ASTM D2070-91(2001)

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An American National Standard
Designation:D2070–91(Reapproved 2001)
Standard Test Method for
Thermal Stability of Hydraulic Oils
This standard is issued under the fixed designation D 2070; 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.
1. Scope are reported for informational purposes. No correlation of the
test to field service has been made.
1.1 This test method is designed primarily to evaluate the
thermal stability of hydrocarbon based hydraulic oils although
5. Apparatus
oxidation may occur during the test.
5.1 An aluminum block with equally spaced holes is used.
1.2 The values stated in SI units are to be regarded as the
An example is described in Fig. A1.1 of Annex A1.
standard.
5.2 Electric gravity convection oven capable of maintaining
1.3 This standard does not purport to address all of the
the aluminum block at a test temperature of 135°C 6 1°C.
safety concerns, if any, associated with its use. It is the
5.2.1 Calibrated thermocouple and temperature indicator
responsibility of the user of this standard to establish appro-
centered in aluminum block.
priate safety and health practices and determine the applica-
5.3 250 mL Griffin beakers of borosilicate glass.
bility of regulatory limitations prior to use.
5.4 Copper test specimens are to be UNS C11000, 99.9 %
2. Referenced Documents pure electrolytic tough pitch copper, 6.35 mm in diameter by
7.6 cm in length (0.25 in. by 3.0 in.).
2.1 ASTM Standards:
5.5 Steel test specimens are to be AISI W-1 1 % carbon
D 4057 Practice for Manual Sampling of Petroleum and
steel, 6.35 mm in diameter 7.6 cm in length (0.25 by 3.0 in.).
Petroleum Products
5.6 Silicon carbide abrasive 320 grit with cloth backing.
2.2 Copper Development Association Standard
5.7 Crocus cloth.
UNS C11000 Electrolytic Tough Pitch Copper
5.8 No. 41 Whatman filter paper, 47 mm diameter.
2.3 American Iron and Steel Institute Standard (AISI)
5.9 Millipore filter, 8 micron Type SC, 47 mm diameter.
W-1 Carbon Tool Steel
5.10 Millipore glass filter holder, 47 mm, Cat #XX10.04700
3. Summary of Test Method
or equivalent.
5.11 Cincinnati Milacron color chart.
3.1 A beaker containing test oil, copper and iron rods is
5.12 25 mL pipette.
placed in an aluminum block in an electric gravity convection
oven for 168 h at a test temperature of 135°C. At the
6. Reagents
completion of the test, the copper and steel rods are rated
6.1 Reagent Grade Heptane—(Warning— Flammable.
visually for discoloration and the oil is analyzed for the
Health hazard.)
quantity of sludge.
6.2 Reagent Grade Acetone—(Warning— Flammable.
4. Significance and Use
Health hazard.)
4.1 Thermal stability characterizes physical and chemical
7. Preparation of Apparatus
property changes which may adversely affect an oil’s lubricat-
7.1 Handletherodsatalltimesusingforcepsorcleancotton
ing performance. This test method evaluates the thermal
gloves.
stability of a hydraulic oil in the presence of copper and steel
7.2 Catalyst preparation—Clean the iron and copper cata-
at 135°C. Rod colors are the evaluation criteria. Sludge values
lyst rods, whether new or previously used, prior to use. Clean
the rods with the 320 silicon carbide abrasive cloth while
This test method is under the jurisdiction of ASTM Committee D02 on rotating the rods in a drill chuck at 1700 to 1800 r/min. Clean
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
the surface until it has a bright copper or steel appearance.
D02.N0.08 on Stability.
Discard rods when diameter is less than 6.2 mm.
Current edition approved May 15, 1991. Published December 1991.
This procedure was adopted from the Cincinnati Milacron Thermal Stability
Test, Cincinnati Milacron Manual 10-SP-89050.
3 6
Annual Book of ASTM Standards, Vol 05.02. Whatman Int. Ltd., Maidstone, England.
4 7
Available from Copper Development Assoc., 2 Greenwich Office Park, Box Millipore Filter Corp., Bedford, MA.
1840, Greenwich, CT 06836. Cincinnati Milacron, 4701 Marburg Ave., Dept 97B Lubricants and Tribology,
Available from AISI, 1133 15th St., NW, Washington, DC 20005. Cincinnati, Ohio, 45209, 513-841-8660.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D2070–91 (2001)
7.3 Prepare surface finally with a crocus cloth. Remove all mL of oil. Therefore, the weight of the original filter paper is
grindmarks.Finishtherodstoalightlypolishedsurfacefinish. subtracted from the dried filter paper plus residue and the
7.4 Wash the rods individually with acetone and air dry on difference divided by two. The weight of the sludge on the 8
completion of the polishing operation. micron Millipore filter pad is also reported as milligrams per
100mL.Theweightoftheoriginalfilterpadissubtractedfrom
8. Procedure
theweightofthedriedresidueplusfilterpadandthedifference
8.1 Place a representative 200-mL sample of test oil ob- multiplied by four. Total sludge is the summation of the sludge
tained per D4057 – 88 sampling procedure in a clean 250-mL
from the No. 41 Whatman filter paper plus the sludge from the
Griffin beaker containing one each of the cleaned and polished 8 micron filter pad. Weight of total sludge (mg/100 mL
...