FED-STD-791D
Method 7501
August 7 , 2006
LOW TEMPERATURE TORQUE TEST METHOD FOR LUBRICATING GREASES
1. SCOPE
1.1 This test method determines the torque values of lubricating greases using
tapered roller bearings when subjected to low temperatures. The method was developed
using greases giving torques of less than 80 N.m at -54 C.
2. APPLICABLE DOCUMENTS
2.1 Government documents.
2.1.1 Specifications. The following specification forms a part of this document
to the extent specified herein. Unless otherwise specified, the issues of these documents
shall be those listed in the issue of the Department of Defense Index of Specifications and
Standards (DODISS) and supplement thereto, cited in the solicitation (see 6.2).
SPECIFICATIONS
MILITARY
MIL-G-23827 -
Grease, Aircraft and Instrument, Gear and Actuator Screw.
(Unless otherwise indicated, copies of federal and military specifications,
standards, and handbooks are available from the Naval Publications and Forms Center,
(ATTN: NPODS), 5801 Tabor Avenue, Philadelphia, PA 19120-5099, or at
https://assist.daps.dla.mil/quicksearch/).
3. SUMMARY
3.1 A worked sample of the test grease is packed into four test specimen
assemblies which simulate the automotive front wheel bearing system. These assemblies
are mildly heated and then rotated one revolution. The test assemblies are soaked for 16
hours at -54 C. At the end of this time, the two test assemblies are rotated consecutively
at 1 rpm and both breakaway (starting torque) and torque after 5 minutes of rotation
(running torque) are then determined. The two remaining test assemblies are tested after
the additional four hours cooling to restore the test temperature.
4. SIGNIFICANCE
4.1 This method was developed to assess the low temperature performance of
greases at -54 C and clearly distinguish between differing grease formulations. The
390
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