ASTM D6482-21

Standard Test Method for Determination of Cooling Characteristics of Aqueous Polymer Quenchants by Cooling Curve Analysis with Agitation (Tensi Method)

SIGNIFICANCE AND USE
5.1 This test method provides a cooling time versus temperature pathway that is directly proportional 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 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 Tensi agitation apparatus.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Nov-2021
• ICS: 75.120 - Hydraulic fluids
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.L0.06 - Non-Lubricating Process Fluids

Relations

• Refers: ASTM D4175-23a - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 15-Dec-2023
• Refers: ASTM D4175-23e1 - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Jul-2023
• Refers: ASTM E220-13 - Standard Test Method for Calibration of Thermocouples By Comparison Techniques
• Effective Date: 01-Nov-2013
• Refers: ASTM D6200-01(2012) - Standard Test Method for Determination of Cooling Characteristics of Quench Oils by Cooling Curve Analysis
• Effective Date: 15-Apr-2012
• Refers: ASTM E220-07a - Standard Test Method for Calibration of Thermocouples By Comparison Techniques
• Effective Date: 01-Nov-2007
• Refers: ASTM D6200-01(2007) - Standard Test Method for Determination of Cooling Characteristics of Quench Oils by Cooling Curve Analysis
• Effective Date: 01-May-2007
• Refers: ASTM E220-07e1 - Standard Test Method for Calibration of Thermocouples By Comparison Techniques
• Effective Date: 01-May-2007
• Refers: ASTM E220-07 - Standard Test Method for Calibration of Thermocouples By Comparison Techniques
• Effective Date: 01-May-2007
• Refers: ASTM E230-03 - Standard Specification and Temperature-Electromotive Force (EMF) Tables for Standardized Thermocouples
• Effective Date: 23-Sep-2003
• Refers: ASTM E220-02 - Standard Test Method for Calibration of Thermocouples By Comparison Techniques
• Effective Date: 10-May-2002
• Refers: ASTM D6200-00 - Standard Test Method for Determination of Cooling Characteristics of Quench Oils by Cooling Curve Analysis
• Effective Date: 10-Aug-2001
• Refers: ASTM D6200-01 - Standard Test Method for Determination of Cooling Characteristics of Quench Oils by Cooling Curve Analysis
• Effective Date: 10-Aug-2001
• Refers: ASTM E230-98 - Standard Specification and Temperature-Electromotive Force (EMF) Tables for Standardized Thermocouples
• Effective Date: 10-Jun-1998
• Refers: ASTM E220-86(1996)e1 - Standard Test Method for Calibration of Thermocouples By Comparison Techniques
• Effective Date: 10-Nov-1996

Overview

ASTM D6482-21 is the standard test method developed by ASTM International for the determination of cooling characteristics of aqueous polymer quenchants by cooling curve analysis with agitation, specifically using the Tensi Method. This standard outlines the procedures and equipment necessary to evaluate the cooling rate of aqueous polymer quenching fluids, which are critical in various thermal processing applications involving metals. By generating precise cooling time versus temperature curves, this test method enables users to assess and compare quenchant performance, ultimately guiding the selection and maintenance of quenching fluids for optimal hardness and quality in metalworking.

Key Topics

• Cooling Curve Analysis: Captures the temperature-time pathway during the quenching of a heated nickel alloy probe into an aqueous polymer quenchant. The cooling curve and its derivative, the cooling rate curve, provide quantitative measures of quenchant effectiveness.
• Tensi Agitation Method: Utilizes a specialized agitation apparatus to ensure consistent and reproducible fluid movement during testing, simulating industrial agitation conditions for accurate results.
• Probe Specifications: Details the use of a type K thermocouple inserted in a nickel alloy probe to monitor real-time temperature changes during quenching.
• Calibration & Repeatability: Emphasizes regular system and probe calibration against reference fluids to ensure the reliability and traceability of results.
• Contaminants and Interferences: Recognizes the potential impact of contaminants (oils, salts, additives) on cooling performance and ensures their consideration in test interpretation.

