ASTM D4310-22a

Standard Test Method for Determination of Sludging and Corrosion Tendencies of Inhibited Mineral Oils

SIGNIFICANCE AND USE
5.1 Insoluble material may form in oils that are subjected to oxidizing conditions.  
5.2 Significant formation of oil insolubles or metal corrosion products, or both, during this test may indicate that the oil will form insolubles or corrode metals, or both, during field service. However, no correlation with field service has been established.
SCOPE
1.1 This test method covers and is used to evaluate the tendency of inhibited mineral oil based steam turbine lubricants and mineral oil based anti-wear hydraulic oils to corrode copper catalyst metal and to form sludge during oxidation in the presence of oxygen, water, and copper and iron metals at an elevated temperature. The test method is also used for testing circulating oils having a specific gravity less than that of water and containing rust and oxidation inhibitors.  
Note 1: During round robin testing copper and iron in the oil, water and sludge phases were measured. However, the values for the total iron were found to be so low (that is, below 0.8 mg), that statistical analysis was inappropriate. The results of the cooperative test program are available (see Section 16).  
1.2 This test method is a modification of Test Method D943 where the oxidation stability of the same kinds of oils is determined by following the acid number of oil. The number of test hours required for the oil to reach an acid number of 2.0 mg KOH/g is the oxidation lifetime.  
1.3 Procedure A of this test method requires the determination and report of the weight of the sludge and the total amount of copper in the oil, water, and sludge phases. Procedure B requires the sludge determination only. The acid number determination is optional for both procedures.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 WARNING—Mercury has been designated by many regulatory agencies as a hazardous substance that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Use Caution when handling mercury and mercury-containing products. See the applicable product Safety Data Sheet (SDS) for additional information. The potential exists that selling mercury or mercury-containing products, or both, is prohibited by local or national law. Users must determine legality of sales in their location.  
1.6 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. For specific warning statements, see Section 7 and X1.1.5.  
1.7 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: 31-Oct-2022
• ICS: 75.040 - Crude petroleum
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.09.0C - Oxidation of Turbine Oils

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 B1-13(2018) - Standard Specification for Hard-Drawn Copper Wire
• Effective Date: 01-Oct-2018
• Refers: ASTM D943-17 - Standard Test Method for Oxidation Characteristics of Inhibited Mineral Oils
• Effective Date: 15-Jun-2017
• Refers: ASTM D664-11a(2017) - Standard Test Method for Acid Number of Petroleum Products by Potentiometric Titration
• Effective Date: 01-May-2017
• Refers: ASTM B1-13 - Standard Specification for Hard-Drawn Copper Wire
• Effective Date: 01-Oct-2013
• Refers: ASTM D874-13a - Standard Test Method for Sulfated Ash from Lubricating Oils and Additives
• Effective Date: 01-Sep-2013
• Refers: ASTM D874-13 - Standard Test Method for Sulfated Ash from Lubricating Oils and Additives
• Effective Date: 01-Aug-2013
• Refers: ASTM E1-13 - Standard Specification for ASTM Liquid-in-Glass Thermometers
• Effective Date: 01-May-2013
• Refers: ASTM B1-12 - Standard Specification for Hard-Drawn Copper Wire
• Effective Date: 15-Nov-2012
• Refers: ASTM D3339-12 - Standard Test Method for Acid Number of Petroleum Products by Semi-Micro Color Indicator Titration
• Effective Date: 15-Apr-2012
• Refers: ASTM D4057-06(2011) - Standard Practice for Manual Sampling of Petroleum and Petroleum Products
• Effective Date: 01-Jun-2011
• Refers: ASTM D3339-11 - Standard Test Method for Acid Number of Petroleum Products by Semi-Micro Color Indicator Titration
• Effective Date: 15-May-2011
• Refers: ASTM D664-11 - Standard Test Method for Acid Number of Petroleum Products by Potentiometric Titration
• Effective Date: 15-May-2011
• Refers: ASTM D664-09 - Standard Test Method for Acid Number of Petroleum Products by Potentiometric Titration
• Effective Date: 01-Mar-2009

Overview

ASTM D4310-22a is the international standard test method for determining sludging and corrosion tendencies of inhibited mineral oils. Developed by ASTM, this test assesses how mineral oil-based lubricants, such as steam turbine lubricants and anti-wear hydraulic oils, perform under oxidizing conditions in the presence of oxygen, water, copper, and iron at elevated temperatures. The standard provides a means to gauge whether these oils are likely to produce sludge or corrode metal components - issues critical to maintaining equipment reliability and longevity in various industries.

Key Topics

• Sludge Formation: Evaluation of insoluble materials formed during the oxidation of inhibited mineral oils.
• Metal Corrosion Assessment: Measurement of copper corrosion products to determine an oil’s potential to corrode metal surfaces under test conditions.
• Oxidation Stability: Assessment of the oil’s resistance to oxidation using procedures that can also measure the acid number, following modifications of test method ASTM D943.
• Applicability: Designed for lubricants and hydraulic fluids containing rust and oxidation inhibitors and specific gravity less than water.
• Test Procedures: Two main procedures:
  • Procedure A: Determines sludge weight and total copper in oil, water, and sludge.
  • Procedure B: Only the amount of sludge is determined; measurement of acid number is optional in both procedures.
• Test Conditions: The method simulates field service by operating under controlled temperatures (typically 95°C) and in the presence of catalysts and water.
• Safety and Compliance: Emphasizes using SI units, adherence to safety precautions regarding mercury and hazardous chemicals, and compliance with internationally recognized standardization principles.

