Success Story

Optimization of Radial Forging Using Finite Element Methods

Radial forging can be used to manufacture high-performance components such as tubes and axles as well as drive and transmission shafts. Forming can be done hot, warm, or cold and ranges from primary forming and the manufacture of semi-finished products to net-shape and near net-shape qualities. The advantages of the process lie in its cost-effectiveness due to low development and tooling costs combined with high flexibility and productivity. The method also enables meeting tight tolerances for inside and outside contours and can be used for producing a wide range of geometries for tubular workpieces. The process design is currently based mainly on the experience of only a few experts.

The newly developed and optimiZed FE simulation model not only facilitates the input of simulation data, but also and more importantly reduces computing time by up to 60 %. Comparative analyses were carried out to examine the suitability of simplified two-dimensional computing models for simulating individual processes and to verify their accuracy using three-dimensional calculations. This makes it possible to further reduce simulation times for some applications and to carry out parameter studies in a faster and more cost-effective way.

Modeling of radial forging using FE methods is very time consuming due to the incremental character of this complex process. The aim of the project was thus to investigate different modeling approaches and to create an automated input interface to reduce both modeling and computing times. The informational value of the different approaches in terms of local parameters (e.g. material fl ow, tensions, strain rates) and global parameters (e.g. forming force required) was examined by verifying two- and three-dimensional calculations. An automated calculation procedure was developed to increase the efficiency of the 3D-simulation as a result of drastically reduced modeling and computing times.

The simulation models developed can be used to analyse influencing factors in different applications of incremental radial forging. The factors investigated include - among others - the influence of the contact area and rotating angle on the workpiece in in-feed and through-feed processes. The project has shown that the maximum wall thickness of a tube produced using the in-feed process can be calculated in advance based on geometric relationships.

Numerous calculations were carried out for the axial radial forming process to show the influence of different tool kinematics on the maximum achievable upset. Accurate radial guidance of the workpiece significantly extends the field of application of axial radial forming.

The project was carried out in close cooperation with the companies GFM GmbH (Steyr), voestalpine Rotec GmbH (Krieglach), Böhler Edelstahl GmbH & Co. KG (Kapfenberg), and the Chair of Metal Forming at the University of Leoben.