ACTIVE WEAR AND FAILURE MECHANISMS OF TIN-COATED HIGH-SPEED STEEL ANDTIN-COATED CEMENTED CARBIDE TOOLS WHEN MACHINING POWDER METALLURGICALLY MADE STAINLESS-STEELS

In this study, active wear and failure mechanisms of both TiN-coated h igh speed steel and TiN-coated cemented carbide tools when machining s tainless steels made by powder metallurgy in low and high cutting spee d ranges, respectively, have been investigated. Abrasive wear mechanis ms, fatigue-induced failure, and adhesive and diffusion wear mechanism s mainly affected the tool life of TiN-coated high speed steel tools a t cutting speeds below 35 m/min, between 35 and 45 m/min, and over 45 m/min, respectively. Additionally, fatigue-induced failure was active at cutting speeds over 45 m/min in the low cutting speed range when ma chining powder metallurgically made duplex stainless steel 2205 and au stenitic stainless steel 316L. In the high cutting speed range, from 1 00 to 250 m/min, fatigue-induced failure together with diffusion wear mechanism, affected the tool life of TiN-coated cemented carbide tools when machining both 316L and 2205 stainless steels. It was noticed th at the tool life of TiN-coated high speed steel tools used in the low cutting speed range when machining 2205 steel was longer than that whe n machining 316L steel, whereas the tool life of TiN-coated cemented c arbide tools used in the high cutting speed range when machining 316L steel was longer than that when machining 2205 steel.