Journal of Advanced Mechanical Design, Systems, and Manufacturing (Jul 2009)
Influence of Additional Electrical Current on Machinability of BN Free-Machining Steel in Turning
Abstract
It is widely known that the electromotive force generated at the interface between the cutting tool and work material, during a metal cutting process, influences the cutting mechanism. Previously published papers describe the influence of the passage of electric current through the contact zone between cutting tool and work material, on tool life in cutting several work materials. However, few papers deal with the influence of this electric current on the behavior of a deposited layer called “belag”, observed in turning work materials such as calcium deoxidized steel and boron and nitrogen, BN added steel. This paper deals with the machinability of BN free-machining steel in turning with a supplied current of various values and different directions of flow. The test materials were, BN added steel based AISI 1045 which has good machinability at high cutting speed and standard AISI 1045. Turning was undertaken using one of three types of cutting tool; K10 and P30 carbide and cermet. The power source for additional current supply was a direct current source and the maximum current flowing in the circuit was 20milliamperes (mA). To investigate the influence of supplied current on the characteristics of the turning process, tool life, cutting force and cutting temperature were determined experimentally. When turning with carbide P30 the maximum crater depth in the tool was reduced drastically when the value of supplied current reached 5mA, regardless of its direction of flow, compared with depths at lower current values. This suggests that the additional electrical current promotes generation of the protective layer, on the rake face, in turning BN free-machining steel.
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