ASTM D6549-06(2015)
(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)
SIGNIFICANCE AND USE
5.1 This test method provides a cooling time versus temperature curve (profile) that can be related to physical properties, such as the hardness obtainable upon quenching of a metal. The results obtained by this test method may be used as a guide in quenchant selection or as a comparison of quench severities of different quenchants, new or used.
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 stated in SI units are to be regarded as standard. The values given 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.
General Information
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D6549 − 06 (Reapproved 2015)
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 D6549; 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 2.4 ASTM Adjuncts:
ADJD6300 D2PP, Determination of Precision and Bias
1.1 This test method covers the equipment and the proce-
Data for Use in Test Methods for Petroleum Products and
dure for evaluation of quenching characteristics of a quenching
Lubricants
fluid by cooling rate determination.
1.2 This test method is designed to evaluate quenching 3. Terminology
fluids with agitation, using the Drayton Agitation Unit.
3.1 Definitions of Terms Specific to This Standard:
1.3 The values stated in SI units are to be regarded as 3.1.1 aqueous polymer quenchant—an aqueous polymer
standard. The values given in parentheses are for information quenchant is an aqueous solution containing a water soluble
only. polymer, typically including poly(alkylene glycol), poly(ethyl
oxazoline), poly(sodium acrylate), and poly(vinyl pyrrolidone)
1.4 This standard does not purport to address all of the
(1, 2, 3). The quenchant solution also typically contains
safety concerns, if any, associated with its use. It is the
additives for corrosion and foam control, if needed. Quench
responsibility of the user of this standard to establish appro-
severity of aqueous polymer quenchants is dependent on
priate safety and health practices and determine the applica-
concentration and molecular weight of the specific polymer
bility of regulatory limitations prior to use.
being evaluated, quenchant temperature, and agitation rate as
shown in Fig. 1, Fig. 2, and Fig. 3, respectively.
2. Referenced Documents
3.1.2 cooling curve—the cooling curve is a graphical repre-
2.1 ASTM Standards:
sentation of the cooling time (t) versus temperature (T)
E220 Test Method for Calibration of Thermocouples By
response of the probe (see 7.3). An example is illustrated in
Comparison Techniques
Fig. 4.
E230 Specification and Temperature-Electromotive Force
(EMF) Tables for Standardized Thermocouples 3.1.3 cooling curve analysis—the process of quantifying the
coolingcharacteristicsofaquenchantbasedonthetemperature
2.2 SAE Standards:
versustimeprofileobtainedbycoolingapreheatedmetalprobe
AMS 5665 NickelAlloy Corrosion and Heat Resistant Bars,
assembly (see Fig. 4) under standard conditions (1-7).
Forgings and Rings
3.1.4 cooling rate curve—the cooling rate curve is a graphi-
2.3 Other Standards:
Wolfson Engineering Group Specification Laboratory Tests cal representation of first derivative of the cooling curve, the
rate of temperature change (dT/dt) versus temperature. An
forAssessing the Cooling Curve Characteristics of Indus-
trial Quenching Media example is illustrated in Fig. 4.
3.1.5 quenchant—a quenching medium may be either a
liquid or a gas. Gasses that are used as quenchants include air,
This test method is under the jurisdiction of ASTM Committee D02 on
nitrogen, argon, and hydrogen and, with the exception of air,
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
which is used at atmospheric pressure, are used under pressure.
Subcommittee D02.L0.06 on Non-Lubricating Process Fluids.
Current edition approved July 1, 2015. Published July 2015. Originally approved Liquid quenchants include water, brine (most commonly dilute
in 2000. Last previous edition approved in 2011 as D6549 – 06 (2011). DOI:
aqueous solutions of sodium chloride or sodium hydroxide),
10.1520/D6549-06R15.
oil, molten salt, molten metal, and aqueous solutions of water
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
soluble polymers. Water, brine, oil, and aqueous polymer
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
quenchants are generally used with agitation.
the ASTM website.
Available from SAE International (SAE), 400 Commonwealth Dr.,Warrendale,
PA 15096-0001, http://www.sae.org. No longer available from ASTM International Headquarters.
