| The main objective of this research is the optimization of a new preform die design for any rotating part, which can increase the minimum effective plastic strain in the Dead Metal Zone for strain homogenizing. This leads to the improvement of mechanical properties of the rotating part. Another concern of this research is optimizing the Zener-Hollomon parameter in order to study the grain structure of the part. Furthermore, the die filling and die contact in the final stage for the chosen preform that satisfied the requirement for obtaining uniform plastic strain is verified. Through experimentation, the theoretical results obtained via finite volume method for the growth of the height, diameter, and filling of the die are validated.;Many different preforms were designed to analyze the effective plastic strain, in order to find the highest value for minimum effective plastic strain and the minimum range (difference between maximum and minimum) for effective plastic strain in the workpiece and to obtain the final product in one, two, or three stages.;For further analysis of these preforms, with respect to other influencing factors, a non-linear regression was performed to determine which of the three factors---die temperature, work piece temperature and friction factor---was most influential in increasing the minimum effective plastic strain.;The study concludes that a two stage preform with a flat lower die and an upper die having a protruding cone with a 10° base angle is best in terms of increasing the minimum strain and decreasing the range of difference for strain. This leads to uniform distribution of effective plastic strain in the workpiece. This preform die design displays good filling in the final stage, the handling of the workpiece is easy (since it is processed in three stages), and the die is safe to work with.;The sensitivity analysis performed, concludes that the friction factor is the most significant factor in increasing the minimum effective plastic strain and reducing the range. The error between the results of the Finite Volume Method simulation and the experimental results in relation to matching the heights and diameters is very small. |
