Analytical and numerical development on the indentation mechanism in a rotary hammer forging process

Abstract

Rotary hammer forging process is getting popular since it has many advantages as compared to the conventional forging process. The mechanism of the movement in terms of orbital motion of the conical upper die becomes a primary concern of this thesis. This thesis presents the three stages of the modeling of the rotary hammer forging. The first stage is the development of the orbital motion of the conical upper die. Three dimensional CAD model of the conical upper die was developed to determine the orbital motion as a function of the four parameters: Nutation, Precession, Spin and Rocking-Die mechanism. A reasonably accurate design of the conical upper die and the workpiece has been developed based on the motion as a result of interaction of conical upper die and upper part of workpiece geometries. The behavior of orbital motion with any active combination of those four parameters was observed. The second stage was the development of the conical upper die with the specific feature in order to generate a product with an unsymmetrical shape of upper part of the product. The forming sequence and mechanism of the formation of the upper part of product were generated. The third stage was the analysis of the stress strain state during the formation of the upper part of the workpiece. An elastic-plastic, dynamic analysis of 3D rotary hammer forging mechanism with the concern at the workpiece and their interaction with a model of dies have been performed. Verification of the indentation mechanism of the rotary hammer forging had been done by validating the result with the existing experimental results.