Title: Strategic surface topographies for enhanced lubrication in sheet forming of stainless steel

Authors: M.S. Nilsson, D.D. Olsson, I. Petrushina, J.L. Andreasen, N. Bay, E. Christensen, N.J. Bjerrum

Addresses: Topsoe Fuel Cell, Nymøllevej 66, 2800 Kgs. Lyngby, Denmark. ' FL Schmidt, R&D Centre Dania, Daniavej 49, dk-9550 Mariager, Denmark. ' Department of Chemistry, Technical University of Denmark, Bldg. 407, dk-2800 Kgs., Lyngby, Denmark. ' Novo Nordisk, Brennum Park 20BS.41, dk-3400 Hilleroed, Denmark. ' Department of Mechanical Engineering, Technical University of Denmark, Building 425, dk-2800 Kgs, Lyngby, Denmark. ' Department of Chemistry, Technical University of Denmark, Bldg. 407, dk-2800 Kgs. Lyngby, Denmark. ' Department of Chemistry, Technical University of Denmark, Bldg. 407, dk-2800 Kgs. Lyngby, Denmark

Abstract: Strategic stainless steel surfaces have been developed for which the tribological properties are significantly improved for sheet-metal forming compared with the as-received surfaces. The improvements have been achieved by modification of the surface to promote Micro-Plasto Hydrodynamic Lubrication (MPHL) by increasing the ratio of closed lubricant pockets and modifying the pocket geometry. These factors influence the retention and subsequent escape of lubricant during forming thus enhancing lubricant permeability to the contact between flattened workpiece asperities and contacting tool. The technique, which has been developed, is based on an electrochemical treatment changing the topography of the stainless steel surface. Comparative testing of the new surface topographies in ironing and deep drawing of stainless steel sheet shows significant improvements and possibilities of replacing chlorinated paraffin oils with environmentally friendly plain mineral oil.

Keywords: sheet metal forming; tribology; surface engineering; liquid lubricants; lubrication mechanism; ironing; deep drawing; MPHL; micro-plasto hydrodynamic lubrication; surface topography; stainless steel; electrochemical treatment.

DOI: 10.1504/IJSURFSE.2010.029630

International Journal of Surface Science and Engineering, 2010 Vol.4 No.1, pp.68 - 79

Published online: 30 Nov 2009 *

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