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METRIC
MIL-PRF-32014A
12 September 2006
SUPERSEDING
MIL-PRF-32014
29 September 1997
PERFORMANCE SPECIFICATION
GREASE, AIRCRAFT AND INSTRUMENT
This specification is approved for use by all Departments and Agencies
of the Department of Defense.
1. SCOPE
1.1 Scope.
This specification covers the general requirements for a multipurpose, water resistant, high
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speed grease for use in the -54 C to +177 C temperature range.
2. APPLICABLE DOCUMENTS
2.1 General.
The documents listed in this section are specified in sections 3 and 4 of this specification. This
section does not include documents cited in other sections of this specification or recommended
for additional information or as examples. While every effort has been made to ensure the
completeness of this list, document users are cautioned that they must meet all specified
requirements documents cited in sections 3 and 4 of this specification, whether or not they are
listed.
Comments, suggestions, or questions on this document should be emailed to
Engineering.Standards@wpafb.af.mil or addressed to ASC/ENOI, 2530 Loop Road West,
Wright-Patterson AFB OH 45433-7101. Since contact information can change, you may want to
verify the currency of this address information using the ASSIST Online database at
assist.daps.dla.mil.
AMSC:NA FSC 9150
DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.
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MIL-PRF-32014A
2.2 Government documents.
2.2.1 Specifications, standards, and handbooks.
The following standard forms a part of this specification to the extent specified herein. Unless
otherwise specified, the issues of these documents are those listed in the solicitation or contract
(see 6.2).
FEDERAL STANDARDS
FED-STD-791 - Lubricants, Liquid Fuels, and Related Products; Methods of Testing
(Copies of federal and military specifications, standards, and handbooks are available from the
Department of Defense Single Stock Point, Standardization Documents Order Desk, Bldg. 4D,
700 Robbins Avenue, Philadelphia PA 19111-5094. Access via ASSIST online at
http://assist.daps.dla.mil.)
2.3 Non-Government publications.
The following documents form a part of this document to the extent specified herein. Unless
otherwise specified, the issues of these documents are those cited in the solicitation or contract.
AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)
ASTM D 97 - Pour Point of Petroleum Products (DoD adopted)
ASTM D 942 - Oxygen Stability of Lubricating Grease by the Oxygen Bomb Method
ASTM D 217 - Cone Penetration of Lubricating Grease
ASTM D 445 - Kinematic Viscosity of Transparent and Opaque Liquids (and the
Calculation of Dynamic Viscosity) (DoD adopted)
ASTM D 1264 - Water Washout Characteristic of Lubricating Greases
ASTM D 1478 - Low Temperature Torque of Ball Bearing Greases
ASTM D 2265 - Dropping Point of Lubricating Grease Over a Wide Temperature Range
ASTM D 2266 - Wear Preventive Characteristics of Lubricating Greases (Four-Ball
Method)
ASTM D 2595 - Evaporation Loss of Lubricating Greases Over Wide-Temperature
Range
ASTM D 2596 - Extreme-Pressure Properties of Lubricating Grease (Four-Ball
Method), Measurement of
ASTM D 3336 - Life of Lubricating Greases at Elevated Temperatures in Ball Bearings
ASTM D 4057 - Manual Sampling of Petroleum and Petroleum Products (DoD adopted)
ASTM D 4048 - Copper Corrosion from Lubricating Greases, Detection of
ASTM D 5706 - Determining Extreme Pressure Properties of Lubricating Greases
Using a High-Frequency, Linear Oscillation (SRV) Test Machine
ASTM D 5949 - Pour Point of Petroleum Products (Automatic Pressure Pulsing
Method)
ASTM D 5969 - Corrosion Preventive Properties of Lubricating Greases in the
Presence of Dilute Synthetic Sea Water
ASTM D 6184 - Oil Separation from Lubricating Greases (Conical Sieve Method)
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MIL-PRF-32014A
(Copies of this document are available from ASTM International, 100 Barr Harbor Drive, PO Box
C700, West Conshohocken, Pennsylvania, USA 19428-2959. Order electronic standards online
at www.astm.org.)
2.4 Order of precedence.
In the event of a conflict between the text of this document and the references cited herein, the
text of this document takes precedence. Nothing in the document, however, supersedes
applicable laws and regulations unless a specific exemption has been obtained.
3. REQUIREMENTS
3.1 Qualification.
Items furnished under this specification shall be products that are authorized by the qualifying
activity for listing on the applicable qualified products list before contract award (see 4. and 6.).
3.2 Materials.
The materials used in formulating this grease shall consist of a base oil conforming to
requirements in table I and suitable additives. A polyalphaolefin, lithium soap thickened
formulation is recommended, but is not mandatory. The thickener system proposed must be
compatible with lithium soap thickened grease.
