Designation: B 917/B 917M – 08

Standard Practice for

Heat Treatment of Aluminum-Alloy Castings from All
Processes1
This standard is issued under the fixed designation B 917/B 917M; 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.
Note—Table 1 and section 7.1 updated and the year date was changed on Aug. 7, 2008.

1. Scope* B 275 Practice for Codification of Certain Nonferrous Met-

1.1 This practice covers, when specified by material speci- als and Alloys, Cast and Wrought
fication or purchase order, the heat treatment of aluminum B 557 Test Methods for Tension Testing Wrought and Cast
alloy castings from all casting processes. Aluminum- and Magnesium-Alloy Products
1.1.1 The heat treatment of aluminum alloy castings used in B 557M Test Methods for Tension Testing Wrought and
specific aerospace applications is covered in AMS 27712 and Cast Aluminum- and Magnesium-Alloy Products (Metric)
specific AMS2 material specifications. B 618 Specification for Aluminum-Alloy Investment Cast-
1.1.2 The heat treatment of wrought aluminum alloys is ings
covered in Practice B 918. B 686 Specification for Aluminum Alloy Castings, High-
1.2 The values stated in either inch-pound units or SI units Strength
are to be regarded separately as standards. The SI units are B 881 Terminology Relating to Aluminum- and
shown in brackets or in separate tables. The values stated in Magnesium-Alloy Products
each system are not exact equivalents, therefore each system B 918 Practice for Heat Treatment of Wrought Aluminum
must be used independent of the other. Combining values from Alloys
the two systems may result in non-conformance with the G 110 Practice for Evaluating Intergranular Corrosion Re-
practice. sistance of Heat Treatable Aluminum Alloys by Immersion
1.3 This standard does not purport to address all of the in Sodium Chloride + Hydrogen Peroxide Solution
safety concerns, if any, associated with its use. It is the 2.3 ANSI Standard:
responsibility of the user of this standard to establish appro- H35.1 Alloy and Temper Designation Systems for Alumi-
priate safety and health practices and determine the applica- num4
bility of regulatory limitations prior to use. 2.4 SAE Standard:
AMS 2771 Heat Treatment of Aluminum Alloy Castings
2. Referenced Documents
3. Terminology
2.1 The following documents of the issue in effect on the
date of material purchase form a part of this specification to the 3.1 Definitions:
extent referenced herein: 3.1.1 Refer to Terminology B 881 for terminology relating
2.2 ASTM Standards: 3 to the heat treatment of castings.
B 26/B 26M Specification for Aluminum-Alloy Sand Cast-
4. Equipment
ings
B 108 Specification for Aluminum-Alloy Permanent Mold 4.1 Heating Media—Aluminum castings are typically heat
Castings treated in air chamber furnaces; however, lead baths, oil baths,
fluidized beds, or even superheated steam may be used in
specific applications. The use of uncontrolled heating is not
1
This practice is under the jurisdiction of ASTM Committee B07 on Light
permitted. Whichever heating means are employed, careful
Metals and Alloys and is the direct responsibility of Subcommittee B07.01 on evaluation is required to ensure that the casting responds
Aluminum Alloy Ingots and Castings. properly to heat treatment and is not overheated or damaged by
Current edition approved Aug. 7, 2008. Published August 2008. Originally the heat treatment environment. Salt baths are not recom-
approved in 2001. Last previous edition approved in 2007 as B 917/B 917M – 2007.
2
Available from Society of Automotive Engineers (SAE), 400 Commonwealth
mended for the commercial heat treatment of aluminum
Dr., Warrendale, PA 15096-0001, http://www.sae.org.
3
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
4
Standards volume information, refer to the standard’s Document Summary page on Available from Aluminum Association, Inc., 1525 Wilson Blvd., Suite 600,
the ASTM website. Arlington, VA 22209, http://www.aluminum.org.

*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.

