Chip Formation Analysis in Finish Turning of Alloy and PM Hardened Tool Steels Using Coated and Uncoated PBCN Tools

The article presents analysis of influence of the type of cutting blades made of composite materials based on cubic boron nitride (CBN) on the selected parameters of chip formation process during finish turning of hardened tool steels: Sverker21® (SV21) alloy steel and Vanadis 4 EXTRA SuperClean® (V4) powder metallurgy steel. The analysis showed smaller value of the average chip thickening coefficient Kh and friction coefficient µ after machining of V4 powder metallurgy steel by all tested blades, and over the entire range of the studied tool feed rates, as compared with SV21 alloy steel. The value of the sliding angle Φ was found to be smaller for all studied variables during machining of SV21 alloy steel. The highest intensity of changes in the values of all studied parameters was found for uncoated blades 7025 during machining of V4 powder metallurgy steel.