ASTM B917/B917M-12(2020)
(Practice)Standard Practice for Heat Treatment of Aluminum-Alloy Castings From All Processes
Standard Practice for Heat Treatment of Aluminum-Alloy Castings From All Processes
ABSTRACT
This practice covers the requirements for the heat treatment of aluminum alloy castings from any casting process such as investment casting, permanent mould casting, sand casting, and others. It excludes castings that are used in specific aerospace applications or those made from wrought aluminum alloys. The aluminum alloys should be subjected to controlled heat treatment using the usual air chamber furnace or other heating media like lead baths, oil baths, fluidized beds, or even superheated steam. Air chambers may be oil or gas fired or may also be electrically heated but the atmosphere inside each should be controlled to prevent porosity. Quenching is normally performed by immersing castings in a hot-water bath. It is 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 covers, when specified by material specification or purchase order, the heat treatment of aluminum alloy castings from all casting processes.
1.1.1 The heat treatment of aluminum alloy castings used in specific aerospace applications is covered in AMS 2771 and specific AMS material specifications.
1.1.2 The heat treatment of wrought aluminum alloys is covered in Practice B918/B918M.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
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
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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: B917/B917M − 12 (Reapproved 2020)
Standard Practice for
Heat Treatment of Aluminum-Alloy Castings From All
Processes
This standard is issued under the fixed designation B917/B917M; 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 2.2 ASTM Standards:
B26/B26M Specification for Aluminum-Alloy Sand Cast-
1.1 This practice covers, when specified by material speci-
ings
fication or purchase order, the heat treatment of aluminum
B108/B108M Specification for Aluminum-Alloy Permanent
alloy castings from all casting processes.
Mold Castings
1.1.1 The heat treatment of aluminum alloy castings used in
B275 PracticeforCodificationofCertainZinc,TinandLead
specific aerospace applications is covered in AMS 2771 and
Die Castings (Withdrawn 2020)
specific AMS material specifications.
B557 Test Methods for Tension Testing Wrought and Cast
Aluminum- and Magnesium-Alloy Products
1.1.2 The heat treatment of wrought aluminum alloys is
B557M Test Methods for Tension Testing Wrought and Cast
covered in Practice B918/B918M.
Aluminum- and Magnesium-Alloy Products (Metric)
1.2 The values stated in either SI units or inch-pound units
B618/B618M Specification forAluminum-Alloy Investment
are to be regarded separately as standard. The values stated in
Castings
each system are not necessarily exact equivalents; therefore, to
B686/B686M Specification for Aluminum Alloy Castings,
ensure conformance with the standard, each system shall be
High-Strength
used independently of the other, and values from the two
B881 Terminology Relating toAluminum- and Magnesium-
systems shall not be combined.
Alloy Products
B918/B918M Practice for Heat Treatment of Wrought Alu-
1.3 This standard does not purport to address all of the
minum Alloys
safety concerns, if any, associated with its use. It is the
B955/B955M SpecificationforAluminum-AlloyCentrifugal
responsibility of the user of this standard to establish appro-
Castings
priate safety, health, and environmental practices and deter-
B969/B969M Specification for Aluminum-Alloy Castings
mine the applicability of regulatory limitations prior to use.
Produced by Squeeze Casting, and the Semi-Solid Thixo-
1.4 This international standard was developed in accor-
cast and Rheocast Casting Processes
dance with internationally recognized principles on standard-
G110 Practice for Evaluating Intergranular Corrosion Resis-
ization established in the Decision on Principles for the
tance of Heat Treatable Aluminum Alloys by Immersion
Development of International Standards, Guides and Recom-
in Sodium Chloride + Hydrogen Peroxide Solution
mendations issued by the World Trade Organization Technical 4
2.3 ANSI Standard:
Barriers to Trade (TBT) Committee.
