Cylindrical Grinding of Nitrided Steels: Grindability, Specific Energy, Temperatures, Residual Stresses and Fatigue Failure

An investigation was made into plunge and traverse cylindrical grinding of nitrided steels in an industrial case involving premature fatigue failure due to residual stresses. The effect of nitriding on grindability was analyzed via specific-energy measurements. Residual stresses were analyzed, including: (1) compressive, from nitriding, with discussion on how this alters stress measurements in practice; (2) compressive, from plastic deformation from grinding; and (3) tensile, from thermal effects in grinding, including the alteration of the nitriding compressive effect. A thermal model was developed to predict surface temperatures in grinding — which were correlated to residual tensile stress measurements — allowing the reduction of stresses and the elimination of fatigue failure.