A new process should allow complex preform operations to be greatly simplified or even omitted in future. Scientists at the IPH are planning to use non-uniform heating to shorten the forging process and save energy and resources.
In future, preform operations in forging will be replaced by non-uniform heating.
Ralf Büchler/IPH
Preform operations are used to approximate the mass distribution of a blank to the desired forging in order to reduce the amount of flash and wearing of the die. A new process currently being researched at the Institut für Integrierte Produktion in Hanover (IPH) gGmbH aims to shorten or even completely eliminate such preform operations. In this process, the blank is non-uniformly heated by induction and then upset in order to approximate the component's mass distribution.
Induction has long been used in forging, but only for uniform or partial heating of components up until now. The special feature of this new process is the use of non-uniform heating. This means that although the blank is heated all over, some areas are heated to 900°C, for example, while others are heated to 1,250°C. This allows more mass to be accumulated in the warmer area than in the colder areas during the upsetting process. In this case, the transition area between the warmer zones and colder zones is of particular interest.
Stable transition area
In pilot testing, scientists identified key figures that characterise the transition area. This allows the researchers to investigate parameters that will allow them to adjust the transition area as precisely as possible later in practice. Ideally, this area is small and stable, with a large change in temperature. However, one problem may be that the areas with different temperatures converge too rapidly so that no clear separation between the zones can be maintained. Using a common rail, a fuel-injection component for a combustion engine, the scientists intend to investigate how a non-uniformly heated microstructure behaves during forging. Later, the process could also be applied to other components from the automotive industry, for example.
In order to determine the benefits of the new method, scientists at the IPH compared the use of non-uniform heating in different process chains with cross wedge rolling. This included checking whether free upsetting can be omitted as an intermediate step, allowing the non-uniformly heated blank to be forged directly. In this case, the new method would allow industry to produce components far more quickly, energy-efficiently and economically.