Table I. Properties of base oil.
Viscosity @ ASTM Method
40oC, cSt, max 140 D 445
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100 C, cSt, min 16 D 445
D 97 or
Pour Point, oC, min -35
D 5949
3.3 Finished grease.
The properties of the finished grease shall be as specified in table II.
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MIL-PRF-32014A
TABLE II. Properties and test methods.
Test Method
Property Test Limits FED- ASTM
STD-
791
Cone penetration, worked 265-305 D 217
worked stability, 100,000 double strokes 350 max
Copper corrosion (1) 1b max D 4048
Corrosion Prevention(2)
Synthetic Sea Water, 5% Pass D 5969
Dirt, particle per millimeter of grease 3005.4
25-74 micrometers, diameter 1000 max
>75 micrometers, diameter None
Dropping point, °C 200 min D 2265
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Evaporation loss, 177± 3 C for 22 hours, percent 10 max D 2595
Extreme pressure properties, wear scar, mm (3) 0.80 max D 5706
High speed bearing performance, hours 25 min See
4.4.5
High speed bearing performance, after 6 mo. humidity 25 min See
storage, hours 4.4.6
Life of lubrication greases at elevated temperature in 400 min D 3336
ball bearings, 160± 2°C, hours
Load wear index, Kgf 30 min D 2596
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Low temperature torque of ball bearings, -54± 1 C 1.4/0.5 max D 1478
start/run @ 1 hour, Newton-meter (Nm)
Odor No odor of
rancidity,
perfume or
free alcohol
Oil separation, percent weight loss 8 max D 6184
Oxidation stability, after 500 hours, psi 35 max D 942
Storage stability, penetration, 2 mo., 20-25°C 3467.1
Worked (change from original), points 30 max
Water washout, 41± 1°C, percent 15 max D 1264
Wear preventative characteristics, wear scar average, 0.65 max D 2266
mm
NOTES:
(1) The grease shall show no green color in that portion contacting the copper strip. The
copper strip shall not tarnish more than a classification of 1b when compared with the
ASTM copper corrosion standards.
(2) Water shall be prepared the day of the testing.
(3) See 4.4.4.
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MIL-PRF-32014A
3.4 Workmanship.
The grease, when examined visually, shall be a smooth and homogeneous mixture, free from
lumps and extraneous materials.
3.5 Compatibility.
The grease shall be compatible with all previously qualified greases when tested in accordance
with 4.4.7. Immediately after mixing, and after undisturbed storage for seven days, the mixture
shall not form resinous gums, sludge, or insoluble solid materials and shall comply with the
worked penetration and worked stability requirements (see table II). In the event of failure, the
previously qualified grease (unmixed with other greases) shall be tested to verify that it meets
the worked penetration and worked stability requirements under the conditions specified in
4.4.7. If the previously qualified sample fails to meet the worked penetration or worked stability
requirement, a fresh sample shall be obtained and the compatibility test repeated. Additional
mix ratios of 90 percent previously qualified and 10 percent new and vice versa may be used
during qualification testing.
4. VERIFICATION
4.1 Classification of inspections.
The inspection requirements specified herein are classified as follows:
a. Qualification inspection (see 4.2).
b. Conformance inspection (see 4.3).
4.1.1 Inspection conditions.
Unless otherwise specified, all inspections shall be performed in accordance with the test
conditions specified in 4.2.
4.2 Qualification inspection.
4.2.1 Qualification sample.
Qualification samples shall consist of four one pound containers of grease and one-half pint of
base oil. The additives, in 4-ounce quantities, may be requested at the option of the qualifying
activity.
4.2.2 Qualification tests.
Qualification sample(s) shall be subject to all the tests specified under 4.4, methods of
inspection.
4.2.3 Retention of qualification.
In order to retain qualification of a product approved for listing on the QPL, the manufacturer
shall verify, by certification, to the Qualifying Activity that the manufacturer’s product complies
with the requirements of this specification. The time of periodic verification by certification shall
be after five years from the date of manufacture and every two years thereafter. The
Government reserves the right to re-examine the qualified product whenever deemed necessary
to determine the product continues to meet any or all of the specification requirements. The
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product will be requalified every five years; to retain qualification, new samples shall be
submitted to the qualifying activity.
4.3 Conformance inspection.
The quality conformance inspection shall consist of examination of the sample of filled
containers and all of the required tests except for base oil kinematic viscosities and pour point.
For grease, text exceptions include extreme pressure properties, high speed bearing tests, life
of lubrication greases at elevated temperature in ball bearings, low temperature torque of ball
bearings, and storage stability. Samples shall be labeled completely with information that
identifies the purposes of the sample, name of product, specification number, lot and batch
number (see 6.4), date of sampling, and contract number.
