Avaliação do potencial do aço AISI H13 endurecido por tratamento termo-reativo de boretação como ferramenta de corte

Abstract

In this work, the effects of the thermo-reactive process of boriding (borax bath with addiction of aluminum) in the main properties of the AISI H13 steel were analyzed, as well as the potential for use of samples submitted to this process as cutting tool. For that, firstly some samples were machined with the geometry for assembly on a tool holder, after that they were sharpened for obtainment of the angles and edges that characterize a cutting tool. After this preparation, the samples were submitted to the superficial treatment of boriding, following by quenching and tempering. In the sequence, it was performed the characterization for the material by optical spectrometry and for the boride’s layer formed during the boriding through microscopic analysis (optical and electronic), micro hardness and hardened layer’s adhesiveness in cross-sections of the samples. The boride layer was confirmed and identified using the X-ray diffractometry technique. Lastly, it was analyzed the potential of usage for the samples treated by boriding as cutting tool in the turning tests. The results showed that the boriding was effective to obtain superficial layer with high hardness value, however the samples presented premature wear in the cutting edge during the machining trials. The result was assigned to the average thickness of the hardened layer, which was insufficient for the severity of the machining process. Besides, the intrinsic fragility to the high hardness of the boride layer and the presence of two phases (FeB e Fe2B) with different mechanical properties could be other factors responsible for the early deterioration of the samples.