ASTM B947-06

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Designation: B947 − 06
StandardPractice 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 B209M Specification for Aluminum and Aluminum-Alloy
Sheet and Plate (Metric)
1.1 This practice establishes the controls required for hot
B557 Test Methods for Tension Testing Wrought and Cast
rolling mill solution heat treatment of the 6xxx series alumi-
Aluminum- and Magnesium-Alloy Products
num alloy plate in Table 1 whenASTM material specifications
B557M Test Methods for Tension Testing Wrought and Cast
allow use of this process in lieu of furnace solution heat
Aluminum- and Magnesium-Alloy Products (Metric)
treatment. For the alloys listed in Table 1, this practice is an
B881 Terminology Relating toAluminum- and Magnesium-
alternate process to solution heat treatment in a furnace, such
Alloy Products
as specified in Practice B918 as the preliminary step for the
B918 Practice for Heat Treatment of Wrought Aluminum
attainment of T651-type tempers (see ANSI H35.1).
Alloys
1.2 This practice applies only to hot rolling mill solution
E2281 Practice for Process and Measurement Capability
heat treatment of plate for the listed aluminum alloys. Precipi-
Indices
tation hardening (aging) processing and equipment calibration
ASTM MNL7 Manual on Presentation of Data and Control
for aging shall meet the practice and requirements of Practice
Chart Analysis
B918.
2.3 ANSI Standards:
1.3 The values stated in either SI units or inch-pound units H35.1 Alloy and Temper Designation Systems for Alumi-
are to be regarded separately as standard. The values stated in num
each system may not be exact equivalents; therefore, each H35.1M Alloy and Temper Designation Systems forAlumi-
system shall be used independently of the other. Combining num [Metric]
values from the two systems may result in nonconformance
2.4 European Standard:
with the standard.
EN 485-2 Aluminium and Aluminium Alloys—Sheet, Strip
And Plate—Part 2: Mechanical Properties
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
3.1 Definitions—For definitions of terms used in this test
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. method, refer to Terminology B881.
3.2 Definitions of Terms Specific to This Standard:
2. Referenced Documents
3.2.1 rolling slab, n—semi-finished or intermediate product
2.1 The following documents of the issue in effect on the
produced by hot rolling which is between ingot and plate form.
date of material purchase form a part of this specification to the
3.2.2 load sensor or load thermocouple, n—sensors that are
extent referenced herein:
attached to the production material or a representation of
2.2 ASTM Standards:
production material, that supply temperature data of the pro-
B209 Specification for Aluminum and Aluminum-Alloy
duction material to process or test instrumentation.
Sheet and Plate
4. Equipment
This practice is under the jurisdiction of ASTM Committee B07 on Light
4.1 Aluminum alloy ingots or rolling slabs are preheated
Metals and Alloys and is the direct responsibility of Subcommittee B07.03 on
prior to being hot rolled as prescribed in 6.2. Controls shall be
Aluminum Alloy Wrought Products.
Current edition approved July 1, 2006. Published July 2006. DOI: 10.1520/
B0947-06.
2 3
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B947 − 06
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].
process is traceable to NIST or national equivalent. Initial
adequate to ensure that the equipment is operated in a manner
calibration shall be within 6 6°F [6 3°C].
which precludes overheating of the ingot or rolling slab or
5.1.2 SAT—Noncontact sensors must be compared weekly
deleterious contamination by the furnace environment. Metal
under operating conditions and temperature to the SAT test
temperature shall be monitored and controlled to not exceed
instrument/sensor (5.3); test sensor must be in contact with the
the maximum temperature shown in Table 1 prior to hot
ingot, hot rolled slab, or plate within 3 in. [75 mm] of the focus
rolling.
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
adjusted to read within the stated tolerance or an offset in
heating equipment achieves very rapid temperature rise and may require
operation must be used to account for the variation and may
the metal to be soaked for a period to ensure that sufficient applicable
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
5.2 Temperature Measuring System Accuracy Test (SAT) for
to charging the metal to the heating equipment (this being accomplished
Contact Systems:
by sufficient prior homogenization/cooling practices).
5.2.1 SAT—The accuracy of temperature measuring sys-
4.1.1 Automatic or manual control and recording devices
tem(s) shall be tested under operating conditions at least once
used to measure temperature at pertinent points in the heating
during each week that the facility is used. The test should be
equipment shall be calibrated as specified in 5.1 and 5.2. Table
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
instrument.Ifnot,thecontactsystemshallbecalibratedtoread
4.3 Equipmentforquenchingthehotrolledslabmayconsist
of, but is not limited to, water or water/glycol mixture in a within the stated tolerance or an offset in operation shall be
used to account for the variation. Once the adjustment or offset
standingwave,quenchtank,spray,orpressurizedwaterdevice.
