Pro­ject Re²Pli

Ini­tial situ­ation

Press-hardenable steels have been used to produce high-strength structural components in lightweight automotive construction since the mid-1980s. Since then they have played an important role in meeting increasingly stringent safety regulations and climate targets. The number of components manufactured per year has been rising steadily since the process was introduced. While 3 million parts per year were manufactured in 1987, the number of manufactured parts in 2017 is already estimated at 300 million. Modern automotive bodies have a share of press-hardened components in the total mass of the BIW of up to 40%. This highlights the relevance of the process to the automotive industry and the importance it has in producing lightweight, durable body components.
In the industrial press hardening process, the blanks are usually heated in a continuous furnace, such as the roller hearth furnace. Due to the heat transfer in the oven in the form of radiation and convection, heating times of up to 5 minutes are required to heat the blanks to a temperature of 950°C. The blanks are then heated to the required temperature. To ensure that sufficient blanks are available to maintain the press cycle, the furnaces must be designed to be correspondingly long. This results in typical furnace lengths of more than 40m. In addition, roller hearth furnaces have long heating and cooling times on the one hand, and on the other, strong temperature fluctuations can damage the ceramic rollers used to transport the piece goods. For this reason, the furnaces often continue to be heated even during a production stoppage in order to ensure smooth operation. This leads to high energy requirements even when a production line is at a standstill.



Induction heating offers many advantages here as an alternative to the conventional roller hearth furnace. Due to the heat generated directly in the component, higher heating rates and better efficiencies can be realized than with heat transfer by convection and radiation. This makes induction a space-saving and energy-efficient process for heating steel components. The process is therefore already finding industrial application in the melting, forging and heat treatment of components. However, the potential of induction for heating sheet blanks in the press hardening process has also been increasingly investigated in recent years. A major focus of these investigations is the influence of induction heating on the homogeneity of the heating and the component properties of the sheet metal blanks.


In order to obtain industry-relevant, representative results, this innovative manufacturing process, the associated manufacturing plant and the required infrastructure are to be examined and tested in a real environment. To this end, they will be integrated into the Neue Mobilität OWL (New Mobility East Westphalia-Lippe) experimental space, which will also enable their early alignment with future working and also living conditions. The cluster initiative New Mobility OWL (NeMo.OWL) has set itself the goal of integrating research fields that have so far been considered in isolation - "mobility research", "vehicle concepts", "energy systems" and "digital ecosystems" - in an experimental space. The aim is to make highly efficient technologies for sustainable protection of the climate and natural resources feasible. The provision and management of supply and demand of sustainable energies for manufacturing processes, everyday life and mobility in the experimental space is the subject of the energy platform. Here, various promising technology paths, such as hydrogen technology and the coupling of electricity and heat systems, are being investigated. Sector coupling is also particularly attractive in this context, as the share of renewably generated electricity in the Paderborn district was already over 100% in 2018 [HSH18]. The entire experimental space is mapped in a digital ecosystem, which enables the planning, coordination and operation of the overall system. Based on the research results, the development of new products can thus take place in a complete system environment, so that the interaction of a new product with its system environment can be incorporated into the development process. This leads to innovative, tailor-made products and thus to high utilization and implementation potentials. More than 50 network partners under the leadership of the University of Paderborn have come together so far to make the New Mobility OWL a showcase project for NRW through experiments and applications.


Re­search Goals

Construction of a production line for press hardening of sheet metal components with inductive heating and manufacture of demonstrator components
The aim is to demonstrate the suitability of the overall concept for series production. The production line is to be designed with energy efficiency in mind. The advantages of an induction plant in terms of space requirements are to be exploited to enable the most effective plant layout possible, taking into account transport, heating and forming.

Implementation of the production line in the experimental space New Mobility OWL
Using a virtual twin of the energy system of the entire experimental space, an optimization algorithm is modeled, which represents an energy management system for coordinating the power flows. This should enable an optimal utilization of regenerative energies based on the current and future weather situation, available energy storage and the production plan. In addition, the energy infrastructure of an inductively operated press hardening line is to be developed. This will be implemented in the regenerative energy network of Neue Mobilität OWL on the basis of the energy management system.

Determination of business and operating models for an inductively operated press hardening line
Closely linked to the energy management system, operating modes for plant operation are to be determined here. The aim is to develop a system which, in communication with machine sizes, energy management and order situation, enables optimized, energy-efficient and economical production of components.

Balance sheet analysis of an inductively operated press hardening line
The energy and raw material requirements for the production of components are also to be determined and compared with existing production methods. The aim is to demonstrate the ecological and economic advantage of a production line powered by regenerative electricity over the use of fossil fuels. In line with the increasing demand for supply chain responsibility, upstream processes for providing the necessary resources are also to be taken into account.