Available from Wolfson Heat Treatment Centre, Federation House, Vyse St., The boldface numbers in parentheses refer to the list of references at the end of
Birmingham, B18 6LT, UK. http://www.sea.org.uk/whtc. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6549 − 06 (2015)
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) Quen-
chant at 0.5 m/s
FIG. 3 Effect of Agitation Rate Variation on Cooling Curve Performance for a 15 % Aqueous Poly(Alkylene Glycol) Quenchant Solution
at 30°C
3.1.6 quench severity—theabilityofaquenchingmediumto
extract heat from a hot metal (8).
D6549 − 06 (2015)
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
4. Summary of Test Method 7.2 Measurement System—The temperature-time measure-
ment system shall be a computer based data acquisition system
4.1 This test method determines the cooling time versus
capable of providing a permanent record of the cooling
temperature of a standard nickel alloy probe assembly after it
characteristics of each sample tested, producing a record of
has been heated in a furnace to 850 °C (1562 °F) and then
variationinthetestprobeassemblyoftemperaturewithrespect
quenched in an aqueous polymer quenchant solution. The
to time and cooling rate with respect to temperature.
temperature inside the probe assembly and the cooling times
are recorded at selected time intervals to establish a cooling
7.3 Probe—The probe shall be cylindrical, having a diam-
temperature versus time curve. The resulting cooling curve
eter of 12.5 mm 6 0.01 mm (0.492 in. 6 0.0004 in.) and a
(profile) may be used to evaluate quench severity (see Note 1).
length of 60 mm 6 0.25 mm (2.362 in. 6 0.01 in.) with a
1.45 mm to 1.65 mm (0.057 in. to 0.065 in.) sheathed Type K
NOTE 1—Where appropriate for production testing, a furnace tempera-
ture from 815 °C to 857 °C (1500 °F to 1575 °F) may be used. thermocouple in its geometric center. The probe shall be made
of a nickelAlloy 600 (UNS N06600), purchased in accordance
5. Significance and Use
with AMS 5665, which has a nominal composition of 76.0 %
5.1 This test method provides a cooling time versus tem- Ni, 15.5 % Cr, 8.0 % Fe, 0.08 % C, and 0.25 % maximum Cu.
The probe shall be attached to a support tube with a minimum
perature curve (profile) that can be related to physical
properties, such as the hardness obtainable upon quenching of length of 200 mm (7.874 in.). The thermocouple sheathing and
a metal. The results obtained by this test method may be used the support tube shall be the same material as the probe (see
as a guide in quenchant selection or as a comparison of quench Note 2). See Fig. 5 for other manufacturing requirements.
severities of different quenchants, new or used.
NOTE 2—Care shall be taken that the probe specimen is not damaged as
surface irregularities will influence results of the test.
6. Interferences
7.4 Drayton Agitation Unit:
6.1 The presence of contaminants, such as oil, salt, metal-
7.4.1 Construction—The sample container, a 2000 mL
working fluids, forging lubricants, and polymer degradation,
stainless steel beaker that is the same as the standard container
may affect cooling curve results obtained by this test method
used in nonagitated cooling curve test, is modified to provide
for aqueous polymer quenchants.
upwardoraxialflowofthequenchantpasttheprobe.Thisflow
7. Apparatus
occurs through a vertical flow tube located in the geometric
center of the container.As shown in Fig. 6, the unit includes a
7.1 Furnace—Use a horizontal or vertical electrical resis-
variable speed dc drive centrifugal pump and large diameter
tance tube-type furnace capable of maintaining a constant
flowmeter for direct measurement of flow velocity. It is noted
minimum temperature of 850 °C (1562 °F) over a heated
that the flow tube is removable, which will provide a more
length of not less than 120 mm (4.72 in.) and a probe posi-
turbulent flow pattern.
tioned in the center of the heating chamber. The furnace shall
be capable of maintaining the probe’s temperature within 7.4.2 Cleaning—The agitation assembly shall be cleaned
62.5 °C (4.5 °F) over the specimen length. The furnace, that prior to use with a detergent solution. After cleaning, the
is, the radiant tube heating media, shall be used with ambient assembly shall be rinsed with water at least three times to
atmosphere. ensure that no quenchant residue or detergent solution remains.
D6549 − 06 (2015)
NOTE 1—Dimensions above are nominal.
