ASTM D7528-22

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: D7528 − 22
Standard Test Method for
Bench Oxidation of Engine Oils by ROBO Apparatus
This standard is issued under the fixed designation D7528; 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.
INTRODUCTION
This test method is written for use by laboratories that make use ofASTM Test Monitoring Center
(TMC) services (see Annex A1 – Annex A4).
TheTMCprovidesreferenceoils,andengineeringandstatisticalservicestolaboratoriesthatdesire
to produce test results that are statistically similar to those produced by laboratories previously
calibrated by the TMC.
In general, the Test Purchaser decides if a calibrated test stand is to be used. Organizations such as
theAmericanChemistryCouncilrequirethatalaboratoryutilizetheTMCservicesaspartoftheirtest
registration process. In addition, the American Petroleum Institute and the Gear Lubricant Review
Committee of the Lubricant Review Institute (SAE International) require that a laboratory use the
TMC services in seeking qualification of oils against their specifications.
The advantage of using the TMC services to calibrate test stands is that the test laboratory (and
hence theTest Purchaser) has an assurance that the test stand was operating at the proper level of test
severity. It should also be borne in mind that results obtained in a non-calibrated test stand may not
be the same as those obtained in a test stand participating in the ASTM TMC services process.
1. Scope* 1.3 This test method is arranged as follows:
Section
1.1 This test method describes a bench procedure to simu-
Scope 1
late the oil aging encountered in Test Method D7320, the
Reference Documents 2
Sequence IIIG engine test method. These aged oils are then Terminology 3
Summary of Test Method 4
tested for kinematic viscosity and for low-temperature pump-
Significance and Use 5
ability properties as described in the Sequence IIIGA engine
Apparatus 6
test, Appendix X1 of Test Method D7320.
Reagents and Materials 7
Hazards 8
1.2 Units—The values stated in SI units are to be regarded
New and Existing Test Stand Calibration 9
Procedure 10
asstandard.Nootherunitsofmeasurementareincludedinthis
Cleaning 11
standard.
Calculations and Determination of Test Results 12
1.2.1 Exceptions—There are no SI equivalents for some
Report 13
Precision and Bias 14
apparatus in Section 6, and there are some figures where inch
Keywords 15
units are to be regarded as standard.
Annexes
ASTM Test Monitoring Center: Organization Annex A1
ASTM Test Monitoring Center: Calibration Procedures Annex A2
This test method is under the jurisdiction of ASTM Committee D02 on
ASTM Test Monitoring Center: Maintenance Activities Annex A3
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
ASTM Test Monitoring Center: Related Information Annex A4
Subcommittee D02.B0.07 on Development and Surveillance of Bench Tests
Reaction Vessel Annex A5
Methods. Reaction Vessel Head Annex A6
Current edition approved April 1, 2022. Published April 2022. Originally Reaction Vessel-to-Head Seal Annex A7
Agitator Turbine Blade Annex A8
approved in 2009. Last previous edition approved in 2021 as D7528–21. DOI:
Agitator Packing Gland Annex A9
10.1520/D7528-22.
Nitrogen Dioxide Graduated Tube Annex A10
Until the next revision of this test method, the ASTM Test Monitoring Center
Vacuum System Plumbing Annex A11
will update changes in the test method by means of information letters. Information
Vacuum Trap Condensers Annex A12
letters may be obtained from the ASTM Test Monitoring Center, 203 Armstrong
Setting the Vacuum Control Valve Annex A13
Drive, Freeport, PA 16229, www.astmtmc.org. Attention: Director. This edition
Appendixes
incorporates revisions in all information letters through No. 21-1.
*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
D7528 − 22
to evaluate other materials (such as seals) that interact with
Section
Sample Preparation and Addition Appendix X1
oils. D4175
Charging the Liquid Nitrogen Dioxide Appendix X2
Nitrogen Dioxide Precision Needle Valve Appendix X3
3.1.4 test oil, n—any oil subjected to evaluation in an
Example of an Assembled ROBO Apparatus Appendix X4
established procedure. D4175
Information Package to Aid Setting Up a New Robo Apparatus Appendix X5
Dilute Nitrogen Dioxide in Air Option Information Appendix X6
3.2 Definitions of Terms Specific to This Standard:
Time-Averaged Subsurface Air Flow Rate Appendix X7
3.2.1 aged oil, n—atestoilafterithasbeensubjectedtothe
1.4 This standard does not purport to address all of the
40h aging process in a ROBO apparatus.
safety concerns, if any, associated with its use. It is the
3.3 Acronyms:
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- 3.3.1 ROBO, n—Romaszewski Oil Bench Oxidation
mine the applicability of regulatory limitations prior to use.
Specific warning statements are given in Sections 7 and 8. 4. Summary of Test Method
1.5 This international standard was developed in accor-
4.1 The test oil is combined with a small amount of iron
dance with internationally recognized principles on standard-
ferrocene catalyst and placed in a 1L reaction vessel. That
ization established in the Decision on Principles for the
mixtureisstirredandheatedfor40hat170ºCwithairflowing
Development of International Standards, Guides and Recom-
across the liquid surface under negative pressure. In addition,
mendations issued by the World Trade Organization Technical
nitrogen dioxide and air are introduced below the reaction
Barriers to Trade (TBT) Committee.
surface. After cooling, the oxidized, concentrated test oil is
subjected to pertinent viscometric tests. Evaporated oil is
2. Referenced Documents
condensed in order to weigh it and calculate evaporative loss.
