TY - GEN

T1 - Investigation of pressing and ejection performance of friction-reducing powder-compaction tool coatings

AU - Behrens, Bernd Arno

AU - Brunotte, Kai

AU - Petersen, Tom

AU - Bohr, Dieter

N1 - 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.

PY - 2021/9/15

Y1 - 2021/9/15

N2 - 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.

AB - 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.

KW - DLC-coating

KW - Lubrication

KW - Metal powder compaction

KW - Powder metallurgy

UR - http://www.scopus.com/inward/record.url?scp=85124359305&partnerID=8YFLogxK

U2 - 10.37904/metal.2021.4179

DO - 10.37904/metal.2021.4179

M3 - Conference contribution

AN - SCOPUS:85124359305

SP - 759

EP - 765

BT - METAL 2021 - 30th Anniversary International Conference on Metallurgy and Materials, Conference Proceedings

T2 - 30th International Conference on Metallurgy and Materials, METAL 2021

Y2 - 26 May 2021 through 28 May 2021

ER -