Estudo da microestrutura de um aço com alto teor de manganês

Abstract

High Manganese steels (Manganese content above 12% by weight) are a trend both in research and in commercial use. Its use in applications that require resistance to wear occurs due to hardenability and high tenacity, favoring its use in the construction, mining, railroad, crushing and mill industries (Chiaverini, 2015). Its use as an alloying element provides high strength and ductility. Currently, it is intended to use High Manganese steel for cryogenic purposes in the manufacture of liquefied gas storage tanks. The samples underwent a metallographic preparation. The chemical analysis was obtained through the technique of Dispersive Energy Spectroscopy (EDS). To study the microstructure, an optical microscopy and then scanning electron microscopy were performed using the secondary electron mode (SE). Hardness and microhardness tests were performed. The study analyzed the microstructural changes caused by a thermal treatment of experimental solubilization at two different temperatures (700ºC and 1000ºC) for 30 minutes, with cooling in water, air and liquid nitrogen, in six samples from a larger sample, cold rolled of a Fe27Mn1Si alloy. Analyzes of Optical Microscopy and Scanning Electron, proved the presence of ε-martensitic microstructure. Microhardness measurements have shown that ε-martensite is softer at higher treatment temperatures and lower cooling rates (1000 ° C and air cooling), proving a reduction in hardness from the dendritic structure of the raw melt material.