Effect of Slip Condition on the Contact Fatigue Strength for Pitting of the Carburized Steel
Taizo MAKINO, Masayuki HORIMOTO and Hitoshi MATSUMOTO
Abstract:The objective of the present paper is to clarify the effect of slip condition, ie. Slip ratio, outer surface velocity, and lubrication oil temperature on the contact fatigue strength for pitting (pitting strength) of the carburized steel. Rolling contact fatigue (RCF) tests were conducted on 26mm diameter specimens made of carburized steel under oil lubrication. Then, slip ratio, outer surface velocity, and lubrication oil temperature as the slip condition were changed on the RCF tests. As a result, pitting strength decreased with the increase of slip ratio, the decrease of outer surface velocity, and the decrease of lubrication oil temperature. Furthermore, relationships between the above-mentioned three parameters, friction coefficient, and contact surface temperature were evaluated. Then slip ratio, outer surface velocity, and lubrication oil temperature influenced to friction coefficient and contact surface temperature. The friction coefficient slightly decreased when contact surface temperature increased. Lastly, it was found that the friction coefficient was main parameter which directly determines the pitting strength. Key Words:Rolling contact fatigue (RCF), Slip condition, Pitting, Carburized steel, Friction coefficient, Lubrication oil temperature, Contact surface temperature