High manganese nitrogen-containing steel sheet having high strength and high ductility, and method for manufacturing same

Abstract

Provided is a high manganese nitrogen-containing steel sheet. The high manganese nitrogen-containing steel sheet according to the present invention comprises 0.5 to 1.0 wt % of carbon, 10 to 20 wt % of manganese, 0.02 to 0.3 wt % of nitrogen, with a remainder of Fe and unavoidable impurities. The high manganese nitrogen-containing steel sheet according to the present invention produces an austenite phase at room temperature, in which the stacking fault energy is effectively controlled by adding chrome and nitrogen. Accordingly, the high manganese nitrogen-containing steel sheet of the present invention produces a mechanical twin during the plastic deformation of the steel sheet, thereby increasing the work hardening rate, tensile strength, and workability.

Description

technical field [0001] The present invention relates to a high-manganese-nitrogen steel sheet having high strength and high ductility, and more particularly to a steel sheet for automobiles requiring high formability and shock absorbing materials such as bumper reinforcements for automobiles High manganese nitrogen steel plate and its manufacturing method. Background technique [0002] Steel sheets used for automobile bodies and the like basically require high formability. In order to meet this need, in the past, ultra-low carbon steel with low tensile strength of only about 200-300Mpa but excellent formability was mostly used as automobile steel plate. However, with the recent focus on environmental issues such as air pollution, many methods for improving the fuel efficiency of automobiles have been proposed. In particular, with emphasis on the weight reduction of automobiles in order to improve fuel efficiency, automobile steel sheets are required to have not only high f...

AI Technical Summary

Problems solved by technology

[0009] However, the twin-induced plasticity steels developed so far have a high manganese content of about 18-30% for ensuring austenite stability and adjusting stacking fault energy, and in addition to manganese, a large amount of aluminum or silicon must be added. , and thus has defects that lead to a substantial increase in material or manufacturing costs

In addition, it also has the disadvantage of causing a large additional manufacturing cost burden due to volatilization of manganese or temperature drop in the steelmaking process or continuous casting process. Therefore, there is a demand for the development of twin-induced plasticity steel with reduced manganese content.

Moreover, from the perspective of mechanical properties, the yield strength of the twin-induced plasticity steel developed so far is only about 300Mpa, and the tensile strength does not exceed 1GPa. steel plate with increased strength

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