Development of a Process Model for Online-Optimization of Open Die Forging of Large Workpieces

Abstract

The basic idea of this paper is developing process models which are online capable, i.e. which combine data from online measurements and simplified plastomechanical interrelations for the forecast of equivalent strain, equivalent strain rate and the temperature in the core of the part being forged. These models deliver the numerical basis for the forecast of the microstructures obtained. In combination with optimization methods a numerical assistant for the forging press operator can be implemented. At the Institute of Metal Forming of the RWTH Aachen University, models for the core fibre of a forged block were developed. The development of the models was based on reference solutions which were derived from FEM‐calculations. The equivalent strain and equivalent strain rate are thereby determined by the change of the geometry of the workpiece (i.e. change in length or change in height). For the determination of the temperature distribution along the core fibre an explicit Finite Difference model is used. This model considers the loss of temperature at the surface due to radiation and convection, and also the dissipation in the core fibre. For the subsequent prediction of the microstructure the module STRUCSIM, which was developed at the Institute of Metal Forming, is used. The results of the models show good agreements with the FEM‐solutions.

Fast models for online-optimization during open die forging

“…The basics of a one dimensional temperature model for the open die forging process are described in [3]. It divides the workpiece in different sections while heat transfer is only considered in one direction in each section.…”

“…As a simplification, only dynamic recrystallization is considered in the first step. As prior work showed, it is possible to describe the equivalent strain distribution after one forging pass [3]. Yet the problem is to superpose the individual strain distributions after several forging passes.…”

“…To calculate the equivalent strain after one forging stroke, some simplifications or assumptions have to be made. These assumptions are according to [3,4] (see also Fig. 1):…”

Energy-Saving Hot Open Die Forging Process of Heavy Steel Forgings on an Industrial Hydraulic Forging Press

“…The basic idea of Ref. [10] was to develop process models that would combine data from online measurements and a simplified plastomechanical model for the forecasting of the equivalent strain rate and the temperature in the core of the part being forged. In Ref.…”

Optimization of Open Die Ironing Process through Artificial Neural Network for Rapid Process Simulation

“…In the past, some authors dedicated to the development of fast models oriented to open die forging process optimization [26][27][28][29][30]. The common idea at the base of the above works was to develop process models able to combine data from online measurements and a simplified plasto-mechanical model for the forecasting of the equivalent strain, strain rate, and the temperature in the core of the forged piece.…”