Investigation of pressing and ejection performance of friction-reducing powder-compaction tool coatings

authored by: Bernd Arno Behrens, Kai Brunotte, Tom Petersen, Dieter Bohr
Abstract: Pressing in dies followed by sintering is the most commonly used process for shaping metal powders into components. The mechanical properties (e.g. tensile and fatigue strength) of the final sintered component depend on the green-compact properties resulting from the compaction process. Apart from the powder material used, process-specific factors, such as geometry complexity, compaction pressure and lubrication strategy, have a major impact on the properties of the green compact. The lubrication strategy is also decisive for the economic efficiency of the process as it influences the service life of the tools. Friction-reducing powder-compaction tool coatings (e.g. diamond-like-carbon-based/DLC) provide the potential to positively influence the lubrication conditions during compaction and ejection, thus simultaneously improving product quality and service life. In this study, experimental investigations on the performance of friction-reducing coatings in the die pressing of steel powder (Fe + 0.6 wt% C) with and without admixed lubricant (AncorLube, GKN Hoeganaes) are presented. The results are evaluated by force-displacement measurements, which allows for a more profound analysis of compaction and ejection behaviour. It is shown that the application of the coatings reduces the ejection loads significantly when no admixed lubricant is used, and moderately when lubricant is admixed. However, without lubricant, wear still occurs after a few pressing cycles, so it cannot be completely avoided.
Organisation(s): Institute of Metal Forming and Metal Forming Machines
Type: Conference contribution
Pages: 759-765
No. of pages: 7
Publication date: 15.09.2021
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Mechanics of Materials, Surfaces, Coatings and Films, Metals and Alloys
Electronic version(s): https://doi.org/10.37904/metal.2021.4179 (Access: Open)
: Details in the research portal "Research@Leibniz University"

BibTeX

@inproceedings{ab27ac54f77e4c1c85d980e2a0e5b572,
title = "Investigation of pressing and ejection performance of friction-reducing powder-compaction tool coatings",
abstract = "Pressing in dies followed by sintering is the most commonly used process for shaping metal powders into components. The mechanical properties (e.g. tensile and fatigue strength) of the final sintered component depend on the green-compact properties resulting from the compaction process. Apart from the powder material used, process-specific factors, such as geometry complexity, compaction pressure and lubrication strategy, have a major impact on the properties of the green compact. The lubrication strategy is also decisive for the economic efficiency of the process as it influences the service life of the tools. Friction-reducing powder-compaction tool coatings (e.g. diamond-like-carbon-based/DLC) provide the potential to positively influence the lubrication conditions during compaction and ejection, thus simultaneously improving product quality and service life. In this study, experimental investigations on the performance of friction-reducing coatings in the die pressing of steel powder (Fe + 0.6 wt% C) with and without admixed lubricant (AncorLube, GKN Hoeganaes) are presented. The results are evaluated by force-displacement measurements, which allows for a more profound analysis of compaction and ejection behaviour. It is shown that the application of the coatings reduces the ejection loads significantly when no admixed lubricant is used, and moderately when lubricant is admixed. However, without lubricant, wear still occurs after a few pressing cycles, so it cannot be completely avoided.",
keywords = "DLC-coating, Lubrication, Metal powder compaction, Powder metallurgy",
author = "Behrens, {Bernd Arno} and Kai Brunotte and Tom Petersen and Dieter Bohr",
note = "Funding Information: This contribution is part of a basic research project funded by the German Research Foundation (DFG), project number 403432892. The authors would like to express their gratitude for the financial support of this project. Furthermore, the authors would like to thank GKN Sinter Metals Engineering for providing the metal powders. ; 30th International Conference on Metallurgy and Materials, METAL 2021 ; Conference date: 26-05-2021 Through 28-05-2021",
year = "2021",
month = sep,
day = "15",
doi = "10.37904/metal.2021.4179",
language = "English",
pages = "759--765",
booktitle = "METAL 2021 - 30th Anniversary International Conference on Metallurgy and Materials, Conference Proceedings",
publisher = "TANGER Ltd.",
}