Applications

• Quenchant Selection: Supports heat treatment professionals in choosing the right aqueous polymer quenchant by providing objective data on their cooling characteristics, essential for achieving desired mechanical properties such as hardness and microstructure.
• Quality Control: Enables regular monitoring of quenchant degradation or contamination over time, ensuring consistent part quality and minimizing defects in production environments.
• Process Optimization: Helps optimize agitation rates, fluid concentrations, and bath temperatures for different quenching operations, contributing to improved process efficiency and part performance.
• Comparative Analysis: Facilitates benchmarking between new, used, or alternative quenching fluids to make informed decisions about fluid replacement or maintenance.

Related Standards

• ASTM D4175: Provides terminology relevant to petroleum products, liquid fuels, and lubricants used in this context.
• ASTM D6200: Describes methods for determining the cooling characteristics of quench oils by cooling curve analysis.
• ASTM E220: Covers methods for calibration of thermocouples by comparison techniques.
• ASTM E230: Specifies temperature-electromotive force (emf) tables for standardized thermocouples.
• SAE AMS 5665: Relates to the specification of nickel alloy probes used in the testing process.
• JIS K 2242, JIS K 6753: Japanese industrial standards relevant to heat treating oils and test fluids.

Practical Value

Implementing ASTM D6482-21 aids in standardized evaluation of aqueous polymer quenchants, assuring consistent heat treatment results and part quality. This standard is particularly important for industries such as automotive, aerospace, and heavy manufacturing, where metallurgical integrity is paramount. By adhering to this method, organizations can ensure compliance with international best practices, improve process control, and extend the lifespan of both quenching fluids and metal components.