Applications

ASTM D4310-22a is specifically valuable for:

• Lubricant Manufacturers: To qualify steam turbine and hydraulic oils before deployment, ensuring minimal sludge formation and metal corrosion.
• Power Generation Plants: As part of predictive maintenance for steam turbines, minimizing downtime and extending the life of lubricated assets.
• Industrial Equipment Operators: For circulating oils in heavy machinery, refineries, and petrochemical plants, where long-term oil stability is crucial.
• Quality Control Laboratories: For routine product testing and research into lubricant performance and improvement.
• Purchasing Specifications: As a reference in technical procurement documents to ensure high-quality lubricants are supplied.

Key practical values include improved equipment protection, reduced maintenance costs, and increased reliability by identifying oils susceptible to sludging or corrosion under harsh operating conditions.

Related Standards

• ASTM D943: Standard Test Method for Oxidation Characteristics of Inhibited Mineral Oils; the basis for acid number determination in the modified test method.
• ASTM D664 / D3339: Methods for determining the acid number of petroleum products by potentiometric titration or using color indicators.
• ASTM D874: Test Method for Sulfated Ash from Lubricating Oils and Additives, applicable for ashing sludge residues.
• ASTM D4057: Practice for Manual Sampling of Petroleum and Petroleum Products, referenced for appropriate sampling techniques.
• ASTM D4175: Terminology relevant to petroleum products, liquid fuels, and lubricants.
• ASTM E1: Specification for ASTM Liquid-in-Glass Thermometers, relevant for temperature measurement in test apparatus.

Conclusion

Adhering to ASTM D4310-22a helps ensure inhibited mineral oils are fit for purpose in applications where oxidative stability and corrosion resistance are crucial. Its systematic approach supports oil manufacturers, end-users, and quality assurance professionals in making informed product selections and maintaining high operational standards in lubrication systems. This ultimately promotes efficiency and equipment longevity in industries reliant on high-performance lubricants.

