ASTM B947-06(2013)
(Practice)Standard Practice for Hot Rolling Mill Solution Heat Treatment for Aluminum Alloy Plate
Standard Practice for Hot Rolling Mill Solution Heat Treatment for Aluminum Alloy Plate
ABSTRACT
This practice covers hot rolling solution heat treatment for aluminum alloy plate. Aluminum alloy ingots or rolling slabs are preheated prior to being hot rolled. Controls shall be adequate to ensure that the equipment is operated in a manner which precludes overheating of the ingot or rolling slab or deleterious contamination by the furnace environment. Metal temperature shall be monitored and controlled to not exceed the maximum temperature prescribed. Non-contact sensors shall be calibrated prior to initial use by an ISO 17025 or A2LA. Noncontact sensors must be compared weekly under operating conditions and temperature to the SAT test instrument/sensor. The accuracy of temperature measuring system(s) shall be tested under operating conditions at least once during each week that the facility is used. For continuous or batch furnaces, the type of survey and procedures for performing the survey shall be established and documented for each particular furnace or furnace type involved. The hot rolling mill solution heat treatment procedures are presented in details. The mechanical properties shall be determined in accordance with test method B557 or B557M. Tensile tests shall be representative of the thinnest and the thickest material to be heat treated; intermediate thickness samples shall be included when necessary to ensure proper production hot rolling mill solution heat treatment. Whenever any qualified equipment is changed or reworked, it shall be requalified unless it is known that the change or rework will not have a detrimental effect upon the properties of products.
SCOPE
1.1 This practice establishes the controls required for hot rolling mill solution heat treatment of the 6xxx series aluminum alloy plate in Table 1 when ASTM material specifications allow use of this process in lieu of furnace solution heat treatment. For the alloys listed in Table 1, this practice is an alternate process to solution heat treatment in a furnace, such as specified in Practice B918 as the preliminary step for the attainment of T651-type tempers (see ANSI H35.1).TABLE 1 Ingot High Limit TemperatureA
Alloy
Ingot Upper Limit Temperature
°F [°C]
6061
1050 [565] A These upper limit temperatures avoid the possibility of eutectic melting due to overheating, and include a safety factor of approximately 25°F [15°C].
1.2 This practice applies only to hot rolling mill solution heat treatment of plate for the listed aluminum alloys. Precipitation hardening (aging) processing and equipment calibration for aging shall meet the practice and requirements of Practice B918.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.
1.4 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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Standards Content (Sample)
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Designation: B947 − 06(Reapproved 2013)
Standard Practice for
Hot Rolling Mill Solution Heat Treatment for Aluminum Alloy
Plate
This standard is issued under the fixed designation B947; 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.
1. Scope B209 Specification for Aluminum and Aluminum-Alloy
Sheet and Plate
1.1 This practice establishes the controls required for hot
B209M Specification for Aluminum and Aluminum-Alloy
rolling mill solution heat treatment of the 6xxx series alumi-
Sheet and Plate (Metric)
num alloy plate in Table 1 whenASTM material specifications
B557 Test Methods for Tension Testing Wrought and Cast
allow use of this process in lieu of furnace solution heat
Aluminum- and Magnesium-Alloy Products
treatment. For the alloys listed in Table 1, this practice is an
B557M Test Methods for Tension Testing Wrought and Cast
alternate process to solution heat treatment in a furnace, such
Aluminum- and Magnesium-Alloy Products (Metric)
as specified in Practice B918 as the preliminary step for the
B881 Terminology Relating toAluminum- and Magnesium-
attainment of T651-type tempers (see ANSI H35.1).
Alloy Products
1.2 This practice applies only to hot rolling mill solution
B918 Practice for Heat Treatment of Wrought Aluminum
heat treatment of plate for the listed aluminum alloys. Precipi-
Alloys
tation hardening (aging) processing and equipment calibration
E2281 Practice for Process and Measurement Capability
for aging shall meet the practice and requirements of Practice
Indices
B918.
