ASTM B661-12(2020)
(Practice)Standard Practice for Heat Treatment of Magnesium Alloys
Standard Practice for Heat Treatment of Magnesium Alloys
ABSTRACT
This practice is intended as an aid for establishing a suitable procedure for the heat treatment of magnesium alloys to achieve the proper physical and mechanical properties. Air chamber furnaces that may be either electrically heated, or oil- or gas-fired, are usually used for the heat treatment process. Each furnace must be gas tight, have suitable equipment for protective atmosphere, be equipped with a high-velocity fan or any other comparable means for circulating the atmosphere, and designed so that no direct radiation from the heating elements or impingement of the flame on the magnesium. It is also important that the furnace be calibrated before it is used initially and after any change in the furnace. Likewise, temperature-measurement systems should be regularly checked for accuracy.
SCOPE
1.1 This practice is intended as an aid in establishing a suitable procedure for the heat treatment of magnesium alloys to assure proper physical and mechanical properties.
1.2 Times and temperatures are typical for various forms, sizes, and manufacturing methods and may not exactly describe the optimum heat treatment for a specific item. Consequently, it is not intended that this practice be used as a substitute for a detailed production process or procedure.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 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.
General Information
Standards Content (Sample)
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: B661 − 12 (Reapproved 2020)
Standard Practice for
1
Heat Treatment of Magnesium Alloys
This standard is issued under the fixed designation B661; 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 aging and age softening, it is the result of precipitation from a
solid solution of one or more compounds whose solubility
1.1 This practice is intended as an aid in establishing a
decreases with decreasing temperature; for each alloy suscep-
suitable procedure for the heat treatment of magnesium alloys
tible to aging, there is a unique range of time-temperature
to assure proper physical and mechanical properties.
combinations to which it will respond.
1.2 Times and temperatures are typical for various forms,
3.1.2 heat treatment—a combination of heating and cooling
sizes, and manufacturing methods and may not exactly de-
operationsappliedtoametaloralloyinthesolidstatetoobtain
scribe the optimum heat treatment for a specific item.
desiredconditionsofproperties;heatingforthesolepurposeof
Consequently, it is not intended that this practice be used as a
hot working is excluded from the meaning of this definition.
substitute for a detailed production process or procedure.
3.1.3 quenching—rapid cooling; when applicable, the fol-
1.3 This standard does not purport to address all of the
lowing more specific terms should be used: still air quenching,
safety concerns, if any, associated with its use. It is the
forced air quenching, hot water/polymer quenching.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
3.1.4 solution heat treatment—a treatment in which an alloy
mine the applicability of regulatory limitations prior to use.
is heated to a suitable temperature and held at this temperature
1.4 This international standard was developed in accor-
for a sufficient length of time to allow a desired constituent to
dance with internationally recognized principles on standard-
enter into solid solution, followed by rapid cooling to hold the
ization established in the Decision on Principles for the
constituent in solution; the material is then in a supersaturated,
Development of International Standards, Guides and Recom-
unstable state, and may subsequently exhibit Age Hardening.
mendations issued by the World Trade Organization Technical
3.1.5 T4—solution heat-treated and naturally aged to a
Barriers to Trade (TBT) Committee.
substantially stable condition.
2. Referenced Documents
3.1.6 T5—artificially aged only; applied to products which
2
2.1 ASTM Standards: are artificially aged after an elevated-temperature rapid-cool
fabrication process, such as casting or extrusion, to improve
B557 Test Methods for Tension Testing Wrought and Cast
Aluminum- and Magnesium-Alloy Products mechanical properties or dimensional stability, or both.
E21 TestMethodsforElevatedTemperatureTensionTestsof
3.1.7 T6—solution heat-treated and then artificially aged;
Metallic Materials
applies to products which are not cold worked after solution
heat-treatment.
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
4. Apparatus
3.1.1 aging—describes a time-temperature-dependent
4.1 Furnaces used for the heat treatment of magnesium are
change in the properties of certain alloys; except for strain
usually of the air chamber type and may be electrically heated
or oil- or gas-fired. Because of the atmospheres used for
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This practice is under the jurisdiction of ASTM Committee B07 on Light
solution heat treatment, furnaces must be gas tight and contain
Metals and Alloys and is the direct responsibility of Subcommittee B07.04 on
suitable equipment for the introduction of protective
Magnesium Alloy Cast and Wrought Products.
atmospheres, and means for control of those atmospheres. In
Current edition approved Nov. 1, 2020. Published December 2020. Originally
ordertopromoteuniformityoftemperature,furnacesshouldbe
approved in 1979. Last previous edition approved in 2012 as B661 – 12. DOI:
10.1520/B0661-12R20.
equipped with a high-velocity fan or comparable means for
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
circulating the atmosphere. In the design of the furnace it is
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
desirable that there be no direct radiation f
...
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