ANSI H35.1/H35.1M Alloy and Temper Designation Sys-
tems for Aluminum
2. Referenced Documents 5
2.4 SAE Standard:
AMS 2771 Heat Treatment of Aluminum Alloy Castings
2.1 The following documents of the issue in effect on the
date of material purchase form a part of this practice to the
extent referenced herein:
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
1 3
This practice is under the jurisdiction of ASTM Committee B07 on Light The last approved version of this historical standard is referenced on
Metals and Alloys and is the direct responsibility of Subcommittee B07.01 on www.astm.org.
Aluminum Alloy Ingots and Castings. Available fromAluminumAssociation, 1400 Crystal Dr., Suite 430,Arlington,
Current edition approved Nov. 1, 2020. Published December 2020. Originally VA 22202, http://www.aluminum.org.
approved in 2001. Last previous edition approved in 2012 as B917/B917M – 12. Available from SAE International (SAE), 400 Commonwealth Dr.,Warrendale,
DOI: 10.1520/B0917_B0917M-12R20. PA 15096, http://www.sae.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B917/B917M − 12 (2020)
material is thoroughly and effectively flushed is satisfactory for quench-
3. Terminology
ing. Alternative quench media are frequently contingent on the particular
3.1 Definitions:
alloy and the end use of the casting.
3.1.1 RefertoTerminologyB881forterminologyrelatingto
the heat treatment of castings.
5. Furnace Temperature Uniformity and Calibration
Requirements
4. Equipment
5.1 Calibration of Equipment:
4.1 Heating Media—Aluminum castings are typically heat
5.1.1 Thermocouple wire and sensors shall be calibrated
treated in air chamber furnaces; however, lead baths, oil baths,
against wire or sensors whose calibration is traceable to NIST.
fluidized beds, or even superheated steam may be used in
Thermocouplesmadefromcalibratedwirerollsmaybeusedin
specific applications. The use of uncontrolled heating is not
lieuofindividuallycalibratedthermocouplesinwhichcase,the
permitted. Whichever heating means are employed, careful
roll calibration shall be that of the average of samples taken
evaluation is required to ensure that the casting responds
from both ends of the roll. The roll shall not be used if the
properlytoheattreatmentandisnotoverheatedordamagedby
difference in the highest and lowest reading exceeds 2 °F
the heat treatment environment. Salt baths are not recom-
[1 °C].
mended for the commercial heat treatment of aluminum
5.1.2 Working instruments shall be calibrated at least once
castings in volume. (Warning—Nitrate baths must not be used
every three months against a test instrument that is traceable to
in the heat treatment of 5xx.0 series castings because of the
NIST. Accuracy shall be 6 \0.3 % of range.
inherent explosion hazard.)
5.2 Furnace Temperature Survey:
4.2 Air Chamber Furnaces—Air chamber furnaces may be
5.2.1 A temperature survey, to ensure compliance with the
oil or gas-fired or may be electrically heated. The atmosphere
applicable recommendations presented herein, shall be per-
in air chamber furnaces must be controlled to prevent porosity
formed for each furnace.
resulting from solution heat treatment. Furnace components
5.2.2 A new temperature survey shall be made after any
that are significantly hotter than the metal should be suitably
modification, repair, adjustment (for example, to power
shielded for section thicknesses of less than 0.250 in. [6 mm]
controls, or baffles), or rebuild which may have altered the
to prevent adverse radiation effects. The atmosphere in air
temperature uniformity characteristics of the furnace and
chamber furnaces must be controlled to prevent porosity
reduced the effectiveness of the heat treatment.
resulting from solution heat treatment (see Note 1). The
suitability of the atmosphere in an air-chamber furnace can be 5.3 Batch Furnace Surveys:
5.3.1 The initial temperature survey shall be made at the
demonstrated by testing, in accordance with 8.4.3.1, that
products processed in that furnace are substantially free of heat maximum and minimum temperature of solution heat treat-
ments and precipitation heat treatments for which each furnace
treat induced porosity.