Keywords: ASTM D6482-21, aqueous polymer quenchant, cooling curve analysis, Tensi method, heat treatment, cooling characteristics, metal hardening, quenching process, agitation, metallurgical testing.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D6482 − 21
Standard Test Method for
Determination of Cooling Characteristics of Aqueous
Polymer Quenchants by Cooling Curve Analysis with
Agitation (Tensi Method)
This standard is issued under the fixed designation D6482; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* (emf) Tables for Standardized Thermocouples
2.2 SAE Standard:
1.1 This test method covers the equipment and the proce-
AMS 5665NickelAlloy Corrosion and Heat Resistant Bars,
dureforevaluationofquenchingcharacteristicsofaquenching
Forgings and Rings
fluid by cooling rate determination.
2.3 Japanese Industrial Standards:
1.2 This test method is designed to evaluate quenching
JIS K 2242Heat Treating Oil
fluids with agitation, using the Tensi agitation apparatus.
JIS K 6753Di-2-ethylhexyl Phthalate
1.3 The values stated in SI units are to be regarded as
2.4 Wolfson Engineering Group:
standard. The values given in parentheses are for information
Wolfson Engineering Group Specification Laboratory Tests
only.
for Assessing the Cooling Curve of Industrial Quenching
1.4 This standard does not purport to address all of the
Media
safety concerns, if any, associated with its use. It is the
2.5 ASTM Adjuncts:
responsibility of the user of this standard to establish appro-
ADJD6300 D2PP, Determination of Precision and Bias
priate safety, health, and environmental practices and deter-
Data for Use in Test Methods for Petroleum Products
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor-
3. Terminology
dance with internationally recognized principles on standard-
3.1 Definitions of Terms Specific to This Standard:
ization established in the Decision on Principles for the
3.1.1 For definitions of terms used in this test method, refer
Development of International Standards, Guides and Recom-
to Terminology D4175.
mendations issued by the World Trade Organization Technical
3.1.2 aqueous polymer quenchant, n—an aqueous solution
Barriers to Trade (TBT) Committee.
containing a water soluble polymer; typically including poly-
(alkylene glycol), poly(ethyl oxazoline), poly(solium acrylate)
2. Referenced Documents
and poly(vinyl pyrrolidone) (1, 2). The quenchant solution
2.1 ASTM Standards:
also typically contains additives for corrosion and foam
D4175Terminology Relating to Petroleum Products, Liquid
control, if needed. Quench severity of aqueous polymer quen-
Fuels, and Lubricants
chants is dependent on concentration and molecular weight of
D6200Test Method for Determination of Cooling Charac-
the specific polymer being evaluated, quenchant temperature,
teristics of Quench Oils by Cooling Curve Analysis
and agitation rate as shown in Figs. 1-3, respectively.
E220Test Method for Calibration of Thermocouples By
3.1.3 cooling curve, n—a graphical representation of the
Comparison Techniques
cooling time (t)-temperature (T) response of the probe (see
E230Specification for Temperature-Electromotive Force
7.3). An example is illustrated in Fig. 4A.
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of AvailablefromSAEInternational(SAE),400CommonwealthDr.,Warrendale,
Subcommittee D02.L0.06 on Non-Lubricating Process Fluids. PA 15096-0001, http://www.sae.org.
Current edition approved Dec. 1, 2021. Published January 2022. Originally Available from Japanese Standards Organization (JSA), 4-1-24 Akasaka
approved in 1999. Last previous edition approved in 2016 as D6482 – 06 (2016). Minato-Ku, Tokyo, 107-8440, Japan, http://www.jsa.or.jp.
DOI: 10.1520/D6482-21. WolfsonHeatTreatmentCentre,FederationHouse,VyseSt.,Birmingham,B18
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 6LT, UK, http://www.sea.org.uk/whtc.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM No longer available from ASTM International Headquarters.
Standards volume information, refer to the standard’s Document Summary page on Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
the ASTM website. this standard.
*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
D6482 − 21
FIG. 1 Illustration of the Effect of Quenchant Concentration on Cooling Curve Performance for Poly(Alkylene Glycol) Quenchant at 30°C
and 0.5 m/s
FIG. 2 Illustration of the Effect of Bath Temperature Variation on Cooling Curve Performance for 15 % Aqueous Solution of Poly (Alky-
