ASTM E527-23
(Practice)Standard Practice for Numbering Metals and Alloys in the Unified Numbering System (UNS)
Standard Practice for Numbering Metals and Alloys in the Unified Numbering System (UNS)
SIGNIFICANCE AND USE
4.1 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 same material; and by the opposite situation of having the same number assigned to two or more entirely different materials. It also provides the uniformity necessary for efficient indexing, record keeping, data storage and retrieval, and cross referencing.
4.2 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 elsewhere.
Note 5: Organizations that issue specifications should report to appropriate UNS number-assigning offices (3.1.2) any specification changes that affect descriptions shown in published UNS listings.
SCOPE
1.1 This practice (Note 1) covers a unified numbering system (UNS) for metals and alloys that have a “commercial standing” (see Note 2), 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 5 describes the procedure for requesting number assignment to metals and alloys for which UNS numbers have not previously been assigned.
Note 1: UNS designations are not to be used for metals and alloys that are not registered under the system described herein, or for any metal or alloy whose composition differs from those registered.
Note 2: The terms “commercial standing,” “production usage,” and other similar terms are intended to apply to metals and alloys in active commercial production and use, although the actual amount of such use will depend, among other things, upon the type of metals and alloys involved and their application.
The various standardizing organizations involved with the individual industries apply their own established criteria to define the status of a metal or alloy in terms of when a UNS designation number will be assigned. For instance, ASTM Committee A01 requires details of heat analysis, mechanical properties, and processing requirements for addition of a new grade or alloy to its specifications. The Copper Development Association requires that the material be “in commercial use (without tonnage limits);” the Aluminum Association requires that the alloy be “offered for sale (not necessarily in commercial use);” the SAE Aerospace Materials Division calls for “repetitive procurement by at least two users.”
Thus, while no universal definition for usage criteria is established, the UNS numbers are intended to identify metals and alloys that are generally in regular production and use. A UNS number will not ordinarily be issued for a material that has just been conceived or that is still in only experimental trial.
1.2 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E527 − 23
Standard Practice for
Numbering Metals and Alloys in the Unified Numbering
1
System (UNS)
This standard is issued under the fixed designation E527; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
for a material that has just been conceived or that is still in only
1. Scope*
experimental trial.
1.1 This practice (Note 1) covers a unified numbering
1.2 This international standard was developed in accor-
system (UNS) for metals and alloys that have a “commercial
dance with internationally recognized principles on standard-
standing” (see Note 2), and covers the procedure by which
ization established in the Decision on Principles for the
such numbers are assigned. Section 2 describes the system of
Development of International Standards, Guides and Recom-
alphanumeric designations or “numbers” established for each
mendations issued by the World Trade Organization Technical
family of metals and alloys. Section 3 outlines the organization
Barriers to Trade (TBT) Committee.
established for administering the system. Section 5 describes
the procedure for requesting number assignment to metals and
2. Description of Numbers (or Codes) Established for
alloys for which UNS numbers have not previously been
Metals and Alloys
assigned.
2.1 The UNS establishes 19 series of numbers for metals
NOTE 1—UNS designations are not to be used for metals and alloys that
and alloys, as shown in Table 1. Each UNS number consists of
are not registered under the system described herein, or for any metal or
a single letter-prefix followed by five digits. In most cases the
alloy whose composition differs from those registered.
letter is suggestive of the family of metals identified; for
NOTE 2—The terms “commercial standing,” “production usage,” and
other similar terms are intended to apply to metals and alloys in active
example, A for aluminum, P for precious metals, and S for
commercial production and use, although the actual amount of such use
stainless steels.
will depend, among other things, upon the type of metals and alloys
involved and their application. 2.2 Whereas some of the digits in certain UNS number
The various standardizing organizations involved with the individual
groups have special assigned meaning, each series is indepen-
industries apply their own established criteria to define the status of a
dent of the others in such significance; this practice permits
metal or alloy in terms of when a UNS designation number will be
greater flexibility and avoids complicated and lengthy UNS
assigned. For instance, ASTM Committee A01 requires details of heat
numbers.
analysis, mechanical properties, and processing requirements for addition
of a new grade or alloy to its specifications. The Copper Development
NOTE 3—This arrangement of alphanumeric six-character numbers is a
Association requires that the material be “in commercial use (without
compromise between the thinking that identification numbers should
tonnage limits);” the Aluminum Association requires that the alloy be
indicate many characteristics of the material, and the belief that numbers
“offered for sale (not necessarily in commercial use);” the SAE Aerospace
should be short and uncomplicated to define only the chemical composi-
Materials Division calls for “repetitive procurement by at least two users.”
tion and leaving the other properties to the specifications involved.
