ASTM D6549-00
(Test Method)Standard Test Method for Determination of Cooling Characteristics of Quenchants by Cooling Curve Analysis with Agitation (Drayton Unit)
Standard Test Method for Determination of Cooling Characteristics of Quenchants by Cooling Curve Analysis with Agitation (Drayton Unit)
SCOPE
1.1 This test method covers the equipment and the procedure for evaluation of quenching characteristics of a quenching fluid by cooling rate determination.
1.2 This test method is designed to evaluate quenching fluids with agitation, using the Drayton Agitation Unit.
1.3 The values in SI units are to be regarded as the standard. The values in parentheses are for information only.
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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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: D 6549 – 00 An American National Standard
Standard Test Method for
Determination of Cooling Characteristics of Quenchants by
Cooling Curve Analysis with Agitation (Drayton Unit)
This standard is issued under the fixed designation D 6549; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope (1,2,3). The quenchant solution also typically contains addi-
tives for corrosion and foam control, if needed. Quench
1.1 This test method covers the equipment and the proce-
severity of aqueous polymer quenchants is dependent on
dure for evaluation of quenching characteristics of a quenching
concentration and molecular weight of the specific polymer
fluid by cooling rate determination.
being evaluated, quenchant temperature, and agitation rate as
1.2 This test method is designed to evaluate quenching
shown in Fig. 1, Fig. 2, and Fig. 3 respectively.
fluids with agitation, using the Drayton Agitation Unit.
3.1.2 cooling curve—the cooling curve is a graphical rep-
1.3 The values in SI units are to be regarded as the standard.
resentation of the cooling time (t) versus temperature (T)
The values in parentheses are for information only.
response of the probe (see 7.3). An example is illustrated in
1.4 This standard does not purport to address all of the
Fig. 4.
safety concerns, if any, associated with its use. It is the
3.1.3 cooling curve analysis—the process of quantifying the
responsibility of the user of this standard to establish appro-
cooling characteristics of a quenchant based on the temperature
priate safety and health practices and determine the applica-
versus time profile obtained by cooling a preheated metal probe
bility of regulatory limitations prior to use.
assembly (see Fig. 4) under standard conditions (1-7).
2. Referenced Documents
3.1.4 cooling rate curve—the cooling rate curve is a graphi-
cal representation of first derivative of the cooling curve, the
2.1 ASTM Standards:
rate of temperature change (dT/dt) versus temperature. An
E 220 Test Method for Calibration of Thermocouples by
example is illustrated in Fig. 4.
Comparison Techniques
3.1.5 quenchant—a quenching medium may be either a
E 230 Temperature-Electromotive Force (EMF) Tables for
liquid or a gas. Gasses that are used as quenchants include air,
Standardized Thermocouples
nitrogen, argon, and hydrogen and, with the exception of air,
2.2 SAE Standards:
which is used at atmospheric pressure, are used under pressure.
AMS 5665 Nickel Alloy Corrosion and Heat Resistant Bars,
Liquid quenchants include water, brine (most commonly dilute
Forgings and Rings
aqueous solutions of sodium chloride or sodium hydroxide),
2.3 Other Standards:
oil, molten salt, molten metal, and aqueous solutions of water
Wolfson Engineering Group Specification Laboratory Tests
soluble polymers. Water, brine, oil, and aqueous polymer
for Assessing the Cooling Curve Characteristics of Indus-
quenchants are generally used with agitation.
trial Quenching Media
3.1.6 quench severity—the ability of a quenching medium
3. Terminology
to extract heat from a hot metal (8).
3.1 Definitions of Terms Specific to This Standard:
4. Summary of Test Method
3.1.1 aqueous polymer quenchant—an aqueous polymer
4.1 This test method determines the cooling time versus
quenchant is an aqueous solution containing a water soluble
temperature of a standard nickel alloy probe assembly after it
polymer, typically including poly(alkylene glycol), poly(ethyl
has been heated in a furnace to 850°C (1562°F) and then
oxazoline), poly(sodium acrylate), and poly(vinyl pyrrolidone)
quenched in an aqueous polymer quenchant solution. The
temperature inside the probe assembly and the cooling times
are recorded at selected time intervals to establish a cooling
This test method is under the jurisdiction of ASTM Committee D02 on temperature versus time curve. The resulting cooling curve
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
(profile) may be used to evaluate quench severity (see Note 1).
D02.L0.06 on Nonlubricating Process Fluids.
Current edition approved April 10, 2000. Published June 2000.
NOTE 1—Where appropriate for production testing, a furnace tempera-
Annual Book of ASTM Standards, Vol 14.03.
ture from 815 to 857°C (1500 to 1575°F) may be used.
Available from Society of Automotive Engineers, 400 Commonwealth Drive,
Warrendale, PA 15096.