2.1 ASTM Standards:
D445Test Method for Kinematic Viscosity of Transparent
5. Significance and Use
and Opaque Liquids (and Calculation of DynamicViscos-
5.1 This bench test method is intended to produce compa-
ity)
rable oil aging characteristics to those obtained with ASTM
D4175Terminology Relating to Petroleum Products, Liquid
TMC Sequence IIIGAmatrix reference oils 434, 435, and 438
Fuels, and Lubricants
after aging in the Sequence IIIG engine test.
D4485Specification for Performance ofActiveAPI Service
Category Engine Oils
5.2 To the extent that the method generates aged oils
D4684Test Method for Determination of Yield Stress and
comparable to those from the Sequence IIIG engine test, the
Apparent Viscosity of Engine Oils at Low Temperature
measured increases in kinematic and MRV viscosity indicate
D5293Test Method for Apparent Viscosity of Engine Oils
the tendency of an oil to thicken because of volatilization and
and Base Stocks Between –10°C and –35°C Using
oxidation,asintheSequenceIIIGandIIIGA(seeAppendixX1
Cold-Cranking Simulator
in Test Method D7320) engine tests, respectively.
D7320Test Method for Evaluation of Automotive Engine
5.3 This bench test procedure has potential use in specifi-
Oils in the Sequence IIIG, Spark-Ignition Engine
cations and classifications of engine lubricating oils, such as
2.2 SAE Standard:
Specification D4485.
SAE J300Engine Oil Viscosity Classification
5.4 The results of this test method are valid when seeking
qualificationofoilsagainstpublishedspecificationsonlywhen
3. Terminology
run on a test stand that has successfully met the calibration
3.1 Definitions:
requirements specified under the TMC’s ROBO test monitor-
3.1.1 candidate oil, n—an oil that is intended to have the
ing program.
performance characteristics necessary to satisfy a specification
and is to be tested against that specification. D4175
6. Apparatus
3.1.2 non-reference oil, n—anyoilotherthanareferenceoil,
6.1 Balances:
suchasaresearchformulation,commercialoilorcandidateoil.
D4175 6.1.1 Analytical Balance—Capable of weighing 200 g with
a minimum indication resolution of 0.1 g.
3.1.3 reference oil, n—an oil of known performance
6.1.2 Analytical Balance—Capableofweighing0.1gwitha
characteristics, used as a basis for comparison.
minimum indication resolution of 0.001 g.
3.1.3.1 Discussion—Reference oils are used to calibrate
testing facilities, to compare the performance of other oils, or
6.2 Fume Hood, that vents to the outside atmosphere (see
Section 8).
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 Kinker, B. G., Romaszewski, R. A., and Palmer, P. A., “ROBO–A Bench
the ASTM website. ProceduretoReplaceSequenceIIIGAEngineTest,” Journal of ASTM International
Available from SAE International, 400 Commonwealth Drive, Warrendale, PA (JAI), Vol 4, No. 10, 2007, Paper ID JAI 100916. Available online from
15096-0001, http://www.sae.org. www.astm.org.
D7528 − 22
6.3 Reaction Vessel (ACE Glass, Inc. part number with a valve to switch between the two gas sources. The
6,7
D120676), a1L,thick-walledglassvesselhavinganominal volume fraction of nitrogen dioxide in air needed is 1.13%.
100mminnerdiameterandwithabottom,sample/drainvalve. See Appendix X6 for how this is derived.The volume fraction
8,7
The lower half has an Instatherm coating, rated at approxi- as certified by the supplier must fall in the range of 1.07% to
mately400W,forheatingthetestmixture.Adiagramisshown 1.19%.
NOTE1—Astheamountoftestoilremainingattheendofthetestisnot
in Fig. A5.1.
always known at the beginning of the test, it is advisable to configure the
6.4 Vessel Head—Thevesselheadisastainlesssteelplateof
dry-air tube location such that the opening of the tube is as close to the
sufficient diameter to completely cover the lower glass vessel agitator and as close to the bottom of the reactor as practical (without
contacting the agitator or blocking the tube opening).
and provide ample material for a sturdy mounting system.
9,7
Reimel Machine, Inc. part number RMI-1002-DH has been
6.8 Nitrogen Dioxide Delivery System—There are two op-
shown to be suitable for this application. The vessel head may
tions for adding nitrogen dioxide. One uses liquid nitrogen
also be constructed as described in AnnexA6. Users may also
dioxide and the other uses dilute nitrogen dioxide in air.
source some parts from Reimel Machine, Inc. and some
6.8.1 Graduated Tube for Liquid Nitrogen Dioxide (Ace
6,7
in-house.Ensuretheplatehasacenterholeforanagitatorshaft
Glass, Inc., part number D120677), 12mL capacity, with
and threaded ports to allow filling and for the attachment of
0.1mL graduations and having appropriate provisions for
air/nitrogen dioxide lines, vacuum control and relief valves,
connection to the reaction vessel’s subsurface gas delivery
and a temperature probe. Fig. A6.1 defines the locations of
system—see AnnexA10 for more details. By receiving liquid
these ports. Mill the bottom surface of this stainless steel plate
phase nitrogen dioxide from a gas bottle, this tube allows
to accept a polytetrafluoroethylene (PTFE) ring seal for cen-
measurement of nitrogen dioxide depletion from the tube over
tered attachment of the glass vessel as described in AnnexA7.
the course of the reaction.This graduated tube is only used for
9,7
Reimel Machine, Inc. part number RMI-1007-DH has been
the liquid nitrogen dioxide option.
found suitable for this purpose.
