High-strength sheet steel is usually formed by press hardening. The sheet is first given a protective coating, which is often made of Zn or AlSi. However, this layer often causes cracks to form in the workpiece, which have a negative effect on the service life of the component. The aim of the Neue Materialien Bayreuth and Formtech Werkzeug- und Formenbau GmbH project was to develop new or customized coating materials for the protective layer on high-strength sheet metal during press hardening.
The new approach is to use thermal spraying as a coating process. This enables the production of new coating materials during the coating application process. By melting different materials, specific alloys can be produced for in-situ coating. This means that a significantly larger number of materials are available for coating. The use of thermal spraying opens up even greater potential if the metallic protective layers are custom alloyed for the sheet metal to be coated. The materials developed in the project are based on the modification of Al-Si-X materials, with which the thermal and mechanical protective properties of the high-strength sheet metal can be improved both during forming and in the finished component. The new protective coatings and the use of thermal spraying open up the way to an increased service life for high-strength steels and thus create the conditions for extended applications.