1
 B 917/B 917M – 08
castings in volume. (Warning—Nitrate baths must not be used 5.2 Furnace Temperature Survey:
in the heat treatment of 5xx.0 series castings because of the 5.2.1 A temperature survey, to ensure compliance with the
inherent explosion hazard. applicable recommendations presented herein, shall be per-
4.2 Air Chamber Furnaces—may be oil or gas-fired or may formed for each furnace.
be electrically heated. The atmosphere in air chamber furnaces 5.2.2 A new temperature survey shall be made after any
must be controlled to prevent porosity resulting from solution modification, repair, adjustment (for example, to power con-
heat treatment. Furnace components that are significantly trols, or baffles), or rebuild which may have altered the
hotter than the metal should be suitably shielded for section temperature uniformity characteristics of the furnace and
thicknesses of less than 0.250 in. [6 mm] to prevent adverse reduced the effectiveness of the heat treatment.
radiation effects. The atmosphere in air chamber furnaces must
be controlled to prevent porosity resulting from solution heat 5.3 Batch Furnace Surveys:
treatment (see Note 1). The suitability of the atmosphere in an 5.3.1 The initial temperature survey shall be made at the
air-chamber furnace can be demonstrated by testing, in accor- maximum and minimum temperature of solution heat treat-
dance with 8.4.3.1, that products processed in that furnace are ments and precipitation heat treatments for which each furnace
substantially free of heat treat induced porosity. is to be used. There shall be at least one test location for each
25 ft3 [0.70 m3] of air furnace volume up to a maximum of 40
NOTE 1—Heat treat induced porosity may lower mechanical properties
test locations, with a minimum of nine test locations, one in
and commonly causes blistering of the surface of the material. The
condition is most likely to occur in furnaces in which the products of each corner and one in the center.
combustion contact the work, particularly if the gases are high in water 5.3.2 After the initial survey, each furnace shall be surveyed
vapor or contain compounds of sulfur. Surface discoloration is a normal monthly, except as provided in 5.3.7. The monthly survey shall
result of solution heat treatment of aluminum alloys and should not be be at one operating temperature for solution heat treatment and
interpreted as evidence of damage from overheating or as heat treat
one for precipitation heat treatment.
induced porosity.
5.3.3 There shall be at least one test location for each 40 ft3
4.3 Automatic Recording and Control Equipment—to con- [1 m3] of load volume, with a minimum of nine test locations,
trol temperature of air furnaces shall be capable of maintaining one in each corner and one in the center.
temperature in the working zone to within 610°F [65°C] of
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
solution heat-treating facilities to minimize delay in quenching. 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
temperature range being surveyed. From that time until thermal
NOTE 2—Quenching may be performed by alternative means such as equilibrium is reached, the temperature of all test locations
total immersion in a glycol and water solution, a liquefied gas, cold water, should be determined at 2-min intervals in order to detect any
hot water, or boiling water, or by air blast or fog to minimize distortion
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 susceptibil- determine the recurrent temperature pattern, but for not less
ity than if the metal was immersion quenched in cold water. The use of than 30 min. Before thermal equilibrium is reached, none of the
water sprays or high-velocity high-volume jets of water in which the temperature readings should exceed the maximum temperature
material is thoroughly and effectively flushed is satisfactory for quench- of the range being surveyed. After thermal equilibrium is
ing. Alternative quench media are frequently contingent on the particular
reached, the maximum temperature variation of all elements
alloy and the end use of the casting.
(both load and furnace thermocouples) shall not exceed 20°F
5. Furnace Temperature Uniformity and Calibration [10°C] and shall not vary outside the range being surveyed.
Requirements 5.3.5 For furnaces of 10 ft3 [0.25 m3] or less the temperature
5.1 Calibration of Equipment: survey may be made with a minimum of three thermocouples
5.1.1 Thermocouple wire and sensors shall be calibrated located at front, center, and rear or at top, center, and bottom of
against wire or sensors whose calibration is traceable to NIST). the furnace.
Thermocouples made from calibrated wire rolls may be used in 5.3.6 For furnaces used only for precipitation treatment,
lieu of individually calibrated thermocouples in which case, the after the initial temperature-uniformity survey, as outlined in
roll calibration shall be that of the average of samples taken 5.3.7, surveys need not be made more often than at each
from both ends of the roll. The roll shall not be used if the 6-month interval provided that (1) test specimens from each lot
difference in the highest and lowest reading exceeds 2°F [1°C]. are tested and meet applicable material specifications require-
5.1.2 Working instruments shall be calibrated at least once ments, (2) the furnace is equipped with a multipoint recorder,
every three months against a test instrument that is traceable to or (3) one or more separate load thermocouples are employed
NIST. Accuracy shall be 6 \0.3 % of range. to measure and record actual metal temperatures.

2
 B 917/B 917M – 08
5.3.7 Monthly surveys for batch furnaces are not necessary 5.5 Monitoring of Quench—A monitoring plan shall be
when the furnace or bath is equipped with a permanent developed and utilized for all modes of quenching for all
multipoint recording system with at least two sensing thermo- products covered by this practice. The plan should incorporate
couples in each zone or when one or more separate load conductivity or hardness checking, or both, to determine the
thermocouples are employed to measure actual metal tempera- uniformity of the quench. Areas having substantially higher
ture, providing that uniformity surveys show a history of conductivity or lower hardness than other areas of similar
satisfactory performance for a period of at least 6 months. The thickness in the lot shall be investigated to ensure that the
sensing thermocouples shall be installed so as to record the requirements of the material specification are met.
temperature of the heated media (air, lead, and so forth) or
5.6 Temperature-Measuring System Check—The accuracy
actual metal temperatures. However, periodic surveys shall
of the temperature-measuring system shall be checked under
also be made at 6-month intervals in accordance with the
procedures outlined for the monthly survey. operating conditions weekly. Check should be made by insert-
5.4 Continuous Furnace Surveys: ing a calibrated test temperature-sensing element adjacent to
5.4.1 For continuous heat-treating furnaces, the type of the furnace temperature-sensing element and reading the test
survey and the procedures for performing the survey should be temperature-sensing element with a calibrated test potentiom-
established for each particular furnace involved. The types of eter. When the furnace is equipped with dual potentiometer
continuous heat-treating furnaces may vary considerably, de- measuring systems which are checked daily against each other,
pending upon the product and sizes involved. For some types the above checks may be conducted every 3 months rather than
and sizes of furnaces, the only practical way to survey the every week. The test temperature-sensing element, potentiom-
furnace is to perform an extensive mechanical property survey eter, and cold junction compensation combination shall have
of the limiting product sizes to verify conformance with the been calibrated against NIST primary or secondary certified
specified mechanical properties for such items. When the type temperature-sensing elements, within the previous 3 months, to
and size of the furnace makes this practical, monthly surveys an accuracy of 62°F [61°C].
should be made, using a minimum of two load thermocouples 5.6.1 If the difference between the two readings in 5.6
attached to the material. The surveys should reflect the normal exceeds 610°F [66°C], the cause of the difference shall be
operating characteristics of the furnace. The results of these determined and corrected before commencing additional ther-
surveys shall indicate that the metal temperature never exceeds mal processing. The responsible quality organization shall be
the allowable maximum metal temperature specified for solu-
notified and appropriate corrective action shall be taken and
tion heat treatment (Tables 1-4 as appropriate) after all load
documented including an evaluation of the possible effects of
thermocouples have reached the minimum metal temperature
the deviation on castings processed since the last successful
specified.
5.4.2 Furnace control temperature-measuring instruments test.
shall not be used to read the temperature of the test temperature
sensing elements.

