Title: Influence of material structure on deep hole machinability of super high strength steels: application to crankshaft manufacturing

Authors: Anne Bomont-Arzur, Mario Confente, Olivier Bomont, Emmanuel Schneider, Christophe Lescalier

Addresses: Mittal Steel Europe R&D, Amneville 57 360, France. ' Mittal Steel Europe R&D, Amneville 57 360, France. ' CER ENSAM, Technopole de Metz, 4 rue Augustin Fresnel, Metz 57070, France. ' CER ENSAM, Technopole de Metz, 4 rue Augustin Fresnel, Metz 57070, France. ' CER ENSAM, Technopole de Metz, 4 rue Augustin Fresnel, Metz 57070, France

Abstract: The gain of productivity in machining is generally sought through tools and/or cutting conditions optimisation however an increase in productivity is achievable too through the work-material optimisation. The metallurgical structure as well as the chemical composition of steels widely influences their ability to be machined. Mittal Steel Europe Research and Development (R&D) develops new steel grades such as the Super High Strength Steels whose tensile stresses may reach 1000 or 1200 MPa. A cooperative research programme between Mittal Steel Europe R&D and ENSAM tends to propose a methodology able to sort the steel grades in terms of ability to be manufactured (in forging and machining). This study focuses on such an industrial application: the heavy vehicles crankshaft manufacturing. The operation investigated consists in deep hole drilling of the crankshaft lubrication holes. This paper proposes some relevant criteria to compare the different steel grades and/or structures. Some experimental results are proposed.

Keywords: super high strength steel; SHSS; bainite; machinability; deep hole drilling; crankshaft manufacturing; tensile stress; heavy vehicles; lubrication holes.

DOI: 10.1504/IJMMM.2007.013789

International Journal of Machining and Machinability of Materials, 2007 Vol.2 No.2, pp.282 - 298

Published online: 28 May 2007 *

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