Hot die forging with nitrided and thermally stabilized DLC coated tools

authored by: Martin Siegmund, Christian Kipp, Julius Peddinghaus, Kai Brunotte, Günter Bräuer, Bernd Arno Behrens
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.
Organisation(s): Institute of Metal Forming and Metal Forming Machines
External Organisation(s): Technische Universität Braunschweig
Type: Conference contribution
Pages: 583-590
No. of pages: 8
Publication date: 19.04.2023
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Materials Science(all)
Electronic version(s): https://doi.org/10.21741/9781644902479-63 (Access: Open)
: Details in the research portal "Research@Leibniz University"

BibTeX

@inproceedings{5fd074d77c534df8947e3bdeb42888ae,
title = "Hot die forging with nitrided and thermally stabilized DLC coated tools",
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{\textquoteright}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 = "Coating, Diamond-Like Carbon, Hot Die Forging, Nitriding, Tool Life, Wear",
author = "Martin Siegmund and Christian Kipp and Julius Peddinghaus and Kai Brunotte and G{\"u}nter Br{\"a}uer and Behrens, {Bernd Arno}",
note = "Funding Information: The results presented were obtained in the research project “Investigations on the application of metal containing DLC-coatings as wear protection systems for forging dies” financed under project number 283898001 by the German Research Foundation (DFG). The authors would like to thank the German Research Foundation for the financial support.; 26th International ESAFORM Conference on Material Forming, ESAFORM 2023 ; Conference date: 19-04-2023 Through 21-04-2023",
year = "2023",
month = apr,
day = "19",
doi = "10.21741/9781644902479-63",
language = "English",
isbn = "9781644902462",
series = "Materials Research Proceedings",
publisher = "Association of American Publishers",
pages = "583--590",
editor = "Lukasz Madej and Mateusz Sitko and Konrad Perzynsk",
booktitle = "Material Forming",
}