TABLE 1 Recommended Heat Treatment for Sand and Investment Type Alloys (Inch-Pound Units)

Solution Heat TreatmentB,C Precipitation Heat TreatmentD

AlloyA Final TemperA Metal Temperature, Time at Metal Temperature, Time at
610°F Temperature, h 610°F Temperature, h
201.0 T6 960 2E room temperature 12 to 24
then 980 14 to 20 then 310 20
T7 960 2E room temperature 12 to 24
then 980 14 to 20 then 370 5
A201.0 T7 955 2E room temperature 12 to 24
then 985 14 to 20 then 370 5
203.0 T6 955 2E room temperature 12 to 24
then 1010 5 then 425 16
204.0 T4 970 10 room temperature 5 daysF
A206.0 T4 950 2E room temperature 5 days
then 985 14 to 20
T43 950 2E room temperature 12 to 24
then 985 14 to 20 then 320 0.5 to 1
G
T6 950 2E room temperature 12 to 24
then 985 14 to 20 then 310 20
T7 950 2E room temperature 12 to 24
then 985 14 to 20 then 370 4 to 5
222.0 OD,H ... ... 600H 3
T61 945 6 to 12 310 11
242.0 OD,H ... ... 650H 3
T571 ... ... 400 8
T61 960 2 to 6I 450 1 to 3
A242.0 T75 965 6 to 10 550 2 to 5
295.0 T4 960 6 to 12 ... ...

3
 B 917/B 917M – 08

TABLE 1 Continued
Solution Heat TreatmentB,C Precipitation Heat TreatmentD
AlloyA Final TemperA Metal Temperature, Time at Metal Temperature, Time at
610°F Temperature, h 610°F Temperature, h
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 4 to 8 ... ...
T6 950 4 to 8 310 2 to 8
T7 950 4 to 8 500 4 to 6
319.0 T4 940 6 to 10 ... ...
T5 ... ... 400 8
T6 940 6 to 12 310 2 to 5
328.0 T6 960 12 310 2 to 5
355.0 T51 ... ... 440 7 to 9
T6 980 6 to 12 310 3 to 5
T7 980 6 to 12 440 3 to 5
T71 980 6 to 12 475 4 to 6
C355.0J T6 985 6 to 12 room temperature 8
then 310 3 to 5
356.0 T51 ... ... 440 7 to 9
T6 1000 6 to 12 310 3 to 5
T7 1000 6 to 12 400 3 to 5
T71 1000 6 to 12 475 2 to 4
A356.0 T6 1000 6 to 12 310 2 to 5
T61 1000 6 to 12 330 6 to 12
T7 1000 6 to 12 440 8
T71 1000 6 to 12 475 3 to 6
357.0 T6 1000H 8 330 6 to 12
T61 1000 10 to 12 310 10 to 12
A357.0J T61 1000H 8 to 10 room temperature 8
then 310 8
520.0 T4 810 12 to 18K ... ...
705.0 T1 ... ... room temperature 21 days
T5 210 8
707.0 T1 ... ... room temperature 21 days
T5† ... ... 210 8
T7† 990 8 to 16 350 4 to 10
710.0 T5 ... ... room temperature 21 days
or 315 6 to 8
712.0 T5 ... ... room temperature 21 days
or 315 6 to 8
713.0 T1 ... ... room temperature 21 days
T5 250 16
771.0 T5 ... ... 355 3 to 5
T51 ... ... 405 6
T52 ... ... 330J 6 to 16L
T6 1090 6D 265 3
T53 ... ... 360J,D 4
T71 1090 6D 285 15
850.0 T5 ... ... 430 7 to 9
851.0 T5 ... ... 430 7 to 9
852.0 T5 ... ... 430 7 to 9
A
Designations conform to ANSI H35.1 and to Practice B 275.
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) Hold at 775 6 25°F for 5 h; (2) Furnace cool to 650°F for 2 or more h; (3) Furnace cool to 450°F
for not more than 3⁄4 h; (4) Furnace cool to 250°F for approximately 2 h; and (5) Cool to room temperature in still air outside the furnace.
K
Quench in water at 150 to 212°F for a controlled time of 10 to 20 s, then cool in still air outside the furnace.
L
Time required depends on variations in cooling rate between 650° and 450°F during stress-relief procedure (Footnote J).
† Editorially corrected