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: D4310 − 22a
Standard Test Method for
Determination of Sludging and Corrosion Tendencies of
Inhibited Mineral Oils
This standard is issued under the fixed designation D4310; 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* mercury or mercury-containing products, or both, is prohibited
by local or national law. Users must determine legality of sales
1.1 This test method covers and is used to evaluate the
in their location.
tendency of inhibited mineral oil based steam turbine lubri-
cants and mineral oil based anti-wear hydraulic oils to corrode
1.6 This standard does not purport to address all of the
copper catalyst metal and to form sludge during oxidation in
safety concerns, if any, associated with its use. It is the
thepresenceofoxygen,water,andcopperandironmetalsatan
responsibility of the user of this standard to establish appro-
elevated temperature. The test method is also used for testing
priate safety, health, and environmental practices and deter-
circulating oils having a specific gravity less than that of water
mine the applicability of regulatory limitations prior to use.
and containing rust and oxidation inhibitors.
For specific warning statements, see Section 7 and X1.1.5.
1.7 This international standard was developed in accor-
NOTE 1—During round robin testing copper and iron in the oil, water
dance with internationally recognized principles on standard-
and sludge phases were measured. However, the values for the total iron
were found to be so low (that is, below 0.8 mg), that statistical analysis
ization established in the Decision on Principles for the
was inappropriate. The results of the cooperative test program are
Development of International Standards, Guides and Recom-
available (see Section 16).
mendations issued by the World Trade Organization Technical
1.2 This test method is a modification of Test Method D943
Barriers to Trade (TBT) Committee.
where the oxidation stability of the same kinds of oils is
determinedbyfollowingtheacidnumberofoil.Thenumberof
2. Referenced Documents
test hours required for the oil to reach an acid number of
2.1 ASTM Standards:
2.0 mg KOH/g is the oxidation lifetime.
A510 Specification for General Requirements forWire Rods
1.3 Procedure A of this test method requires the determina-
and Coarse Round Wire, Carbon Steel (Metric) A0510_
tion and report of the weight of the sludge and the total amount
A0510M
of copper in the oil, water, and sludge phases. Procedure B
B1 Specification for Hard-Drawn Copper Wire
requires the sludge determination only. The acid number
D664 Test Method for Acid Number of Petroleum Products
determination is optional for both procedures.
by Potentiometric Titration
D874 Test Method for Sulfated Ash from Lubricating Oils
1.4 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this and Additives
D943 Test Method for Oxidation Characteristics of Inhibited
standard.
Mineral Oils
1.5 WARNING—Mercury has been designated by many
D1193 Specification for Reagent Water
regulatory agencies as a hazardous substance that can cause
D3339 Test Method forAcid Number of Petroleum Products
serious medical issues. Mercury, or its vapor, has been dem-
by Semi-Micro Color Indicator Titration
onstrated to be hazardous to health and corrosive to materials.
D4057 Practice for Manual Sampling of Petroleum and
Use Caution when handling mercury and mercury-containing
Petroleum Products
products. See the applicable product Safety Data Sheet (SDS)
D4175 Terminology Relating to Petroleum Products, Liquid
for additional information. The potential exists that selling
Fuels, and Lubricants
E1 Specification for ASTM Liquid-in-Glass Thermometers
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 D02.09.0C on Oxidation of Turbine Oils. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2022. Published November 2022. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1983. Last previous edition approved in 2022 as D4310 – 22. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D4310-22A. the ASTM website.
*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
D4310 − 22a
2.2 Energy Institute Standard: depth of 390 mm 6 10 mm and in the heating liquid itself to a
Specification for IP Standard Thermometers depth of 355 mm 6 10 mm.
6.2.1 Studies have suggested that direct sunlight or artificial
2.3 British Standard:
light may adversely influence the results of this test. To
BS 1829 Reference Tables for Iron v. Constantan Thermo-
minimize effects of light exposure on the lubricant being
couples
tested, light shall be excluded from the lubricant by one or
more of the following ways:
3. Terminology
6.2.1.1 Use of heated liquid baths that are designed and
3.1 Definitions:
constructed of metal, or combinations of metals and other
3.1.1 See Terminology D4175 for a list of terms relating to
suitable opaque materials, that prevent light from entering the
petroleum products, liquid fuels, and lubricants.
test cell from the sides is preferred. If a viewing window is
3.2 Definitions of Terms Specific to This Standard:
included in the design, this viewing window shall be fitted with
3.2.1 sludge, n—a precipitate or sediment from oxidized
a suitable opaque cover and be kept closed when no observa-
mineral oil and water that is insoluble in n-heptane.
tion is being made.
6.2.1.2 If glass heating baths are used, the bath shall be
4. Summary of Test Method
wrapped with aluminum foil or other opaque material.
4.1 An oil sample is contacted with oxygen in the presence
6.2.1.3 Bright light entering the test cell from directly
of water and an iron-copper catalyst at 95 °C for 1000 h. The
overhead can be eliminated by use of an opaque shield.
weight of insoluble material is determined by vacuum filtration
6.3 Flowmeter, with a flow capacity of at least 3 L of
of the oxidation tube contents through 5 µm pore size filter
oxygen/hour, and an accuracy of 60.1 L⁄h.
disks. The total amount of copper in the oil, water, and sludge
6.4 Heating Bath Thermometer—ASTM Solvents Distilla-
phases is also determined for Procedure A. Procedure B
tion Thermometer having a range from 72 °C to 126 °C and
requires the sludge determination. The copper determination is
conforming to the requirements for Thermometer 40C as
not required. The acid number determination is optional for
prescribed in Specification E1, or for Thermometer 70C as
both procedures.
prescribed in Specifications for IP Standard Thermometers.
NOTE 2—Optionally, some operators may choose to: (1) assess the
Alternatively, temperature–measuring devices of equal or bet-
change in weight of the catalyst coil, or (2) determine the acid number at
ter accuracy may be used.
1000 h, or both. The acid number may serve as a criterion to determine if
measurement of insoluble material is warranted. Normally, further testing
