Significance and Use
This test method was developed using greases having very low torque characteristics at −54°C (−65°F). Specifications for greases of this type commonly require testing at this temperature. Specifications for greases of other types can require testing at temperatures from −75 to −20°C (−100 to 0°F).
This test method has proved helpful in the selection of greases for low-powered mechanisms, such as instrument bearings used in aerospace applications. The suitability of this test method for other applications requiring different greases, speeds, and temperatures should be determined on an individual basis.
Test Method D4693 may be better suited for applications using larger bearings or greater loads. However, greases having such characteristics that permit torque evaluations by either this test method or Test Method D4693 will not give the same values in the two test methods (even when converted to the same torque units) because the apparatus and test bearings are different.
1.1 This test method covers the determination of the extent to which a grease retards the rotation of a slow-speed ball bearing by measuring starting and running torques at low temperatures (below −20°C (0°F)).
1.1.1 Torque measurements are limited by the capacity of the torque-measuring equipment.
Note 1—When initially developed, the original dynamometer scale limited the torque capacity to approximately 30 000 g·cm; the original dynamometer scale is obsolete, however. The suggested replacement scale has not been evaluated; it could extend the limit to approximately 75 000 g·cm.
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only. The exception is torque values that are given in cgs-metric units, which are universally used in grease specifications.
1.3 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 and warning statements, see 6.1.1, 7.2, 7.4, 8.7, and 8.11.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
Standard 20-1987 Radial Bearings of Ball, Cylindrical, Roller, and Spherical-Roller Type--Metric Designs (AFBMA Code 20BCO2JO) Available from AFBMA (Anti-Friction Bearing Manufacturers Association), 1101 Connecticut Avenue, N.W., Suite 700, Washington, DC 20036-4303.
D4693 Test Method for Low-Temperature Torque of Grease-Lubricated Wheel Bearings
ball bearing grease; ball bearing torque; low-temperature torque; lubricating grease; torque; Ball/roller bearings (lubricating grease); Low-temperature testing; Lubricating grease; Temperature tests--petroleum products;
ICS Number Code 75.100 (Lubricants, industrial oils and related products)
ASTM International is a member of CrossRef.
Citing ASTM Standards
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