Polycrystalline Cubic Boron Nitride (PCBN) Tool Life and Wear in Turning of Amorphous-Crystalline Iron-Based Coatings

摘要

The paper presents PCBN-Ciborit cutting tools life and wear test results. The effects of the machining regime when turning amorphous-crystalline Fe_(80)B_(20) and Fe_(79)Cr_(16)B_5 coating systems applied to conventional workpiece materials were assessed. It has been shown that the observed tool wear mechanisms are complex in their character and are dominated by abrasive-mechanical, adhesive and chemical effects in the cutting zone. Under changing turning conditions tool life is affected by the structural-phase composition and by the non-homogeneous structure of the coating. Specifically, when turning gas-flame coatings deposited with a Fe_(80)B_(20) electrode and electro-arc coatings with a Fe_(79)Cr_(16)B_5 electrode the lowest wear and the highest tool life was achieved at cutting speeds of v = 1.1 to 1.2 m/s and a back rake angle of y = -10°. It has been demonstrated that a change of the back rake angle from y = 0 to -10° does not have a great effect on tool life contrary to the case with y = -20°.