Influence of the temperature in machining hard-to-work steel

Abstract

† In turning hardtowork austenitic steel using oxide-carbide cutting ceramic (whose surface layer has been preliminarily saturated with nitrogen), one of the most important factors is the heat formed as a result of cutting. The laws of heat formation explain many phenomena associated with the load on a cut� ting tool equipped with VOK�60 cutting ceramic, its working life, and the quality of the machined surface. The following research is intended to assist in the cor� rect use of cutting tools on hardtowork steel. The heat Q formed in cutting includes the following components: Qdef, the heat due to internal friction of the metal in deformation; Qf.fr, the heat due to external friction of the chip at the cutter's front surface; Q r.fr , the heat due to external friction of the cutting surface and the machined surface at the rear surface of the VOK�60 ceramic plate; Qdisp is the heat liberated as a result of chip breakaway and dispersion (the formation of new surfaces). Hence Q = Qdef + Qf.fr + Qr.fr + Qdisp .( 1) Assuming that the mechanical work of cutting is completely converted to heat, we may write the result� ing heat (kcal/min) in the form