Posco Co., Ltd

Posco

Dae-Woo Kim

Young-Jin Jung

Woo-Yeol Cha

Sang-Deok Kang

Kyung-Keun Um

Jong-Kyo Choi

Tae-Il So

An embodiment of the present invention provides a steel material, for a pressure vessel, comprising, in weight %, 0.06-0.25% of carbon (C), 0.05-0.50% of silicon (Si), 1.0-2.0% of manganese (Mn), 0.005-0.40% of aluminum (Al), 0.010% or less of phosphorus (P), 0.0010% or less of sulfur (S), 0.001-0.03% of niobium (Nb), 0.001-0.03% of vanadium (V), 0.001-0.03% of titanium (Ti), 0.01-0.20% of chromium (Cr), 0.05-0.15% of molybdenum (Mo), 0.01-0.50% of copper (Cu), 0.05-0.50% of nickel (Ni), 0.0005-0.0050% of magnesium (Mg), 0.0005-0.0050% of calcium (Ca), 0.0020% or less of oxygen (O), and the remainder being Fe and other unavoidable impurities. A microstructure comprises in terms of area fraction 30% or less of pearlite and the remainder being ferrite. A non-metallic inclusion contains Mg—Al—Ca—O composite oxide.

Steel material, for pressure vessel, showing excellent hydrogen-induced cracking resistance and method for preparing same

An embodiment of the present invention provides a steel plate for a pressure vessel having excellent hydrogen-induced cracking resistance and a method of manufacturing same, the steel plate comprising, in weight %, 0.2 to 0.3% of carbon (C), 0.05 to 0.50% of silicon (Si), 0.1% to 0.5% (exclusive) of manganese (Mn) , 0.005 to 0.1% of aluminum (Al), 0.010% or less of phosphorus (P) , 0.0015% or less of sulfur (S), 0.001 to 0.03% of niobium (Nb), 0.001 to 0.03% of vanadium (V) , 0.001 to 0.03% of titanium (Ti), 0.01 to 0.20% of chromium (Cr), 0.01 to 0.15% of molybdenum (Mo) , 0.01 to 0.50% of copper (Cu) , 0.05 to 0.50% of nickel (Ni), 0.0005 to 0.0040% of calcium (Ca), and the balance of Fe and other inevitable impurities, wherein the average grain size of ferrite is 5-20 μm.

Steel plate for pressure vessel having excellent hydrogen induced cracking resistance and method of manufacturing same

One embodiment of the present invention provides an ultrahigh-strength steel having excellent cold workability and SSC resistance, comprising, by wt %, carbon (C) in an amount of more than 0.08% and equal to or less than 0.2%, 0.05-0.5% of silicon (Si), 0.5-2% of manganese (Mn), 0.005-0.1% of aluminum (Al), 0.01% or less of phosphorus (P), 0.0015% or less of sulfur (S), 0.001-0.03% of niobium (Nb), 0.001-0.03% of vanadium (V), 0.001-0.03% of titanium (Ti), 0.01-1% of chromium (Cr), 0.01-0.15% of molybdenum (Mo), 0.01-0.5% of copper (Cu), 0.05-4% of nickel (Ni), 0.0005-0.004% of calcium (Ca), and the balance of Fe and other inevitable impurities, wherein the microstructure of a surface layer part, which is the region from the surface to 10% of the total thickness, comprises 90 area % or more of polygonal ferrite, the microstructure of the region excluding the surface layer part comprises 90 area % or more of tempered martensite or 90 area % or more of a mixed structure of tempered martensite and tempered bainite, and the dislocation density of the surface layer part is 3×10 14/m 2 or less.

Ultrahigh-strength steel having excellent cold workability and SSC resistance, and manufacturing method therefor

The present invention relates to a highly thick steel material and a manufacturing method therefor and, more specifically, to a highly thick steel material that exhibits excellent low-temperature impact toughness after long-term PWHT although the steel sheet is thick, and a manufacturing method therefor.

Highly thick steel material having excellent low-temperature impact toughness and manufacturing method therefor

A steel material showing excellent hydrogen-induced cracking resistance according to an aspect of the present invention comprises, in weight %, 0.10-0.25% of C, 0.05-0.50% of Si, 1.0-2.0% of Mn, 0.005-0.1% of Al, 0.010% or less of P, 0.0015% or less of S, 0.001-0.03% of Nb, 0.001-0.03% of V, 0.01-0.15% of Mo, 0.01-0.50% of Cu, 0.05-0.50% of Ni, and the remainder being Fe and unavoidable impurities, and has a thickness of 100-300 mm. The maximum size of pores formed inside can be 1 &#x3bc;m or less.

Steel material showing excellent hydrogen-induced cracking resistance and method for preparing same

An aspect of the present invention provides: a steel for a pressure vessel, the steel having excellent surface quality while having excellent strength and toughness even after a long-term post-weld heat treatment (PWHT); and a method for manufacturing same.

Steel for pressure vessel having excellent surface quality and impact toughness, and method for manufacturing same

The present disclosure relates to a steel for pressure vessels used in a hydrogen sulfide atmosphere, and relates to a steel material for pressure vessels having excellent resistance to hydrogen induced cracking (HIC) and a manufacturing method thereof.

Steel for pressure vessels having excellent resistance to hydrogen induced cracking and manufacturing method thereof

The present invention relates to pressure vessel steel to be used in a hydrogen sulfide atmosphere, and relates to pressure vessel steel having excellent resistance to hydrogen induced cracking (HIC), and a manufacturing method therefor.

Pressure vessel steel having excellent hydrogen induced cracking resistance, and manufacturing method therefor

Provided is a high-strength steel plate for a pressure vessel having excellent low temperature toughness after a post weld heat treatment (PWHT). The high-strength steel plate for a pressure vessel includes: by wt %, 0.02-0.15% of carbon (C), 0.05-0.50% of silicon (Si), 1.0-2.0% of manganese (Mn), 0.005-0.1% of aluminum (Al), 0.015% or less of phosphorus (P), 0.0015% or less of sulfur (S), 0.01-0.03% of niobium (Nb), 0.01-0.03% of vanadium (V), 0.01-0.03% of titanium (Ti), 0.005% or less of chromium (Cr), 0.005% or less of molybdenum (Mo), 0.02-0.50% of copper (Cu), 0.05-0.60% of nickel (Ni), 0.0002-0.0010% of boron (B), 0.0035-0.0065% of nitrogen (N), and a balance of iron (Fe) and other inevitable impurities. A microstructure of the high-strength steel plate includes a complex structure of ferrite having an area fraction of 35-40% and a balance of bainite, and the bainite has a packet size of 15 &#x3bc;m or less.

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Pohang-si, South Korea

Dae-Woo Kim