Influência do tratamento criogênico nas propriedades mecânicas e tribológicas do aço ABNT M2

Abstract

The increased resistance of steels has always been under investigation since the earliest times. In the last two centuries, with the rise of industrialization, the demand for increasingly resistant materials became even greater. Among the metallic materials, tool steels are the most investigated in the search for higher hardness and wear resistance, essential to use requirements. In recent years it has been demonstrated that deep cryogenic treatment applied to tool steels causes not only the transformation of residual austenite into martensite, precipitation of fine carbides in the metal matrix, mainly by increasing wear resistance. This research aimed to study the influence of deep cryogenic treatment on mechanical properties and tribological steel AISI M2. Hardness tests were performed HRC, HV and HK microhardness, Charpy impact, abrasive wear, optical and scanning electron microscopy in ABNT M2 steel samples subjected to conventional heat treatment (quenching and tempering) and conventional heat treatment with cryogenic treatment. The cryogenic treatment was performed by direct nebulization with heating and cooling rate of 0.3° C/min and 24 hours residence in -190° C. The austenitization temperatures used were 1170° C, 1200° C and 1230° C. Samples were analyzed with tempering application before, after and before after the cryogenic treatment. It was concluded that deep cryogenic treatment applied before tempering samples austenitized at a temperature of 1200° C increases the hardness, abrasive wear resistance and toughness of the treated material.