FIG. 5 Probe Details and General Probe Assembly
FIG. 6 Drayton Agitation Unit
D6549 − 06 (2015)
7.4.3 Flow Velocity—The variable speed pump and flow 8.1.1 If results do not comply with the specified ranges, the
meter allow reproducible setting of quenchant flow through the probe shall be replaced or reconditioned (see 9.3) or system
tube. The flowmeter is calibrated for water at 25 °C. Flow adjustments made. Compliance to the specified limits of the
velocity for other fluids will vary with fluid viscosity and primaryreferencefluidiscriticalforestablishingthevalidityof
temperature. subsequent test results. It has been shown that the test method
7.4.4 Fluid Volume—The resulting cooling curve is influ- has an excellent level of repeatability and reproducibility when
enced by the temperature rise during the quench, which is the probe and system are shown to be in calibration (9, 10).
dependent on the total fluid volume. Therefore, the cooling 8.1.2 A secondary reference fluid may be used, provided
curve test shall be performed with a fixed volume of fluid. that sufficient statistical cooling curve testing has been con-
ducted so that the results are (1) traceable to the primary
7.5 Temperature Measurement—Any temperature detection
referencefluidand(2)comparedonthebasisofthesixprimary
device may be used that is capable of measuring quenching
cooling characteristics.
fluid temperature to within 61 °C (1.8 °F).
8.1.3 Reference fluids shall be stored in a sealed container
7.6 Transfer Mechanism—One of the following shall be
when not in use and shall be replaced after 200 quenches or
used to transfer the heated probe from the furnace to the test
two years, whichever is sooner.
fluid.
8.2 Polishing Paper, 600 grit emery.
7.6.1 Mechanical Transfer—The agitation unit is positioned
with the center of the test chamber coincident with the probe 8.3 Cotton Cloth or Paper, lintless and absorbent.
centerline.Thetransfermechanismissettodelivertheprobeto
9. Cleaning and Conditioning
the vertical center of the sample.
9.1 Cleaning Used Probes—Wipe the probe with a clean,
7.6.2 Manual Transfer—The probe is transferred to the
wet, lintless cotton cloth or absorbent paper after removal from
agitation unit through a probe guide, which is set (1) to the test
thequenchantandpriortoreturningtothefurnace.Unmounted
chamber centerline and (2) with a preset stop that causes the
probes may be cleaned in the same manner or, alternatively,
probe to rest in the vertical center of the sample. The unit is
washedunderastreamofwater,andthenwipeddry.(Warning
illustrated further in the sketch and photograph of Fig. 6 and
—The probe shall always be considered hot as a temperature
Fig.7,respectively.Atimershallbeusedtoensureamaximum
below visual hot temperatures can still cause injury to the skin
transfer time of 3.0 s.
or ignition of the cloth or paper used in 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,
8. Reagents and Materials
or a grater number if required to achieve consistency, using a
clean, neutral, general purpose hydrocarbon oil. Clean the
8.1 Reference Quenching Fluid, used for initial calibration
probe assembly between quenches, as specified in 9.1. Quench
and for periodic calibration verification. Data collected from
the probe in the reference quenching fluid and check in
quench tests with the reference fluid shall be evaluated for
accordance with 12.3. If the probe does not meet the require-
compliance to the specified values for the six primary charac-
ments of 12.3, recondition in accordance with 9.3 and then
teristics.These characteristics, as defined inWolfson Engineer-
recalibrate again in accordance with 12.3. Do not use probes
ing Group Specification, are as follows:
that do not meet these requirements.
Time to cool to 600 °C (1112 °F) 12 s–14 s
Time to cool to 400 °C (752 °F) 19 s–21 s
9.3 Probe Reconditioning—The probe shall be recondi-
Time to cool to 200 °C (392 °F) 50 s–55 s
tioned when the probe calibration, as described in 12.3, does
Maximum cooling rate 47 °C ⁄ s–53 °C ⁄ s
(85 °F ⁄ s–95 °F ⁄ s)
not meet the calibration limits of the six cooling characteristics
Temperature of the maximum cooling rate 490 °C–530 °C
specified for the reference fluid. Recondition the probe by
(914 °F–986 °F)
polishing with emery paper. Although coarser 320-grit paper
Cooling rate at 300 °C (572 °F) 6 °C ⁄ s–8 °C ⁄ s
(10.8 °F ⁄ s–14.4 °F ⁄ s)
may be used for initial polishing, the final finish shall be
provided by use of 600-grit emery paper. Following this
procedure, the probe shall be quenched until satisfactory
cooling curve results are obtained from the reference fluid.
