Efeito da microestrutura do aço-manganês austenítico no desempenho tribológico em desgaste por deslizamento

Abstract

Austenitic manganese steel is widely used in the industry in equipment prone to abrasive or impact wear. This material is chosen for these situations due to its microstructural changes that occur when subjected to deformation, ensuring an increase in its mechanical strength and considerable surface hardening. Three austenitic manganese steels were evaluated in this study, one as-cast and non-solution treated (HF-NS), one solution treated and rolled (HF-IMP), and another solution treated and also cast (HF-NAC), having nearly the same chemical composition. These steels were tested in reciprocating sliding wear tests using pin-on-disc configuration with normal forces of 90 N, 150 N, 180 N, and 380 N. Each test lasted 12 hours, with five tests conducted for each condition. Based on the iron and manganese contents of these materials, it is expected that there will be no martensitic transformation. The only expected mechanisms contributing to increased mechanical strength are deformation twins, slip of crystal planes, and strain hardening due to dislocation movement. Components that worked in the field made of Hadfield steel were evaluated, with their wear mechanisms characterized and replicated in laboratory tests. HF-NS exhibited the lowest values for both friction coefficient and wear. Furthermore, martensitic transformation was detected in HF-NS using EBSD technique, attributed to carbon depletion within the austenitic grains, thereby reducing austenite stability at room temperature. This suggests that the absence of solution treatment for austenitic manganese steel is beneficial for the studied application, as it not only provides good tribological performance but also reduces production cost and time.