Gradient Speed Control Method to Reduce the Residual Stress on a Turbine Disk in Forging Process

Abstract

The distribution of the residual stress on the turbine disk is affected by the forging process. The residual stress will reduce fatigue life of the turbine disk and increase the assemble error to meet the production. And the process parameters such as forging speed, forging temperature and friction will all affect the residual stress. In order to reduce the residual stress and improve the service life of the turbine disk, the relationship between the forging speed and residual stress on the turbine disk in the forging process was studied in this paper. By the combination of numerical simulation method and the forging process test, the numerical model of the forging process for the superalloy turbine disk was established, and the relationship between the residual stress distribution and forging speed was analyzed and calculated. Based on this, a gradient speed control method for reducing residual stress of the turbine disk was proposed. The calculation results showed that the gradient speed controlling in the forging process of the turbine disk effectively reduced the residual stress, decreased the usage and fee of the energy, and improved the service life of the turbine disk. According to the geometrical characteristics of the turbine disk, the gradient forging speed range was designed and optimized in this research. The results show that the residual stress of the turbine disk can be greatly reduced by the optimized gradient speed control method, which is a feasible way to reduce the residual stress of the superalloy turbine disks in the forging process.