Cryogenic austenitic high-manganese steel having excellent corrosion resistance, and manufacturing method therefor

Abstract

The cryogenic austenitic high-manganese steel having excellent corrosion resistance, according to one aspect of the present invention, comprises 0.2-0.5 wt% of C, 23-28 wt% of Mn, 0.05-0.5 wt% of Si, 0.03 wt% or less of P, 0.005 wt% or less of S, 0.5 wt% or less of Al, and 3-4 wt% of Cr, with the remainder being Fe and other unavoidable impurities, also comprises at least 95 area% of austenite as a microstructure, and has Cr concentration sections continuously formed within an area of 50 um in the thickness direction from the surface, wherein the Cr concentration sections comprise a high Cr concentration section having a relatively high concentration of Cr, and a low Cr concentration section having a relatively low concentration of Cr, and the high Cr concentration section may be distributed at 30 area% or less (but not 0%) relative to the whole surface area of the Cr sections.

Description

technical field [0001] The present invention relates to an austenitic high manganese steel material and a manufacturing method thereof, more specifically, to an austenitic high manganese steel material with excellent ultra-low temperature toughness and excellent corrosion resistance and a manufacturing method thereof. Background technique [0002] With the strengthening of environmental pollution control and the depletion of petroleum energy, the demand for green energy such as LNG and LPG as an alternative energy source is increasing, and the attention to the development and use of technology is increasing. As the demand for non-polluting fuels such as LNG and LPG transported in a cryogenic liquid state increases, the development of materials for low-temperature structures for storing and transporting these fuels is actively progressing. Materials for low-temperature structures are required to have mechanical properties such as low-temperature strength and toughness. The mo...

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Problems solved by technology

[0003] 9% Nickel steel has excellent characteristics in terms of economic efficiency and weldability, however, because it has similar corrosion resistance to ordinary carbon steel, it is not suitable especially in environments where deformation and corrosion coexist

In addition, although 304 stainless steel has excellent corrosion resistance, there are technical difficulties in ensuring economic efficiency and low temperature physical properties

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