Closed die isothermal forging is a consecutive compressive process of billet to obtain the final part under the same temperature of billet and die. Usually, one or more intermediate steps are required to obtain the final desired design. The intermediate preform design steps should account for uniform material deformation without cracks, folds and underfill. Uniform material deformation can be ensured if the strain variance is minimum. Strain variance of final forged component depends on preform design and process parameters such as die temperature, billet temperature, die speed, and among others. In literature, optimal preform is obtained using different methods such as response surface method (RSM), sensitivity based optimization and geometrical resemblance. Most of the proposed methods are computationally expensive except geometrical resemblance methods. Real world application typically requires specified material properties in a specified region to increase the strength of the component. The uniformity of material deformation and the microstructure of the resulting forged component can be altered by appropriately fine-tuning the strain variance. And also, It is essential to determine the necessary number of preforms and achieve the best preform design for all intermediate processes of isothermal forging. Therefore in this work, We propose a method to obtain region specified strain variance and to obtain the required number of intermediate stages and their preform.
1. The proposed methodology envisages to obtain specific strain variance in the desired region by dividing or segmenting the design region and extracting the design response, ‘strain variance’ on those regions to a surrogate for each region and perform multi-objective optimization (MOO) to obtain a targeted strain variance.
2. we propose a method which utilizes two approaches namely geometrical resemblance and shape complexity factor to obtain the number of intermediate forgings required and their preform design for producing axisymmetric part