Posco Co., Ltd

Posco

Un-Hae Lee

Sang-Ho Han

Sung-Kyu Kim

Yong-Jin Kim

Sang-Deok Kang

Soon-Gi Lee

Hong-Yeol Oh

Yu-Mi Ha

Il-Cheol Yi

Tae-Kyo Han

Young-Deok Jung

Young-Ju Kim

Dong-Ho Lee

Jeong-Hun Seok

Bo-Sung Kim

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 μm 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.

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

Provided according to one embodiment of the present invention are a non-magnetic steel material and a method for manufacturing the same. The steel material comprises 15-27 wt % of manganese, 0.1-1.1 wt % of carbon, 0.05-0.50 wt % of silicon, 0.03 wt % or less (0% exclusive) of phosphorus, 0.01 wt % or less (0% exclusive) of sulfur, 0.050 wt % or less (0% exclusive) of aluminum, 5 wt % or less (0% inclusive) of chromium, 0.01 wt % or less (0% inclusive) of boron, 0.1 wt % or less (0% exclusive) of nitrogen, and a balance amount of Fe and inevitable impurities, has an index of sensitivity of 3.4 or less, the index of sensitivity being represented by the following relational expression (1): [Relational expression 1]−0.451+34.131*P+111.152*Al−799.483*B+0.526*Cr≤3.4 (wherein [P], [Al], [B] and [Cr] each mean a wt % of corresponding elements), and contains a microstructure with austenite at an area fraction of 95% or greater therein.

Austenitic steel material having excellent hot workability and manufacturing method therefor

A high-strength austenite-based high-manganese steel material and a manufacturing method for the same, the steel material comprising: manganese (Mn): 20 to 23 wt %, carbon (C): 0.3 to 0.5 wt %, silicon (Si): 0.05 to 0.50 wt %, phosphorus (P): 0.03 wt % or less, sulfur (S): 0.005 wt % or less, aluminum (Al): 0.050 wt % or less, chromium (Cr): 2.5 wt % or less, boron (B): 0.0005 to 0.01 wt %, nitrogen (N): 0.03 wt % or less, and a balance of iron (Fe) and other inevitable impurities, wherein stacked defect energy (SFE) represented by the following relationship 1 is 3.05 mJ/mor more, and a microstructure comprises 95 area % or more (including 100 area %) of austenite, and comprises 6 area % or more of strain grain boundaries in an austenite recrystallized grain, is provided.SFE(mJ/m)=&#x2212;24.2+0.950*Mn+39.0*C&#x2212;2.53*Si&#x2212;5.50*Al&#x2212;0.765*Cr&#x2003;&#x2003;[Relationship 1]where Mn, C, Cr, Si, and Al denote weight percent of respective components.

High-strength austenite-based high-manganese steel material and manufacturing method for same

The present invention relates to a high manganese steel for low temperature applications and a method for manufacturing the same. The high manganese steel contains 0.3 wt % to 0.8 wt % of C, 18 wt % to 26 wt % of Mn, 0.01 wt % to 1 wt % of Si, 0.01 wt % to 0.5 wt % of Al, 0.1 wt % or less of Ti (excluding 0%), 1 wt % to 4.5 wt % of Cr, 0.1 wt % to 0.9 wt % of Cu, 0.03 wt % or less of S (excluding 0%), 0.3 wt % or less of P (excluding 0%), 0.001 wt % to 0.03 wt % of N, 0.004 wt % or less of B (excluding 0%), and a remainder of Fe and other inevitable impurities, wherein a microstructure comprises an austenite single phase structure, and an average grain size of the austenite is 50 &#x3bc;m or less.

High manganese steel for low temperature applications having excellent surface quality and a manufacturing method thereof

Provided according to one embodiment of the present invention are a non-magnetic steel material and a method for manufacturing the same. The steel material comprises 15-27 wt % of manganese, 0.1-1.1 wt % of carbon, 0.05-0.50 wt % of silicon, 0.03 wt % or less (0% exclusive) of phosphorus, 0.01 wt % or less (0% exclusive) of sulfur, 0.050 wt % or less (0% exclusive) of aluminum, 5 wt % or less (0% inclusive) of chromium, 0.01 wt % or less (0% inclusive) of boron, 0.1 wt % or less (0% exclusive) of nitrogen, and a balance amount of Fe and inevitable impurities, has an index of sensitivity of 3.4 or less, the index of sensitivity being represented by the following relational expression (1): [Relational expression 1]&#x2014;0.451+34.131*P+111.152*Al&#x2212;799.483*B+0.526*Cr&#x2264;3.4 (wherein [P], [Al], [B] and [Cr] each mean a wt % of corresponding elements), and contains a microstructure with austenite at an area fraction of 95% or greater therein.

Non-magnetic steel material having excellent hot workability and manufacturing method therefor

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Gwangyang-si, South Korea

Un-Hae Lee