Publication Date:
2019-07-13
Description:
Ball bearings with lead- and lead-alloy-coated retainers were operated in liquid hydrogen at 30,000 rpm under a thrust load of 400 lb. Bearing lives were compared using different: (1) lead- and lead-alloy coatings, (2) coating thicknesses, (3) substrate materials, (4) retainer locating surfaces, and (5) plating techniques. Longer bearing run times were achieved using retainers with a lead-tin-copper alloy coating electroplated onto a leaded-bronze material and an aluminum-bronze alloy. Thirty percent of the bearings tested achieved the desired objective of 10 hours. All of the lead-alloy coated retainers exceeded this objective. A coating thickness of at least 0.0014 in. was used for all bearings exceeding the 10-hour goal.
Keywords:
MACHINE ELEMENTS AND PROCESSES
Type:
NASA-TM-X-68268
,
E-7573
,
Joint Lubrication Conf; Oct 16, 1973 - Oct 18, 1973; Atlanta GA; United States
Format:
application/pdf
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