ASTM D942-90(1995)e1
(Test Method)Standard Test Method for Oxidation Stability of Lubricating Greases by the Oxygen Bomb Method
Standard Test Method for Oxidation Stability of Lubricating Greases by the Oxygen Bomb Method
SCOPE
1.1 This test method determines resistance of lubricating greases to oxidation when stored statically in an oxygen atmosphere in a sealed system at an elevated temperature under conditions of test.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements see Sections 6 and 7.
General Information
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Standards Content (Sample)
e1
Designation: D 942 – 90 (Reapproved 1995) An American National Standard
|hN|hM Designation: 142/85 (92)
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Oxidation Stability of Lubricating Greases by the Oxygen
Bomb Method
This standard is issued under the fixed designation D 942; 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 (e) indicates an editorial change since the last revision or reapproval.
This test method has been approved by the sponsoring committee and accepted by the cooperating societies in accordance with the
established procedures.
This standard has been approved for use by agencies of the Department of Defense.
e NOTE—Section 11 was added editorially in October 1995.
1. Scope 3. Summary of Test Method
1.1 This test method determines resistance of lubricating 3.1 The sample of grease is oxidized in a bomb heated to
greases to oxidation when stored statically in an oxygen 99°C (210°F) and filled with oxygen at 110 psi (758 kPa).
atmosphere in a sealed system at an elevated temperature under Pressure is observed and recorded at stated intervals. The
conditions of test. degree of oxidation after a given period of time is determined
1.2 This standard does not purport to address all of the by the corresponding decrease in oxygen pressure.
safety concerns, if any, associated with its use. It is the
NOTE 1—The accepted unit of pressure is the pascal (Pa) for ASTM
responsibility of the user of this standard to establish appro-
methods and will be parenthetically included after the conventional
priate safety and health practices and determine the applica-
pound-force per square inch (psi) value. The Institute of Petroleum uses
bility of regulatory limitations prior to use.For specific hazard
the bar as a pressure measurement. Conversion of units may be obtained
as follows:
statements see Sections 6 and 7.
To convert from pound-force per square inch (psi) to pascal (Pa)
2. Referenced Documents multiply by 6.894757 3 10 .
To convert from pound-force per square inch (psi) to bar multiply by
2.1 ASTM Standards:
0.06894757.
A 240 Specification for Heat-Resisting Chromium and 5
To convert from bar to pascal (Pa) multiply by 10 .
Chromium-Nickel Stainless Steel Plate, Sheet, and Strip
4. Significance and Use
for Pressure Vessels
E 1 Specification for ASTM Thermometers
4.1 This test method measures the net change in pressure
2.2 Other Standards:
resulting from consumption of oxygen by oxidation and gain in
IP Specification for Standard IP Thermometers
pressure due to formation of volatile oxidation by-products.
BS970:1983 Part I, Section S
This test method may be used for quality control to indicate
Compressed Gas Association Booklets G-4 and G-4-1
batch-to-batch uniformity. It predicts neither the stability of
greases under dynamic service conditions, nor the stability of
greases stored in containers for long periods, nor the stability
This test method is under the jurisdiction of ASTM Committee D-2 on
of films of greases on bearings and motor-parts. It should not
Petroleum Products and Lubricantsand is the direct responsibility of Subcommittee
be used to estimate the relative oxidation resistance of different
D02.09on Oxidation.
In the IP, this test method is under the jurisdiction of the Standardization grease types.
Committee.
Current edition approved April 27, 1990. Published June 1990. Originally
5. Apparatus
e2
published as D 942 – 47. Last previous edition D 942 – 78 (1984) .
5.1 Oxidation Bomb, Sample Dish, Dish Holder, Pressure
Annual Book of ASTM Standards, Vol 01.03.
Annual Book of ASTM Standards, Vol 14.03.
Gage and Oil Bath as described in detail in the Annex.
Available from The Institute of Petroleum, 61 New Cavendish St., London
NOTE 2—Other constant-temperature baths may be used if they are
W1M, 8AR, England.
Available from British Standards Institute, 2 Park St., London, England equivalent in heat capacity and thermal gradient characteristics to the oil
WIA2B5.
bath described in the Annex and can be shown to maintain the bomb at the
Available from Compressed Gas Assn., 500 Fifth Ave., New York, NY 10036.