4.4 Methods of inspection.
4.4.1 Inspection.
Inspection shall be in accordance with method 9601 of FED-STD 791.
4.4.2 Grease.
The grease shall conform to the requirements for base oil and finished grease which shall be
determined by appropriate examination and testing in accordance with 4.4.3.
4.4.3 Physical and chemical values.
Tests shall be performed in accordance with the applicable methods specified in tables II and III
and 4.4.4 through 4.4.7. Physical and chemical values specified in section 3 apply to the
arithmetic average of the determinations made on the samples for those values which fall within
any stated repeatability or reproducibility limits of the applicable test method.
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TABLE III. Conformance properties and test methods.
Test Method
Property Test Limits FED- ASTM
STD-
791
Cone penetration, worked 265-305 D 217
worked stability, 100,000 double strokes 350 max or
D 1403
Copper corrosion (1) 1b max D 4048
Corrosion Prevention (2)
Synthetic Sea Water, 5% Pass D 5969
Dirt, particle per millimeter of grease 3005.4
25-74 micrometers, diameter 1000 max
>75 micrometers, diameter None
Dropping point, °C 200 min D 2265
o
Evaporation loss, 175± 3 C for 22 hours, percent 10 max D 2595
Load wear index, Kgf 30 min D 2596
Odor No odor of
rancidity,
perfume or
free alcohol
Oil separation, percent weight loss 8 max D 6184
Oxidation stability, after 500 hours, psi 35 max D 942
o
Water washout, 41± 1 C , percent 15 max D 1264
Wear preventative characteristics, wear scar average, 0.65 max D 2266
mm
Workmanship Pass See 3.4
NOTES:
(1) The grease shall show no green color in that portion contacting the copper strip. The
copper strip shall not tarnish more than a classification of 1b when compared with the
ASTM copper corrosion standards.
(2) Water shall be prepared the day of the testing.
4.4.4 Modification of ASTM D 5706 for the use of the reciprocating tribometer.
Follow ASTM D 5706 with these exceptions:
• Use disks polished to 4 microns or less
• Use individual washings of hexane, acetone, and isopropanol, for ultrasonic cleaning
• Use 0.5 gm of test grease
• Preload 10N for run-in for 2 min
• 2.3 mm (+ 0.2 mm) stroke length
• Manually load to 600 N after run-in and run at 600 N thereafter
• Test time: 30 minutes total including run-in
• Report size of wear scar on ball using ASTM D 2266 for ball measurements
• Graph coefficient of friction and contact resistance for each test, if possible
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4.4.5 High speed bearing performance.
4.4.5.1 Apparatus.
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Performance shall be determined in a Marlin Rockwell 538 C grease testing unit developed for
the CRC L-54 research technique, or equivalent, using ASTM D 3336 test method with the
following modifications: A variable-speed electric drive motor installed with a large balanced
pulley and a light-weight flat belt to rotate a spindle supported by two ball bearings. The rig
shall be modified to accommodate a 17 mm bore size 203 test ball bearing located at the
opposite end of the spindle from the drive pulley. This bearing shall be made of M-50 tool steel
and phenolic resin with aluminum side plates fastened with rivets. Dished side shields shall be
used to retain additional lubricant. The spindle support bearing located next to the pulley shall
be Marlin Rockwell type 204 S-17 or equivalent with races and balls made of M-50 tool steel
and bore diameters of 20 mm or equivalent. The ball retainer shall be a stamped ribbon type
made of silver plated beryllium copper. A thermocouple in contact with the outer race of the test
bearing shall be connected to at temperature controller, a recorder, and a data logger. An oven
capable of maintaining the test temperature is required. An air cylinder connected to a steel
cable is required to apply thrust load to the test bearing housing.
4.4.5.2 Procedure.
Prior to testing, the side shields of the 203 test bearing shall be removed and all the bearing
components cleaned thoroughly with hexane. The bearing shall be packed with 0.535 + 0.050
grams of test grease and 0.625 + 0.050 grams of grease in each of the two shields. The shields
shall then be replaced carefully. After installing on the tester, the test bearing shall be run at
30,000 rpm, thrust loading at 1769 + 9 N. The test is started at room temperature for four hours
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and than at a temperature of 115.5 + 2 C for a total test time of 25 hours.
4.4.6 High speed bearing performance after storage.
A 203 size bearing is also packed as in 4.4.5.2 and stored vertically from nichrome wire in an
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oven at 71+2 C and 98 to 100 percent relative humidity. After six months, the bearing is
removed and tested as in 4.4.5.2.
