FED-STD-791D
Method 3452.2
September 30 1986
BEARING COMPATIBILITY OF TURBINE OILS
1. SCOPE
1.1 This method is used for determining the bearing compatibility (lacquering,
deposits, and corrosion) and stability of MIL-L-17331 turbine lubricating oils when
subjected to an endurance test.
2. SUMMARY
2.1 A Journal is operated at specified speed in a babbitt metal bearing lubricated
with the test lubricant for 200 h; examining the test bearings and checking the lubricant
for changes in viscosity, total acid number, and carbon residue; and computing the work
factor from the changes noted.
3. SAMPLE SIZE
3.1 4 L (1 gal) of the oil to be used in each test. (An additional 20 L (5 gal)
should be on hand for use in repeating the 3-L (3-qt) flushing procedure as required.)
4. REFERENCES, STANDARDS, AND APPARATUS
4.1 Test equipment illustrated schematically in Figure 1 consist of:
a. Journal (H), shaft material, 4340 steel, 2.750-inch diameter (at bearing surfaces)
and hardened to a Rockwell "C" hardness of 40-45, finish ground not to exceed
0.041 m (16 in) rms.
b. Bearings (I, J, and K) babbitt metal in split bearing housing (to accommodate
journal), size 6.9886-6.9936 cm (2.7514-2.7534 in) (vertical diameter when
installed) by 4.60 cm (1-13/16 in) long. (Bearings should be free of scratches
or other blemishes). The bearing material over steel backing is 0.013 to 0.025
cm (0.005 to 0.010 in) thick tin base babbitt (SAE 12 babbitt); composition as
per SAE standard 1460 is: Sn, 88.25% (minimum); Sb, 7.0-8.0%; Pb, 0.50%
(maximum); Cu, 3.0-4.0% (maximum); Fe, 0.08% (maximum); As, 0.10%
(maximum); Bi 0.08 (maximum), Zn, 0.005 (maximum); Al, 0.005 (maximum);
and others 0.20 (maximum) total. Bearings of this size and composition may be
obtained from Mogul-Bower Bearings, Incorporated, Detroit 13, Michigan
under the following part numbers: Upper half B-10994, Lower half B-10995.
c. Loading Device (O), hydraulic cylinder or other suitable unit capable of
maintaining a load of 1520 20 gage kPa (220 3 psig) of projected bearing
area on the loading bearing (j). (This loading equivalent to approximately 4,400
N [1000-lb force] on the loading yoke.)
d. Drive unit (f), to drive journal at a speed of either 1750 or 3500 rpm.
202
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business