lene Glycol) Quenchant at 0.5 m/s
3.1.4 cooling curve analysis, n—the process of quantifying 4. Summary of Test Method
the cooling characteristics of a quenchant based on the tem-
4.1 The nickel alloy probe assembly’s cooling time versus
perature versus time profile obtained by cooling a preheated
temperature is determined after placing the assembly in a
metalprobeassembly(seeFig.5)understandardconditions (1,
furnace and heating to 850°C (1562°F) and then quenching
3, 4).
into an aqueous polymer quenchant solution. The temperature
3.1.5 cooling rate curve, n—obtainedbycalculatingthefirst
insidetheprobeassemblyandthecoolingtimesarerecordedat
derivative (dT/dt) of the cooling time-temperature curve. An
selected time intervals to establish a cooling temperature
example is illustrated in Fig. 4B.
versus time curve. The resulting cooling curve may be used to
3.1.6 quench severity, n—theabilityofaquenchingmedium
evaluate quench severity (see Note 1).
to extract heat from a hot metal (5).
NOTE 1—For production testing, the furnace temperature of 815°C to
3.1.7 quenchant, n—any medium, liquid or gas that may be
857°C (1500°F to 1575°F) may be used.
used to mediate heat transfer during the cooling of hot metal.
D6482 − 21
FIG. 3 Effect of Agitation Rate Variation on Cooling Curve Performance for a 15 % Aqueous Poly(Alkylene Glycol) Quenchant Solution
at 30°C
A. Cooling time - temperature curve (cooling curve) B. Cooling rate - temperature curve (cooling rate curve)
FIG. 4 Typical Temperature/Time and Temperature/Cooling Rate Plots for Test Probe Cooled in Quenching Oil
5. Significance and Use 7. Apparatus
5.1 This test method provides a cooling time versus tem-
7.1 Furnace—Use a horizontal or vertical electrical resis-
perature pathway that is directly proportional to physical
tance tube-type furnace capable of maintaining a constant
properties such as the hardness obtainable upon quenching of
minimum temperature of 850°C (1562°F) over a heated
a metal. The results obtained by this test method may be used
length of not less than 120mm (4.72in.) and a probe posi-
as a guide in quenchant selection or comparison of quench
tioned in the center of the heating chamber. The furnace shall
severities of different quenchants, new or used.
be capable of maintaining the probe’s temperature within
62.5°C (4.5°F) over the specimen length. The furnace, that
6. Interferences
is, the radiant tube heating media, shall be used with ambient
6.1 The presence of contaminants, such as oil, salt, metal-
atmosphere.
working fluids, forging lubricants, and polymer degradation,
7.2 Measurement System—The temperature-time measure-
may affect cooling curve results obtained by this test method
mentsystemshallbeacomputerbaseddataacquisitionsystem
foraqueouspolymerquenchants.Contaminants,suchaswater,
capable of providing a permanent record of the cooling
hydraulicfluids,sludge,additiveloss,andoildegradation,may
similarly affect the cooling curve behavior of oil quenchants. characteristics of each oil sample tested, producing a record of
D6482 − 21
FIG. 5 Probe Details and General Probe Assembly
variationinthetestprobeassemblyoftemperaturewithrespect 15.5%Cr,8.0%Fe,0.08%C,and0.25%maximumCu.The
to time and of cooling rate with respect to temperature. probe shall be attached to a support tube with a minimum
lengthof200mm(7.874in.).Thethermocouplesheathingand
7.3 Probe, shall be cylindrical, having a diameter of
the support tube shall be the same material as the probe (see
12.5mm 6 0.01mm (0.492in. 6 0.0004 in.) and a length of
Note 2). See Fig. 4 for recommended manufacturing details.
60mm 6 0.25mm (2.362in. 6 0.01in.) with a 1.45mm to
1.65mm(0.057in.to0.065in.)sheathedtype Kthermocouple NOTE2—Exercisecarethattheprobespecimenisnotdamagedbecause
surface irregularities will influence the results of the test.
in its geometric center. The probe shall be made of a nickel
alloy 600 (UNS N06600) purchased to SAE specification (see 7.4 Tensi Agitation Assembly:
AMS 5665), that has a nominal composition of 76.0% Ni, 7.4.1 Construction:
D6482 − 21
7.4.1.1 The 125mm by 60mm by 60mm Tensi agitation
assemblyisillustratedinFig.6.Thevolumeoftheassemblyis
–3 3
approximately 1.5 by 10 m . This assembly may be con-
structed from glass or any transparent and temperature-
resistant synthetic material that is chemically compatible with
the quenching fluids to be evaluated. Alternatively, the agita-
tion assembly, illustrated in Fig. 7, may be purchased as-
sembled.
