Artigo
Effects of milling condition on the surface integrity of hot forged steel
Fecha
2010-01-01Registro en:
Journal of The Brazilian Society of Mechanical Sciences and Engineering. Rio de Janeiro Rj: Abcm Brazilian Soc Mechanical Sciences & Engineering, v. 32, n. 1, p. 37-43, 2010.
1678-5878
S1678-58782010000100006
WOS:000277928000006
S1678-58782010000100006-en.pdf
0184075204510977
Autor
Universidade Estadual Paulista (Unesp)
Resumen
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.