Temperature evaluation when machining hardened hot work die steel using PCBN tooling

The aim of this work is to investigate the temperature distribution and heat generation when turning fully hardened AISI H13 hot work die steel (52 HRC) using De Beers DBC50 cutting tools over a range of operating parameters. Three different techniques were used: a) infrared radiation (using an optical pyrometer), b) implanted thermocouple and c) tool/chip thermocouple. Temperature was found to increase with cutting speed, feed rate, depth of cut and tool wear. Highest temperature values were observed when employing the tool/chip thermocouple, followed by the infrared pyrometer and the implanted thermocouple. However, an analysis of variance of the results indicated that the level of significance of each operating parameter to the recorded temperature varied according to the measuring technique.