4
 B 917/B 917M – 08
TABLE 2 Recommended Heat Treatment for Sand and Investment Type Aluminum Alloys [SI Units]

Solution Heat TreatmentB,C Precipitation Heat TreatmentD

AlloyA Final TemperA Metal Temperature, Time at Metal Temperature, Time at
65°C Temperature, h 65°C Temperature, h
201.0 T6 515 2E room temperature 12 to 24
then 525 14 to 20 then 155 20
T7 515 2E room temperature 12 to 24
then 525 14 to 20 then 190 5
A201.0 T7 515 2E room temperature 12 to 24
then 530 14 to 20 then 190 5
203.0 T6 515 2E room temperature 12 to 24
then 545 5 then 220 16
204.0 T4 520 10 room temperature 5 daysF
A206.0 T4 510 2E room temperature 5 days
then 530 14 to 20
T43 510 2E room temperature 12 to 24
then 530 14 to 20 then 160 0.5 to 1
T6G 510 2E room temperature 12 to 24
then 530 14 to 20 then 155 20
T7 510 2E room temperature 12 to 24
then 530 14 to 20 then 190 4 to 5
222.0 OD,H ... ... 315H 3
T61 510 6 to 12 155 11
242.0 OD,H ... ... 345H 3
T571 ... ... 205 8
T61 515 2 to 6I 230 1 to 3
A242.0 T75 520 6 to 10 290 2 to 5
295.0 T4 515 6 to 12 ... ...
T6 515 6 to 12 155 3 to 6
T62 515 6 to 12 155 12 to 24
T7 515 6 to 12 260 4 to 6
296.0 T4 510 4 to 8 ... ...
T6 510 4 to 8 155 2 to 8
T7 510 4 to 8 260 4 to 6
319.0 T4 505 6 to 10 ... ...
T5 ... ... 205 8
T6 505 6 to 12 155 2 to 5
328.0 T6 515 12 155 2 to 5
355.0 T51 ... ... 225 7 to 9
T6 525 6 to 12 155 3 to 5
T7 525 6 to 12 225 3 to 5
T71 525 6 to 12 245 4 to 6
C355.0J T6 530 6 to 12 room temperature 8
then 155 3 to 5
356.0 T51 ... ... 225 7 to 9
T6 540 6 to 12 155 3 to 5
T7 540 6 to 12 205 3 to 5
T71 540 6 to 12 245 2 to 4
A356.0 T6 540 6 to 12 155 2 to 5
T61 540 6 to 12 165 6 to 12
T7 540 6 to 12 225 8
T71 540 6 to 12 245 3 to 6
357.0 T6 540H 8 165 6 to 12
T61 540 10 to 12 155 10 to 12
A357.0J T61 540H 8 to 10 room temperature 8
then 155 8
520.0 T4 430 12 to 18K ... ...
705.0 T1 ... ... room temperature 21 days
T5 100 8
707.0 T1 ... ... room temperature 21 days
T5 ... ... 99 8
T7 530 8 to 16 175 4 to 10
710.0 T5 ... ... room temperature 21 days
or 155 6 to 8
712.0 T5 ... ... room temperature 21 days
or 155 6 to 8
713.0 T1 ... ... room temperature 21 days
T5 120 16

5
 B 917/B 917M – 08

TABLE 2 Continued
Solution Heat TreatmentB,C Precipitation Heat TreatmentD
AlloyA Final TemperA Metal Temperature, Time at Metal Temperature, Time at
65°C Temperature, h 65°C Temperature, h
771.0 T5 ... ... 180 3 to 5
T51 ... ... 205 6
T52 ... ... 165J 6 to 16L
T6 590 6D 130 3
T53 ... ... 180J,D 4
T71 590 6D 140 15
850.0 T5 ... ... 220 7 to 9
851.0 T5 ... ... 220 7 to 9
852.0 T5 ... ... 220 7 to 9
A
Designations conform to ANSI H35.1 and to Practice B 275.
B
Quench in water at 65 to 100°C except as noted.
C
Time at solution temperature may be increased for section thickness over 25 mm.
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 125°C 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 545°C may be used (to obtain higher solubility) provided no portion of the heat treat oven exceeds 550°C.
I
Quenching is accomplished by air blast.
J
Stress relieve for dimensional stability in the following manner: (1) Hold at 415 6 15°C for 5 h; (2) Furnace cool to 345°C for 2 or more h; (3) Furnace cool to 230°C
for not more than 3⁄4 h; (4) Furnace cool to 120°C for approximately 2 h; and (5) Cool to room temperature in still air outside the furnace.
K
Quench in water at 65 to 100°C for a controlled time of 10 to 20 s, then cool in still air outside the furnace.
L
Time required depends on variations in cooling rate between 345° and 230°C during stress-relief procedure (Footnote J).

