Barış ÖZLÜ, Halil DEMİR, Mustafa TÜRKMEN, Süleyman GÜNDÜZ

INVESTIGATION OF MACHINABILITY OF COOLED MICROALLOY STELL IN OIL AFTER THE HOT FORGING WITH COATED AND UNCOATED CBN CUTTING TOOLS

The aim of this study was to investigate the cutting forces and surface roughness of 38MnVS6 microalloyed steel quenched in oil following hot forging. The machinability tests were carried out by turning under dry cutting conditions using coated and uncoated cubic boron nitride (CBN) cutting tools at five different cutting speeds (120, 150, 180, 210 and 240 m / min), a constant feed rate (0.04 mm / rev) and a constant chip depth (0.6 mm). The microalloyed steel used in the experimental study was optically examined and a hardness test was applied. Scanning electron microscopy (SEM) was used to evaluate the wear on the cutting tools. The findings for the 38MnVS6 steel which was oil quenched after forging showed that due to the high cooling rate, a martensite structure had been formed and the hardness value was high. The lowest surface roughness values of 0.367 μm and 0.164 μm were obtained at a cutting speed of 180 m / min with the coated and the uncoated CBN cutting tools, respectively. In the turning experiments, the surface roughness values measured using the coated CBN cutting tool were about 103% higher than those measured using the uncoated CBN cutting tool and the highest cutting forces were obtained at a cutting speed of 120 m / min.

Keywords:

Hot forging, microalloyed steel, machinability, CBN cutter.,

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