6.5 Oxidation Cell Thermometer,havingarangefrom80 °C
is not recommended on a highly oxidized oil (that is an oil which has
to 100 °C, graduated in 0.1 °C, total length—250 mm, stem
attained an acid number >2.0 mg KOH/g). Instructions for these optional
diameter—6.0 mm to 7.0 mm, calibrated for 76 mm immer-
tests are not included in this test method.
sion. Temperature measuring devices such as liquid-in-glass
thermometers, thermocouples, or platinum resistance ther-
5. Significance and Use
mometers that provide equivalent or better accuracy and
5.1 Insoluble material may form in oils that are subjected to
precision that cover the temperature range, may be used.
oxidizing conditions.
6.6 Wire Coiling Mandrel, as shown in Fig. 2.
5.2 Significant formation of oil insolubles or metal corro-
6.7 Thermometer Bracket—Optional, for holding the oxida-
sion products, or both, during this test may indicate that the oil
tion cell thermometer, of 18-8 stainless steel, having the
will form insolubles or corrode metals, or both, during field
dimensions shown in Fig. 3. The thermometer is held in the
service. However, no correlation with field service has been
bracket by two fluoro-elastomer O-rings of approximately
established.
5 mm inside diameter. Alternatively, thin stainless steel wire
may be used.
6. Apparatus
6.8 Abrasive Cloth, silicon carbide, 100-grit with cloth
6.1 Oxidation Cell, of borosilicate glass, as shown in Fig. 1,
backing.
consisting of a test tube, condenser, and oxygen delivery tube.
The test tube has a calibration line at 300 mL 6 1 mL. This
6.9 Flexible Tubing, poly vinyl chloride or fluoroelastomer
calibration applies to the test tube alone using water at 20 °C. copolymer approximately 6.4 mm ( ⁄4 in.) inside diameter
with a 2.4 mm ( ⁄32 in.) wall for delivery of oxygen to the
6.2 Heating Bath: Liquid Bath or Metal Block, thermostati-
oxidation cell.
cally controlled, capable of maintaining the oil sample in the
7,8
oxidation cell at a temperature of 95 °C 6 0.2 °C, fitted with a 6.10 Membrane Filters, white,plain,47 mmor90 mmin
diameter, pore size 5 µm.
suitable stirring device to provide a uniform temperature
throughout the bath, and large enough to hold the desired
Supporting data (summary of the results of these studies) have been filed at
number of oxidation cells immersed in the heating bath to a
ASTM International Headquarters and may be obtained by requesting Research
Report RR:D02-1365. Contact ASTM Customer Service at [e-mail].
Fluoroelastomer copolymer is manufactured asViton, a trademark owned by E.
Available from Energy Institute, 61 New Cavendish St., London, W1G 7AR, I. duPont de Nemours.
U.K., http://www.energyinst.org. If you are aware of alternative suppliers, please provide this information to
Available from British Standards Institution (BSI), 389 Chiswick High Rd., ASTM International Headquarters. Your comments will receive careful consider-
London W4 4AL, U.K., http://www.bsigroup.com. ation at a meeting of the responsible technical committee, which you may attend.
D4310 − 22a
All dimensions are in millimetres (inches)
NOTE 1—Open tube ends to be ground and fire-polished.
FIG. 1 Oxidation Cell
7,9 7,10
6.11 Filter Holder, 47 mm or 90 mm, consisting of a 6.12 Weighing Bottle, cylindrical body with ground-
borosilicate glass funnel and a funnel base with a coarse grade glass stopper; approximate inside diameter 45 mm, height of
(40 µm to 60 µm) fritted-glass filter support or stainless steel body 65 mm, capacity 60 mL.
screen support such that the filter can be clamped between the
6.13 Vacuum Source, to provide pressure reduction to
ground-glass sealing surfaces of the funnel and its base by
13.3 kPa 6 0.7 kPa (100 mm 6 5 mm Hg) absolute pressure.
means of a metal clamp.
6.14 Cooling Vessel—A desiccator or other type of tightly
covered vessel for cooling the weighing vessels before weigh-
The sole source of supply of the Millipore SM membrane filters (MF-type,
ing. The use of a drying agent is not recommended.
cellulose esters) known to the committee at this time is Millipore Filter Corp.,
Bedford, MA.
The sole source of supply of the Millipore Pyrex XX-10-047-00 or XX-10-
047-30 filter holder known to the committee at this time is Millipore Filter Corp., The sole source of supply of the Fisher 3-415 weighing bottle, size G, known
Bedford, MA. to the committee at this time is Fisher Scientific Co., Pittsburgh, PA.
D4310 − 22a
FIG. 2 Mandrel for Winding Catalyst Coils
D4310 − 22a
All dimensions are in millimetres (inches).
Material: 18-8 Stainless Steel. 22 Gauge (0.792 mm).
FIG. 3 Thermometer Bracket
6.15 Drying Oven, capable of maintaining a temperature of (0.063 in.) inside diameter, 559 mm 6 2 mm (22.0 in. 6
105 °C 6 2 °C. 0.08 in.) long, with one end finished at 90° and the other end
fitted with a Luer-Lok female connector.
6.16 Forceps, having unserrated tips.
6.21 Filter Flasks, with a capacity of 1000 mL.
6.17 Separatory Funnels, with a capacity of 1000 mL.
6.18 Rubber Policeman.
6.22 Syringe Water Addition Tube—Optional, 304.8 mm 6
2 mm (12 in. 6 0.08 in.) long, with one end fitted with a
6.19 Syringes, glass or plastic, with Luer-Lok locking
Luer-Lok female connector.
connectors, 10 mL and 60 mL capacities for sampling, and
water additions, respectively.
6.20 Syringe Sampling Tube, Grade 304 stainless steel
tubing, 2.11 mm (0.083 in.) outside diameter, 1.60 mm
D4310 − 22a
7. Reagents and Materials 8. Sampling
7.1 Purity of Reagents—Reagent grade chemicals shall be 8.1 Samples for this test can come from tanks, drums, small
used in all tests. Unless otherwise indicated, it is intended that
containers, or even operating equipment. Therefore, use the
all reagents conform to the specifications of the Committee on applicable apparatus and techniques described in Practice
Analytical Reagents of the American Chemical Society where
D4057.
such specifications are available. Other grades may be used,
8.2 For one single determination the minimum required
provided it is first ascertained that the reagent is of sufficiently
sample size is 300 mL.
high purity to permit its use without lessening the accuracy of
the determination.
9. Preparation of Apparatus
7.2 Purity of Water—Unless otherwise indicated, references
9.1 Cleaning Catalyst—Immediately prior to winding a
to water shall be understood to mean reagent water as defined
catalyst coil, clean a 3.00 m 6 0.01 m length of iron wire and
by Type II of Specification D1193.
an equal length of copper wire with wads of absorbent cotton
7.3 Acetone—Reagent grade. (Warning—Health hazard,
wet with n-heptane and follow by abrasion with abrasive cloth
flammable.)
until a fresh metal surface is exposed. Then wipe with dry
absorbent cotton until all loose particles of metal and abrasive
7.4 Cleaning Reagent, cleaning by a 24 h soak at room
7,12