6.8.2 Gas Cylinder Containing Dilute Nitrogen Dioxide in
Air—Secondgassourceusingdilutenitrogendioxideindryair
6.5 Stirrer Motor—An electric motor with drill chuck collet
as defined in 6.7.2. This is only used for the dilute nitrogen
capable of sustained operation at 200 r/min 6 5 r/min.
dioxide option.
6.6 Stirrer—An 8mm diameter stainless steel rod, 300mm
6.9 Temperature Control System—A controller and probe
longwithameansofattachingabladeassemblyatthebottom.
capable of being programmed to control reaction temperature
Theturbinebladeassemblydiameteris2.58in.(65.5mm)with
via low output wattage at or below 40Vac and with an
1.4mm thick blades attached at a 45° pitch with an overall
operational hysteresis of 0.1°C using an on/off algorithm.
blade height of 0.985 in. (25.0 mm). Construct the stirrer as
Alternatively, a proportional-integral-derivative (PID) algo-
described in Annex A8. Reimel Machine, Inc. part number
9,7
rithm may also be used. Position the temperature probe tip so
RMI-1001-DH has been found suitable for this purpose.
that it is level with the bottom of the turbine blade with a
6.6.1 Attach the stirrer to the reactor head by means of a
distanceof8mmbetweentheprobecenterandthebladeedge.
packing gland constructed as described in Annex A9. Reimel
9,7
6.9.1 Asthetemperaturemaynotbeuniformthroughoutthe
Machine, Inc. part number RMI-1004-DH has been found
reactor, it is important from the point of view of precision that
suitable for this purpose.Attach the stirrer to the stirrer motor
the temperature is always monitored and controlled at the
by inserting the 8mm steel rod through the opening in the
specified position inside the reactor. When reassembling the
reactor head and the packing gland, and insert PTFE rope
reactorforanewrun,repositiontheprobe,ifnecessary,asitis
packing to create a seal.
easily bent.
6.6.2 Positiontheblade6mmfromthebottomofthevessel.
6.10 Flow Meters:
6.7 Air Supply System—A gas source capable of delivering
6.10.1 Acrylic Block Airflow Meter (King Instrument Co.,
anuninterruptedflowofdryairintothetestoilviaasubsurface
10,7
7520 Series, Order number 2C-17), having a scale of 0.4 to
feedthroughoutthereactiontimeperiod.Anin-line,desiccant-
4 Standard Cubic Feet per Minute (SCFM), with ⁄4 in. NPT
charged, drying system has been found suitable.
threaded female pipe end. It is used for measuring air flow in
6.7.1 Ensure the subsurface feed tube opening remains
10.3.2.The machined fitting for the top of the flow meter shall
below the surface of the test fluid for the duration of the test.
accommodate the vacuum line from the condenser to the
Do not place the tube in the drain area of the reaction flask.
reactor with a ⁄8 in. inside diameter or larger. The machined
6.7.2 A second gas source consisting of a gas cylinder
fitting for the bottom of the flow meter shall accommodate the
containing dilute nitrogen dioxide in air may be added along
⁄4 in. vacuum control valve.
NOTE 2—SCFM is the volumetric flow rate of a gas corrected to
standardized conditions of temperature, pressure, and relative humidity,
The sole source of supply of the apparatus known to the committee at this time
thus representing a precise mass flow rate. However, the definitions of
is Ace Glass, Inc., P.O. Box 688, 1430 NW Blvd., Vineland, NJ 08362-0688.
standardconditionsvary.Inthismethod,theflowmeteriscalibratedwith
If you are aware of alternative suppliers, please provide this information to
ASTM. Your comments will receive careful consideration at a meeting of the air at standard conditions defined as a temperature of 70°F, a pressure of
responsible technical committee which you may attend.
InstathermisaregisteredtrademarkofAceGlass,Inc.,P.O.Box688,1430NW
Blvd., Vineland, NJ 08362-0688.
9 10
The sole source of supply of the apparatus known to the committee at this time Thesolesourceofsupplyoftheapparatusknowntothecommitteeatthistime
is Reimel Machine, Inc., 2575 Wyandotte Rd., Willow Grove, PA 19090. is King Instrument Co., 12700 Pala Drive Garden Grove, CA 92841.
D7528 − 22
14.6 psia and 0% relative humidity.
7.1.1 Liquid Nitrogen Dioxide (Used with the Option in
6.8.1)—Produces a reddish-brown gas with a pungent odor.
6.10.2 Airflow Meter, with a scale calibrated in mL/min for
(Warning—VERYTOXIC if inhaled or ingested. Explosive if
measuring subsurface airflow of 185 mL/min in 10.3.1 and
mixed with combustible material. Irritating to eyes and respi-
10.3.2. Two air flow meters may be used in the dilute nitrogen
ratory system. Danger of very serious irreversible health
dioxide configuration depending on the location of the switch-
effects.).
ing valve.
7.1.2 Dilute Nitrogen Dioxide in Air (Used with the Option
6.10.2.1 Adigital mass flow controller may also be used to
in 6.8.2)—(Warning—Compared to liquid nitrogen dioxide,
measure and control the flow rate. This type of flow controller
the exposure risk is greatly reduced, but not negligible.)
is recommended, but not required, for the dilute nitrogen
dioxide in air option.
7.2 Iron Ferrocene—98% or higher purity. (Warning—Do
not breathe dust. Harmful if swallowed.)
6.11 Vacuum System—A pump with a free air capability of
at least 160 L/min is required to ensure a constant air flow
7.3 Oil—100 Neutral, API Group II, for mixing with iron
across the reaction surface in the vessel of 2.0SCFM 6
ferrocene catalyst.
