Title: Influences of lubricant pocket geometry and working conditions upon micro-lubrication mechanisms in upsetting and strip drawing

Authors: Ichiro Shimizu, Paulo A.F. Martins, Niels Bay, Jan L. Andreasen, Jakob I. Bech

Addresses: Graduate School of Natural Science and Technology, Okayama University, 3-1-1, Tsushima-naka, Okayama 700-8530, Japan. ' Instituto Superior Tecnico, TULisbon, Departamento de Engenharia Mecanica, Av. Rovisco Pais, 1049-001 Lisboa, Portugal. ' Department of Mechanical Engineering, Technical University of Denmark, Building 425, dk-2800 Kgs, Lyngby, Denmark. ' Novo Nordisk, Brennum Park 20BS.41, dk-3400 Hilleroed, Denmark. ' Materials Research Department, Risoe-DTU, Building afm-228, 4000 Roskilde, Denmark

Abstract: Micro-lubricant pockets located in the surface of plastically deforming workpieces are recognised to improve the performance of fluid lubrication in a metal-forming process. This work investigates the joint influence of pocket geometry and process working conditions on micro-lubrication mechanisms, during upsetting and strip drawing, by means of a rigid-viscoplastic finite-element formulation. Special emphasis is placed on the effect of pocket geometry on the build-up of hydrostatic pressure, which is responsible for the onset of micro-lubrication mechanisms. A good agreement is found between the numerically predicted and the experimentally measured distributions of hydrostatic stress.

Keywords: metal forming; tribology; liquid lubrication; lubrication mechanism; lubricant pocket geometry; finite element analysis; FEA; upsetting; strip drawing; microlubrication; hydrostatic pressure.

DOI: 10.1504/IJSURFSE.2010.029628

International Journal of Surface Science and Engineering, 2010 Vol.4 No.1, pp.42 - 54

Published online: 30 Nov 2009 *

Full-text access for editors Access for subscribers Purchase this article Comment on this article