Posco

Kyong-Su Park

Kyoo-Young Lee

Young-Roc Im

Jae-Kon Lee

Han-Chul Shin

Hyoung-Kuk Park

Jae-Hwa Ryu

Jae-Hoon Jang

Chon-Kue Kim

Deuk-Jung Kim

Jung-Hyeung Lee

Yeong-Woo Jeon

A process control system according to one embodiment of the present invention comprises: a first system for generating thickness information about an internal defect layer included in a carbon steel product; and a second system which receives the thickness information about the internal defect layer from the first system through a network, and which controls an etching process for removing at least a part of the internal defect layer from the carbon steel product by using the thickness information about the internal defect layer, wherein the first system provides the second system with a calculation module necessary for the second system to control the etching process, and the second system provides the first system with the information necessary for the first system to update the calculation module.

Process control system and operating method therefor

Disclosed are a quenched steel sheet and a method for manufacturing the same. The quenched steel sheet according to an aspect of the present invention contains, in terms of wt %, C: 0.05&#x2dc;0.25%, Si: 0.5% or less (excluding 0), Mn: 0.1&#x2dc;2.0%, P: 0.05% or less, S: 0.03% or less, the remainder Fe, and other unavoidable impurities, wherein a refined structure of the steel sheet comprises 90 volume % or more of martensite with a first hardness and martensite with a second hardness.

Quenched steel sheet having excellent strength and ductility

Provided is a method of manufacturing a high-carbon hot-rolled steel sheet, including the steps of i) preparing high-carbon steel materials comprising C: 0.7 to 0.9%, Si: 0.5% or less, Mn: 0.1 to 1.5%, Cr: 0.5% or less, P: 0.05% or less, and S: 0.03% or less in wt % and remaining Fe and other inevitable impurities; ii) heating the high-carbon steel materials again and manufacturing a steel sheet by performing hot rolling in an austenite region in which a finishing temperature for the hot rolling is an Ar3 transformation temperature or higher; iii) rapidly cooling the steel sheet at 520 to 620&#xb0; C. before phase transformation is started in a Run-Out Table (ROT); iv) uniformly maintaining a cooling retention temperature so that the cooled steel sheet is subject to phase transformation in any one temperature between 520 to 620&#xb0; C.; and v) winding the steel sheet in the cooling retention temperature. Also provided is the high-carbon steel sheet made by the above-described method.

High-carbon hot-rolled steel sheet, high-carbon cold-rolled steel sheet, and method of manufacturing the same

A high carbon steel sheet having superior strength and ductility and a method for manufacturing the same comprising: 0.2 to 1.0 wt % carbon (C), 0 to 3.0 wt % silicon (Si), 0 to 3.0 wt % manganese (Mn), 0 to 3.0 wt % chromium (Cr), 0 to 3.0 wt % nickel (Ni), 0 to 0.5 wt % molybdenum (Mo), 0 to 3.0 wt % aluminum (Al), 0 to 0.01 wt % boron (B), 0 to 0.5 wt % titanium (Ti), and the remainder substantially being iron (Fe) and inevitable impurities. The contents of carbon, manganese, chromium, and nickel satisfy the following Equation 1, and the contents of silicon and aluminum satisfy the following Equation 2: (3.0&#x2212;2.5&#xd7;C)wt %&#x2266;(Mn+Cr+Ni/2)&#x2266;8.5 wt %&#x2014;(Equation 1) Si+Al&#x3e;1.0 wt % (Equation 2).

High carbon steel sheet superior in tensile strength and elongation and method for manufacturing the same

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Pohang-shi, South Korea

Kyong-Su Park