0.1SCFM with 61 kPa vacuum for 40 h. Instructions for
7.4 Cleaning Solvent—Commercialheptanes,orsimilarsol-
constructing the vacuum plumbing for the vessel are given in
vents that evaporate without leaving a residue, are suitable.
AnnexA11.As explained in AnnexA11, it is critical to follow
(Warning—flammable.)
these instructions precisely.
7.5 Acetone—A technical grade of acetone is suitable pro-
6.12 Vacuum Control Valve—A stainless steel needle valve
videditdoesnotleavearesidueuponevaporation.Thisisused
with ⁄4 in. outside diameter tube connections and a flow
forafinalcleaningrinse.Acetonewilldegradefluoroelastomer
coefficient (Cv) of 0.37 has been found suitable for this
seals and can dissolve or deteriorate acrylics. (Warning—
application.
flammable.)
6.13 Vacuum Trap System—Supplies coolant at an inlet
7.6 Dry Air—Desiccated air is suitable.
temperature <20 °C to the vacuum trap condensers in order to
7.7 Reference Oils—The current TMC reference oils are
removevaporsfromtheeffluentpriortoentering(andpossibly
required for setting up the ROBO apparatus test stand (see
damaging) the vacuum system and has a means of recovering
Section 9). The TMC maintains and distributes these oils.
the distillate for weighing. Redundant (serial) condensers are
These oils are formulated or selected to represent specific
beneficial as long as the required airflow across the reaction
chemical types or performance levels, or both. See A2.4 for
surfaceismaintained.AnnexA12providesinformationontwo
additional information regarding reference oils.
systems that have been found to be satisfactory.
7.7.1 The TMC is responsible for managing a system that
6.14 Time Controller—Atiming device accurate to 1 min is
ensures the performance and formulation consistency of the
used to deactivate the heat source.
reference oils. Store the reference oils in locations where the
6.15 Precision Needle Valve, having a low Cv for precise ambient temperature does not exceed 32 °C. Under these
controloftheflowofnitrogendioxide.Examplesofvalvesthat
conditions, the expected shelf life of a reference oil is five
have been found satisfactory are given in Appendix X3. This years. In some circumstances, however, the TMC may specify
valve is used with the liquid nitrogen dioxide option in 6.8.1. a shelf life longer than five years. In such cases, theTMC uses
It is not required for the dilute nitrogen dioxide option documentedanalysisprocedurestojustifythelongershelflife.
described in 6.8.2.
7.7.2 Unless specifically authorized by the TMC, do not
analyze TMC reference oils, either physically or chemically.
6.16 Beaker—300mL capacity.
The testing laboratory tacitly agrees to use the TMC reference
6.17 Glass Jar—250mL capacity which can be sealed.
oils exclusively in accordance with the TMC’s published
Policies for Use andAnalysis ofASTM Reference Oils, and to
6.18 Shaker—Use either a reciprocal or an elliptical shaker.
run and report the reference oil test according to TMC
6.19 Assembled ROBO Apparatus—Fig. X4.1 shows an
guidelines.
example of an assembled ROBO apparatus. However, because
NOTE3—PoliciesfortheUseandAnalysisofASTMReferenceOilsare
it is assembled from different components, some of which are
available from the TMC.
site specific (for example, geometry of fume hood, local safety
considerations, use of different parts such as temperature
8. Hazards
controllers,andsoforth),thereisnostandardROBOapparatus
assembly. As an aid to building and setting up a new ROBO 8.1 Specific Hazards—Duetonitrogendioxidetoxicity,with
apparatus, a package of information is available on the TMC the exception of weighing, perform steps 10.3 – 10.8 of the
website. This (non-mandatory) information supplements that procedure in the fume hood. See also 7.1.
giveninSection6.Anindextothecontentsofthisinformation
package is given in Appendix X5.
9. New and Existing Test Stand Calibration
9.1 New Test Stand at New Test Laboratory Calibration—
7. Reagents and Materials
For new ROBO apparatus at existing laboratory, proceed to
7.1 Nitrogen Dioxide: 9.2. For existing ROBO apparatus test stands, proceed to 9.3.
D7528 − 22
9.1.1 Obtain the required, current reference oils from the 9.3.1.2 Initial calibration verification of a new test stand or
TMC for the purpose of setting up a new ROBO apparatus repeated consecutive unacceptable calibration verifications on
stand. (See 7.7.2 and Annex A2 for conditions of use for the a test stand requires passing two consecutive TMC reference
TMC reference oils.) oil tests.
9.1.2 Test the assigned reference oils according to the 9.3.1.3 The same nitrogen dioxide delivery configuration
procedure described in Section 10. must be used to re-verify the calibration status and then
9.1.2.1 Itisimperativethatthevacuumcontrolvalve(VCV) continued to be used for subsequent certified runs.
setpositionbesetonthefirstset-uptestandnotchangedagain 9.3.1.4 Certain operational changes to the test stand, as
for subsequent set-up qualifying runs. specified in the TMC calibration requirements, voids the
9.1.2.2 If the VCV set position is changed by more than TMC test stand calibration status and requires passing two
60.125 revolutions after the start of the first qualifying set-up consecutiveTMCreferenceoilteststore-verifythecalibration
test run, all previous tests in the set-up test sequence are void; status of the modified test stand.
repeat the test stand setup runs from 9.1.1 – 9.1.4. 9.3.1.5 Duringthetimeofconductingareferenceoilteston
9.1.3 Determine the viscometric properties of the aged one test stand, non-reference oil tests may be conducted on
reference oils as described in Section 12 and report according other previously calibrated stands.
to Section 13.
