S13800-S17780 | Precipitation Hardenable Cr-Ni-Al-Mo-(Cu, Ti) Stainless Steels |
S20100-S39000 | Austenitic Cr-Mn-Ni (Si,Mo,Cu,Al) Stainless Steel; Thermal Spray Wire; Austenitic Cr-Mn-Ni Stainless Steel and Welding Filler Metal; Austenitic Cr-Ni Heat Resisting Steel and Welding Filler Metal; Precipitation Hardenable Cr-Ni-(Si, Ti, Mo, Al) Stainless Steel, etc. |
S40300-S46800 | Martensitic Cr Stainless Steel; Ferritic Cr Stainless Steel with Ti or Ni or Mo; Martensitic Cr-Ni-Mo Stainless Steel; Hardenable Cr Stainless Steel |
S50100-S50500 | Cr Heat Resisting Steels and Filler Metal |
S63005-S64007 | Valve Steel |
S65006-S65007 | Valve Steel |
S65150-S67956 | Iron Base Super alloy |
T00001-T99999 | Tool steels, wrought and cast |
T11301-T12015 | High-Speed Tool Steels |
T20810-T20843 | Hot-Work Tool Steels |
T30102-T 30407 | Cold Work Tool Steels |
T31501-S31507 | Oil-Hardening Steels |
T41901-T41907 | Shock-Resisting Tool Steels |
T51602-T51621 | Mold Steels |
T60601-T60602 | C-W Tool Steels |
T61202-T61206 | Low-Alloy Tool Steels |
T72301-T72305 | Water Hardening Tool Steels |
T74000-T75008 | Cr-Steels Solid Welding Wire for Machinable Surfaces and Tool and Die Surfaces |
T87510-T87520 | Thermal Spray Wire |
T90102-T91907 | Cast Tool Steels |
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