SURFACE DURABILITY OF CASE-HARDENED NICKEL-CHROMIUM STEEL ROLLERS UNDER PURE ROLLING AND SLIDING-ROLLING CONTACTS

Rolling contact fatigue tests were performed under sliding-rolling and pure rolling contacts using case-hardened steel rollers with three different case depths as models of gear tooth surfaces to study the surface durability and the optimum design condition of surface-hardened steel gears. The test results in conjunction with the subsurface shear stresses indicated that the relations between the rolling fatigue lives and the maximum amplitudes of the ratio of orthogonal shear stress to Vickers hardness may be used as a measure of surface strength. Using these relations the optimum case depths for surface durability at various relative radii of curvature were calculated for sliding-rolling and pure rolling contacts. © 1979.