9.3.2 Test Numbering:
9.1.4 Report test results to the TMC using the standardized
9.3.2.1 The test number shall follow the format AAA-BB-
reporting protocols (see 9.3.3 and Section 13). Be sure to
CCCC. AAA represents the test stand identification. BB repre-
include all required operational parameters as defined in the sentsthenumberoftestssincelastreference. CCCCrepresents
reporting protocol data dictionary.
thetotalnumberoftestsonthestand.Asanexample,6-10-175
9.1.5 Review all initial set-up results on new instruments represents the 175 test on Stand 6 and the tenth test since the
and receive approval from the TMC.
lastreference.Consecutivelynumberalltestsonagivenstand.
9.1.5.1 Test results will be posted to the TMC website. Lab
9.3.3 Reporting of Reference Oil Test Results—Report the
identification will be coded by the TMC for confidentiality of
results of all reference oil tests to the TMC according to the
the testing laboratory.
following instructions:
9.1.6 If all the required test stand set-up runs meet the
9.3.3.1 Transmit results according to the ROBO Standard-
current, approved ROBO TMC calibration requirements
ized Report Forms and Data Dictionary to the TMC within
(both operationally and statistically), the TMC will notify the
five days of test completion via electronic data transfer
laboratorythatitcanproceedwithcalibratingtheteststandper
protocol as outlined in the Data Communication Committee,
9.3.
Electronic Test Report Transmission Model (ETRTM).
9.1.7 If the TMC’s review determines that the required test
NOTE 4—Be sure to collect data on all the required parameters defined
stand set-up runs do not collectively meet the approved
in the ROBO Standardized Data Dictionary (see Section 13). Validity
requirements (both operationally and statistically), the TMC
evaluation of test results cannot be made if critical evaluation parameters
willnotifythelaboratorythatadditionaladjustmentsneedtobe are missing.
made to the test stand and one or more of the set-up runs will
9.3.4 Evaluation of Reference Oil Test Results—The TMC
have to be repeated.
evaluates the referenceoil test results for both operational
9.2 New Test Stand at Existing Laboratory Calibration: validity and statistical acceptability. The TMC may consult
with the test laboratory in case of difficulty, as follows:
9.2.1 Laboratory can proceed with calibrating the test stand
per 9.3. 9.3.4.1 Uponreceiptofthereferenceoiltestresultsfromthe
test laboratory, the TMC evaluates the laboratory’s reported
9.3 Existing Test Stand Calibration:
operational parameters for compliance with the current test
9.3.1 Reference Oil Test Frequency—TheTMCrequirestest
method. For operationally valid tests, the TMC then evaluates
stands to pass periodic calibration verification with reference
the pass/fail parameters for statistical validity.TheTMC sends
oils supplied by the TMC. These calibration verification runs
a test confirmation report to the test laboratory indicating the
are typically run on blind-coded reference oil samples.
overallvalidityofthecalibrationtestresults,anddisclosingthe
9.3.1.1 Prior to conducting a TMC reference oil test for the
non-blind industry reference oil code.
purpose of stand calibration, procure a supply of reference oil
9.3.4.2 Intheeventthereferenceoiltestisunacceptable,the
directly from the TMC. (See 7.7.2 and Annex A2 for condi-
test laboratory shall provide an explanation of the problem
tions of use for theTMC reference oils.)The reference oils are
relating to the failure. If the problem is not obvious, carry out
usually supplied directly to a testing laboratory with blind-
operational re-checks (instrumentations, settings, and proce-
coded identification numbers to ensure that the laboratory is
dures). Following the re-checks, the TMC assigns another
not influenced by prior knowledge of a reference oil’s accept-
reference oil for testing by the laboratory. If this reference oil
ableperformanceresultsinassessingthetestresults.TheTMC
will determine which specific reference oil or oils the labora-
tory shall test in accordance with the calibration requirements.
The ROBO Standardized Report Forms and Data Dictionary specification is
available at: ftp://ftp.astmtmc.org/datadict/robo/current/.
The Data Communication Committee, Electronic Test Report Transmission
The ROBO LTMS Calibration Requirements document is available at: Model (ETRTM) document is available at: ftp://ftp.astmtmc.org/docs/
http://www.astmtmc.org/ftp/docs/ltms/ltms.pdf. datacommunicationscommittee/electronic_test_report_transmission_specification/.
D7528 − 22
NOTE 6—Steps 10.5.1 – 10.5.3 may be carried out in any order or
test is unacceptable, a reassessment of the stand setup as
simultaneously.
described in 9.1 or 9.2 may be necessary.
9.3.4.3 It is recognized that a certain percentage of calibra- 10.5.1 Sample Preparation—Introduce 3.0g 6 0.1g of
tion tests will fall outside the acceptance limits because of the prepared iron ferrocene catalyst solution and 197.0g 6 1.0g
application of statistics in the development of the acceptance test oil to the reaction vessel. See Appendix X1 for suggested
limits. The TMC decides, with consultation as needed with mixingprocedures.Ifthedirectweighingprocedure(X1.1.2)is
industry experts (testing laboratories, members of the ASTM used, do the vessel seal check (10.3) and the preset vacuum
Technical Guidance Committee, the surveillance panel, and so flow (10.4) procedure after the apparatus is reassembled.
forth), whether the reason for any failure of a reference oil test
NOTE 7—The total mass of oil in the reactor is 200g 6 1.0g (197.0g
is a false alarm, testing apparatus, testing laboratory, or
6 1.0g from the test oil and 3.0 g from the catalyst solution).
industry-related problem. The ROBO surveillance panel adju-
10.5.1.1 Start the stirrer motor and agitate at 200r⁄min 6
dicates all industry problems.
