OPTIMIZATION OF THE MACHINING PARAMETERS IN TURNING OF HARDENED HOT WORK TOOL STEEL USING CRYOGENICALLY TREATED TOOLS

This paper addresses an approach based on the Taguchi method with gray relational analysis for optimizing the turning parameters of hardened DIN 1.2344 hot work tool steel (54 HRC) with multiple performance characteristics. A gray relational grade obtained from the gray relational analysis was used for the performance characteristic in the Taguchi method L-18 (2(1) X 3(2)). The optimal turning parameters for surface roughness and tool wear were determined using the parameter design proposed by the Taguchi method. Dry turning tests were carried out using cryogenically treated and untreated uncoated carbide cutting tools. The cutting tool (Untreated and Deep Cryogenic Treated), cutting speed (200, 250 and 300 m/min) and feed rate (0.09, 0.12 and 0.15 mm/rev) were selected as experiment parameters. The analysis results revealed that the feed rate (72.84%) was the dominant factor affecting surface roughness and the cutting speed (93.93%) was the dominant factor affecting flank wear. The optimum turning parameters for the lowest Ra values were A(2)B(1)C(2) and for the lowest Vb values were A(1)B(3)C(2). According to the results of gray relational analysis, the optimum parameters for minimum average surface roughness and minimum flank wear were A(1)B(2)C(2).