ASTM B296-20

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: B296 − 20
Standard Practice for
Temper Designations of Magnesium Alloys, Cast and
Wrought
This standard is issued under the fixed designation B296; 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 2.3 Basic temper designations consist of letters. Subdivi-
sions of the basic tempers, where required, are indicated by a
1.1 This practice covers a system for designating the tem-
digit or digits following the letter. These designate specific
pers of magnesium alloys, cast and wrought. The designations
sequences of basic treatments, but only operations recognized
used in ASTM specifications under the jurisdiction of Com-
as significantly influencing the characteristics of the product
mitteeB07formagnesiumalloycastingsandwroughtproducts
2 are indicated. Should some other variation of the same se-
conform to this practice.
quence of basic operations be applied to the same alloy,
1.2 This international standard was developed in accor-
resulting in different characteristics, then additional digits are
dance with internationally recognized principles on standard-
added to the designation.
ization established in the Decision on Principles for the
NOTE 1—In material specifications containing reference to two or more
Development of International Standards, Guides and Recom-
tempers of the same alloy which result in identical mechanical properties,
mendations issued by the World Trade Organization Technical
the distinction between the tempers should be covered in suitable
Barriers to Trade (TBT) Committee.
explanatory notes.
2. Basis of Codification 2.4 The temper designations and the subdivisions are fully
defined and explained in Table 1. A brief outline for quick
2.1 The designations for temper are used for all forms of
reference is given in Table 2.
magnesium and magnesium-alloy products except ingots and
are based on the sequence of basic treatments used to produce
3. Referenced Documents
the various tempers.
3.1 ANSI Standard:
2.2 The temper designation follows the alloy designation,
ANSI H35.1/H35.1M American National Standard Alloy
the two being separated by a dash.
and Temper Designation Systems for Aluminum
This practice is under the jurisdiction of the ASTM Committee B07 on Light
4. Keywords
Metals and Alloys and is the direct responsibility of Subcommittee B07.04 on
Magnesium Alloy Cast and Wrought Products.
4.1 cast and wrought alloys; magnesium alloys; temper
Current edition approved May 1, 2020. Published June 2020. Originally
designations
approved in 1954. Last previous edition approved in 2014 as B296 – 03 (2014).
DOI: 10.1520/B0296-20.
The designations used in ASTM Committee B07 specifications for aluminum-
alloy wrought and cast products conform to the American National Standard Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
H35.1/H35.1M. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B296 − 20
TABLE 1 Temper Designations
Temper Designation and
Description
Sub-division (if any)
F As Fabricated —Applies to products that acquire some temper from shaping processes not having special control over the amount of
strain hardening or thermal treatment.
O Annealed, Recrystallized—Applies to the softest temper of wrought products.
H Strain Hardened (Wrought Products Only)—Applies to products that have their strength increased by strain hardening with or without
supplementary thermal treatments to produce partial softening. Two or more digits always follow the H.
H1 Strain Hardened Only—Applies to products that are strain hardened to obtain the desired mechanical properties without supplementary
thermal treatment. The number following this designation indicates the final degree of strain hardening.
H2 Strain Hardened and Then Partially Annealed—Applies to products that are strain hardened more than the desired final amount and then
reduced in strength to the desired final amount by partial annealing.
The number following this designation indicates the final degree of strain hardening remaining after the product has been partially
annealed.
H3 Strain Hardened and Then Stabilized—Applies to products that are strain hardened and then stabilized by a low temperature heating to
slightly lower their strength and increase ductility. This designation applies only to alloys which, unless stabilized, gradually age soften at
room temperature.
The number following this designation indicates the degree of strain hardening remaining after the product has been strain hardened
a specific amount and then stabilized.
Subdivisions The digit following the designations “H1,” “H2,” and “H3” indicates the final degree of strain hardening. Tempers between 0 (annealed)
of H1, H2, and H3 and 8 (full hard) are designated by numerals 1 through 7. Material having a strength about midway between that of the 0 temper and
that of the 8 temper is designated by the numeral 4 (half hard); between 0 and 4 by the numeral 2 (quarter hard); between 4 and 8 by
the numeral 6 (three-quarter hard); and so forth.
The third digit, when used, indicates a variation of a two-digit H temper. It is used when the degree of control
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