D 942
prescribed test temperature.
oxidation bomb and the metal supports for the bomb dishes by
immersing in hot solvent and scrubbing with a bristle brush
5.2 Thermometer, having a range as shown below and
followed by drying. Scrub further with water and a fine
conforming to the requirements as prescribed in Specification
scouring powder until all the lacquer deposits are removed.
E 1 or in the Specifications for IP Standard Thermometers:
Follow the scouring operation by a thorough tap water rinse, a
Thermometer Number
Temperature Range ASTM IP distilled water rinse, and drying in an oven. Handle the clean
95 to 103°C 22C 24C
metal supports only with forceps.
204 to 218°F 22F 24F
6. Material
8. Procedure
6.1 Oxygen, of not less than 99.5 % purity.
8.1 Fill each of the five dishes with 4.00 6 0.01 g of grease.
Distribute the samples in the dishes in a uniform layer with a
NOTE 3—Precaution: Since oxygen vigorously accelerates combus-
tion, observe the following procedures: smooth level upper surface. Place the filled dishes on the five
bottom shelves of the holder, leaving the top shelf to act as a
(1) Keep oil and grease away from oxygen at high pressure.
cover to prevent condensing volatile products from dropping
Keep oil and grease away from all regulators, gauges and
into the grease samples. When assembling the bomb, place a
control equipment. (2) Use oxygen only with equipment
small ball of glass wool in the bottom of the stem.
conditioned for oxygen service by careful cleaning to remove
8.2 Place the dish holder in the bomb and close the bomb by
oil and grease from area in contact with high pressure oxygen.
tightening the bolts slowly and uniformly. Clear the air from
(3) Keep combustibles away from oxygen and eliminate
the bomb by introducing oxygen slowly until a pressure of 100
ignition sources. (4) Keep surfaces clean to prevent ignition or
psi (689 kPa) is attained, then allow the oxygen to escape
explosion, or both, upon contact with high pressure oxygen. (5)
slowly; repeat four times. Bring the oxygen pressure to a value
Always use a pressure regulator to deliver oxygen. Release
as shown in the following table:
regulator tension before opening oxygen cylinder. (6) All
equipment used must be suitable and recommended for oxygen Room Temperature Pressure
°C °F psi kPa
service. (7) Never attempt to transfer oxygen from cylinder in
17 to 20 62 to 68 85 586
which it is received to any other cylinder prior to use. (8)Do
20 to 23 68 to 74 86 593
23 to 27 74 to 80 87 600
not drop oxygen cylinders. (9) Keep cylinder valve closed
27 to 30 80 to 86 88 607
when not in use. (10) Stand away from valve when opening
30 to 33 86 to 92 89 614
cylinder. (11) Do not breathe or use technical grade oxygen for
33 to 37 92 to 98 90 621
37 to 40 98 to 104 91 627
inhalation purposes. (12) See Compressed Gas Association
Booklets G-4 and G-4-1 for details of safe practice in the use
Allow the bomb to stand overnight to make sure there are no
of oxygen.
leaks.
6.2 n-Heptane. (Warning—See Note 4.)
NOTE 8—It has been found that pressure readings as shown above will
NOTE 4—Warning: Flammable. Harmful if inhaled. Precaution—
result in a pressure reading of 110 6 2 psi (758 6 14 kPa) when the bomb
Keep away from heat, sparks, and open flame. Keep container closed. Use
is placed in the bath in the following step, 8.3, and consequently no release
with adequate ventilation. Avoid breathing vapor or spray mist. Avoid
of oxygen will be required in most cases. This minimizes the chance of a
prolonged or repeated contact with skin.
leak developing at the valve after the overnight check for leaks has shown
the bomb to be satisfactory.
6.3 Sulfuric Acid-Chromic Acid.(Warning—See Note 5.)
NOTE 5—Warning: Causes severe burns. A recognized carcinogen. 8.3 Place the bomb in the oil bath maintained at a tempera-
Strong oxidizer; contact with organic material may cause fire. Hygro-
ture of 99 6 0.5°C (210 6 1.0°F). As the pressure rises, if
scopic. Precaution—Do not get in eyes, on skin, or on clothing. Avoid
needed, intermittently release oxygen from the bomb until a
breathing vapor or mist. Keep container closed. Use with adequate
constant pressure of 110 6 2 psi (758 6 14 k
...
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