Rolling-Contact Fatigue Studies With Four Tool Steels and a Crystallized Glass Ceramic

1961 ◽  
Vol 83 (4) ◽  
pp. 603-610 ◽  
Author(s):  
Erwin V. Zaretsky ◽  
William J. Anderson

The rolling-contact fatigue properties of crystallized glass ceramic balls together with AISI M-1, AISI M-50, Halmo, and WB-49 alloy steel balls tempered to various hardness levels were determined in the NASA spin rig and in the five-ball fatigue tester. A continuous increase in fatigue life and load capacity for each steel was observed with increased ball hardness. These results correlate with resistance to plastic deformation as measured with spherical specimens in rolling contact but do not correlate with elastic limit and yield strength measured for bar specimens. These bar specimens showed optimum values at intermediate hardness levels. Extremely low scatter in fatigue life for the ceramic balls indicate that the degree of structural homogeneity may be an important factor in life scatter of bearing materials.

Author(s):  
John W. Lucek

Rolling-contact fatigue test methods were used to measure the wear performance of several silicon nitride materials. Sintered, hot pressed and hot isostatically pressed materials exhibited wear rates ranging over three orders of magnitude. Hot isostatically pressed materials had the lowest wear rates. Despite the disparity in wear performance, all materials tested had useful rolling-contact fatigue lives compared to steel. Fatigue life estimates, failure modes, and rolling wear performance for theses ceramics are compared to M-50 steel. This work highlights the rapid contact stress reductions that occur due to conformal wear in rolling-contact fatigue testing. Candidate bearing materials with unacceptably high wear rates may exhibit useful fatigue lives. Rolling contact bearing materials must possess useful wear and fatigue resistance. Proper performance screening of candidate bearing materials must describe the failure mode, wear rate, and the fatigue life. Guidelines for fatigue testing methods are proposed.


1963 ◽  
Vol 85 (3) ◽  
pp. 439-447 ◽  
Author(s):  
E. V. Zaretsky ◽  
L. B. Sibley ◽  
W. J. Anderson

The five-ball fatigue tester was used to determine the rolling-contact fatigue life of 1/2-inch-diameter M-1 steel balls with four lubricants at 300 deg F. Film thickness measurements were made with the rolling-contact disk machine under simulated five-ball test conditions. Under certain conditions, elastohydrodynamic lubrication was found to exist at initial maximum Hertz stress levels up to 800,000 psi. There appears to be a correlation among the following variables: Plastically deformed profile radius of the ball specimen at ambient temperature; lubricant type; and rolling-contact fatigue. No correlation was found between contact temperature obtained with different lubricants and fatigue life.


1970 ◽  
Vol 92 (4) ◽  
pp. 557-564 ◽  
Author(s):  
R. K. Kepple ◽  
E. R. Mantel ◽  
O. J. Klingenmaier ◽  
R. L. Mattson

A new approach to the material cleanliness problem in rolling contact fatigue involving the use of hardened electrolytically deposited iron (or iron-nickel alloy) is discussed. It was demonstrated that the fatigue strength of surfaces prepared by case hardening electrodeposited iron or iron–4 percent nickel can be equivalent to the best of commercial rolling element bearing materials. Three base materials to which the plated material was applied were investigated. These covered a broad range of quality. The associated deposit thickness problem was investigated. Excellent fatigue properties were obtained if the deposit thickness was great enough to avoid fatigue development in the base material. With deposit thicknesses less than this amount, some improvement in fatigue life was obtained over that of the unplated base material.


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