5r⁄min.
9.3.5 Reference Oil Accountability:
10.5.2 Make the electrical connections to the heater.
9.3.5.1 Laboratories conducting calibration tests are re-
(Warning—To avoid electric shock and possible ignition
quired to provide a full accounting of the identification and
spark, check that the power is de-energized before making
quantities of all reference oils used.
electrical connections.)
9.3.5.2 With the exception of analysis required in this test
10.5.3 Charging Nitrogen Dioxide:
method, no additional physical or chemical analysis of new or
10.5.3.1 Liquid Nitrogen Dioxide Option Only—Transfer
usedreferenceoilsispermittedwithouttheexpresspermission
2.0mL 6 0.1mLof liquid nitrogen dioxide (see Section 8 and
oftheTMC.(See7.7.2andAnnexA2forconditionsofusefor
warning in 7.1) into the graduated tube. See Appendix X2 for
the TMC reference oils.)
examples of how the transfer may be made.
10.5.3.2 Dilute Nitrogen Dioxide Option Only—Theamount
10. Procedure
of nitrogen dioxide introduced can be calculated. An amount
10.1 Vacuum Control Valve Setting—For a new ROBO
equivalent to 2.0mL 6 0.1mL of liquid nitrogen dioxide is
apparatus test stand, set the vacuum control valve as described
required. See Appendix X6 for example calculation.
in AnnexA13. The control valve setting is critical as it affects
10.6 Oil Aging:
the severity of the test. For all subsequent runs involving test
10.6.1 General—Begin the oil aging by setting the time and
oils, use exactly the same control valve setting to that used
temperature and turning on the vacuum.
during the last successful TMC calibration verification run.
10.6.1.1 Complete steps 10.6.2 – 10.6.5 within 1 min; the
10.2 Catalyst Preparation:
order in which they are carried out is not important.
10.2.1 Weigh 0.1g 6 0.001g of iron ferrocene (see warn-
10.6.2 Setthetimecontrollerto40htoinitiatetheoilaging.
ingin7.2)intoanappropriatecontainersuchasa250mLglass
10.6.3 Set the temperature controller to 170 °C and com-
jar.
mence heating.
10.2.2 Add 99.9g 6 0.1g ofAPI Group II 100 Neutral oil
10.6.4 Adjust the temperature controller voltage output to
to obtain 0.100% 6 0.001% (mass) iron ferrocene.
25V to 40V.
10.2.3 Mix thoroughly, until the catalyst is completely in
10.6.5 Turn the vacuum system on.
solution as determined by a lack of visible particles.
10.6.6 Start the nitrogen dioxide flow.
NOTE 5—This may take 1h or more.
10.6.6.1 Fortheliquidnitrogendioxideoption,immediately
10.3 Vessel Seal Check: after the previous steps, adjust the nitrogen dioxide precision
needle valve to allow introduction of nitrogen dioxide in a
10.3.1 Startsubsurfacedry-airflowatarateof185mL/min.
controlled and gradual manner into the inlet flow stream.
10.3.2 Onanassembledvessel,installtheacrylicblockflow
Ensure that the nitrogen dioxide is completely depleted from
meter between the top connection of the vacuum control valve
the tube and introduced into the reactor within 12h 61h.
and the vacuum source.Apply vacuum to the vessel and block
10.6.6.2 Because changes to the nitrogen dioxide flow rate
thevacuumrelieforificelongenoughtoassurethesystemwill
attain 85 kPa with a subsurface airflow of 185 mL/min. can affect precision, it is imperative that nitrogen dioxide be
introduced to the reactor in a controlled and gradual manner.
10.3.2.1 Theacrylicblockairflowmetershallreadlessthan
Using a flow rate target of 0.167 mL/h, monitor nitrogen
0.6 SCFM.
dioxide depletion closely in the first 2h to 4h, the aim being
10.4 Preset Vacuum Flow—Withthevacuumstillappliedto
to introduce 0.5mL during that time period. Introduce the
the vessel, set the air flow through the reactor to 2.0SCFM 6
remaining 1.5mLat a similar flow rate, ensuring that the total
0.1SCFM by bleeding air, if needed, into the vacuum line
of 2.0mLis delivered between 11h and 13h.Arun is invalid
between the vacuum source and the condenser. Maintain the
if the flow of nitrogen dioxide exceeds 0.5mL during any 1h
vacuum pressure at 61kPa 6 1.7kPa by adjusting the vacuum
period.
reliefvalve.Oncetheseparametersareset,shutoffthevacuum
10.6.6.3 For the dilute nitrogen dioxide option, switch to
and remove the acrylic block flow meter from the system.
dilutenitrogendioxidefor12.0h.Arunisinvalidiftheflowof
10.5 Sample Preparation and Charging Nitrogen Dioxide: dilute nitrogen dioxide in air deviates from the required
D7528 − 22
185mL⁄min by more than 6% during at any of the observa- 11.3 Clean the underside of the reactor cap and all shafts or
tions.At least 6 observations during the first 6h of the air flow probes protruding downward into the vessel with cleaning
must be made and recorded with the last observation being solvent and a lightweight, lint-free towel. Rinse with acetone.
madeatabout6h.Theairflowmaybeadjustedatthesetimes.