have been removed. In subsequent operations handle the
temperature in either Nochromix (Warning—Corrosive,
7,13
catalyst wires with clean gloves (cotton, rubber, or plastic) to
health hazard) or in Micro solution.
prevent contact with the skin.
7.5 n-Heptane—Reagent grade. (Warning—Flammable.
9.2 Preparation of Catalyst Coil—Twist the iron and copper
Harmful if inhaled.)
wires tightly together at one end for three turns and then wind
7.6 Hydrochloric Acid (Warning—Toxic and corrosive.),
them simultaneously alongside each other on a threaded
concentrated [(36 % by mass (relative density 1.19)].
mandrel (see Fig. 2), inserting the iron wire in the deeper
7.7 Isopropyl Alcohol—Reagent grade. (Warning—
thread. Remove the coil from the mandrel, twist the free ends
Flammable.)
of the iron and copper wires together for three turns, and bend
the twisted ends to conform to the shape of the spiral coil. The
7.8 Catalyst Wires:
overall length of the finished coil should be 225 mm 65mm
7.8.1 Low-Metalloid Steel Wire, 1.59 mm (0.0625 in.) in
(8.9 in. 6 0.2 in.). If necessary, the coil may be stretched to
diameter (No. 16 Washburn and Moen Gauge).
give the required length (Note 4 and Note 5).
NOTE 3—Carbon steel wire, soft bright annealed and free from rust of
Grade 1008 as described in Specification A510 is satisfactory. Similar
NOTE 5—The finished catalyst coil is a double spiral of copper and iron
wire conforming to BS 1829, is also satisfactory. If these steels are not
wire, 225 mm 6 5 mm (8.9 in. 6 0.2 in.) overall length and 15.9 mm to
available, other equivalent steels may be used, provided they are found to
16.5 mm (0.625 in. to 0.650 in.) inside diameter. The turns of wire are
be satisfactory in comparative tests using this Test Method D4310.
evenly spaced, and two consecutive turns of the same wire are 3.96 mm to
4.22 mm (0.156 in. to 0.166 in.) apart, center to center. The mandrel
7.8.2 Electrolytic Copper Wire, 1.63 mm (0.064 in.) in di-
showninFig.2isdesignedtoproducesuchacoil.Usingthismandrel,the
ameter (No. 16 Imperial Standard Wire Gauge or No. 14
ironwireiswoundonathreadof14.98 mm(0.590 in.)diameter,whilethe
American Wire Gauge), 99.9 % purity, conforming to Specifi-
copper wire is wound on a thread of 15.9 mm (0.625 in.) diameter. The
cation B1. Soft copper wire of an equivalent grade may also be smaller diameter is to allow for “springback” of the steel wire after
winding, so as to give 15.9 mm consistent inside diameter. Use of a very
used.
softannealedsteelwiremayallowuseofidenticalthreaddiametersforthe
NOTE 4—Alternatively, suitably prepared catalyst coils may be pur-
two wires.Any arrangement that leads to the coil configuration described
chased from a supplier. above is satisfactory.
7,14
7.9 Detergent, water-soluble.
9.3 Catalyst Storage—The catalyst coil may be stored in a
dry, inert atmosphere prior to use. A suitable procedure for
7.10 Oxygen—(Warning—Oxygen vigorously accelerates
catalyst storage is given in Appendix X1. Before use it should
combustion) 99.5 % minimum purity, with pressure regulation
be inspected to assure that no corrosion products or contami-
adequate to maintain a constant flow of gas through the
nating materials are present. For overnight storage (less than
apparatus. The use of a two-stage pressure regulator on tank
24 h) the coil may be stored in n-heptane.
oxygen is recommended.
9.3.1 n-heptane used for catalyst storage must be free of
traces of water and corrosive materials. Redistilled n-heptane
conforming to 7.5 and stored in a tightly sealed bottle is
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
suitable.
Standard-Grade Reference Materials, American Chemical Society, Washington,
DC. For suggestions on the testing of reagents not listed by theAmerican Chemical
9.4 Cleaning New Glassware—Wash new oxygen delivery
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
tubes, condensers, and test tubes with a hot detergent solution
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
and rinse thoroughly with tap water. Clean the interiors of the
copeial Convention, Inc. (USPC), Rockville, MD.
The sole source of supply of Nochromix known to the committee at this time
test tubes, exteriors of the condensers, and both interiors and
is Godax Laboratories, Inc., 720-B Erie Avenue, Takoma Park, MD 20912.
exteriors of the oxygen delivery tubes with a cleaning reagent.
The sole source of supply of Micro known to the committee at this time is
Rinse thoroughly with tap water until all cleaning solution is
International Products Corp., P.O. Box 70, Burlington, NJ 08016.
Alconox has been found satisfactory for this purpose. removed. Rinse all parts with reagent water and allow to dry at
D4310 − 22a
room temperature or in an oven. The final reagent water rinse
maybefollowedbyanisopropylalcoholrinse,oracetonerinse
optionally followed by dry air blowing to hasten drying at
room temperature.
9.5 Cleaning Used Glassware—Immediately following ter-
mination of a test, drain the oil completely from the test tube.
Rinse all the glassware with n-heptane to remove traces of oil,
wash with a hot detergent solution using a long-handled brush,
and rinse thoroughly with tap water. If deposits still adhere to
the glassware, a method that has been found useful is to fill the
test tubes with detergent solution, insert the oxygen delivery
tubes and condensers, and place the tubes in the bath at test
temperature. Several hours soaking in this manner often serves
to loosen all adhering deposits except iron oxide. Subsequent
rinsing with hot (50 °C) hydrochloric acid will serve to remove
iron oxide. After all deposits are removed, rinse all glassware
with a cleaning reagent. Rinse thoroughly with tap water until
all cleaning reagent is removed. Rinse all parts with reagent
water and allow to dry at room temperature or in an oven. The
final reagent water rinse may be followed by an isopropyl
alcohol rinse, or acetone rinse optionally followed by dry air
blowing,tohastendryingatroomtemperature.Storeglassware
in a dry dust-free condition until ready to use.
10. Procedure for Oxidizing the Oil
10.1 Adjust the heating bath to a temperature high enough
to maintain the oil in the oxidation test cell at the required
temperature of 95 °C 6 0.2 °C.
10.2 Fill the empty oxidation test tube with 300 mL of the
oil sample to the calibration line. The oil level shall be read
withthetubeverticalandthemeniscusrestingonthetopofthe
calibration line. Slide the catalyst coil over the inlet of the
oxygen delivery tube. If the wires are uneven at one end of the
coil,positionthecoilsothatthisendisdown.Placetheoxygen
delivery tube with the coil into the test tube. Place the
condenser over the oxygen delivery tube and test tube. Im-
merse the test tube in the heating bath.Adjust the heating bath
liquid level so that the tube is immersed in the liquid to a d
...