Available from Wolfson Heat Treatment Centre, Aston University, Aston
The boldface numbers in parentheses refer to the list of references at the end of
Triangle, Birmingham B4 7ET, England.
this standard.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 6549
FIG. 1 Effect of Quenchant Concentration on Cooling Curve Performance for a Poly(Alkylene Glycol) Quenchant at 30°C and 0.5 m/s
FIG. 2 Effect of Bath Temperature Variation on Cooling Curve Performance for 15 % Aqueous Solution of Poly (Alkylene Glycol)
Quenchant at 0.5 m/s
5. Significance and Use maintaining the probe’s temperature within 62.5°C (4.5°F)
over the specimen length. The furnace, that is, the radiant tube
5.1 This test method provides a cooling time versus tem-
heating media, shall be used with ambient atmosphere.
perature curve (profile) that can be related to physical proper-
7.2 Measurement System—The temperature-time measure-
ties, such as the hardness obtainable upon quenching of a
ment system shall be a computer based data acquisition system
metal. The results obtained by this test method may be used as
capable of providing a permanent record of the cooling
a guide in quenchant selection or as a comparison of quench
characteristics of each sample tested, producing a record of
severities of different quenchants, new or used.
variation in the test probe assembly of temperature with respect
6. Interferences
to time and cooling rate with respect to temperature.
7.3 Probe—The probe shall be cylindrical, having a diam-
6.1 The presence of contaminants, such as oil, salt, metal-
eter of 12.5 6 0.01 mm (0.492 6 0.0004 in.) and a length of
working fluids, forging lubricants, and polymer degradation,
60 6 0.25 mm (2.362 6 0.01 in.) with a 1.45 to 1.65-mm
may affect cooling curve results obtained by this test method
(0.057 to 0.065-in.) sheathed Type K thermocouple in its
for aqueous polymer quenchants.
geometric center. The probe shall be made of a nickel Alloy
7. Apparatus
600 (UNS N06600), purchased in accordance with AMS 5665,
7.1 Furnace—Use a horizontal or vertical electrical resis- which has a nominal composition of 76.0 % Ni, 15.5 % Cr,
tance tube-type furnace capable of maintaining a constant 8.0 % Fe, 0.08 % C, and 0.25 % maximum Cu. The probe shall
minimum temperature of 850°C (1562°F) over a heated length be attached to a support tube with a minimum length of 200
of not less than 120 mm (4.72 in.) and a probe positioned in the mm (7.874 in.). The thermocouple sheathing and the support
center of the heating chamber. The furnace shall be capable of tube shall be the same material as the probe (see Note 2). See
D 6549
FIG. 3 Effect of Agitation Rate Variation on Cooling Curve Performance for 15 % Aqueous Solution of Poly (Alkylene Glycol) Quenchant
at 0.5 m/s
NOTE 1—(a.) Cooling Curve (b.) Cooling Rate Curve
FIG. 4 Typical Temperature/Time and Temperature/Cooling Rate Plots for Test Probe Cooled in a Quenching Oil
Fig. 5 for other manufacturing requirements. assembly shall be rinsed with water at least three times to
ensure that no quenchant residue or detergent solution remains.
NOTE 2—Care shall be taken that the probe specimen is not damaged as
7.4.3 Flow Velocity—The variable speed pump and flow
surface irregularities will influence results of the test.
meter allow reproducible setting of quenchant flow through the
7.4 Drayton Agitation Unit:
tube. The flowmeter is calibrated for water at 25°C. Flow
7.4.1 Construction—The sample container, a 2000-mL
velocity for other fluids will vary with fluid viscosity and
stainless steel beaker that is the same as the standard container
temperature.
used in nonagitated cooling curve test, is modified to provide
upward or axial flow of the quenchant past the probe. This flow
7.4.4 Fluid Volume—The resulting cooling curve is influ-
occurs through a vertical flow tube located in the geometric
enced by the temperature rise during the quench, which is
center of the container. As shown in Fig. 6, the unit includes a
dependent on the total fluid volume. Therefore, the cooling
variable speed dc drive centrifugal pump and large diameter
curve test shall be performed with a fixed volume of fluid.
flowmeter for direct measurement of flow velocity. It is noted
7.5 Temperature Measurement—Any temperature detection
that the flow tube is removable, which will provide a more
device may be used that is capable of measuring quenching
turbulent flow pattern.
fluid temperature to within 61°C (1.8°F).
7.4.2 Cleaning—The agitation assembly shall be cleaned
7.6 Transfer Mechanism—One of the following shall be
prior to use with a detergent solution. After cleaning, the
D 6549
NOTE 1—Dimensions above are nominal.
