Posco

Posco Co., Ltd

Hong-Ju Lee

In-Gyu Park

In-Shik Suh

Soon-Gi Lee

Jong-Kyo Choi

Yong-Jin Kim

Yoen-Jung Park

Hee-Goon Noh

Young-Hwan Park

Hak-Cheol Lee

Sang-Deok Kang

Seong-Ung Koh

Kyung-Keun Um

Woo-Gyeom Kim

Hong-Yeol Oh

Moo-Jong Bae

Woo-Kil Jang

Young-Deok Jung

Hyo-Shin Kim

Hyun-Kwan Cho

The present invention relates to a thick steel suitable for use as a line pipe, a sour-resistant material, or the like and, more specifically, to a high-strength steel having excellent resistance to sulfide stress cracking, and a method for manufacturing same.

High-strength steel having excellent resistance to sulfide stress cracking, and method for manufacturing same

Provided according to one preferred aspect of the present invention are austenitic steel material having superb abrasion resistance and toughness, and a method for producing the austenite steel material. The austenitic steel material having superb abrasion resistance and toughness according to one preferred aspect of the present invention comprises, in wt %, 0.6-1.9% carbon (C); 12-22% manganese (Mn); 5% or lower (excluding 0%) chromium (Cr); 5% or lower (excluding 0%) copper (Cu); 0.5% or lower (excluding 0%) aluminum (Al); 1.0% or lower (excluding 0%) silicon (Si); 0.1% or lower (including 0%) phosphorous (P); 0.02% or lower (including 0%) sulfur (S); and the rest in Fe and unavoidable impurities, and has the microstructure comprising, by surface area fraction, 97% or higher (including 100%) austenite and 3% or lower (including 0%) carbide.

Austenitic steel material having excellent abrasion resistance and toughness and manufacturing method the same

Provided are an austenitic steel having excellent machinability and ultra-low temperature toughness in a weld heat-affected zone including 15 wt % to 35 wt % of manganese (Mn), carbon (C) satisfying 23.6C+Mn&#x2265;28 and 33.5C&#x2212;Mn&#x2264;23, 5 wt % or less (excluding 0 wt %) of copper (Cu), chromium (Cr) satisfying 28.5C+4.4Cr&#x2264;57 (excluding 0 wt %), and iron (Fe) as well as other unavoidable impurities as a remainder, wherein a Charpy impact value of a weld heat-affected zone at &#x2212;196&#xb0; C. is 41 J or more, and a method of manufacturing the steel. According to the present invention, a low-cost ultra-low temperature steel may be obtained, a stable austenite phase may be formed at low temperature, carbide formation may be effectively suppressed, and a structural steel having excellent machinability and ultra-low temperature toughness in a weld heat-affected zone may be provided.

Austenitic steel having excellent machinability and ultra-low temperature toughness in weld heat-affected zone, and method of manufacturing the same

The present invention relates to a high strength austenitic-based steel with remarkable toughness of a welding heat-affected zone and a preparation method therefor. One embodiment of the present invention provides: a high strength austenitic-based steel with remarkable toughness of a welding heat-affected zone, comprising 0.8-1.5 wt % of C, 15-22 wt % of Mn, 5 wt % or less of Cr (except 0), and the balance of Fe and other inevitable impurities, and further comprising at least one of the following (a) and (b), wherein the microstructure of a welding heat-affected zone comprises 90% or more of austenite by volume fraction; and a preparation method therefor. (a) Mo: 0.1-1% and B: 0.001-0.02% (b) Ti: 0.01-0.3% and N: 0.003-0.1%.

High strength austenitic-based steel with remarkable toughness of welding heat-affected zone and preparation method therefor

A high-manganese wear-resistant steel having excellent weldability comprises 5 to 15 wt % of Mn, 16&#x2264;33.5C+Mn&#x2264;30 of C, 0.05 to 1.0 wt % of Si, and a balance of Fe and other inevitable impurities. The microstructure thereof includes martensite as a major component, and 5% to 40% of residual austenite by area fraction.

High-manganese wear resistant steel having excellent weldability and method for manufacturing same

Provided is a wear resistant steel including 2.6 wt % to 4.5 wt % of manganese (Mn), carbon (C) satisfying (6-Mn)/50&#x2266;C&#x2266;(10-Mn)/50, 0.05 wt % to 1.0 wt % of silicon (Si), and iron (Fe) as well as other unavoidable impurities as a remainder, wherein a Brinell hardness of a surface portion is in a range of 360 to 440. The wear resistant steel further includes at least one component selected from the group consisting of 0.1 wt % or less (excluding 0 wt %) of niobium (Nb), 0.1 wt % or less (excluding 0 wt %) of vanadium (V), 0.1 wt % or less (excluding 0 wt %) of titanium (Ti), and 0.02 wt % or less (excluding 0 wt %) of boron (B) to complement the performance thereof. The wear resistant steel is characterized in that a microstructure includes martensite in an amount of 90% or more, and an average packet diameter of the martensite is 20 &#x3bc;m or less.

Wear resistant steel having excellent toughness and weldability

There are provided a wear resistant austenitic steel having superior machinability and toughness in weld heat affected zones and a method for producing the austenitic steel. The austenitic steel includes, by weight %, manganese (Mn): 15% to 25%, carbon (C): 0.8% to 1.8%, copper (Cu) satisfying 0.7C-0.56(%)&#x2266;Cu&#x2266;5%, and the balance of iron (Fe) and inevitable impurities, wherein the weld heat affected zones have a Charpy impact value of 100 J or greater at &#x2212;40&#xb0; C. The toughness of the austenitic steel is not decreased in weld heat affected zones because the formation of carbides during welding is suppressed, and the machinability of the austenitic steel is improved so that a cutting process may be easily performed on the austenitic steel. The corrosion resistance of the austenitic steel is improved so that the austenitic steel may be used for an extended period of time in corrosive environments.

Wear resistant austenitic steel having superior machinability and toughness in weld heat affected zones thereof and method for producing same

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Pohang-si, South Korea

Hong-Ju Lee