TABLE 3 Recommended Heat Treatment for Permanent Mold Type Alloys (Inch-Pound Units)

Solution Heat TreatmentB,C Precipitation Heat TreatmentD

A A
Alloy Final Temper Metal Temperature, Time at Metal Temperature, Time at
610°F Temperature, h 610°F Temperature, h
201.0 T6 960 2 room temperature 12 to 24
then 980 14 to 20 then 310 20
T7 960 2 room temperature 12 to 24
then 980 14 to 20 then 370 5
A201.0 T7 955 2 room temperature 12 to 24
then 985 14 to 20 then 370 5
203.0 T6 955 2 room temperature 12 to 24
then 1010 5 then 425 16
204.0 T4 970 10 room temperature 5 daysE
A206.0 T4 950 2 room temperature 5 days
then 985 14 to 20
T43 950 2 room temperature 12 to 24
then 985 14 to 20 then 320 0.5 to 1
F
T6 950 2 room temperature 12 to 24
then 985 14 to 20 then 310 20
T7 950 2 room temperature 12 to 24
then 985 14 to 20 then 370 5
208.0 T6 940 4 to 12 310 2 to 5
222.0 T551 ... ... 340 16 to 22
T65 950 4 to 12 340 7 to 9
242.0 T571 ... ... 340 22 to 26
or 400 7 to 9
T61 960 4 to 12 400 3 to 5
296.0 T6 950 8 310 1 to 8
319.0 T4 940 4 to 10 ... ...
T6 940 4 to 12 310 2 to 5
332.0 T5 ... ... 400 7 to 9
336.0 T551 ... ... 400 7 to 9
T65 960 8 400 7 to 9
333.0 T5 ... ... 400 7 to 9
T6 940 6 to 12 310 2 to 5
T7 940 6 to 12 500 4 to 6
354.0 T61 980 10 to 12 room temperature 8
then 310 10 to 12
T62 980 10 to 12 room temperature 8
then 340 6 to 10
355.0 T51 ... ... 440 7 to 9
T6 980 4 to 12 310 2 to 5
T62 980 4 to 12 340 14 to 18
T7 980 4 to 12 440 7 to 9
T71 980 4 to 12 475 3 to 6

6
 B 917/B 917M – 08

TABLE 3 Continued
Solution Heat TreatmentB,C Precipitation Heat TreatmentD
AlloyA Final TemperA Metal Temperature, Time at Metal Temperature, Time at
610°F Temperature, h 610°F Temperature, h
C355.0G T61 980 6 to 12 room temperature 8
then 310 10 to 12
356.0 T51 ... ... 440 7 to 9
T6 1000 4 to 12 310 2 to 5
T71 1000 4 to 12 440 7 to 9
G
A356.0 T6 1000 4 to 12 310 2 to 5
T61 1000 4 to 12 room temperature 8
then 310 6 to 12
T7 1000 4 to 12 440 8
T71 1000 4 to 12 475 3 to 6
357.0 T6 1000H 8 330 6 to 12
A357.0G T61 1000H 10 room temperature 8
then 310 8
359.0G T61 1000 10 to 14 room temperature 8
then 310 10 to 12
T62 1000 10 to 14 room temperature 8
then 340 6 to 10
A444.0 T4 1000 8 to 12 ... ...
705.0 T1 ... ... room temperature 21 days
T5 210 10
707.0 T1 ... ... room temperature 21 days
T5 ... ... 210 8
T7 990 8 to 16 350 4 to 10
711.0 T1 ... ... room temperature 21 days
713.0 T1 ... ... room temperature 21 days
T5 250 16
850.0 T5 ... ... 430 7 to 9
851.0 T5 ... ... 430 7 to 9
T6 950 6 430 4
852.0 T5 ... ... 430 7 to 9
A
Designations conform to ANSI H35.1 and to Practice B 275.
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
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.
F
This alloy is stress corrosion crack prone when in the T6 temper and should not be used in the T6 temper for applications in which even mildly corrosive environments
may be encountered.
G
Stress relieve for dimensional stability in the following manner: (1) Hold at 775 6 25°F for 5 h; (2) Furnace cool to 650°F for 2 or more h; (3) Furnace cool to 450°F
for not more than 3⁄4 h; (4) Furnace cool to 250°F for approximately 2 h; (5) Cool to room temperature in still air outside the furnace.
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.

TABLE 4 Recommended Heat Treatment for Permanent Mold Type Alloys [SI Units]

Solution Heat TreatmentB,C Precipitation Heat TreatmentD

A A
Alloy Final Temper Metal Temperature, Time at Metal Temperature, Time at
6 5°C Temperature, h 6 5°C Temperature, h
201.0 T6 515 2 room temperature 12 to 24
then 525 14 to 20 then 155 20
T7 515 2 room temperature 12 to 24
then 525 14 to 20 then 190 5
A201.0 T7 515 2 room temperature 12 to 24
then 530 14 to 20 then 190 5
203.0 T6 515 2 room temperature 12 to 24
then 545 5 then 220 16
204.0 T4 520 10 room temperature 5 daysE
A206.0 T4 510 2 room temperature 5 days
then 530 14 to 20
T43 510 2 room temperature 12 to 24
then 530 14 to 20 then 160 0.5 to 1
T6F 510 2 room temperature 12 to 24
then 530 14 to 20 then 155 20
T7 510 2 room temperature 12 to 24
then 530 14 to 20 then 190 5
208.0 T6 505 4 to 12 155 2 to 5
222.0 T551 ... ... 170 16 to 22
T65 510 4 to 12 170 7 to 9
242.0 T571 ... ... 170 22 to 26
or 205 7 to 9
T61 515 4 to 12 205 3 to 5
296.0 T6 510 8 155 1 to 8