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: D4310 − 22 D4310 − 22a
Standard Test Method for
Determination of Sludging and Corrosion Tendencies of
Inhibited Mineral Oils
This standard is issued under the fixed designation D4310; 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 and is used to evaluate the tendency of inhibited mineral oil based steam turbine lubricants and mineral
oil based anti-wear hydraulic oils to corrode copper catalyst metal and to form sludge during oxidation in the presence of oxygen,
water, and copper and iron metals at an elevated temperature. The test method is also used for testing circulating oils having a
specific gravity less than that of water and containing rust and oxidation inhibitors.
NOTE 1—During round robin testing copper and iron in the oil, water and sludge phases were measured. However, the values for the total iron were found
to be so low (that is, below 0.8 mg), that statistical analysis was inappropriate. The results of the cooperative test program are available (see Section 16).
1.2 This test method is a modification of Test Method D943 where the oxidation stability of the same kinds of oils is determined
by following the acid number of oil. The number of test hours required for the oil to reach an acid number of 2.0 mg KOH/g is
the oxidation lifetime.
1.3 Procedure A of this test method requires the determination and report of the weight of the sludge and the total amount of copper
in the oil, water, and sludge phases. Procedure B requires the sludge determination only. The acid number determination is optional
for both procedures.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 WARNING—Mercury has been designated by many regulatory agencies as a hazardous substance that can cause serious
medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Use Caution
when handling mercury and mercury-containing products. See the applicable product Safety Data Sheet (SDS) for additional
information. The potential exists that selling mercury or mercury-containing products, or both, is prohibited by local or national
law. Users must determine legality of sales in their location.
1.6 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. For specific warning statements, see Section 7 and X1.1.5.
1.7 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.
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
D02.09.0C on Oxidation of Turbine Oils.
Current edition approved July 1, 2022Nov. 1, 2022. Published July 2022November 2022. Originally approved in 1983. Last previous edition approved in 20202022 as
D4310 – 20a.D4310 – 22. DOI: 10.1520/D4310-22.10.1520/D4310-22A.
*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
D4310 − 22a
2. Referenced Documents
2.1 ASTM Standards:
A510 Specification for General Requirements for Wire Rods and Coarse Round Wire, Carbon Steel (Metric) A0510_A0510M
B1 Specification for Hard-Drawn Copper Wire
D664 Test Method for Acid Number of Petroleum Products by Potentiometric Titration
D874 Test Method for Sulfated Ash from Lubricating Oils and Additives
D943 Test Method for Oxidation Characteristics of Inhibited Mineral Oils
D1193 Specification for Reagent Water
D3339 Test Method for Acid Number of Petroleum Products by Semi-Micro Color Indicator Titration
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
E1 Specification for ASTM Liquid-in-Glass Thermometers
2.2 Energy Institute Standard:
Specification for IP Standard Thermometers
2.3 British Standard:
BS 1829 Reference Tables for Iron v. Constantan Thermocouples
3. Terminology
3.1 Definitions:
3.1.1 See Terminology D4175 for a list of terms relating to petroleum products, liquid fuels, and lubricants.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 sludge, n—a precipitate or sediment from oxidized mineral oil and water that is insoluble in n-heptane.
4. Summary of Test Method
4.1 An oil sample is contacted with oxygen in the presence of water and an iron-copper catalyst at 95 °C for 1000 h. The weight
of insoluble material is determined by vacuum filtration of the oxidation tube contents through 5 μm pore size filter disks. The total
amount of copper in the oil, water, and sludge phases is also determined for Procedure A. Procedure B requires the sludge
determination. The copper determination is not required. The acid number determination is optional for both procedures.
NOTE 2—Optionally, some operators may choose to: (1) assess the change in weight of the catalyst coil, or (2) determine the acid number at 1000 h, or
both. The acid number may serve as a criterion to determine if measurement of insoluble material is warranted. Normally, further testing is not
recommended on a highly oxidized oil (that is an oil which has attained an acid number >2.0 mg KOH/g). Instructions for these optional tests are not
included in this test method.
5. Significance and Use
5.1 Insoluble material may form in oils that are subjected to oxidizing conditions.
5.2 Significant formation of oil insolubles or metal corrosion products, or both, during this test may indicate that the oil will form
insolubles or corrode metals, or both, during field service. However, no correlation with field service has been established.
6. Apparatus
6.1 Oxidation Cell, of borosilicate glass, as shown in Fig. 1, consisting of a test tube, condenser, and oxygen delivery tube. The
test tube has a calibration line at 300 mL 6 1 mL. This calibration applies to the test tube alone using water at 20 °C.
6.2 Heating Bath: Liquid Bath or Metal Block, thermostatically controlled, capable of maintaining the oil sample in the oxidation
cell at a temperature of 95 °C 6 0.2 °C, fitted with a suitable stirring device to provide a uniform temperature throughout the bath,
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 Energy Institute, 61 New Cavendish St., London, W1G 7AR, U.K., http://www.energyinst.org.
Available from British Standards Institution (BSI), 389 Chiswick High Rd., London W4 4AL, U.K., http://www.bsigroup.com.
D4310 − 22a
All dimensions are in millimetres (inches)
NOTE 1—Open tube ends to be ground and fire-polished.
FIG. 1 Oxidation Cell
and large enough to hold the desired number of oxidation cells immersed in the heating bath to a depth of 390 mm 6 10 mm and
in the heating liquid itself to a depth of 355 mm 6 10 mm.
6.2.1 Studies have suggested that direct sunlight or artificial light may adversely influence the results of this test. To minimize
