Avaliação da integridade superficial do aço ABNT H13 submetido à operação de fresamento frontal

Abstract

AISI H13 hot work tool steel is normally used in inject molds and dies. One of the ways of processing this work material is through milling. As a result of machining, surface integrity becomes a critical characteristic for the performance of the produced component. The present work consists on the study of the influence of milling conditions on the process forces and temperature, machined surface roughness and residual stresses induced on annealed AISI H13 steel. It was sought to vary the parameters cutting speed, feed per tooth, depth cutting and cutting fluid using carbide and cermet inserts. Cutting forces were measured by a dynamometer and the machined surface temperature was measured using a thermographic camera. Roughness was evaluated by measuring the mean arithmetic deviation of the evaluated profile (Ra), mean squared deviation (Rq), the total profile height (Rt) and maximum profile height (Rz). Residual stresses were measured using the incremental blind hole method. The results indicated that the parameters that led to the highest cutting forces were axial depth of cut and the feed per tooth and that the intensity of the cutting forces did not depend on the insert grade. The only factor that affected temperature was the axial depth of cut (the larger the depth of cut, the higher the temperature on the machined surface). Regarding surface, cutting fluid influenced all roughness parameters. Comparing the two inserts under the same machining conditions, it was observed that the cermet inserts promoted lower roughness mean values. The results for residual stresses indicated that in the layer immediately below the surface, tensile residual stresses prevailed, which can be detrimental to the performance of the component.