7
 B 917/B 917M – 08

TABLE 4 Continued
Solution Heat TreatmentB,C Precipitation Heat TreatmentD
AlloyA Final TemperA Metal Temperature, Time at Metal Temperature, Time at
6 5°C Temperature, h 6 5°C Temperature, h
319.0 T4 505 4 to 10 ... ...
T6 505 4 to 12 155 2 to 5
332.0 T5 ... ... 205 7 to 9
336.0 T551 ... ... 205 7 to 9
T65 515 8 205 7 to 9
333.0 T5 ... ... 205 7 to 9
T6 505 6 to 12 155 2 to 5
T7 505 6 to 12 260 4 to 6
354.0 T61 525 10 to 12 room temperature 8
then 155 10 to 12
T62 525 10 to 12 room temperature 8
then 170 6 to 10
355.0 T51 ... ... 255 7 to 9
T6 525 4 to 12 155 2 to 5
T62 525 4 to 12 170 14 to 18
T7 525 4 to 12 225 7 to 9
T71 525 4 to 12 245 3 to 6
C355.0G T61 525 6 to 12 room temperature 8
then 155 10 to 12
356.0 T51 ... ... 225 7 to 9
T6 540 4 to 12 155 2 to 5
T71 540 4 to 12 225 7 to 9
G
A356.0 T6 540 4 to 12 155 2 to 5
T61 540 4 to 12 room temperature 8
then 155 6 to 12
T7 540 4 to 12 225 8
T71 540 4 to 12 245 3 to 6
357.0 T6 540H 8 165 6 to 12
A357.0G T61 540H 10 room temperature 8
then 155 8
359.0G T61 540 10 to 14 room temperature 8
then 155 10 to 12
T62 540 10 to 14 room temperature 8
then 170 6 to 10
A444.0 T4 540 8 to 12 ... ...
705.0 T1 ... ... room temperature 21 days
T5 100 10
707.0 T1 ... ... room temperature 21 days
T5 ... ... 99 8
T7 530 8 to 16 175 4 to 10
711.0 T1 ... ... room temperature 21 days
713.0 T1 ... ... room temperature 21 days
T5 120 16
850.0 T5 ... ... 220 7 to 9
851.0 T5 ... ... 220 7 to 9
T6 510 6 220 4
852.0 T5 ... ... 220 7 to 9
A
Designations conform to ANSI H35.1 and to Practice B 275.
B
Quench in water at 65 to 100°C except as noted.
C
Time at solution temperature may be increased for section thickness over 25 mm.
D
No quenching required. Cool in still air outside the furnace.
E
In order to expedite testing, alloy 204.0 test specimens may be precipitation heat treated after quenching by holding at 125°C for 2 h.
F
This alloy is stress corrosion crack prone when in the T6 temper and should not be used in the T6 temper for applications in which even mildly corrosive environments
may be encountered.
G
Stress relieve for dimensional stability in the following manner: (1) Hold at 415 6 15°C for 5 h; (2) Furnace cool to 345°C for 2 or more h; (3) Furnace cool to 230°C
for not more than 3⁄4 h; (4) Furnace cool to 120°C for approximately 2 h; (5) Cool to room temperature in still air outside the furnace.
H
Solution treatment temperature of 545°C may be used (to obtain higher solubility) provided no portion of the heat treat oven exceeds 550°C.

TABLE 5 Recommended Heat Treatment for Centrifugal Casting Alloys (Inch-Pound Units)
AlloyA Final TemperA Solution Heat TreatmentB,C Precipitation Heat TreatmentD
Metal Temperature, 6 10°F Time at Temperature, h Metal Temperature, 6 10°F Time at Temperature, h
356.0 T6 1000 4 to 12 310 2 to 5
505.0 T61 985 6 to 12 370 6 to 8
709.0 T61 870 9 to 12 250 24
850.0 T5 ... ... 430 7 to 9
A
Designations conform to ANSI H35.1 and to Practice B 275.
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.

8
 B 917/B 917M – 08
TABLE 6 Recommended Heat Treatment for Centrifugal Casting Alloys [SI Units]
A A
Alloy Final Temper Solution Heat TreatmentB,C Precipitation Heat TreatmentD
Metal Temperature, 6 5°C Time at Temperature, h Metal Temperature, 6 5°C Time at Temperature, h
356.0 T6 540 4 to 12 155 2 to 5
505.0 T61 530 6 to 12 190 6 to 8
709.0 T61 465 9 to 12 120 24
850.0 T5 ... ... 220 7 to 9
A
Designations conform to ANSI H35.1 and to Practice B 275.
B
Quench in water at 65 to 100°C, except as noted.
C
Time at solution temperature may be increased for section thickness over 25 mm.
D
No quenching required. Cool in still air outside the furnace.