11.4 Ensure that subsurface air supply lines are clear, then
If all of the readings before adjustments are within 5% of
clean them with cleaning solvent and reassemble when dry.
185mL⁄min,thennomoreobservationsarerequired.Iftheair
11.5 Clean the acrylic block flow meter with cleaning
flow deviates by more than 4% during the first 6h, then six
solvent. Do not use acetone which can dissolve or deteriorate
more observations are required from hours 6 to 12. After
acrylics.
12.0h, switch back to the dry-air supply for the remainder of
the test.
12. Calculations and Determination of Test Results
10.6.6.4 If any deviations from 185mL⁄min of more than
12.1 Increase in Kinematic Viscosity at 40 °C:
2mL⁄min were observed (or calculated at the 12h switching
12.1.1 Calculate as follows:
time), then calculate and report the time-averaged flow rate.
See Appendix X7 for examples.
@KV~aged! 2KV~fresh!#
Percentviscosityincrease PVIS 5100
~ !
KV fresh
~ !
10.7 Shutdown:
(2)
10.7.1 Attheendofthe40hcycle,allowthesystemtocool
to room temperature while maintaining the airflow and agita-
where:
tion.
KV(aged) = kinematic viscosity, mm /s, at 40 °C of the
10.7.2 Turn off the vacuum. (The vacuum flow can be
aged oil as determined by Test Method D445,
turnedoffatanytimeaftercompletionofthe40hcycle.)Bleed
and
the pressure by opening a port, for example, the sample
KV(fresh) = kinematic viscosity, mm /s, at 40 °C of the
addition port. Drain the aged oil into a suitable container.
fresh oil as determined by Test Method D445.
10.8 Mass Percent Volatiles Collected:
12.2 Low-Temperature Viscometric Properties:
10.8.1 Drain the condensed liquid from the vacuum trap
12.2.1 UsingTest Method D5293, measure the Cold Crank-
system into a tared vessel. Determine and record the mass of
ing Simulator (CCS) viscosity of the ROBO-aged oil at the
the condensed liquid to the nearest 0.1 g.
temperature specified for the SAE W grade of the fresh oil.
This temperature can be found in the SAE J300 Viscosity
10.8.2 Calculate as follows:
Classification System (hereafter referred to as SAE J300).
M~volatiles!
Mass% volatiles, %m/m 5100 (1) 12.2.1.1 If the measured CCS viscosity is less than or equal
M fresh
~ !
to the maximum CCS viscosity specified in SAE J300 for the
where:
SAE W grade of the fresh oil, measure the MRV viscosity by
M(fresh) = 200 g = the mass of fresh oil added to the Test Method D4684 at the MRV temperature specified in SAE
reactor in 10.5.1, and J300 for the SAE W grade of the fresh oil.
M(volatiles) = mass, g, of condensate collected in 10.8.1.
12.2.1.2 If the measured CCS viscosity is higher than the
NOTE 8—The significance of the %volatiles parameter is under maximumCCSviscosityspecifiedinSAEJ300fortheSAEW
investigation.
viscosity grade of the fresh oil, measure the MRVviscosity by
Test Method D4684 at 5 °C higher than the MRV temperature
11. Cleaning
specified in SAE J300 for the original SAE W viscosity grade
of the fresh oil (that is, at the MRV temperature specified in
11.1 Clean the reaction vessel with cleaning solvent (see
SAE J300 for the next higher SAE W viscosity grade).
warning in 7.4).
11.1.1 Scrub any residual material off the glass surface
13. Report
while taking care not to scratch the inside of the vessel.
Perform a final rinse with acetone (see warning in 7.5). 13.1 Report Forms—For TMC reference oil tests, use the
standardized report form set and data dictionary.
11.2 Clean the vacuum control valve.
NOTE 9—Report the non-reference oil test results on these same forms
11.2.1 Flush the valve with cleaning solvent or carburetor
if the results are intended to be submitted as candidate oil results against
cleaner, followed with an acetone rinse to remove and avoid
a specification.
anycarbondepositsthatcouldreduceorplugthevalveorifice.
13.1.1 Report reference oil test results to the TMC accord-
11.2.2 Additional optional cleaning may be needed in cases
ing to the ETRTM protocols described in 9.3.3.1.
where there is insufficient vacuum flow (see 10.4). If vacuum
flow is sufficient, skip to step 11.3. 13.2 Reporting Units—Report results in SI units.
11.2.2.1 Disassemble the valve and remove any carbon
13.3 Report the following:
deposits from the plug and inside seat of the valve body.
13.3.1 Kinematic viscosity at 40 °C, by Test Method D445,
11.2.2.2 Flush as in 11.2.1.
of the test oil before and after aging.
11.2.2.3 Reassemble the vacuum control valve, ensuring 13.3.1.1 Report to two decimal places for viscosities be-
2 2
thatthevalvesettingisatexactlythesamepositiontothatused tween 10mm /s and 100mm /s and to one decimal place for
during the last successful TMC calibration verification run. viscosities >100 mm /s.
D7528 − 22
A
TABLE 1 Test Precision
14.1.1 Intermediate Precision Conditions—Conditions
Intermediate Precision Reproducibility
wheretestresultsareobtainedwiththesametestmethodusing
Variable
B C B C
S i.p. S R
i.p. R the same oil, with changing conditions such as operators,
D
PVIS 0.191 0.535 0.267 0.748
measuring equipment, test apparatus, and time.