7.4.1.2 Quenchant agitation is provided by an impeller
mixer. The three-blade impeller is 50mm in diameter with a
pitch setting 42mm ≈ _ × 0.85. The impeller is commercially
available.
NOTE 3—This procedure is recommended for aqueous polymer quen-
chants. Quench oils are not compatible with the poly(methyl methacry-
late) materials used for construction of this apparatus.
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
ensurethatnoquenchantresidueordetergentsolutionremains.
The sole source of supply of the Tensi agitation apparatus, fully assembled,
known to the committee at this time is IVF, The Swedish Institute of Production
EngineeringResearch,Argongatan30,S-43153Mölndal,Sweden.Ifyouareaware
of alternative suppliers, please provide this information to ASTM International
Headquarters.Your comments will receive careful consideration at a meeting of the
responsible technical committee, which you may attend.
FIG. 7 Commercially Available Tensi Agitation Assembly
7.4.3 Flow Velocity—Correlation of flow velocity through
the quenching chamber and impeller rotational speed for water
is illustrated in Fig. 8. Flow velocity for other fluids will vary
with fluid viscosity.
7.4.3.1 Impeller Speed—Fluids shall be controlled by the
rotational speed of the impeller. Standard impeller speed of
1000r⁄min is recommended and is obtained from a plot of
revolutions per minute versus potentiometer setting as illus-
trated in Fig. 9 and described as impeller speed calibration:
Impeller speed shall be determined using an optical tachom-
eter. Optional tachometers operate by emitting and receiving
FIG. 8 Correlation of Flow Velocity Through Quenching Chamber
FIG. 6 Schematic Drawing of Tensi Agitation Assembly and Impeller Rotational Speed for Water
D6482 − 21
tioned (see 9.3). Cooling curve results shall be traceable to a
primary standard fluid, such as that cited inWolfson Engineer-
ing Group Specification or JIS K 2242 and JIS K 6753. The
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. Distilled or deionized water at 50°C may
also be used.
NOTE 5—If a reference fluid other than distilled water is used, the
agitation device described here shall not be used. Instead, a suitable
compatible container consistent with the specified requirement being
FIG. 9 Potentiometer Setting
followed shall be used.
8.2 Cleaning Solvent—A hydrocarbon solvent that will
light to and from a reflector fastened on to the impeller shaft. evaporate at room temperature, leaving no residue.
A typical calibration plot is illustrated in Fig. 8.
(Warning—Flammable. Harmful if inhaled.)
NOTE 4—The impeller velocity will depend to some extent on the 8.3 Polishing Paper, 600 grit emery.
viscosity of the quenchant solution. However, the variation was found to
8.4 Cloth, lintless and absorbent.
be minimal over a wide range of viscosities from water to a polymer
quenchant at 30% by volume.
9. Cleaning and Conditioning
7.4.3.2 Flow Direction—The correct fluid flow direction is
illustrated in Fig. 6. However, if the wiring of the electrical
9.1 Cleaning Used Probes—Wipeprobewithalintlesscloth
motorisreversed,itispossiblethattheflowdirectionwillalso
or absorbent paper after removal from the oil and prior to
bereversed.Ifthisoccurs,whichiseasilydetectedvisually,the
returning to the furnace. (Warning—The probe shall always
polarityoftheelectricalmotorisreversedbyreversingthetwo
be considered hot, as temperature below visual hot tempera-
wire leads to the motor.
tures can still cause injury to the skin.)Acleaning solvent may
7.4.4 Fluid Volume—The resulting cooling curve will be
beused,butcareshouldbetakenthattheprobeisbelow50°C
dependent on the temperature rise during the quench, which is
(122°F). (Warning—Do not use cleaning solvent near the
dependent on the total fluid volume. Therefore, the cooling
furnace opening, especially with automated transfer mecha-
curve analysis shall be performed with the same volume of
nisms.)
fluid.Thefluidshallbelevelwiththelowerdistanceringinthe
9.2 Conditioning New Probes—Conditiontheprobepriorto
support tube, as shown in Fig. 10.
its initial use with any quenchant by carrying out a minimum
7.5 Temperature Measurement—Any temperature detection
ofsixtrialquenches,oragreaternumberifrequiredtoachieve
device may be used that is capable of measuring quenching
consistency, using a general purpose hydrocarbon oil. Consis-
fluid temperature to within 61°C (1.8°F).
tencyshallmeanthelasttwotestsshallhavemaximumcooling
7.6 Transfer Mechani
...