6. Preparation for Heat Treatment tensile requirements shown in the product specifications for
6.1 Furnace Loading: C355.0 and A356.0 sand-castings or investment-castings and
6.1.1 Aluminum alloy castings shall be supported and 354.0, A356.0, A357.0, and A444.0 permanent mold castings.
spaced in the furnace racks so as to permit uniform heating to 7.4 Precipitation Heat Treatment (Artificial Aging):
the final heat-treat temperature. 7.4.1 Recommended times and temperature ranges for pre-
6.1.2 Racking and spacing procedures shall be documented. cipitation heat-treating various heat-treatable aluminum alloys
6.1.3 Racking and spacing procedures shall allow free appear in Tables 1 and 2 for sand castings, and Tables 3 and 4
circulation of the quench media throughout the workload so for permanent mold castings.
that all product surfaces receive an adequate quench to meet 7.4.2 Selection of the correct aging time involves knowl-
the requirements of the material specification. edge of the aging curve for the alloy in question. As a casting
6.1.4 Batch furnace loading of small parts in baskets to be precipitation hardens, there is a natural trade-off of ductility for
water quenched shall be controlled by limiting the depth of strength. In choosing an aging time, this must be kept in mind
parts in each layer and the minimum spacing between layers to as it relates to the application under consideration. Times
preclude steam generated in any portion of the load from towards the minimum in the precipitation hardening ranges in
degrading the quench in another part of the load. Random the tables will generate more ductility at a sacrifice in strength.
packing of castings 1 in. [25 mm] or less in thickness should be Conversely, the long end of the range may well generate higher
limited to a maximum layer thickness of 3 in. [75 mm] with a strength and hardness but a lower ductility.
minimum spacing of 3 in. [75 mm] between layers. 7.4.3 At completion of precipitation time at temperature, the
work shall be allowed to cool normally to room temperature.
NOTE 3—Quenching by dumping small parts into water ensures access
of the quenching media to all surfaces of each part.
8. Quality Assurance
7. Heat Treatment Procedures 8.1 Responsibility for Inspection and Tests—Unless other-
7.1 Solution Heat Treating—Recommended solution heat- wise specified in the contract, the heat treater is responsible for
treatment times and temperatures for various heat-treatable the performance of all inspection and test requirements speci-
aluminum castings appear in Tables 1 and 2 for sand and fied herein.
investment castings, Tables 3 and 4 for permanent mold- 8.1.1 The heat treater may use his own or any other suitable
castings, and Tables 5 and 6 for centrifugal castings. facilities for the performance of inspection and test require-
7.2 Soak Time—The solution heat-treatment temperature ments specified herein.
specified in the tables is the temperature of the metal being 8.2 Records—Records shall be maintained for each furnace
treated. In the absence of a suitable metal temperature measur- to show compliance with this standard. These records shall
ing device, the soaking times appearing in Tables 1-4 as include the following: furnace number or description; size;
applicable, may be used. Note that the time ranges quoted are, temperature range of usage; whether used for solution heat
in most cases quite wide. Typically, structurally modified treatment, precipitation heat treatment, or both; temperature(s)
castings that are solidified rapidly require heat treat soak times at which uniformity was surveyed; dates of each survey,
close to the low end of each range. Examples include thin number and locations of thermocouples used; and dates of
permanent mold castings and sand castings in which a fine major repairs or alterations (see 5.2.2).
microstructure is produced due to a rapid rate of cooling. 8.2.1 The heat treater shall maintain records of all tests
Unmodified castings and those with thick sections will require required by this practice and make them available for exami-
soak times closer to the high end of the appropriate range. In nation at the heat treaters facility.
any situation, the times chosen must result in castings which 8.3 Tests and Verification of Equipment:
meet the required physical and mechanical properties. 8.3.1 Surveillance Test Requirements:
7.3 Quench—During quenching it is important that cooling 8.3.1.1 Heat-treating equipment operated in accordance
proceeds rapidly through the 750 to 500°F [400 to 260°C] with documented procedures, shall have a demonstrated capa-
range in order to avoid the type of premature precipitation bility of producing material and components meeting the
detrimental to tensile properties and corrosion resistance. For tensile and physical properties specified for each alloy heat-
casting alloys the quench delay should not exceed 45 s. treated. Surveillance tests are required to verify the continued
Reduced quench delay time may be necessary to attain the acceptability of the heat treatment.

