Hot die forging with nitrided and thermally stabilized DLC coated tools

Hot die forging with nitrided and thermally stabilized DLC coated tools

SIEGMUND Martin, KIPP Christian, PEDDINGHAUS Julius, BRUNOTTE Kai, BRÄUER Günter, BEHRENS Bernd-Arno

Abstract. Hot forging dies are subjected to high loads, which can lead to early tool failures. Abrasive wear, plastic deformation and thermal softening of the surface layer can be counteracted in particular by a high surface hardness. Thermochemical diffusion treatments and coatings are established as wear protection measures. DLC coatings, which feature excellent frictional properties and high hardness, are commonly applied on cold forging tools. However, the low coating adhesion to steel and the thermal stability of the diamond bond limit the current range of application. In this study, DLC coatings are applied in metallic treatment atmospheres with the aim of increasing the diamond bond’s temperature resistance. Furthermore, the influence of weak and intense nitriding to coating adhesion is investigated to reduce coating delamination. A pre-selection of modified DLC coatings for hot forging dies was carried out on the basis of hardness and scratch tests. The most promising tungsten DLC coating was tested in serial forging tests. Based on tool contour comparisons before and after forging, the potential as a wear protection measure for hot forging dies was determined. Tool wear was reduced by up to 29 % after 100 forging cycles with the tungsten DLC coating compared to the nitrided reference.

Keywords
Hot Die Forging, Wear, Nitriding, Coating, Tool Life, Diamond-Like Carbon

Published online 4/19/2023, 8 pages
Copyright © 2023 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: SIEGMUND Martin, KIPP Christian, PEDDINGHAUS Julius, BRUNOTTE Kai, BRÄUER Günter, BEHRENS Bernd-Arno, Hot die forging with nitrided and thermally stabilized DLC coated tools, Materials Research Proceedings, Vol. 28, pp 583-590, 2023

DOI: https://doi.org/10.21741/9781644902479-63

The article was published as article 63 of the book Material Forming

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

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