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: D6482 − 06 (Reapproved 2016) D6482 − 21
Standard Test Method for
Determination of Cooling Characteristics of Aqueous
Polymer Quenchants by Cooling Curve Analysis with
Agitation (Tensi Method)
This standard is issued under the fixed designation D6482; 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 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 Tensi agitation apparatus.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D6200 Test Method for Determination of Cooling Characteristics of Quench Oils by Cooling Curve Analysis
E220 Test Method for Calibration of Thermocouples By Comparison Techniques
E230 Specification for Temperature-Electromotive Force (emf) Tables for Standardized Thermocouples
2.2 SAE Standard:
AMS 5665 Nickel Alloy Corrosion and Heat Resistant Bars, Forgings and Rings
2.3 Japanese Industrial Standards:
JIS K 2242 Heat Treating Oil
JIS K 6753 Di-2-ethylhexyl Phthalate
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.L0.06 on Non-Lubricating Process Fluids.
Current edition approved July 1, 2016Dec. 1, 2021. Published July 2016January 2022. Originally approved in 1999. Last previous edition approved in 20112016 as D6482
– 06 (2011).(2016). DOI: 10.1520/D6482-06R16.10.1520/D6482-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. 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 Japanese Standards Organization (JSA), 4-1-24 Akasaka Minato-Ku, Tokyo, 107-8440, Japan, http://www.jsa.or.jp.
*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
D6482 − 21
2.4 Wolfson Engineering Group:
Wolfson Engineering Group Specification Laboratory Tests for Assessing the Cooling Curve of Industrial Quenching Media
2.5 ASTM Adjuncts:
ADJD6300 D2PP, Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 For definitions of terms used in this test method, refer to Terminology D4175.
3.1.2 aqueous polymer quenchant—quenchant, n—an aqueous solution containing a water soluble polymer; typically including
poly(alkylene glycol), poly(ethyl oxazoline), poly(solium acrylate) and poly(vinyl pyrrolidone) (1, 2)). . 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 Figs. 1-3, respectively.
3.1.3 cooling curve—curve, n—a graphical representation of the cooling time (t)-temperature (T) response of the probe (see 7.3).
An example is illustrated in Fig. 4A.
3.1.4 cooling curve analysis—analysis, n—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. 5) under standard conditions (1,
3, 4).
3.1.5 cooling rate curve—curve, n—obtained by calculating the first derivative (dT/dt) of the cooling time-temperature curve. An
example is illustrated in Fig. 4B.
3.1.6 quench severity—severity, n—the ability of a quenching medium to extract heat from a hot metal (5).
3.1.7 quenchant—quenchant, n—any medium, liquid or gas that may be used to mediate heat transfer during the cooling of hot
metal.
FIG. 1 Illustration of the Effect of Quenchant Concentration on Cooling Curve Performance for Poly(Alkylene Glycol) Quenchant at 30°C
and 0.5 m/s
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.
D6482 − 21
FIG. 2 Illustration of the Effect of Bath Temperature Variation on Cooling Curve Performance for 15 % Aqueous Solution of Poly (Alky-
lene Glycol) Quenchant 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
4. Summary of Test Method
4.1 The nickel alloy probe assembly’s cooling time versus temperature is determined after placing the assembly in a furnace and
heating to 850 °C (1562 °F) and then quenching into 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 may be used to evaluate quench severity (see Note 1).
NOTE 1—For production testing, the furnace temperature of 815 °C to 857 °C (1500 °F to 1575 °F) may be used.
5. Significance and Use
5.1 This test method provides a cooling time versus temperature pathway that is directly proportional 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 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
D6482 − 21
A. Cooling time - temperature curve (cooling curve) B. Cooling rate - temperature curve (cooling rate curve)
FIG. 4 Typical Temperature/Time and Temperature/Cooling Rate Plots for Test Probe Cooled in Quenching Oil
cooling curve results obtained by this test method for aqueous polymer quenchants. Contaminants, such as water, hydraulic fluids,
sludge, additive loss, and oil degradation, may similarly affect the cooling curve behavior of oil 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) over a heated length of not less than 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) 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 oil sample tested, producing a record of variation in the test
probe assembly of temperature with respect to time and of cooling rate with respect to temperature.
7.3 Probe, shall be cylindrical, having a diameter of 12.5 mm 6 0.01 mm (0.492 in. 6 0.0004 in.) and a 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 thermocouple in its geometric
center. The probe shall be made of a nickel alloy 600 (UNS N06600) purchased to SAE specification (see AMS 5665), that 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.). The thermocouple sheathing and the support tube shall be the same
