Description
P 1249 – Increasing the wear resistance of forging tools by using an intelligent hot-working steel combined with a material-specific nitriding treatment
Forging tools made of this intelligent hot work tool steel have a strong wear resistance in surface areas exposed to high thermomechanical stress. This effect can be explained with the mechanism of cyclic surface layer hardening specific to this alloy, providing continuous wear protection for the highly thermomechanically stressed areas. The thermal loads vary throughout the tool, which locally limits the increase in wear protection. The research project’s goal was to increase the wear resistance of forging tools by using an intelligent hot work tool steel combined with a nitriding treatment specific to this alloy.
In this research project the forging tools made of intelligent hot work tool steel underwent a nitriding surface treatment to reduce the wear in the less thermomechanically stressed tool areas, providing a global increase in wear resistance. Besides characterizing the microstructural transformation and material behaviour, the research project focused on developing a nitriding treatment specific to the intelligent hot work tool steel as well as determining the performance of surface-treated forging tools made of intelligent hot work tool steel in model experiments and under industrial conditions.
Cyclical hardening of the tool edge layer is demonstrated in series forging tests after the nitriding zone has depleted due to wear. Areas with thermomechanically insufficiently stress are protected from wear by the nitriding zone. In industrial processes, nitrided tools made of the modified hot work tool steel predominantly achieve tool lives comparable to reference tool steels. Crack formation in the tool contour is considered to be the main cause of tool failure.
The results help to efficiently combine the mechanism of cyclic surface layer hardening with a nitriding treatment. Small and medium-sized companies in the steel manufacturing and processing industry are given the opportunity to increase their knowledge base, to develop novel materials and tools specifically for the metal forming process, to introduce new products to the market and to profit from the results in terms of an effective wear protection technique leading to a longer tool service life in hot bulk metal forming.
Published in:
2021
Authors:
Prof. Dr.-Ing. B.-A. Behrens, Prof. Dr.-Ing. H. J. Maier
