Fresamento do aço vhsuper nos estados recozido e temperado com metal duro e cermet

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The concept of costs reduction in all the industrial processes has been continually developed aiming to make companies more competitive. In the dies and moulds production chain this concern is not different. Usually, dies and moulds require long machining and polishing times, which represent from 60 to 80% of the production cost. This work aims to investigate the influence of the cutting parameters when dry face milling VHSUPER tool steel in both annealed and hardened conditions. Cutting tools based on cermet and cemented carbide coated by TiCN + TiN and TiCN + TiN + Al2O3 were evaluated. Moreover, the influence of tool material cutting speed (vc) and feed rate per tooth (fz) on tool life, wear mechanisms, machined surface roughness, three component milling forces and dimensional and geometric tolerances was assessed. Additionally, the cutting temperature was evaluated for the hardened steel only. In the case of the annealed tool steel, the results indicated that, within the cutting range tested, tool life decreased with an increase in cutting speed and reduction in feed rate. Best results were obtained with the TiCN + TiN + Al2O3 coated carbide. When milling the hardened steel, the elevation of both cutting speed and feed rate resulted in shorter tool lives and the TiCN + TiN coated carbide gave best results. When machining the annealed steel, the principal wear mechanisms observed were abrasive wear, adhesion and coating delamination, whereas for the hardened tool steel, coating delamination in coated carbides and chipping in cermet, were the predominant wear mechanisms. Best surface finish was obtained using lower feed rates, irrespectively of the cutting speed and tool material grade employed. In addition to that, feed rate was the principal parameter affecting milling forces, however, cutting speed was the principal parameter affecting the milling temperature of the hardened tool steel. Finally, tighter dimensional and geometric tolerances were obtained after up milling the hardened tool steel. Keywords: milling, tool steel, coated carbide, cermet, milling forces.

ASSUNTO(S)

engenharia mecânica teses. aço-ferramenta teses.

ACESSO AO ARTIGO

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