material as the probe (see Note 2). See Fig. 4 for recommended manufacturing details.
NOTE 2—Exercise care that the probe specimen is not damaged because surface irregularities will influence the results of the test.
7.4 Tensi Agitation Assembly:
7.4.1 Construction:
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FIG. 5 Probe Details and General Probe Assembly
7.4.1.1 The 125 mm by 60 mm by 60 mm Tensi agitation assembly is illustrated in Fig. 6. The volume of the assembly is
–3 3
approximately 1.5 by 10 m . This assembly may be constructed from glass or any transparent and temperature-resistant synthetic
material that is chemically compatible with the quenching fluids to be evaluated. Alternatively, the agitation assembly, illustrated
in Fig. 7, may be purchased assembled.
7.4.1.2 Quenchant agitation is provided by an impeller mixer. The three-blade impeller is 50 mm in diameter with a pitch setting
42 mm ≈ _ × 0.85. The impeller is commercially available.
The sole source of supply of the Tensi agitation apparatus, fully assembled, known to the committee at this time is IVF, The Swedish Institute of Production Engineering
Research, Argongatan 30, S-431 53 Mölndal, Sweden. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your
comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
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FIG. 6 Schematic Drawing of Tensi Agitation Assembly
NOTE 3—This procedure is recommended for aqueous polymer quenchants. Quench oils are not compatible with the poly(methyl methacrylate) materials
used for construction of this apparatus.
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—Correlation of flow velocity through the quenching chamber and impeller rotational speed for water is
illustrated in Fig. 8. Flow velocity for other fluids will vary with fluid viscosity.
7.4.3.1 Impeller Speed—Fluids shall be controlled by the rotational speed of the impeller. Standard impeller speed of 1000 r ⁄min
is recommended and is obtained from a plot of revolutions per minute versus potentiometer setting as illustrated in Fig. 9 and
described as impeller speed calibration: Impeller speed shall be determined using an optical tachometer. Optional tachometers
operate by emitting and receiving light to and from a reflector fastened on to the impeller shaft. A typical calibration plot is
illustrated in Fig. 8.
NOTE 4—The impeller velocity will depend to some extent on the viscosity of the quenchant solution. However, the variation was found to be minimal
over a wide range of viscosities from water to a polymer quenchant at 30 % by volume.
7.4.3.2 Flow Direction—The correct fluid flow direction is illustrated in Fig. 6. However, if the wiring of the electrical motor is
reversed, it is possible that the flow direction will also be reversed. If this occurs, which is easily detected visually, the polarity
of the electrical motor is reversed by reversing the two wire leads to the motor.
7.4.4 Fluid Volume—The resulting cooling curve will be dependent on the temperature rise during the quench, which is dependent
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FIG. 7 Commercially Available Tensi Agitation Assembly
FIG. 8 Correlation of Flow Velocity Through Quenching Chamber and Impeller Rotational Speed for Water
on the total fluid volume. Therefore, the cooling curve analysis shall be performed with the same volume of fluid. The fluid shall
be level with the lower distance ring in the support tube, as shown in Fig. 10.
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).
7.6 Transfer Mechanism—The heated probe is transferred manually to the Tensi agitation assembly, which shall be equipped with
a fixture to ensure correct placement in the center of the quenching chamber, as illustrated in Figs. 6 and 7. A timer shall be used
to ensure a maximum transfer time of 3.0 s.
7.7 Timer, graduated in seconds and minutes, and may be part of a computer clock.
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FIG. 9 Potentiometer Setting
FIG. 10 Fluid Level
8. Reagents and Materials
8.1 Reference Quenching Fluid—Use a reference quenching fluid for initial and regular probe calibration to determine if the probe
will give results consistent to those obtained during initial break-in (see Test Method D6200). If the maximum cooling rate is
greater than 63 %, the probe shall be reconditioned (see 9.3). Cooling curve results shall be traceable to a primary standard fluid,
such as that cited in Wolfson Engineering Group Specification or JIS K 2242 and JIS K 6753. The 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. Distilled or
deionized water at 50 °C may also be used.
NOTE 5—If a reference fluid other than distilled water is used, the agitation device described here shall not be used. Instead, a suitable compatible container
consistent with the specified requirement being followed shall be used.
8.2 Cleaning Solvent—A hydrocarbon solvent that will evaporate at room temperature, leaving no residue. (Warning—
Flammable. Harmful if inhaled.)
8.3 Polishing Paper, 600 grit emery.
8.4 Cloth, lintless
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