FIG. 5 Probe Details and General Probe Assembly
FIG. 6 Drayton Agitation Unit
used to transfer the heated probe from the furnace to the test the vertical center of the sample.
fluid. 7.6.2 Manual Transfer—The probe is transferred to the
7.6.1 Mechanical Transfer—The agitation unit is positioned agitation unit through a probe guide, which is set (1) to the test
with the center of the test chamber coincident with the probe chamber centerline and (2) with a preset stop that causes the
centerline. The transfer mechanism is set to deliver the probe to probe to rest in the vertical center of the sample. The unit is
D 6549
illustrated further in the sketch and photograph of Fig. 6 and temperature below visual hot temperatures can still cause
Fig. 7, respectively. A timer shall be used to ensure a maximum injury to the skin or ignition of the cloth or paper used in
transfer time of 3.0 s. cleaning.)
7.7 Timer, graduated in seconds and minutes, and may be 9.2 Conditioning New Probes—Condition the probe prior to
part of a computer clock. its initial use by carrying out a minimum of six trial quenches,
or a grater number if required to achieve consistency, using a
8. Reagents and Materials
clean, neutral, general purpose hydrocarbon oil. Clean the
probe assembly between quenches, as specified in 9.1. Quench
8.1 Reference Quenching Fluid, used for initial calibration
the probe in the reference quenching fluid and check in
and for periodic calibration verification. Data collected from
accordance with 12.3. If the probe does not meet the require-
quench tests with the reference fluid shall be evaluated for
ments of 12.3, recondition in accordance with 9.3 and then
compliance to the specified values for the six primary charac-
recalibrate again in accordance with 12.3. Do not use probes
teristics. These characteristics, as defined in Wolfson Engineer-
that do not meet these requirements.
ing Group Specification, are as follows:
9.3 Probe Reconditioning—The probe shall be recondi-
Time to cool to 600°C (1112°F) 12-14 s
Time to cool to 400°C (752°F) 19-21 s tioned when the probe calibration, as described in 12.3, does
Time to cool to 200°C (392°F) 50-55 s
not meet the calibration limits of the six cooling characteristics
Maximum cooling rate 47-53°C/s (85-95°F/s)
specified for the reference fluid. Recondition the probe by
Temperature of the maximum cooling rate 490-530°C (914-986°F)
Cooling rate at 300°C (572°F) 6-8°C/s (10.8-14.4°F/s)
polishing with emery paper. Although coarser 320-grit paper
may be used for initial polishing, the final finish shall be
8.1.1 If results do not comply with the specified ranges, the
provided by use of 600-grit emery paper. Following this
probe shall be replaced or reconditioned (see 9.3) or system
procedure, the probe shall be quenched until satisfactory
adjustments made. Compliance to the specified limits of the
cooling curve results are obtained from the reference fluid.
primary reference fluid is critical for establishing the validity of
subsequent test results. It has been shown that the test method
10. Sampling
has an excellent level of repeatability and reproducibility when
10.1 Take care that the gross media, from which the sample
the probe and system are shown to be in calibration (9, 10).
is taken to fill the agitation unit, is well mixed to ensure that the
8.1.2 A secondary reference fluid may be used, provided
sample is representative of the media being tested. Any
that sufficient statistical cooling curve testing has been con-
containers used to secure the quenchant sample must be clean
ducted so that the results are (1) traceable to the primary
and dry.
reference fluid and (2) compared on the basis of the six primary
cooling characteristics.
11. Preparation of Apparatus
8.1.3 Reference fluids shall be stored in a sealed container
11.1 Preheat furnace to 850 62°C (1562 64°F), or alterna-
when not in use and shall be replaced after 200 quenches or
tively, to 815 to 857°C (1500 to 1575°F) for production testing.
two years, whichever is sooner.
11.2 Connect a dry, conditioned, calibrated probe in accor-
8.2 Polishing Paper, 600 grit emery.
dance with the equipment manufacturer’s instructions, and
8.3 Cotton Cloth or Paper, lintless and absorbent.
insert in furnace.
11.3 Heat or cool the aqueous polymer quenchant to the
9. Cleaning and Conditioning
desired temperature if production testing is being performed.
9.1 Cleaning Used Probes—Wipe the probe with a clean,
Continuously agitate the quenchant sample at the desired flow
wet, lintless cotton cloth or absorbent paper after removal from
rate while the sample is being heated. If the primary reference
the quenchant and prior to returning to the furnace. Unmounted
quenching fluid is being tested, heat it to 40 62°C (104
probes may be cleaned in the same manner or, alternatively,
63.6°F), but do not agitate the fluid during the calibration test.
washed under a stream of water, and then wiped dry.
(WARNING—The probe shall always be considered hot as a
12. Calibration and Standardization
12.1 Probe:
12.1.1 Check the accuracy of the probe thermocouple by
attaching a previously calibrated thermocouple to the outer
surface of the probe. Locate the tip of the calibrated thermo-
couple 30 mm (1.181 in.) from
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