Process for Improving Fatigue Resistance of a Component by Tailoring Compressive Residual Stress Profile, and Article

Author:  Kenneth W. Burris; Thomas E. Clements
Source:  US Patent 5,841,033
Doc ID:  1998070
Year of Publication:  1998
Abstract:  
A process for improving fatigue resistance of a case hardened component having a case thickness "t", subjected to one or more of rolling, sliding, abrasion, bending and pitting includes determining the magnitude of fatigue strength at surface and at a plurality of pre-selected points along thickness "t" of a component. The applied fatigue stresses acting upon the component at the surface and at the plurality of pre-selected points long thickness "t" are also determined. Then, a compressive residual stress profile is tailored from the surface to thickness "t" of the component. The compressive residual stresses at the surface and at the plurality of the pre-selected points along thickness "t" respectively have a magnitude sufficient to attain a net resultant stress which is at least 25% lower than the fatigue strength at the surface and the corresponding plurality of pre-selected points.