Machining and Machinability of Tool Steels: Effects of Lubrication and Machining Conditions on Tool Wear and Tool Life Data

Abstract

The machinability of materials depends on various factors including the workpiece materials and condition, the cutting tool data and the machining conditions (wet or dry). Most tool life data found in literature are established using dry machining conditions. This makes it difficult to make suitable comparison with wet machining conditions, to compute cost effective machining conditions or to simulate the machining processes, especially for newly developed alloys. In the present paper, the machinability of tool steels is investigated using dry and wet milling process. Tools steels with different compositions and hardness were milled using carbide inserts and the tool wear/tool life performance studied. The coefficients of the Taylor model of tool life were established for each steel and then used to compute the economically speeds and the maximum productivity speeds. It was found that the dry milling is more advantageous for the tested steels, especially for roughing operations, but the tool life data in dry machining conditions was very sensitive to materials compositions and hardness compared to wet machining conditions.