is to be used. There shall be at least one test location for each
NOTE 1—Heat treat induced porosity may lower mechanical properties
3 3
25 ft [0.70 m ] of air furnace volume up to a maximum of 40
and commonly causes blistering of the surface of the material. The
test locations, with a minimum of nine test locations, one in
condition is most likely to occur in furnaces in which the products of
combustion contact the work, particularly if the gases are high in water each corner and one in the center.
vapor or contain compounds of sulfur. Surface discoloration is a normal
5.3.2 After the initial survey, each furnace shall be surveyed
result of solution heat treatment of aluminum alloys and should not be
monthly, except as provided in 5.3.7.The monthly survey shall
interpreted as evidence of damage from overheating or as heat treat
be at one operating temperature for solution heat treatment and
induced porosity.
one for precipitation heat treatment.
4.3 Automatic Recording and Control Equipment, to control
5.3.3 There shall be at least one test location for each 40 ft
temperature of air furnaces shall be capable of maintaining
[1 m ] of load volume, with a minimum of nine test locations,
temperature in the working zone to within 610 °F [65 °C] of
one in each corner and one in the center.
the specified temperature.
5.3.4 The surveys shall reflect the normal operating charac-
4.4 Quench Baths—Quenching is normally performed by
teristics of the furnace. If the furnace is normally charged after
immersion of castings in a hot-water bath as described in
being stabilized at the correct operating temperature, the
Tables 1-4. The water baths must be located close enough to
temperature-sensing elements shall be similarly charged. If the
solutionheat-treatingfacilitiestominimizedelayinquenching.
furnace is normally charged cold, the temperature-sensing
Tanks must be of adequate size for the expected work load and
elements shall be charged cold. After insertion of the
must have the means of providing adequate circulation of the
temperature-sensing elements, readings should be taken fre-
quenching media about the work load. Means for heating or
quently enough to determine when the temperature of the
cooling the quench water should be available when needed.
hottest region of the furnace approaches the bottom of the
temperaturerangebeingsurveyed.Fromthattimeuntilthermal
NOTE 2—Quenching may be performed by alternative means such as
total immersion in a glycol and water solution, a liquefied gas, cold water, equilibrium is reached, the temperature of all test locations
hot water, or boiling water, or by air blast or fog to minimize distortion
should be determined at 2-min intervals in order to detect any
provided samples from the material, so quenched, will conform to the (1)
over-shooting. After thermal equilibrium is reached, readings
mechanical properties, (2) other requirements of the applicable casting
should be taken at 5-min intervals for sufficient time to
specification, and (3) not exhibit more intergranular corrosion suscepti-
determine the recurrent temperature pattern, but for not less
bility than if the metal was immersion quenched in cold water. The use of
water sprays or high-velocity high-volume jets of water in which the than30min.Beforethermalequilibriumisreached,noneofthe
B917/B917M − 12 (2020)
TABLE 1 Recommended Heat Treatment for Sand and Investment Type Alloys (Inch-Pound Units)