4.4.7 Compatibility.
Fill standard grease cups with equal volumes of the grease being tested and previously
qualified greases. The cup shall be filled by alternately adding 60 grams of each of the two
greases being tested, until the cup is full (approximately 454 grams). Mix the two greases by
working the sample for 60 double strokes in accordance with the worked penetration procedure
of ASTM D217 or ASTM D 1403 and then let the mixture stand undisturbed for seven days at
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19.0 to 29.5 C (65 to 85 F) and 50 ± 10 percent relative humidity. Examine the worked
penetration and then the worked stability in accordance with table II, using the same sample of
grease mixture for both tests. Small amounts of fresh grease may be added to the worker cup
just prior to the worked stability, as needed to maintain a full cup for testing.
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5. PACKAGING
5.1 Packaging.
For acquisition purposes, the packaging requirements shall be as specified in the contract or
order (see 6.2). When actual packaging is to be performed by DoD personnel, these personnel
need to contact the responsible packaging activity to ascertain requisite packaging
requirements. Packaging requirements are maintained by the Inventory Control Point’s
packaging activity with the Military Department or Defense Agency, or within the Military
Department’s System Command. Packaging data retrieval is available from the managing
Military Department’s or Defense Agency’s automated packaging files, CD-ROM products, or by
contacting the responsible packaging activity.
6. NOTES
(This section contains information of a general or explanatory nature, which may be helpful but
is not mandatory.)
6.1 Intended use.
The grease covered by the specification is intended as a general purpose aircraft lubricant and
is used to lubricate main shaft bearings in missile engines. It provides water resistance and
corrosion protection for aircraft and missiles over an extended period. It will be operational
between -54 and 175°C.
6.2 Acquisition requirements.
Acquisition documents must specify the following:
a. Title, number, and date of the specification.
b. Issue of DoDISS to be cited in the solicitation, and if required, the specific issue of
individual documents referenced (see 2.3).
c. Packaging requirements (see 5.1).
d. Quantity desired.
e. Type and capacity of container (see 5.1)
6.3 Qualification.
With respect to products requiring qualification, awards will be made only for products which
are, at the time of award of contract, qualified for inclusion in Qualified Products List QPL-32014
whether or not such products have actually been so listed by that date. The attention of the
contractors is called to these requirements, and manufacturers are urged to arrange to have the
products that they propose to offer to the Federal Government tested for qualification in order
that they may be eligible to be awarded contracts or purchase orders for the products covered
by this specification. Information pertaining to qualification of products may be obtained from
AFRL/MLBT, Bldg 654, 2941 Hobson Way, Rm 136, WPAFB OH 45433-7750.
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6.3.1 Data to accompany qualification samples.
The samples will be accompanied by a Material Safety Data Sheet and a test report from the
manufacturer or a commercial laboratory that contains complete information about the source
and type of base stock and additive materials used, the formulation and composition of the
finished grease, and laboratory data that show quantitative results of all the tests required by
this specification except storage stability, high speed bearing tests and humidity storage test.
Separate qualification inspection will be required for each base stock used. The samples will be
plainly identified by securely attached, durable tags or labels marked with the following
information:
Sample for Qualification Inspection
GREASE, AIRCRAFT AND INSTRUMENT
Specification MIL-PRF-32014
Name of ingredient (for ingredient material)
Name of manufacturer
Product code number
Date of manufacture
6.3.2 Formulation sheet.
An example of a satisfactory form for the formulation sheet, indicating the weight percentage
and nature of each ingredient is as follows:
Base stock (chemical composition, CAS number, manufacturer’s name and number)
percentage
Thickener(chemical composition, CAS number, manufacturer’s name and number)
percentage
Each additive (chemical composition, CAS number, manufacturer’s name and number)
percentage
6.4 Definitions.
6.4.1 Bulk lot.
A bulk lot (batch) is an indefinite quantity of a homogeneous material mixture offered for
acceptance in a single, isolated container or manufactured in a single-plant run (not to exceed
48 hours), through the same processing equipment, with no change in ingredient material.
6.4.2 Packaged lot.
A packaged lot is an indefinite number of 55-gallon drums or smaller unit containers of identical
size and type, offered for acceptance, and filled with a homogeneous material mixture from one
isolated container or filled with a homogeneous material mixture manufactured is a single-plant
run (not to exceed 48 hours), through the same processing equipment, with no change in
ingredient material.
6.5 Subject term (key word) listing.
General purpose grease
Missile engine grease
Water resistant grease
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6.6 Changes from previous issue.
Marginal notations are not used in this revision to identify changes with respect to the previous
issue due to the extensiveness of the changes.
Custodians Preparing Activity
Army - CR4 Air Force 11
Navy - AS
Air Force - 11
(Project No. 9150-2006-001)
Review activities
Army - AV, MI, AR, EA
Navy - SH
DLA - PS
NOTE: The activities listed above were interested in this document as of the date of this
document. Since organizations and responsibilities can change, you should verify the currency
of the information above using the ASSIST Online database at http://assist.daps.dla.mil.
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