ASTM B661-03
(Practice)Standard Practice for Heat Treatment of Magnesium Alloys
Standard Practice for Heat Treatment of Magnesium Alloys
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:B661–03
Standard Practice for
1
Heat Treatment of Magnesium Alloys
This standard is issued under the fixed designation B 661; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope* or oil- or gas-fired. Because of the atmospheres used for
solution heat treatment, furnaces must be gas tight and contain
1.1 This practice is intended as an aid in establishing a
suitable equipment for the introduction of protective atmo-
suitable procedure for the heat treatment of magnesium alloys
spheres, and means for control of those atmospheres. In order
to assure proper physical and mechanical properties.
to promote uniformity of temperature, furnaces should be
1.2 Times and temperatures are typical for various forms,
equipped with a high-velocity fan or comparable means for
sizes, and manufacturing methods and may not exactly de-
circulating the atmosphere. In the design of the furnace it is
scribe the optimum heat treatment for a specific item. Conse-
desirable that there be no direct radiation from the heating
quently, it is not intended that this practice be used as a
elements or impingement of the flame on the magnesium.
substitute for a detailed production process or procedure.
4.2 Automatic recording and control equipment to control
1.3 This standard does not purport to address all of the
the temperature of the furnaces, which must be capable of
safety concerns, if any, associated with its use. It is the
maintaining temperature in the working zone to within 610°F
responsibility of the user of this standard to establish appro-
(66°C) of the specified temperature.
priate safety and health practices and determine the applica-
4.3 There must be a separate manual reset safety cutout
bility of regulatory limitations prior to use.
which will turn off the heat source in the event of any
2. Referenced Documents malfunctioning or failure of the regular control equipment.
Thesesafetycutoutsshallbesetascloselyaspracticableabove
2.1 ASTM Standards:
themaximumtemperatureforthealloybeingheattreated.This
B 557 Test Methods of Tension Testing Wrought and Cast
2
willbeabovethevariationexpected,butshallnotbemorethan
Aluminum- and Magnesium-Alloy Products
10°F(6°C)abovethemaximumsolutionheattreatingtempera-
E 21 Test Methods for Elevated Temperature Tension Tests
3
ture for the alloy being heat treated. Protective devices shall
of Metallic Materials
also be installed to turn off the heat source in case of stoppage
E 44 Definitions of Terms Relating to Heat Treatment of
4
of circulation of air, and they shall be interconnected with a
Metals
5
manual reset control.
E 527 Practice for Numbering Metals and Alloys (UNS)
4.4 Thefurnacesorovensusedforagingtreatmentsmaybe
3. Terminology
heated by means of electricity, gas, or oil. The temperature at
any point in the working zone, for any charge, shall be
3.1 Definitions:
maintained within 610°F (66°C) of the desired aging tem-
3.1.1 The definitions relating to heat treatment of metals
perature after the furnace has been brought up to the aging
appearinginDefinitionsE 44areconsideredasapplyingtothis
temperature.
practice.
4.5 Quenching:
4. Apparatus
4.5.1 Normally magnesium work loads are cooled in air.
This should be by fan cooling the furnace charge after removal
4.1 Furnaces used for the heat treatment of magnesium are
from the furnace in such a way that the cooling is uniform on
usually of the air chamber type and may be electrically heated
various parts of the furnace charge.
4.5.2 Some alloys (notably EQ21A and QE22A) are
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This practice is under the jurisdiction of ASTM Committee B07 on Light
quenched in water or other suitable media from the solution
Metals and Alloys and is the direct responsibility of Subcommittee B07.04 on
heattreatingtemperature.Quenchtanksshouldbesituatednear
Magnesium Alloy Cast and Wrought Products.
Current edition approved Apr. 10, 2003. Published August 2003. Originally
the heat treatment furnaces. If required, means of heating the
approved in 1979. Last previous edition approved in 1999 as B 661 – 99.
quench medium should be provided. Handling equipment shall
2
Annual Book of ASTM Standards, Vol 02.02.
3 be such that it is possible to quench heat treatment loads within
Annual Book of ASTM Standards, Vol 03.01.
4
30 s after the opening of the furnace door.
Discontinued; Replaced by Terminology A 941, seeAnnual Book of ASTM
Standards, Vol 01.01.
5
Annual Book of ASTM Standards, Vol 01.01.
*A Summary of Changes section appears at the end of this standard.
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