2009 yallese cbn hard turning

journal of mat erials pro cessing te chnology 20 9 (2 00 9) 1092–1104 journal homepage: www.elsevier.com/locate/jmatprotec Hard machining of hardened bearing steel using cubic boron nitride tool Mohamed Athmane Y allese a , Kamel Chaoui b,∗ , Nassereddine Zeghib b , Lakhdar Boulanouar b , Jean -Franc ¸ ois Rigal c a Laboratoire de M ´ ecanique et des Structures (LMS), 8 May 1945 University, P.O. Box 401, Guelma 24000, Algeria b Laboratoire de Recherche M ´ ecanique des Mat ´ eriaux et Maintenance Industrielle (LR3MI), Badji Mokhtar University, P.O. Box 12, Annaba 23000, Algeria c Laboratoire de M ´ ecanique des Contacts et des Solides (LaMCoS) INSA of Lyon, 20 Albert Einstein Avenue, 69621 Villeurbanne Cedex, France a r t i c l e i n f o Article history: Received 11 July 2007 Received in revised form 7 March 2008 Accepted 15 March 2008 Keywords: Hard turning Hardened steel Cubic boron nitride Wear Roughness Cutting forces a b s t r a c t In many cases, hard machining remains an economic alternative for bearing parts fabrica- tion using hardened steels. The aim of this experimental investigation is to establish the behaviour of a CBN tool during hard turning of 100Cr6-tempered steel. Initially, a series of long-duration wear tests is planned to elucidate the cutting speed effects on the vari- ous tool wear forms. Then, a second set of experiments is devoted to the study of surface rou ghn ess , cutting for ces and temper ature changes in bot h the chip and the wor kpi ece. The results show that CBN tool offers a good wear resistance despite the aggressiveness of the 100Cr6 at 60HRC. The major part of the heat generated during machining is mainly dissi- pated through the chip. Beyond 280m/min, the machining system becomes unstable and produces significant sparks and vibrations after only a few minutes of work. The optimal productivity of machined chip was recorded at a speed of 120 m/min for an acceptable tool flank wear below 0.4 mm. Beyond this limiting speed, roughness ( R a ) is stabilized because of a reduction in the cutting forces at high speeds leading to a stability of the machining system. The controlling parameter over roughness, in such hard turning cases, remains tool advance although ideal models do not describe this effect rationally. Surface quality obtained with CBN tool significantly compared with that of grinding despite an increase in the advance by a factor of 2.5. A relationship between flank wear (VB) and roughness ( R a ) is deduced from parametric analysis based on extensive experimental data. © 2008 Elsevier B.V. All rights reserved. 1. In troduction During the process of material cutting, complex and mutual interactions are created between tool and workpiece at the contact surf ace. Cons eque ntly , in this syst em, sign ificant forces and high temperatures are recorded causing wear and sometimes breakage of the tool. Usually , such conditions lead ∗ Corresponding author. Tel.: +213 38 87 11 09; fax: +213 38 87 11 09. E-mail address: [email protected] (K. Chaoui). to the damage of both contact surfaces and reduce the pre- cision on the geometrical shapes or modify the mechanical characteristics. It is well known that wear process of cutting tools is a very complicated phenomenon as contact surfaces of the system are subjected to physical and chemica l changes which contribute to the progressive destruction of the active part surface layers. Moreover, wear also affects geometrical 0924-0136/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.jmatprotec.2008.03.014

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