Wear mechanisms of solid carbide cutting tools in dry and cryogenic machining of AISI H13 steel with varying cutting-edge radius

This study presents an experimental investigation on tool wear mechanisms in dry and cryogenic machining when milling AISI H13 steel with varying cutting-edge radius. The aim was to study the effect of cutting-edge radius on the wear mechanism of rounded cutting-edge radius of an uncoated carbide cutting tool under dry and cryogenic machining. Uncoated four flute cemented carbide cutting tools of 6 mm diameter with prepared cutting-edge radius, R_n of 0.03 mm and commercial cutting-edge radius, R_n of 0.018 mm were used in the study. The machining parameters applied were cutting speed, V_c = 200 m/min, feed rate, f = 0.03 mm/tooth and depth of cut, a_p = 0.1 mm. The coolant used for cryogenic machining was liquid nitrogen (LN₂). The results revealed that longer tool life time was achieved in cryogenic machining rather than in dry machining. Compared to a commercial tool with cutting-edge radius, R_n = 0.018 mm under dry machining, the obtained results showed that a prepared tool with cutting-edge radius, R_n = 0.03 mm under cryogenic machining condition enhanced the cutting tool performance with a 55% increase of tool life time. In mechanisms of wear, adhesive and abrasive wear are the major wear mechanisms which take place under dry and cryogenic machining, of which the formation of adhesive and abrasive wear is more severe in dry machining rather than in cryogenic machining. These important results in cryogenic application have good potential in the future which can be applied commercially in the machining industry.