Influence of the austenite grain size variation on the surface finishing in the micromilling process of the hardened AISI H13steel

The focus of this work was to study the influence of austenite grain size in the surface finish during micro milling of hardened steels. Work pieces with hardness of 46 HRC and different grain sizes were milled with micro end mills with a diameter of 0.5 mm. The experimental tests were carried out with two cutting speeds and two feed rates. The results were evaluated using an analysis of variance, and they demonstrated that the cutting speed and the feed rate have no influence on the responses surface roughness Ra and Rz. Thus, it could be observed that the most important factor was the grain size that influenced the roughness Ra and Rz, significantly. Moreover, it was also observed that the interaction of input parameters did not show significant influence on the response surface roughness Ra and Rz.

micromilling; grain size; hardened steels; Surface Roughness Ra and Rz