effects of light exposure on the lubricant being tested, light shall be excluded from the lubricant by one or more of the following
ways:
6.2.1.1 Use of heated liquid baths that are designed and constructed of metal, or combinations of metals and other suitable opaque
Supporting data (summary of the results of these studies) have been filed at ASTM International Headquarters and may be obtained by requesting Research Report
RR:D02-1365. Contact ASTM Customer Service at [e-mail].
D4310 − 22a
materials, that prevent light from entering the test cell from the sides is preferred. If a viewing window is included in the design,
this viewing window shall be fitted with a suitable opaque cover and be kept closed when no observation is being made.
6.2.1.2 If glass heating baths are used, the bath shall be wrapped with aluminum foil or other opaque material.
6.2.1.3 Bright light entering the test cell from directly overhead can be eliminated by use of an opaque shield.
6.3 Flowmeter, with a flow capacity of at least 3 L of oxygen/hour, and an accuracy of 60.1 L ⁄h.
6.4 Heating Bath Thermometer—ASTM Solvents Distillation Thermometer having a range from 72 °C to 126 °C and conforming
to the requirements for Thermometer 40C as prescribed in Specification E1, or for Thermometer 70C as prescribed in
Specifications for IP Standard Thermometers. Alternatively, temperature–measuring devices of equal or better accuracy may be
used.
6.5 Oxidation Cell Thermometer, having a range from 80 °C to 100 °C, graduated in 0.1 °C, total length—250 mm, stem
diameter—6.0 mm to 7.0 mm, calibrated for 76 mm immersion. Temperature measuring devices such as liquid-in-glass
thermometers, thermocouples, or platinum resistance thermometers that provide equivalent or better accuracy and precision that
cover the temperature range, may be used.
6.6 Wire Coiling Mandrel, as shown in Fig. 2.
6.7 Thermometer Bracket—Optional, for holding the oxidation cell thermometer, of 18-8 stainless steel, having the dimensions
shown in Fig. 3. The thermometer is held in the bracket by two fluoro-elastomer O-rings of approximately 5 mm inside diameter.
Alternatively, thin stainless steel wire may be used.
6.8 Abrasive Cloth, silicon carbide, 100-grit with cloth backing.
6.9 Flexible Tubing, poly vinyl chloride or fluoroelastomer copolymer approximately 6.4 mm ( ⁄4 in.) inside diameter with a
2.4 mm ( ⁄32 in.) wall for delivery of oxygen to the oxidation cell.
7,8
6.10 Membrane Filters, white, plain, 47 mm or 90 mm in diameter, pore size 5 μm.
7,9
6.11 Filter Holder, 47 mm or 90 mm, consisting of a borosilicate glass funnel and a funnel base with a coarse grade (40 μm
to 60 μm) fritted-glass filter support or stainless steel screen support such that the filter can be clamped between the ground-glass
sealing surfaces of the funnel and its base by means of a metal clamp.
7,10
6.12 Weighing Bottle, cylindrical body with ground-glass stopper; approximate inside diameter 45 mm, height of body 65 mm,
capacity 60 mL.
6.13 Vacuum Source, to provide pressure reduction to 13.3 kPa 6 0.7 kPa (100 mm 6 5 mm Hg) absolute pressure.
6.14 Cooling Vessel—A desiccator or other type of tightly covered vessel for cooling the weighing vessels before weighing. The
use of a drying agent is not recommended.
6.15 Drying Oven, capable of maintaining a temperature of 105 °C 6 2 °C.
6.16 Forceps, having unserrated tips.
Fluoroelastomer copolymer is manufactured as Viton, a trademark owned by E. I. duPont de Nemours.
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.
The sole source of supply of the Millipore SM membrane filters (MF-type, cellulose esters) known to the committee at this time is Millipore Filter Corp., Bedford, MA.
The sole source of supply of the Millipore Pyrex XX-10-047-00 or XX-10-047-30 filter holder known to the committee at this time is Millipore Filter Corp., Bedford,
MA.
The sole source of supply of the Fisher 3-415 weighing bottle, size G, known to the committee at this time is Fisher Scientific Co., Pittsburgh, PA.
D4310 − 22a
FIG. 2 Mandrel for Winding Catalyst Coils
D4310 − 22a
All dimensions are in millimetres (inches).
Material: 18-8 Stainless Steel. 22 Gauge (0.792 mm).
FIG. 3 Thermometer Bracket
6.17 Separatory Funnels, with a capacity of 1000 mL.
6.18 Rubber Policeman.
6.19 Syringes, glass or plastic, with Luer-Lok locking connectors, 10 mL and 60 mL capacities for sampling, and water additions,
respectively.
6.20 Syringe Sampling Tube, Grade 304 stainless steel tubing, 2.11 mm (0.083 in.) outside diameter, 1.60 mm (0.063 in.) inside
diameter, 559 mm 6 2 mm (22.0 in. 6 0.08 in.) long, with one end finished at 90° and the other end fitted with a Luer-Lok female
connector.
6.21 Filter Flasks, with a capacity of 1000 mL.
D4310 − 22a
6.22 Syringe Water Addition Tube—Optional, 304.8 mm 6 2 mm (12 in. 6 0.08 in.) long, with one end fitted with a Luer-Lok
female connector.
D4310 − 22a
7. Reagents and Materials
7.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such
specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity
to permit its use without lessening the accuracy of the determination.
7.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by Type
II of Specification D1193.
7.3 Acetone—Reagent grade. (Warning—Health hazard, flammable.)
7,12
7.4 Cleaning Reagent, cleaning by a 24 h soak at room temperature in either Nochromix (Warning—Corrosive, health hazard)
7,13
or in Micro solution.
7.5 n-Heptane—Reagent grade. (Warning—Flammable. Harmful if inhaled.)
7.6 Hydrochloric Acid (Warning—Toxic and corrosive.), concentrated [(36 % by mass (relative density 1.19)].
7.7 Isopropyl Alcohol—Reagent grade. (Warning—Flammable.)
7.8 Catalyst Wires:
7.8.1 Low-Metalloid Steel Wire, 1.59 mm (0.0625 in.) in diameter (No. 16 Washburn and Moen Gauge).
NOTE 3—Carbon steel wire, soft bright annealed and free from rust of Grade 1008 as described in Specification A510 is satisfactory. Similar wire
conforming to BS 1829, is also satisfactory. If these steels are not available, other equivalent steels may be used, provided they are found to be satisfactory
in comparative tests using this Test Method D4310.
7.8.2 Electrolytic Copper Wire, 1.63 mm (0.064 in.) in diameter (No. 16 Imperial Standard Wire Gauge or No. 14 American Wire
Gauge), 99.9 % purity, conforming to Specification B1. Soft copper wire of an equivalent grade may also be used.
NOTE 4—Alternatively, suitably prepared catalyst coils may be purchased from a supplier.
