Wear analysis of ultra-fine grain coated carbide tools in hard turning of AISI 420C stainless steel

• Published in: Wear 2017-04, Vol.376-377, p.172-177
• Main Authors: Rosa, Guilherme C., Souza, André J., Possamai, Elizeu V., Amorim, Heraldo J., Neis, Patric D.
• Format: Article
• Language: English
• Subjects: Abrasive wear; Abrasives; Adhesion tests; Built up edge; Carbide cutting tools; Carbide tools; Comminution; Corrosion resistance; Cutting speed; Cutting wear; Dental materials; Feed rate; Hardened AISI 420C stainless steel; Heat treatment; Machinability; Machine tools; Mechanical properties; Oxidation; Protective coatings; Scanning electron microscopy; Stainless steel; Stainless steels; Surface finish; Surgical equipment; Surgical instruments; TiAlN coated carbide tool; Tool life; Tool wear; Tool wear analysis; Turning (machining); Wear; Wear mechanisms
• ISSN: 0043-1648; 1873-2577
• DOI: 10.1016/j.wear.2017.01.088

Hardened AISI 420C stainless steel is a material used in surgical and dental tools due to its mechanical properties, allied with corrosion resistance. However, despite its advantages, this material presents poor machinability. Also, practitioners have often found difficulties using this material due to the lack of information concerning its behavior in machining processes, especially after heat treatment. The present paper investigates tool wear and wear mechanisms involved in hard turning of AISI 420C stainless steel with TiAlN coated ultra-fine grain carbide tool under different cutting conditions. Tool life tests were carried out using different feed rate and cutting speed levels. Machining tests were periodically interrupted in order to evaluate flank wear. The surface finish of the machined parts were evaluated throughout tool life, and the tools were analyzed through both optical and scanning electronic microscopy (SEM/EDS). Test results indicate influence of both cutting speed and feed rate over tool life. After reaching the tool life criterion of 0.2mm flank wear, SEM microscopy evidenced abrasive wear for all tested conditions. Delamination of tool coating and crater wear were observed in some specific tested conditions. EDS analysis revealed significant amounts of iron and chrome adhered on all tools and oxygen at the highest cutting speed, indicating oxidation wear mechanism. The observation of built up edge in some tested conditions along with extensive adhesion suggests the occurrence of attrition wear mechanism over tool life. •Hard machining of AISI 420C with coating carbide tools was evaluated.•Tool life was negatively affected by the increase of cutting speed and feed rate.•High amounts of adhered material were identified in all tested conditions.•Abrasive wear was identified in all tested conditions.•Results suggest the occurrence of attrition and oxidation wear mechanisms.