ASTM MNL7 Manual on Presentation of Data and Control
Chart Analysis
1.3 The values stated in either SI units or inch-pound units
are to be regarded separately as standard. The values stated in
2.3 ANSI Standards:
each system may not be exact equivalents; therefore, each
H35.1 Alloy and Temper Designation Systems for Alumi-
system shall be used independently of the other. Combining
num
values from the two systems may result in nonconformance
H35.1M Alloy and Temper Designation Systems forAlumi-
with the standard.
num [Metric]
1.4 This standard does not purport to address all of the
2.4 European Standard:
safety concerns, if any, associated with its use. It is the
EN 485-2 Aluminium and Aluminium Alloys—Sheet, Strip
responsibility of the user of this standard to establish appro-
And Plate—Part 2: Mechanical Properties
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
3. Terminology
2. Referenced Documents
3.1 Definitions—For definitions of terms used in this test
method, refer to Terminology B881.
2.1 The following documents of the issue in effect on the
date of material purchase form a part of this specification to the
3.2 Definitions of Terms Specific to This Standard:
extent referenced herein:
3.2.1 rolling slab, n—semi-finished or intermediate product
produced by hot rolling which is between ingot and plate form.
2.2 ASTM Standards:
3.2.2 load sensor or load thermocouple, n—sensors that are
attached to the production material or a representation of
This practice is under the jurisdiction of ASTM Committee B07 on Light
production material, that supply temperature data of the pro-
Metals and Alloys and is the direct responsibility of Subcommittee B07.03 on
duction material to process or test instrumentation.
Aluminum Alloy Wrought Products.
Current edition approved May 1, 2013. Published May 2013. Originally
approved in 2006. Last previous edition approved in 2006 as B947 – 06. DOI:
10.1520/B0947-06R13.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 4th Floor, New York, NY 10036.
Standards volume information, refer to the standard’s Document Summary page on Available from European Committee for Standardization (CEN), 36 rue de
the ASTM website. Stassart, B-1050, Brussels, Belgium.
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B947 − 06 (2013)
A
TABLE 1 Ingot High Limit Temperature TABLE 3 Homogenization and Pre-heat Furnace
Temperature Tolerance
Ingot Upper Limit Temperature
Alloy
°F [°C]
Pre-heat Oven Temperature Range
Alloy
6061 1050 [565] °F [°C]
A
6061 ± 15 [± 8]
These upper limit temperatures avoid the possibility of eutectic melting due to
overheating, and include a safety factor of approximately 25°F [15°C].
5.1.1 Initial Calibration—Non-contact sensors shall be cali-
4. Equipment
brated prior to initial use by an ISO 17025 orA2LA(American
Association for Laboratory Accreditation) certified laboratory.
4.1 Aluminum alloy ingots or rolling slabs are preheated
It may also be certified by the manufacturer if their calibration
prior to being hot rolled as prescribed in 6.2. Controls shall be
process is traceable to NIST or national equivalent. Initial
adequate to ensure that the equipment is operated in a manner
which precludes overheating of the ingot or rolling slab or calibration shall be within 6 6°F [6 3°C].
5.1.2 SAT—Noncontact sensors must be compared weekly
deleterious contamination by the furnace environment. Metal
temperature shall be monitored and controlled to not exceed under operating conditions and temperature to the SAT test
instrument/sensor (5.3); test sensor must be in contact with the
the maximum temperature shown in Table 1 prior to hot
rolling. ingot, hot rolled slab, or plate within 3 in. [75 mm] of the focus
point of the noncontact sensor (see Note 2). The noncontact
NOTE 1—Some aspects of the metallurgical structure of the alloy after
sensor must read within 6 2°F [6 1°C] of the contact pyrom-
solution heat treatment are influenced by the thermal characteristics of the
etry system; if not, the noncontact sensor system must be
heatingequipmentused,andthestartingmicrostructureoftheingot.Some
heating equipment achieves very rapid temperature rise and may require
adjusted to read within the stated tolerance or an offset in
the metal to be soaked for a period to ensure that sufficient applicable
operation must be used to account for the variation and may
alloying elements are taken into solid solution. This soaking stage may be
then be used for production.
minimized if the alloying elements are substantially in solid solution prior
to charging the metal to the heating equipment (this being accomplished
5.2 Temperature Measuring System Accuracy Test (SAT) for
by sufficient prior homogenization/cooling practices).