10. Sampling
10.1 Take care that the gross media, from which the sample
istakentofilltheagitationunit,iswellmixedtoensurethatthe
sample is representative of the media being tested. Any
containers used to secure the quenchant sample must be clean
and dry.
11. Preparation of Apparatus
11.1 Preheat furnace to 850 °C 6 2 °C (1562 °F 6 4 °F), or
alternatively, to 815 °C to 857 °C (1500 °F to 1575 °F) for
FIG. 7 Commercially Available Drayton Agitation Unit production testing.
D6549 − 06 (2015
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6549 − 06 (Reapproved 2011) D6549 − 06 (Reapproved 2015)
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 D6549; 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
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 stated in SI units are to be regarded as standard. The values given 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.
2. Referenced Documents
2.1 ASTM Standards:
E220 Test Method for Calibration of Thermocouples By Comparison Techniques
E230 Specification and Temperature-Electromotive Force (EMF) Tables for Standardized Thermocouples
2.2 SAE Standards:
AMS 5665 Nickel Alloy Corrosion and Heat Resistant Bars, Forgings and Rings
2.3 Other Standards:
Wolfson Engineering Group Specification Laboratory Tests for Assessing the Cooling Curve Characteristics of Industrial
Quenching Media
2.4 ASTM Adjuncts:
ADJD6300 D2PP, Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 aqueous polymer quenchant—an aqueous polymer quenchant is an aqueous solution containing a water soluble polymer,
typically including poly(alkylene glycol), poly(ethyl oxazoline), poly(sodium acrylate), and poly(vinyl pyrrolidone) (1, 2, 3). The
quenchant solution also typically contains additives for corrosion and foam control, if needed. Quench severity of aqueous polymer
quenchants is dependent on concentration and molecular weight of the specific polymer being evaluated, quenchant temperature,
and agitation rate as shown in Fig. 1, Fig. 2, and Fig. 3, respectively.
3.1.2 cooling curve—the cooling curve is a graphical representation of the cooling time (t) versus temperature (T) response of
the probe (see 7.3). An example is illustrated in Fig. 4.
3.1.3 cooling curve analysis—the process of quantifying the cooling characteristics of a quenchant based on the temperature
versus time profile obtained by cooling a preheated metal probe assembly (see Fig. 4) under standard conditions (1-7).
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.L0.06 on Non-Lubricating Process Fluids.
Current edition approved May 1, 2011July 1, 2015. Published August 2011July 2015. Originally approved in 2000. Last previous edition approved in 20062011 as
D6549D6549 – 06 (2011).–06. DOI: 10.1520/D6549-06R11.10.1520/D6549-06R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001, http://www.sae.org.
Available from Wolfson Heat Treatment Centre, Federation House, Vyse St., Birmingham, B18 6LT, UK. http://www.sea.org.uk/whtc.
No longer available from ASTM International Headquarters.
The boldface numbers in parentheses refer to the list of references at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6549 − 06 (2015)
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) Quen-
chant at 0.5 m/s
FIG. 3 Effect of Agitation Rate Variation on Cooling Curve Performance for a 15 % Aqueous Poly(Alkylene Glycol) Quenchant Solution
at 30°C
3.1.4 cooling rate curve—the cooling rate curve is a graphical representation of first derivative of the cooling curve, the rate
of temperature change (dT/dt) versus temperature. An example is illustrated in Fig. 4.
D6549 − 06 (2015)
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
3.1.5 quenchant—a quenching medium may be either a liquid or a gas. Gasses that are used as quenchants include air, nitrogen,
argon, and hydrogen and, with the exception of air, which is used at atmospheric pressure, are used under pressure. Liquid
quenchants include water, brine (most commonly dilute aqueous solutions of sodium chloride or sodium hydroxide), oil, molten
salt, molten metal, and aqueous solutions of water soluble polymers. Water, brine, oil, and aqueous polymer quenchants are
generally used with agitation.