B,C D
Solution Heat Treatment Precipitation Heat Treatment
A A
Alloy Final Temper
Metal Temperature, Time at Metal Temperature, Time at
±10 °F Temperature, h ±10 °F Temperature, h
E
201.0 T6 960 2 room temperature 12 to 24
14 to 20
then 980 then 310 20
E
T7 960 2 room temperature 12 to 24
14 to 20
then 980 then 370 5
E
A201.0 T7 955 2 room temperature 12 to 24
14 to 20
then 985 then 370 5
E
203.0 T6 955 2 room temperature 12 to 24
then 1010 then 425 16
F
204.0 T4 970 10 room temperature 5 days
E
A206.0 T4 950 2 room temperature 5 days
14 to 20
then 985
E
T43 950 2 room temperature 12 to 24
14 to 20
then 985 then 320 0.5to1
G E
T6 950 2 room temperature 12 to 24
14 to 20
then 985 then 310 20
E
T7 950 2 room temperature 12 to 24
14 to 20
then 985 then 370 4to5
D,H H
222.0 O . . 600 3
T61 310
945 6to12 11
D,H H
242.0 O . . 650 3
T571 400
... ... 8
T61 I 450
960 2to6 1to3
A242.0 T75 965 6 to 10 550 2 to 5
295.0 T4 960 6 to 12 . .
T6 960 6 to 12 310 3 to 6
T62 960 6 to 12 310 12 to 24
T7 960 6 to 12 500 4 to 6
296.0 T4 950 4to8 . .
T6 950 4to8 310 2to8
T7 950 4to8 500 4to6
319.0 T4 940 6to10 . .
T5 . . 400 8
T6 940 6to12 310 2to5
328.0 T6 960 12 310 2 to 5
355.0 T51 . . 440 7to9
T6 980 6to12 310 3to5
T7 980 6to12 440 3to5
T71 980 6to12 475 4to6
J
C355.0 T6 985 6 to 12 room temperature 8
then 310 3to5
356.0 T51 . . 440 7to9
K
T6 1000 6to12 310 3to5
K
6to12
T7 1000 400 3to5
K
6to12
T71 1000 475 2to4
K
A356.0 T6 1000 6to12 310 2to5
K
6to12
T61 1000 330 6to12
K
6to12
T7 1000 440 8
K
6to12
T71 1000 475 3to6
H K
357.0 T6 1000 8 330 6to12
K
1000 10 to 12
T61 310 10 to 12
J H K
A357.0 T61 1000 8to10 room temperature 8
then 310 8
A390.0 T6 925 8 to 12 350 8
L
520.0 T4 810 12 to 18 . .
705.0 T1 . . room temperature 21 days
T5 210 8
707.0 T1 . . room temperature 21 days
T5 . . 210 8
T7 990 8to16 350 4to10
710.0 T5 . . room temperature 21 days
or 315 6to8
712.0 T5 . . room temperature 21 days
or 315 6to8
713.0 T1 . . room temperature 21 days
T5 250 16
771.0 T5 . . 355 3to5
T51 . . 405 6
J M
T52 . . 330 6to16
D
265 3
T6 1090 6
J,D
360 4
...
T53 .
D
285 15
T71 1090
850.0 T5 . . 430 7 to 9
851.0 T5 . . 430 7 to 9
B917/B917M − 12 (2020)
TABLE 1 Continued
B,C D
Solution Heat Treatment Precipitation Heat Treatment
A A
Alloy Final Temper
Metal Temperature, Time at Metal Temperature, Time at
±10 °F Temperature, h ±10 °F Temperature, h
852.0 T5 . . 430 7 to 9
A
Designations conform to ANSI H35.1/H35.1M and to Practice B275.
B
Quench in water at 150 to 212 °F except as noted.
C
Time at solution temperature may be increased for section thickness over 1 in.
D
No quenching required. Cool in still air outside the furnace.
E
Cooling not required prior to second step.
F
In order to expedite testing, alloy 204.0 test specimens may be precipitation heat treated after quenching by holding at 255 °F for 2 h.
G
This alloy is stress corrosion crack prone when in the T6 temper and should not be used in the T6 temper for applications that see, even mildly corrosive environments.
H
Solution treatment temperature of 1010 °F may be used (to obtain higher solubility) provided no portion of the heat treat oven exceeds 1020 °F.
I
Quenching is accomplished by air blast.
J
Stress relieve for dimensional stability in the following manner: (1)holdat775±25°Ffor5h,(2) furnace cool to 650 °F for 2 or more h, (3) furnace cool to 450 °F for
not more than ⁄4 h, (4) furnace cool to 250 °F for approximately 2 h, and (5) cool to room temperature in still air outside the furna
...
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