An investigation for control of residual stress in roller-straightened rails

Abstract

The cold roller straightening operation is the most critical process for the development of residual stress in rails during manufacturing. Knowledge of the residual stress in ‘as-manufactured’ rails is important for evaluation of the fatigue behaviour of rails during actual use. While experimental investigations have been reported on the induced residual stress in rails, the formulation of an appropriate simulated model for computation of the residual stress generated during the roller straightening process is still in the developmental stage. In the present investigation, an attempt has been made to develop a simulated model using the finite element (FE) method to evaluate the residual stress and to reduce its magnitude by controlling the relevant parameters of the straightening operation. The straightness of the finished rail has also been examined, and a suitable procedure for examination of the straightness of finished rails is indicated. Process parameters are recommended for reducing the residual stress in ‘as-manufactured’ rails while maintaining their straightness within specified limits.