3.1.6 quench severity—the ability of a quenching medium to extract heat from a hot metal (8).
4. Summary of Test Method
4.1 This test method determines the cooling time versus temperature of a standard nickel alloy probe assembly after it has been
heated in a furnace to 850°C (1562°F)850 °C (1562 °F) and then 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
temperature versus time curve. The resulting cooling curve (profile) may be used to evaluate quench severity (see Note 1).
NOTE 1—Where appropriate for production testing, a furnace temperature from 815815 °C to 857°C (1500857 °C (1500 °F to 1575°F)1575 °F) may
be used.
5. Significance and Use
5.1 This test method provides a cooling time versus temperature curve (profile) that can be related to physical properties, such
as the hardness obtainable upon quenching of a metal. The results obtained by this test method may be used as a guide in quenchant
selection or as a comparison of quench severities of different quenchants, new or used.
6. Interferences
6.1 The presence of contaminants, such as oil, salt, metalworking fluids, forging lubricants, and polymer degradation, may affect
cooling curve results obtained by this test method for aqueous polymer quenchants.
7. Apparatus
7.1 Furnace—Use a horizontal or vertical electrical resistance tube-type furnace capable of maintaining a constant minimum
temperature of 850°C (1562°F)850 °C (1562 °F) over a heated length of not less than 120 mm (4.72 in.) 120 mm (4.72 in.) and
a probe positioned in the center of the heating chamber. The furnace shall be capable of maintaining the probe’s temperature within
62.5°C (4.5°F)62.5 °C (4.5 °F) over the specimen length. The furnace, that is, the radiant tube heating media, shall be used with
ambient atmosphere.
7.2 Measurement System—The temperature-time measurement system shall be a computer based data acquisition system
capable of providing a permanent record of the cooling characteristics of each sample tested, producing a record of variation in
the test probe assembly of temperature with respect to time and cooling rate with respect to temperature.
7.3 Probe—The probe shall be cylindrical, having a diameter of 12.5 6 0.01 mm (0.492 6 0.0004 in.) 12.5 mm 6 0.01 mm
(0.492 in. 6 0.0004 in.) and a length of 60 6 0.25 mm (2.362 6 0.01 in.) with a 1.45 to 1.65-mm (0.057 to 0.065-in.)60 mm 6
0.25 mm (2.362 in. 6 0.01 in.) with a 1.45 mm to 1.65 mm (0.057 in. to 0.065 in.) sheathed Type K thermocouple in its geometric
D6549 − 06 (2015)
center. The probe shall be made of a nickel Alloy 600 (UNS N06600), purchased in accordance with AMS 5665, which has a
nominal composition of 76.0 % Ni, 15.5 % Cr, 8.0 % Fe, 0.08 % C, and 0.25 % maximum Cu. The probe shall be attached to a
support tube with a minimum length of 200 mm (7.874 in.). 200 mm (7.874 in.). The thermocouple sheathing and the support tube
shall be the same material as the probe (see Note 2). See Fig. 5 for other manufacturing requirements.
NOTE 2—Care shall be taken that the probe specimen is not damaged as surface irregularities will influence results of the test.
7.4 Drayton Agitation Unit:
7.4.1 Construction—The sample container, a 2000-mL2000 mL stainless steel beaker that is the same as the standard container
used in nonagitated cooling curve test, is modified to provide upward or axial flow of the quenchant past the probe. This flow
occurs through a vertical flow tube located in the geometric center of the container. As shown in Fig. 6, the unit includes a variable
speed dc drive centrifugal pump and large diameter flowmeter for direct measurement of flow velocity. It is noted that the flow
tube is removable, which will provide a more turbulent flow pattern.
7.4.2 Cleaning—The agitation assembly shall be cleaned prior to use with a detergent solution. After cleaning, the assembly
shall be rinsed with water at least three times to ensure that no quenchant residue or detergent solution remains.
7.4.3 Flow Velocity—The variable speed pump and flow meter allow reproducible setting of quenchant flow through the tube.
The flowmeter is calibrated for water at 25°C.25 °C. Flow velocity for other fluids will vary with fluid viscosity and temperature.
7.4.4 Fluid Volume—The resulting cooling curve is influenced by the temperature rise during the quench, which is dependent
on the total fluid volume. Therefore, the cooling curve test shall be performed with a fixed volume of fluid.
