Residual stresses in rolling contact

Abstract

The paper reports an experimental investigation into the residual strsses induced into cylndrical discs by the action of rolling-contact loads sufficiently high to cause some plastic deformation in the near-surface layers. A general method is first described for finding both circumferential and axial components of residual stress in cylindrical bodies in circumstances where the stresses vary with the radial co-ordinate only. This method is believed to be an improvement on previous methods for separating the two components of residual stress, particularly where only specimens of restricted length are available. For example, the method could be applied to thick-walled tubes. Measurements have been made of the residual stresses due to rolling contact, in pure rolling and in combined rolling and sliding. In all cases both components of residual stress were compressive and reached a maximum value below the surface at about the depth of the maximum Hertz shear stress. The measured residual stresses in the sub-surface region were roughly in agreement with the theoretical predictions of Merwin, Johnson, and Jefferis. A subsidiary peak of compressive stress was found at the surface itself. Neither the surface nor the subsurface stresses were found to be greatly influenced by the presence of friction forces when sliding accompanied rolling.