9
 B 917/B 917M – 08
8.3.1.2 Frequency of Tests—Tests shall be made once each eutectic gives evidence of solution heat treatment. Sections
month or more frequently as may be required. Testing one load taken from product or test specimens shall be compared to
per furnace per month shall constitute conformance with the suitable known specimens in both the F temper and the T4, T6,
requirements of this paragraph. or T7 tempers. The fine fibrous eutectic Si seen in structurally
8.3.1.3 Use of Production Test Results—In all cases, the modified 3xx.0 castings in the F temper will have undergone
results of tests made to determine conformance of heat-treated ripening and spheroidization if properly solution heat treated.
material to the requirements of the respective material speci- This test shall only be applied to structurally modified Al-Si
fications are acceptable as evidence of the properties being based foundry alloys. A comparison pair of micrographs is
obtained with the equipment and procedure employed. reproduced in Fig. 1 as an example of the difference to be
8.3.1.4 When frequent testing is desired, per batch or daily, expected in Al-Si eutectic microstructure before and after
the use of separately cast tensile bars or cast-on coupons as a solution heat treatment.
surveillance test for heat treatment is highly recommended. 8.5 Interpretation of Results:
Separately cast bars shall be cast as per the recommendations 8.5.1 Test specimens prepared in accordance with 8.3, and
of Specifications B 26/B 26M, B 108, or B 618 as appropriate treated in accordance with the applicable parts of Section 7
to sand, permanent mold, or investment castings respectively. shall meet the requirements specified below. Failure to meet
The bars shall be processed through the heat treatment equip- the specified mechanical or physical requirements is reason to
ment together with the related castings. In the case of high disqualify the heat-treating equipment and associated process
strength castings in which cast-on coupons are used, these shall until the reason for the failure is determined and appropriate
be processed as outlined in Specification B 686. corrective action completed.
8.4 Surveillance Test Methods: 8.5.2 Tensile Properties—Heat-treated test samples or sepa-
8.4.1 Tensile Properties—Tensile properties specified for rately cast test bars shall exhibit tensile strength, yield strength,
the alloy involved shall be established by tension testing in and elongation properties not less than those specified in
accordance with Test Methods B 557 [B 557M]. applicable procurement specifications or detail drawings.
8.4.2 When allowed by the casting specification, separately 8.5.3 Eutectic Melting—Specimens shall be free from eu-
cast tensile bars may be used for both furnace surveillance and tectic melting as evidenced by rosettes or eutectic structure at
production tensile testing. Note that these bars shall meet a
grain boundary triple points.
pass/fail material specification established for the given alloy
and temper, as separately cast bars. The separately cast bars 8.5.4 Intergranular Corrosion—There shall be no evidence
may differ from those machined from the castings, particularly of excessive intergranular corrosion. Consideration shall be
with respect to ductility, a property very sensitive to section given to size and thickness of the material in deciding whether
thickness and solidification rate. In any case, the required tests the intergranular corrosion is excessive. Degree of susceptibil-
for casting properties shall conform to the respective casting ity to intergranular corrosion shall be not greater than normally
specifications and any mechanical property requirements called experienced when following this practice.
out on the drawings. In the case of cast-on coupons the test 8.5.5 Metallographic Examination of Eutectic Si—The mor-
results shall meet the highest strength requirements of the phology of the Al-Si eutectic must be consistent with the heat
casting in accordance with Specification B 686. treatment. Solution heat treating shall be deemed to have failed
8.4.3 Periodic Physical Property Testing—The following if the eutectic morphology is consistent with the F-temper.
physical property tests may be specified as part of the reaction 8.5.6 Rejection and Reheat Treatment—Materials heat
or Failure Mode and Effects Analysis (FMEA) for dealing with treated in the furnace since the time of the previous satisfactory
failure to meet mechanical properties. They may also be tests and found unsatisfactory shall be rejected or reheat treated
specified as part of regular testing under circumstances in (beginning with the solution heat treatment) in an acceptable
which the combination of alloy, temper, and service environ- furnace, depending on the character of the failed tests. Mate-
ment makes this advisable. rials in which eutectic melting resulting from solution heat
8.4.3.1 Eutectic Melting and Porosity Resulting from Solu- treatment is found shall be rejected and no reheat treatment
tion Heat Treatment—Specimens from heat-treated product or permitted. Materials that fail for reasons other than those
samples shall be sectioned and the sections polished to enumerated above may be heat treated again.
appropriate fineness. The unetched surface shall be examined
at 500 diameters magnification with a metallurgical micro- 9. Precision and Bias
scope to detect evidence of porosity resulting from solution 9.1 No information is presented about either precision or
heat treatment. The sections may then be mildly etched bias of metallurgical testing for evaluation of eutectic melting
(approximately 2 s) in an etchant and examined at 500 and heat treat induced porosity (8.4.3.1), or intergranular
diameters magnification to detect evidence of eutectic melting. corrosion (8.4.3.2), since the test results are non-quantitative.
8.4.3.2 Intergranular Corrosion Test—Intergranular Corro-
sion tests shall be conducted in accordance with the procedure 10. Keywords
outlined in Practice G 110.
8.4.3.3 Metallographic Examination of Eutectic Si—In the 10.1 aluminum alloys; investment casting; permanent mold
case of structurally modified 3xx.0 and 4xx.0 alloys, which casting; precipitation heat treatment; sand casting; solution
exhibit large amounts of Al-Si eutectic, the coarseness of the heat treatment

10
 B 917/B 917M – 08

Comparison of the microstructure of a Sr modified A356 sample in the F temper (left) and after a full T6 heat treatment (right). The Si fibres spheroidize and ripen. For
best results this comparison should only be made between samples solidified at the same rate as evidenced by the secondary dendrite arm spacing. Ideally, samples being
compared should come from the same location in the same casting.
FIG. 1 Microstructure Comparison

SUMMARY OF CHANGES

Committee B07 has identified the location of selected changes to this standard since the last issue
(B 917/B 917M – 01(2005)) that may impact the use of this standard. (Approved Sept. 1, 2007)

(1) Added 707.0–T5 heat treat cycle to Tables 1-4. (3) Added reference to Tables 5 and 6 to 7.1.
(2) Added new Tables 5 and 6 for Heat Treatment of Centirfu- (4) Revised Footnote 4 to reference The Aluminum
gal Casting Alloys with alloys 356.0–T6, 505.0-T61, 709.0- Association.
T61, and 850.0-T5.

ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned
in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk
of infringement of such rights, are entirely their own responsibility.

This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and
if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards
and should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the
responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should
make your views known to the ASTM Committee on Standards, at the address shown below.

This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,
United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above
address or at 610-832-9585 (phone), 610-832-9555 (fax), or service@astm.org (e-mail); or through the ASTM website
(www.astm.org).

11