Effects of milling condition on the surface integrity of hot forged steel

This paper presents a study on the influence of milling condition on workpiece surface integrity focusing on hardness and roughness. The experimental work was carried out on a CNC machining center considering roughing and finishing operations. A 25 mm diameter endmill with two cemented carbide inserts coated with TiN layer were used for end milling operation. Low carbon alloyed steel Cr-Mo forged at 1200 degrees C was used as workpiece on the tests. Two kinds of workpiece conditions were considered, i.e. cur cooled after hot forging and normalized at 950 degrees C for 2 h. The results showed that finishing operation was able to significantly decrease the roughness by at least 46% without changing the hardness. on the other hand, roughing operation caused an increase in hardness statistically significant by about 6%. The machined surface presented deformed regions within feed marks, which directly affected the roughness. Surface finish behavior seems to correlate to the chip ratio given the decrease of 25% for roughing condition, which damaged the chip formation. The material removal rate for finishing operation 41% greater than roughing condition demonstrated to be favorable to the heat dissipation and minimized the effect on material hardness.

Análise do processo de lixamento tubular da madeira de Corymbia citriodora

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Medição e análise do acabamento superficial da madeira de eucalipto na usinagem de torneamento cilínrico e lixamento

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo do fresamento de madeiras em centro de usinagem CNC

The lack of research related to wood machining processes, including the milling, as well as the increased use of this material in the industrial sector, it creates a need to increase research involving these processes, as the sector is in full technological and environmental remodeling. This paper studies the process of milling wood, presenting an analysis of the effects of cutting speed on surface quality by measuring roughness. We used a forward speed three cutting speeds, two species of wood (Pinus elliottii and Eucalyptus grandis) and two milling tools (roughing and finishing) machined by milling concordant and discordant. Each condition was repeated six times, and the measurements were performed in the opposite direction and in favor of cutting tool, generating results of the parameters Ra (average roughness) totaling 144 trials with it. These results were statistically analyzed using analysis of variance and Tukey test. Finally it was concluded that there are significant differences between the results of varying roughness when cutting speeds, milling and types of machining types tested

A influência do tamanho de grão ferrítico da peça na integridade superficial de peças erodidas

Pós-graduação em Engenharia Mecânica - FEIS