Estudo experimental da influência do comprimento de corte no comportamento de desgaste de ferramentas com revestimento de TiN/TiALN durante fresagem de Inconel 718

• Autor(a) principal: Sebbe, Naiara Poli Veneziani
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.22/23204
• topic: Machining; Milling; Tool wear mechanisms; TiN/TiAlN films; Inconel 718; PVD coatings; HiPIMS; Machined surface quality; Maquinagem; Fresagem; Mecanismos de desgaste das ferramentas; Revestimento multicamada de TiN/TiAlN; Inconel 718; Deposição PVD; Qualidade da superfície maquinada

The Inconel 718 alloy displays high mechanical strength at high temperatures, high hardness, tendency to undergo work hardening and low thermal conductivity, which makes it widely used in the aeronautical, aerospace, biomedical and petrochemical industries. However, due to these characteristics, this alloy is considered a difficult-to-machine material, which can cause great damage or breakage in the cutting tools, excessive wear, and short tool lifetime. Milling process is the most used in the machining of this alloy, since it is a flexible process in the production of dissimilar shapes and high surface quality finishing parts. The use of coatings applyed over the surface of the machining tools has been observed to improve their performance and the surface quality of the machining parts. Based on this, the objective of this project was to evaluate the wear behavior of endmill coated tools during the machining of Inconel 718 alloy, using multi-layered TiN/TiAlN coating, deposited by sputtering HiPIMS process. For this, different machining parameters such as cutting speed, cutting length and feed per tooth were varied. After the machining tests, the surface quality of the machined material was assessed, the wear of the tool was evaluated, the wear mechanisms characterized, and the tool lifespan analyzed. It was found that the cutting length has a great influence on the machined surface and the resulting wear. The greater this parameter, the worse the surface quality and the higher the resulting wear. As for the predominant wear mechanisms, abrasion and material adhesion were identified, both on the coating and on the substrate of the tool, in all tested conditions. In addition, in some cases, builtup edges were developed. It was also observed that the TiN undercoat improved resistance to crack propagation, as this phenomenon was not identified in tools after milling operations. As for tool lifespan, it was found that the higher the cutting speed, the higher the flank wear, and consequently, the shorter the tool lifespan. Thus, the parameter that had the greatest influence on tool lifespan, in addition to cutting length, was the cutting speed.