7,14
7.9 Detergent, water-soluble.
7.10 Oxygen—(Warning—Oxygen vigorously accelerates combustion) 99.5 % minimum purity, with pressure regulation
adequate to maintain a constant flow of gas through the apparatus. The use of a two-stage pressure regulator on tank oxygen is
recommended.
8. Sampling
8.1 Samples for this test can come from tanks, drums, small containers, or even operating equipment. Therefore, use the applicable
apparatus and techniques described in Practice D4057.
8.2 For one single determination the minimum required sample size is 300 mL.
ACS Reagent Chemicals, Specifications and Procedures for Reagents and Standard-Grade Reference Materials, American Chemical Society, Washington, DC. For
suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and
the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
The sole source of supply of Nochromix known to the committee at this time is Godax Laboratories, Inc., 720-B Erie Avenue, Takoma Park, MD 20912.
The sole source of supply of Micro known to the committee at this time is International Products Corp., P.O. Box 70, Burlington, NJ 08016.
Alconox has been found satisfactory for this purpose.
D4310 − 22a
9. Preparation of Apparatus
9.1 Cleaning Catalyst—Immediately prior to winding a catalyst coil, clean a 3.00 m 6 0.01 m length of iron wire and an equal
length of copper wire with wads of absorbent cotton wet with n-heptane and follow by abrasion with abrasive cloth until a fresh
metal surface is exposed. Then wipe with dry absorbent cotton until all loose particles of metal and abrasive have been removed.
In subsequent operations handle the catalyst wires with clean gloves (cotton, rubber, or plastic) to prevent contact with the skin.
9.2 Preparation of Catalyst Coil—Twist the iron and copper wires tightly together at one end for three turns and then wind them
simultaneously alongside each other on a threaded mandrel (see Fig. 2), inserting the iron wire in the deeper thread. Remove the
coil from the mandrel, twist the free ends of the iron and copper wires together for three turns, and bend the twisted ends to conform
to the shape of the spiral coil. The overall length of the finished coil should be 225 mm 6 5 mm (8.9 in. 6 0.2 in.). If necessary,
the coil may be stretched to give the required length (Note 4 and Note 5).
NOTE 5—The finished catalyst coil is a double spiral of copper and iron wire, 225 mm 6 5 mm (8.9 in. 6 0.2 in.) overall length and 15.9 mm to 16.5 mm
(0.625 in. to 0.650 in.) inside diameter. The turns of wire are evenly spaced, and two consecutive turns of the same wire are 3.96 mm to 4.22 mm (0.156 in.
to 0.166 in.) apart, center to center. The mandrel shown in Fig. 2 is designed to produce such a coil. Using this mandrel, the iron wire is wound on a thread
of 14.98 mm (0.590 in.) diameter, while the copper wire is wound on a thread of 15.9 mm (0.625 in.) diameter. The smaller diameter is to allow for
“springback” of the steel wire after winding, so as to give 15.9 mm consistent inside diameter. Use of a very soft annealed steel wire may allow use of
identical thread diameters for the two wires. Any arrangement that leads to the coil configuration described above is satisfactory.
9.3 Catalyst Storage—The catalyst coil may be stored in a dry, inert atmosphere prior to use. A suitable procedure for catalyst
storage is given in Appendix X1. Before use it should be inspected to assure that no corrosion products or contaminating materials
are present. For overnight storage (less than 24 h) the coil may be stored in n-heptane.
9.3.1 n-heptane used for catalyst storage must be free of traces of water and corrosive materials. Redistilled n-heptane conforming
to 7.5 and stored in a tightly sealed bottle is suitable.
9.4 Cleaning New Glassware—Wash new oxygen delivery tubes, condensers, and test tubes with a hot detergent solution and rinse
thoroughly with tap water. Clean the interiors of the test tubes, exteriors of the condensers, and both interiors and exteriors of the
oxygen delivery tubes with a cleaning reagent. Rinse thoroughly with tap water until all cleaning solution is removed. Rinse all
parts with reagent water and allow to dry at room temperature or in an oven. The final reagent water rinse may be followed by
an isopropyl alcohol rinse, or acetone rinse optionally followed by dry air blowing to hasten drying at room temperature.
9.5 Cleaning Used Glassware—Immediately following termination of a test, drain the oil completely from the test tube. Rinse all
the glassware with n-heptane to remove traces of oil, wash with a hot detergent solution using a long-handled brush, and rinse
thoroughly with tap water. If deposits still adhere to the glassware, a method that has been found useful is to fill the test tubes with
detergent solution, insert the oxygen delivery tubes and condensers, and place the tubes in the bath at test temperature. Several
hours soaking in this manner often serves to loosen all adhering deposits except iron oxide. Subsequent rinsing with hot (50 °C)
hydrochloric acid will serve to remove iron oxide. After all deposits are removed, rinse all glassware with a cleaning reagent. Rinse
thoroughly with tap water until all cleaning reagent is removed. Rinse all parts with reagent water and allow to dry at room
temperature or in an oven. The final reagent water rinse may be followed by an isopropyl alcohol rinse, or acetone rinse optionally
followed by dry air blowing, to hasten drying at room temperature. Store glassware in a dry dust-free condition until ready to use.
10. Procedure for Oxidizing the Oil
10.1 Adjust the heating bath to a temperature high enough to maintain the oil in the oxidation test cell at the required temperature
of 95 °C 6 0.2 °C.
10.2 Fill the empty oxidation test tube with 300 mL of the oil sample to the calibration line. The oil level shall be read with the
tube vertical and the meniscus resting on the top of the calibration line. Slide the catalyst coil over the inlet of the oxygen delivery
tube. If the wires are uneven at one end of the coil, position the coil so that this end is down. Place the oxygen delivery tube with
the coil into the test tube. Place the condenser over the oxygen delivery tube and test tube. Immerse the test tube in the heating
bath. Adjust the heating bath liquid level so that the tube is immersed in the liquid to a depth of 355 mm 6 10 mm. Connect the
condenser to the cooling water
...