Análise de temperabilidade e correlação microestrutural dos aços ABNT 1045 e ABNT 4140

Abstract

This work aims to analyze the hardenability of ABNT 1045 and ABNT 4140 steels using the Jominy End Quench Test and correlate the properties with the microstructural variation due to the heat transfer gradient through the test subjects, and thus analyze the effect of the alloying elements. The Jominy End Quench Test was performed following the ASTM A 255-10 norm. It was observed that the ABNT 4140 presents a better hardenability then the ABNT 1045 due to the higher quench depth and, consequently, presented more products of martensitic transformations in greater depths of the test subject. Since the content of carbon present in both steels are approximately equal, the better hardenability of the ABNT 4140 is due to the alloying elements. The alloying elements present in the ABNT 4140 contributes to a higher percentage of carbon equivalent, compared to the ABNT 1045 and thus, shifting the isothermal transformation diagram to the right which reduces the critical cooling rate.