7.5 Temperature Measurement—Any temperature detection device may be used that is capable of measuring quenching fluid
temperature to within 61°C (1.8°F).61 °C (1.8 °F).
7.6 Transfer Mechanism—One of the following shall be used to transfer the heated probe from the furnace to the test fluid.
7.6.1 Mechanical Transfer—The agitation unit is positioned with the center of the test chamber coincident with the probe
centerline. The transfer mechanism is set to deliver the probe to the vertical center of the sample.
7.6.2 Manual Transfer—The probe is transferred to the agitation unit through a probe guide, which is set (1) to the test chamber
centerline and (2) with a preset stop that causes the probe to rest in the vertical center of the sample. The unit is illustrated further
in the sketch and photograph of Fig. 6 and Fig. 7, respectively. A timer shall be used to ensure a maximum transfer time of 3.0
s.
NOTE 1—Dimensions above are nominal.
FIG. 5 Probe Details and General Probe Assembly
D6549 − 06 (2015)
FIG. 6 Drayton Agitation Unit
FIG. 7 Commercially Available Drayton Agitation Unit
7.7 Timer, graduated in seconds and minutes, and may be part of a computer clock.
8. Reagents and Materials
8.1 Reference Quenching Fluid, used for initial calibration and for periodic calibration verification. Data collected from quench
tests with the reference fluid shall be evaluated for compliance to the specified values for the six primary characteristics. These
characteristics, as defined in Wolfson Engineering Group Specification, are as follows:
Time to cool to 600°C (1112°F) 12-14 s
Time to cool to 400°C (752°F) 19-21 s
Time to cool to 200°C (392°F) 50-55 s
Maximum cooling rate 47-53°C/s (85-95°F/s)
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)
Time to cool to 600 °C (1112 °F) 12 s–14 s
Time to cool to 400 °C (752 °F) 19 s–21 s
Time to cool to 200 °C (392 °F) 50 s–55 s
Maximum cooling rate 47 °C ⁄ s–53 °C ⁄ s
(85 °F ⁄ s–95 °F ⁄ s)
Temperature of the maximum cooling rate 490 °C–530 °C
(914 °F–986 °F)
Cooling rate at 300 °C (572 °F) 6 °C ⁄ s–8 °C ⁄ s
(10.8 °F ⁄ s–14.4 °F ⁄ s)
D6549 − 06 (2015)
8.1.1 If results do not comply with the specified ranges, the probe shall be replaced or reconditioned (see 9.3) or system
adjustments made. Compliance to the specified limits of the primary reference fluid is critical for establishing the validity of
subsequent test results. It has been shown that the test method has an excellent level of repeatability and reproducibility when the
probe and system are shown to be in calibration (9, 10).
8.1.2 A secondary reference fluid may be used, provided that sufficient statistical cooling curve testing has been conducted so
that the results are (1) traceable to the primary reference fluid and (2) compared on the basis of the six primary cooling
characteristics.
8.1.3 Reference fluids shall be stored in a sealed container when not in use and shall be replaced after 200 quenches or two
years, whichever is sooner.
8.2 Polishing Paper, 600 grit emery.
8.3 Cotton Cloth or Paper, lintless and absorbent.
9. Cleaning and Conditioning
9.1 Cleaning Used Probes—Wipe the probe with a clean, wet, lintless cotton cloth or absorbent paper after removal from the
quenchant and prior to returning to the furnace. Unmounted probes may be cleaned in the same manner or, alternatively, washed
under a stream of water, and then wiped dry. (Warning —The probe shall always be considered hot as a temperature below visual
hot temperatures can still cause injury to the skin or ignition of the cloth or paper used in cleaning.)
9.2 Conditioning New Probes—Condition the probe prior to its initial use by carrying out a minimum of six trial quenches, or
a grater number if required to achieve consistency, using a clean, neutral, general purpose hydrocarbon oil. Clean the probe
assembly between quenches, as specified in 9.1. Quench the probe in the reference quenching fluid and check in accordance with
12.3. If the probe does not meet the requirements of 12.3, recondition in accordance with 9.3 and then recalibrate again in
accordance with 12.3. Do not use probes that do not meet these requiremen
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