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Effect of lubricant extreme-pressure additives on surface fatigue life of AISI 9310 spur gearsSurface fatigue tests were conducted with AISI 9310 spur gears using a formulated synthetic tetraester oil (conforming to MIL-L-23699 specifications) as the lubricant containing either sulfur or phosphorus as the EP additive. Four groups of gears were tested. One group of gears tested without an additive in the lubricant acted as the reference oil. In the other three groups either a 0.1 wt % sulfur or phosphorus additive was added to the tetraester oil to enhance gear surface fatigue life. Test conditions included a gear temperature of 334 K (160 F), a maximum Hertz stress of 1.71 GPa (248 000 psi), and a speed of 10,000 rpm. The gears tested with a 0.1 wt % phosphorus additive showed pitting fatigue life 2.6 times the life of gears tested with the reference tetraester based oil. Although fatigue lives of two groups of gears tested with the sulfur additive in the oil showed improvement over the control group gear life, the results, unlike those obtained with the phosphorus oil, were not considered to be statistically significant.
Document ID
Document Type
Technical Publication (TP)
Scibbe, H. W.
(NASA Lewis Research Center Cleveland, OH, United States)
Townsend, D. P.
(NASA Lewis Research Center Cleveland, OH, United States)
Aron, P. R.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 5, 2013
Publication Date
December 1, 1984
Subject Category
Mechanical Engineering
Report/Patent Number
NAS 1.60:2408
Accession Number
Funding Number(s)
PROJECT: RTOP 505-40-42
Distribution Limits
Work of the US Gov. Public Use Permitted.
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