Prediction of Microstructure and Resulting Rolling Forces by Application of a Material Model in a Hot Ring Rolling Process

Abstract

Ring rolling is a versatile incremental bulk forming process. Due to the incremental character of the process, it consists of a large number of deformation and dwell steps. Finite element (FE) simulations of bulk forming processes are capable of predicting loads, stresses and material flow. In recent years, the finite element analysis of ring rolling processes has become feasible both in terms of calculation time as well as regarding the closed loop control of the kinematic degrees of freedom [1]. Accordingly, the focus of interest now includes the prediction of the microstructure evolution. The accuracy of such numerical simulations strongly depends on the models characterizing the material behavior and boundary conditions. In this paper, a finite element based simulation study was conducted, in order to evaluate the impact of boundary conditions such as transfer time, radiation, heat transfer and friction on the target values of the ring rolling process. The results of the simulation study were compared to ring rolling experiments on an industrial size ring rolling device. A good accordance regarding the evolution of the outer diameter and radial force was observed. Strong contingencies of transfer time on the forces throughout the process were detected and considered in the simulation study. In a post processing step, the evolution of the microstructure considering the dynamic and static recrystallization as well as the grain growth was calculated using the FE results. The calculated grain sizes show good accordance with the experimentally observed microstructure of the ring before and after the rolling. Furthermore, the impact of process parameters on the evolution of the grain size was investigated.

Data based model predictive control for ring rolling

“…Texture evolution during the process of cold ring rolling has been invetigated by Ryttberg et al [9]. The simulation of the evolution of the microstructure in ring rolling of steel has been realized by Schwich et al [10] using FEMcode DEFORM combined with a recrystallization model in post-processing. Good agreement between simulation and experimental results has been observed in this study.…”

Perceptive Review of Ferrous Micro/Macro Material Models for Thermo-Mechanical Processing Applications

“…Since 2000, several new applications of this approach have been proposed, among which simulation of forging of heavy crankshafts, simulation of welding, optimization of manufacturing of AHSS strips, and controlled cooling of rails can be recalled. As it has been mentioned, mean field models do not cause an increase of the FE computing costs and they can be used for very complex processes when millions of elements are needed in the macro scale, see modeling of ring rolling . The first two case studies mentioned above, in which high complexity macro scale mesh is needed, are described briefly below.…”

Recent development of ring rolling theory and technique

“…Besides, the modelling skill of dual mesh and hybrid mesh was used to improve the simulation accuracy and computational efficiency Ward, 2002b, 2003;Kim et al, 2013). Microstructure evolution during RARR was also tried by FE modelling methods (Yeom et al, 2010;Schwich et al, 2014;Zhu et al, 2014a). Through FE simulation, the deformation behaviour, forming laws and process parameters' effects during RARR were revealed visually (Qian et al, 2013c;Xu et al, 2013;Zhu et al, 2014b;Zhou et al, 2010aZhou et al, , 2011aZhou et al, , 2011bZhou et al, , 2012.…”