Thus, while no universal definition for usage criteria is established, the
UNS numbers are intended to identify metals and alloys that are generally
2.3 Wherever feasible, identification “numbers” from pre-
in regular production and use. A UNS number will not ordinarily be issued
vious systems are incorporated into the UNS numbers. For
example: carbon steel, originally identified by “American Iron
1
and Steel Institute (AISI) 1020,” is covered by “UNS G10200,”
This practice is under the jurisdiction of ASTM Committee A01 on Steel,
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
and free cutting brass, presently identified by “Copper Devel-
A01.91 on Editorial.
opment Association (CDA) C36000,” is covered by
Current edition approved Sept. 1, 2023. Published September 2023. Originally
“UNS C36000.” Table 2 shows the secondary division of some
approved in 1974. Last previous edition approved in 2016 as E527 – 16.
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E527 − 16 E527 − 23
Standard Practice for
Numbering Metals and Alloys in the Unified Numbering
1
System (UNS)
This standard is issued under the fixed designation E527; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 This practice (Note 1) covers a unified numbering system (UNS) for metals and alloys that have a “commercial standing” (see
Note 2), 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 5 describes the procedure for requesting number assignment to metals and alloys for which UNS
numbers have not previously been assigned.
NOTE 1—UNS designations are not to be used for metals and alloys that are not registered under the system described herein, or for any metal or alloy
whose composition differs from those registered.
NOTE 2—The terms “commercial standing,” “production usage,” and other similar terms are intended to apply to metals and alloys in active commercial
production and use, although the actual amount of such use will depend, among other things, upon the type of metals and alloys involved and their
application.
The various standardizing organizations involved with the individual industries apply their own established criteria to define the status of a metal or
alloy in terms of when a UNS designation number will be assigned. For instance, ASTM Committee A01 requires details of heat analysis, mechanical
properties, and processing requirements for addition of a new grade or alloy to its specifications. The Copper Development Association requires that the
material be “in commercial use (without tonnage limits);” the Aluminum Association requires that the alloy be “offered for sale (not necessarily in
commercial use);” the SAE Aerospace Materials Division calls for “repetitive procurement by at least two users.”
Thus, while no universal definition for usage criteria is established, the UNS numbers are intended to identify metals and alloys that are generally in
regular production and use. A UNS number will not ordinarily be issued for a material that has just been conceived or that is still in only experimental
trial.
1.2 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Description of Numbers (or Codes) Established for Metals and Alloys
2.1 The UNS establishes 19 series of numbers for metals and alloys, as shown in Table 1. Each UNS number 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, A for
aluminum, P for precious metals, and S for stainless steels.
2.2 Whereas some of the digits in certain UNS number groups have special assigned meaning, each series is independent of the
others in such significance; this practice permits greater flexibility and avoids complicated and lengthy UNS numbers.
1
This practice is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.91
on Editorial.
Current edition approved Sept. 1, 2016Sept. 1, 2023. Published September 2016September 2023. Originally approved in 1974. Last previous edition approved in 20122016
as E527 – 12.E527 – 16. DOI: 10.1520/E0527-16.10.1520/E0527-23.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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E527 − 23
TABLE 1 Primary Series of Numbers
Nonferrous Metals and Alloys
A00001–A99999 aluminum and aluminum alloys
B00001–B99999 aluminum and aluminum alloys
C00001–C99999 copper and copper alloys
E00001–E99999 rare earth and rare earth-like metals and alloys (18
items; see Table 2)
L00001–L99999 low melt
...
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