Manufacturing and Tribological Investigation of Hot Micro-Coined Lubrication Pockets


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Friction and wear of lubricated machine elements can be reduced by the introduction of lubrication pockets produced by surface texturing. Different manufacturing methods can be taken into consideration whereas a forming process offers the possibility for mass production. Hot micro coining is a forming process, which allows manufacturing of surface textures with different shapes and dimensions into a flat and deformable material, e.g. seals made of steel. In this work hemispherical and ellipsoid pockets with a maximum depth of 100 µm have been embossed into stainless steel (AISI 304). To ensure that the used process parameters will not lead to tool damage, Finite Element simulations were performed and experimentally verified. First tribological experiments were conducted on a ball-on-disk tribometer in order to study the tribological properties of hemispherical structures with pockets depths of 50 and 100 µm. Different sliding velocities were applied to study the coefficient of friction and wear volume for different lubrication conditions. A comparison between coined and not‑coined specimens demonstrates that the micro coined surface textures lead to a significant reduction in the wear volume at boundary and mixed lubrication conditions.



Key Engineering Materials (Volumes 611-612)

Edited by:

Jari Larkiola




A. Szurdak et al., "Manufacturing and Tribological Investigation of Hot Micro-Coined Lubrication Pockets", Key Engineering Materials, Vols. 611-612, pp. 417-424, 2014

Online since:

May 2014




* - Corresponding Author

[1] I. Etsion, Improving tribological performance of mechanical components by laser surface texturing. Tribology Letters (2004) Vol. 17 No. 4, pp.733-737.


[2] A. Ramesh, W. Akram et al, Friction characteristics of microtextured surfaces under mixed and hydrodynamic lubrication. Tribology International (2013) 57, pp.170-176.


[3] A. Hoppermann, M. Kordt, Tribologische Optimierung durch laserstrukturierte Kontaktflächen. Ölhydraulik und Pneumatik (2002) 46, pp.560-564.

[4] M. Wakuda, Y. Yamauchi et al, Effect of surface texturing on friction reduction between ceramic and steel materials under lubricated sliding contact. Wear (2003) 254, pp.356-363.


[5] H. Ike, Surface deformation vs. bulk plastic deformation - a key for microscopic control of surfaces in metal forming. Journal of Materials Processing Technology (2003) 138, pp.250-255.


[6] M. Thome, G. Hirt, B. Rattay, Metal Flow and Die Filling in Coining of Micro Structures with and without Flash. Advanced Materials Research (2005) 6-8, pp.631-638.


[7] J. Böhm, A. Schubert, T. Otto, T. Burkhardt, Micro-metalforming with silicon dies. Microsystem Technologies (2001) 7, pp.191-195.


[8] K. Zhao, B. Wietbrock, G. Hirt, Numerical and Experimental Analysis of Closed Die Micro Warm Coining of Stainless Steel. Proc. 10th Int. Conf. Techn. Plast. (ICTP) (2011) pp.133-138.


[9] A. Szurdak, G. Hirt: submitted to Steel Research International (2013).

[10] Information on http: /www1. rz. rwth-aachen. de/manuals/ABAQUS/Documentation/docs/v6. 11.

[11] DIN EN ISO 4957 (2001).