Contact Systems:
4.1.1 Automatic or manual control and recording devices 5.2.1 SAT—The accuracy of temperature measuring sys-
tem(s) shall be tested under operating conditions at least once
used to measure temperature at pertinent points in the heating
equipment shall be calibrated as specified in 5.1 and 5.2. Table during each week that the facility is used. The test should be
made by placing a calibrated test temperature sensing element
3 shows preheat/homogenizing furnace temperature tolerance.
(5.3) to make contact with the surface (ingot, hot rolled slab or
4.2 The hot rolling and quench equipment and controls shall
plate) being measured within 3 in. [75 mm] of the system’s
beadequatetoensurethatingotsarecapableofbeinghotrolled
sensing element and reading the test temperature sensing
in accordance with the process requirements for the products
element with a calibrated test potentiometer (see Note 2). The
being produced, as prescribed in 6.3 and 6.4.
contact system must read within 6 2°F [6 1°C] of the test
4.3 Equipmentforquenchingthehotrolledslabmayconsist
instrument.Ifnot,thecontactsystemshallbecalibratedtoread
of, but is not limited to, water or water/glycol mixture in a
within the stated tolerance or an offset in operation shall be
standingwave,quenchtank,spray,orpressurizedwaterdevice.
used to account for the variation. Once the adjustment or offset
Controls shall be adequate to assure that the equipment is
is in use, the system may then be used for production. When
operated in a manner which achieves the required quench
the system is equipped with dual potentiometer measuring
conditions in Table 2.
systems which are checked daily against each other and agree
within 6 2°F [6 1°C], the above checks and corrections shall
5. Equipment Calibration and System Accuracy Tests
be conducted at least once every three months.
(SAT)
5.3 Test Instrument/Sensor for SAT—The contact pyrometer
5.1 Non-Contact Sensor System (Remote Sensing System)
thermocouple(sensor)andtestinstrumentmustbecalibratedto
Calibration and SAT:
a NIST (or equivalent national standard) traceable source
before first use and calibrated within 3 months of use and
recalibrated every 3 months thereafter when used. Calibration
TABLE 2 Minimum Temperature Entering Quench and Cooling
A,B
error of the instrument shall be no more than 6 1°F [6 0.6°C]
Rate in the Quench Zone
and the sensor shall be within 6 2°F [6 1°C] or 0.4 % of true
Min Temp Entering Quench Min Cooling Rate
Alloy
°F [°C] °F/min [°C/min]
temperature (whichever is greater).
6061 870 [465] 600 [335]
NOTE 2—Warning: Advice should be sought from the equipment
A manufacturer to determine precautions necessary when inserting sensing
The cooling rate is defined as the average temperature drop per unit of time
elements to avoid incurring any safety hazards.
when subjected to a constant cooling system from initial slab temperature, down to
400°F [205°C], forced cooling allowed at a reduced rate down to 350°F [175°C],
5.4 Preheat/Slab Reheat Furnace Calibration and Tempera-
and cooling continuing to ambient.
B
These minimum temperatures and cooling rates may be altered when statistical ture Uniformity Survey—For continuous or batch furnaces, the
analysis of mechanical property test data substantiates that the material will meet
type of survey and procedures for performing the survey shall
the tensile property requirements of 7.1 and other required material characteristics
be established and documented for each particular furnace or
such as corrosion resistance.
furnace type involved.
