Mechanical Properties of Two Manganese Steels

Abstract

The article is focused on thermomechanical and plastic properties of two high-manganese TRIPLEX type steels with an internal marking 1043 and 1045. Tensile tests at ambient temperature and at a temperature interval 600°C to 1100°C were performed for these heats with a different chemical composition. After the samples having been ruptured, ductility was observed which was expressed by reduction of material after the tensile test. Then the stacking fault energy was calculated and dilatation of both high-manganese steels was measured. At ambient temperature (20°C), 1043 heat featured higher tensile strength by 66MPa than 1045 heat. Microhardness was higher by 8HV0,2 for 1045 steel than for 1043 steel (203HV0,2). At 20°C, ductility only differed by 3% for the both heats. Decrease of tensile properties occurred at higher temperatures of 600 up to 1100°C. This tensile properties decrease at high temperatures is evident for most of metals. The strength level difference of the both heats in the temperature range 20°C up to 1100°C corresponded to 83 MPa, while between 600°C and 1100°C the difference was only 18 MPa. In the temperature range 600°C to 800°C, a decrease in ductility values down to 14 % (1045 heat), or 22 % (1043 heat), was noticed.This decrease was accompanied with occurrence of complex Aluminium oxides in a superposition with detected AlN particles. Further ductility decrease was only noted for 1043 heat where higher occurrence of shrinkage porosity was observed which might have contributed to a slight decrease in reduction of area values in the temperature range 900°C to 1100°C, in contrast to 1045 heat matrix.

Thermophysical Properties and Solidification Defects of Fe-22Mn-0.7C TWIP Steel

“…Chojecki and Telejko experimentally analyzed the solidification property of high manganese steel and found shrinkage porosity formation in the matrix was probably due to the inadequate feeding induced by coarse dendrite . Cagala et al made a comparison on the solidification structure of TWIP steels with different manganese alloying, in which a more obvious shrinkage was observed in the specimen with higher manganese. It was inferred that the compactness of Fe–Mn–C TWIP steel should also be an important issue.…”

“…Steels with wide mushy zone spacing are liable to solidify as pasty pattern, which leads to the increase of shrinkage cavities between coarsening dendrites. Calage and Black made investigations on the compactness defect of high manganese TWIP steels by experiment . Lan numerically analyzed the solidification process of high carbon bearing steel previously and unveiled the mutual promotion between segregation and shrinkage .…”

“…The quantitative comparison on the heat transfer performance between TWIP steel and others has been rarely reported. It is of great importance to determine the thermophysical properties of TWIP steel to effectively control its internal defect such as segregation, shrinkage, and coarse grains …”

Análise da temperatura ótima de corte para o par: metal duro revestido x aço ABNT 1045

“…Conforme exposto em [9], em temperaturas elevadas (correspondendo com a faixa de temperatura do vale de ductilidade do aço) e alta taxa de deformação (característica peculiar da operação de corte no torneamento) estão associados à precipitação de MnS nos contornos de grão causando fragilização do aço, ou seja, contribuiria para o vale de ductilidade. Além disso, conforme [10] a formação de óxidos de alumínio na faixa de temperatura de 600 °C a 800 °C também poderia contribuir para o vale de ductilidade. Assim, é admissível que para as V c maiores e, portanto temperaturas mais elevadas o vale de ductilidade pode ter apresentado uma curvatura menos acentuada, o que deixaria o aço mais dúctil nessa faixa de temperatura, aumentado o desgaste da ferramenta.…”

“…Uma das causas foi proposta por [7] que evidencia o aparecimento de vazios nos contornos de grão, provocadas pelo empilhamento de discordâncias nessa região. As outras causas, encontradas em respectivamente [9,10] apontam para precipitações de MnS e casos mais específicos, a ocorrência de óxidos de alumínio complexos, provocando a fragilização do aço.…”