Controls shall be adequate to assure that the equipment is is in use, the system may then be used for production. When
the system is equipped with dual potentiometer measuring
operated in a manner which achieves the required quench
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
5.1.1 Initial Calibration—Non-contact sensors shall be cali-
before first use and calibrated within 3 months of use and
brated prior to initial use by an ISO 17025 orA2LA(American
recalibrated every 3 months thereafter when used. Calibration
Association for Laboratory Accreditation) certified laboratory.
error of the instrument shall be no more than 6 1°F [6 0.6°C]
It may also be certified by the manufacturer if their calibration
and the sensor shall be within 6 2°F [6 1°C] or 0.4 % of true
temperature (whichever is greater).
NOTE 2—Warning: Advice should be sought from the equipment
TABLE 2 Minimum Temperature Entering Quench and Cooling
manufacturer to determine precautions necessary when inserting sensing
A,B
Rate in the Quench Zone
elements to avoid incurring any safety hazards.
Min Temp Entering Quench Min Cooling Rate
Alloy
°F [°C] °F/min [°C/min] 5.4 Preheat/Slab Reheat Furnace Calibration and Tempera-
6061 870 [465] 600 [335] ture Uniformity Survey—For continuous or batch furnaces, the
A
type of survey and procedures for performing the survey shall
The cooling rate is defined as the average temperature drop per unit of time
when subjected to a constant cooling system from initial slab temperature, down to
be established and documented for each particular furnace or
400°F [205°C], forced cooling allowed at a reduced rate down to 350°F [175°C],
furnace type involved.
and cooling continuing to ambient.
B
These minimum temperatures and cooling rates may be altered when statistical 5.4.1 A temperature uniformity survey shall be performed
analysis of mechanical property test data substantiates that the material will meet
before first use and at least each 6 months thereafter using load
the tensile property requirements of 7.1 and other required material characteristics
thermocouples in each corner that represent the ends and
such as corrosion resistance.
corners as well as the remainder of the ingot or slab. Variation
B947 − 06
instantaneous values at a specific point, or give average values over time
within and across zones of the furnace should be tested. This
or over an area. Note that gradients may differ between various heating
shall be done for both the thickest and thinnest ingot or slab
equipment.
being heated. These load thermocouple tests shall be per-
NOTE 5—The minimum starting ingot temperature is at the producer’s
formed at normal production settings; ingot temperature shall
option. This is due to state of the art in roll speed control and reduction
meet requirements of Table 3 for the alloy specified.
capabilities. Documented Work Instructions shall be developed for each
product thickness/alloy group (as established by the producer).
5.4.2 Testinstrumentandthermocouplesforthetemperature
uniformity survey must be calibrated to a NIST (or equivalent
6.3 Minimum Temperatures:
national standard) traceable source before first use, within 1
6.3.1 The minimum slab temperature upon entering the
year of use, and annually thereafter. Calibration error of the
quench zone or chamber shall not be less than the temperature
instrument shall be no more than 6 1°F [6 0.6°C] and the
shown for the alloy in Table 2.
thermocouple shall be within 6 2°F [6 1°C] or 0.4 % of true
6.3.2 Any rolled product that does not meet temperature
temperature (whichever is greater).
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,
6.5 For precipitation hardening (aging) and equipment cali-
temperature, and cooling,
brationthereof,therequirementsofPracticeB918shallbemet.
6.1.2 Ingot temperature in the heating equipment (6.2),
6.1.3 Ingot temperature upon being charged onto the hot
7. Process Capability and Quality Assurance
rolling mill (6.2),
7.1 Demonstration of Process Capability—Before produc-
6.1.4 Time from ingot discharge from heating furnace to
tionofproductforbuyers,eachproductrangeshallbequalified
charging of ingot onto the hot mill,
by tensile and metallurgical testing of hot rolling mill solution
6.1.5 Reduction pass schedule,
heat treated samples (after subsequent processing, i.e., aging)
6.1.6 Roll speed,
to clarify the alloy to be qualified.The producer’s process shall
6.1.7 Roll force,
have been proven, with documented evidence of statistically
6.1.8 Lubricant spray practices,
verified capability, to produce product in various product
6.1.9 Reaction plan for delays on the hot line which deviate
thicknesses which conform to required mechanical property
from hot mill practice (shall include time allowed between
minimums or limits. Methods to demonstrate statistical capa-
passes in the mill and or allowable slab temperature range
bility are defined in Practice E2281. Appropriate models shall
between passes,
be used for representation of the data as well as the generation
6.1.10 Material temperature at quench entry (6.3),
of control charts. For further information see Manual ASTM
6.1.11 Material temperature at completion of quench,
MNL7A. Use of MMPDS methods for establishing capability
6.1.12 Quench media temperature,
is also acceptable.
6.1.13 Quench rate (6.4), and
7.1.1 Mechanical Properties shall be determined in accor-
6.1.14 System reaction to unplanned interruptions (warning
dance with Test Method B557 or B557M.
lights/audible alarms, system interlo
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