B947 − 06 (2013)
5.4.1 A temperature uniformity survey shall be performed the true metal temperature does not exceed the upper limit
before first use and at least each 6 months thereafter using load shown, or the instrument shall be recalibrated in accordance
thermocouples in each corner that represent the ends and with 5.1.
corners as well as the remainder of the ingot or slab. Variation NOTE 4—The surface temperature of a ingot may differ significantly
from its interior temperature. Temperature sensing devices may give
within and across zones of the furnace should be tested. This
instantaneous values at a specific point, or give average values over time
shall be done for both the thickest and thinnest ingot or slab
or over an area. Note that gradients may differ between various heating
being heated. These load thermocouple tests shall be per-
equipment.
formed at normal production settings; ingot temperature shall
NOTE 5—The minimum starting ingot temperature is at the producer’s
meet requirements of Table 3 for the alloy specified.
option. This is due to state of the art in roll speed control and reduction
capabilities. Documented Work Instructions shall be developed for each
5.4.2 Testinstrumentandthermocouplesforthetemperature
product thickness/alloy group (as established by the producer).
uniformity survey must be calibrated to a NIST (or equivalent
national standard) traceable source before first use, within 1 6.3 Minimum Temperatures:
year of use, and annually thereafter. Calibration error of the
6.3.1 The minimum slab temperature upon entering the
instrument shall be no more than 6 1°F [6 0.6°C] and the
quench zone or chamber shall not be less than the temperature
thermocouple shall be within 6 2°F [6 1°C] or 0.4 % of true
shown for the alloy in Table 2.
temperature (whichever is greater).
6.3.2 Any rolled product that does not meet temperature
requirements of 6.3.1 shall be either furnace solution re-heat
5.5 Control instruments for the furnace shall be calibrated at
treated in accordance with Practice B918 or scrapped. Material
least annually to a NIST (or equivalent national standard)
from the same slab shall not be sorted by testing individual
traceable source. Instruments shall be calibrated to limits of
sectionsoftheslab.Wherepracticesexistforcroppingmaterial
6 2°F [1.1°C].
at start or end of slab, these portions shall be excluded from
testing requirements.
6. Hot Rolling Mill Solution Heat Treat Procedure
6.4 The minimum cooling or quench rate of the slab in the
6.1 Pertinent control points requiring defined written oper-
quench zone or chamber shall conform to Table 2. The cooling
ating practices, data collection, and record keeping include, but
equipment shall be operated in a manner to preclude reheating
are not limited to:
of the slab.
6.1.1 Ingot homogenization and/or preheat processing time,
temperature, and cooling,
6.5 For precipitation hardening (aging) and equipment cali-
6.1.2 Ingot temperature in the heating equipment (6.2),
brationthereof,therequirementsofPracticeB918shallbemet.
6.1.3 Ingot temperature upon being charged onto the hot
rolling mill (6.2),
7. Process Capability and Quality Assurance
6.1.4 Time from ingot discharge from heating furnace to
7.1 Demonstration of Process Capability—Before produc-
charging of ingot onto the hot mill,
tionofproductforbuyers,eachproductrangeshallbequalified
6.1.5 Reduction pass schedule,
by tensile and metallurgical testing of hot rolling mill solution
6.1.6 Roll speed,
heat treated samples (after subsequent processing, i.e., aging)
6.1.7 Roll force,
to clarify the alloy to be qualified.The producer’s process shall
6.1.8 Lubricant spray practices,
have been proven, with documented evidence of statistically
6.1.9 Reaction plan for delays on the hot line which deviate
verified capability, to produce product in various product
from hot mill practice (shall include time allowed between
thicknesses which conform to required mechanical property
passes in the mill and or allowable slab temperature range
minimums or limits. Methods to demonstrate statistical capa-
between passes,
bility are defined in Practice E2281. Appropriate models shall
6.1.10 Material temperature at quench entry (6.3),
be used for representation of the data as well as the generation
6.1.11 Material temperature at completion of quench,
of control c
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