Furação de ferros fundidos austemperados e nodular perlítico

Abstract

Many materials have mechanical proprieties improved by heat treatments, but this can cause changes in the structure of the material, worsening its machinability, as in the case of austempered ductile iron (ADI) that despite of presenting better mechanical proprieties it has lower machinability when compared with the conventional ductile iron and steel of similar strength. Being an excellent engineering material recently developed research about ADI behavior has been intensified. In this direction the present work was developed. The aim is to compare the machinability, in drilling process, of three materials: a perlitic ductile iron as cast (FE70003) and two grades of austempered ductile iron with different temperatures and times of austenitization: the ISO 1.050-6 and the ISO 800-10. To compare the machinability of these materials experimental tests were carried out, following a 24 factorial planning, consisting of two quantitative variable: cutting speed (Vc) and feed rate (f) and two qualitative variable: work material and cutting fluid application technique. The machinability was expressed by the length of the drilled holes in constant pressure tests and tool wear, cutting forces, power consumption, vibration and surface quality of the holes produced by the long tool life tests. The results showed that the ADI grade ISO 800-10 (207 HB) was the material with higher machinability, followed by the ductile iron grade FE70003 (263 HB) and by the ADI grade ISO 1.050-6 (288 HB) which showed the worst machinability. The machinability of the materials studied are therefore closely related to the heat treatments that they were submitted, producing different microstructures and hardness.