D
MRV viscosity 0.25 0.70 0.40 1.12
NOTE 10—Intermediate precision is the appropriate term for this test
A
These statistics are based on results obtained from an interlaboratory program
method, rather than repeatability, which defines more rigorous within-
inwhichsevensamplesweretestedinsevenlaboratoriesontentestrigs(see14).
laboratory conditions.
The samples consisted of SAE 5W-XX and 10W-30 multigrade engine oils
including ASTM Test Monitoring Center Reference Oils 434, 435, and 438.
14.1.1.1 Intermediate Precision Limit (i.p.)—The difference
B
S = Standard deviation.
C between two results obtained under intermediate precision
This value is obtained by multiplying the standard deviation by 2.8.
D
conditionsthatwouldinthelongrun,inthenormalandcorrect
The original units for PVIS are percent viscosity increase. The original units for
MRV viscosity are mPa·s. These parameters are transformed using ln(result).
conduct of the test method, exceed the values shown in Table
When comparing two test results on these parameters, first apply this transforma-
1 in only one case in twenty. When only a single test result is
tiontoeachtestresult.Comparetheabsolutedifferencebetweenthetransformed
results with the appropriate (intermediate precision or reproducibility) precision available, the Intermediate Precision Limit can be used to
limit.
calculate a range (test result 6 Intermediate Precision Limit)
outside of which a second test result would be expected to fall
about one time in twenty.
14.1.2 Reproducibility Conditions—Conditions where test
results are obtained with the same test method using the same
13.3.2 Percentincreaseinkinematicviscosityat40°Cafter
test oil in different laboratories with different operators using
aging (PVIS)—see 12.1.
different equipment.
13.3.2.1 Report to nearest 0.1%.
14.1.2.1 Reproducibility Limit (R)—The difference between
13.3.3 SAE W grade of the fresh oil.
two results obtained under reproducibility conditions that
13.3.4 The CCS viscosity and temperature of measurement
would,inthelongrun,inthenormalandcorrectconductofthe
of the ROBO-aged oil by Test Method D5293.
test method, exceed the values in Table 1 in only one case in
13.3.5 The MRV viscosity, yield stress and temperature of
twenty.
measurement of the aged oil by Test Method D4684—see
12.2.1.1 and 12.2.1.2. 14.2 Bias—No estimate of the bias for this procedure is
possible because the performance results for an oil are deter-
13.3.6 The option used to add nitrogen dioxide. Liquid
nitrogen dioxide or dilute nitrogen dioxide. mined only under the specific conditions of the test and no
absolute standards exist.
13.3.6.1 If the dilute nitrogen dioxide option was used,
calculate and report the total amount of nitrogen dioxide
14.3 Dilute Nitrogen Dioxide Option Effect on Precision
delivered to the reactor to the nearest one-tenth of a milliliter.
and Bias—The precision and bias in sections 14.1 and 14.2
were determined with the original liquid nitrogen dioxide
14. Precision and Bias
option.TheASTMROBOSurveillancePanelapprovedtheuse
of the dilute nitrogen dioxide option based on the limited data
14.1 Precision—The precision of this test method as deter-
obtained from which no effect on precision or bias was
minedbythestatisticalexaminationoftheinterlaboratorytests
detected.
results is given in Table 1.
15. Keywords
15.1 evaporative loss; low-temperature pumpability; MRV
Supporting data have been filed atASTM International Headquarters and may
viscosity; oil aging; oil oxidation; oil viscosity; ROBO test;
beobtainedbyrequestingResearchReportRR:D02-1660.ContactASTMCustomer
Service at service@astm.org. sequence IIIG test; sequence IIIGA test; volatiles
D7528 − 22
ANNEXES
(Mandatory Information)
A1. ASTM TEST MONITORING CENTER: ORGANIZATION
A1.1 The Test Monitoring Center (TMC), an affiliate of vested in the ASTM Test Monitoring System Executive
ASTM International, is a nonprofit organization located at 203 Committee, whose members are elected by Subcommittee
Armstrong Drive, Freeport, PA 16229. It is staffed to admin-
D02.B0. The TMC operates under its associated bylaws and
ister engineering studies; conduct laboratory visits; perform
regulations, the bylaws of Committee D02 and of Subcommit-
statistical analyses of test data; to blend, store, and ship
tee D02.B0, and the Rules and Regulations of theASTM Test
reference oils; and to provide associated administrative func-
Monitoring System. The operating income of the TMC is
tions connected with the referencing and calibration of various
obtainedfromfeesleviedonthereferenceoilssuppliedandon
lubricanttests.TheTMCmaintainsacloseconnectionwithtest
test reviews. These fees are set by the Test Monitoring Center
sponsors, test developers, the surveillance panels, and the
Board of Directors.
testing laboratories. The management of these functions is
A2. ASTM TEST MONITORING CENTER: CALIBRATION PROCEDURES
A2.1 Reference Oils—These oils are formulated or selected A2.4 Analysis of Reference Oil—Unless specifically autho-
to represent specific chemical, or performance levels, or both. rized by the TMC, do not analyze TMC reference oils, either
Theyareusuallysupplieddirectlytoatestinglaboratoryunder
physicallyorchemically.DonotresellASTMreferenceoilsor
codenumberstoensurethatthelaboratoryisnotinfluencedby
supply them to other laboratories without the approval of the
prior knowledge of acceptable results in assessing test results.
TMC. The reference oils are supplied only for the intended
The TMC determines the specific reference oil the laboratory
purpose of obtaining calibration under the ASTM Test Moni-
shall test.
toring System.Any unauthorized use is strictly forbidden. The
testing laboratory tacitly agrees to use the TMC
...