Posco

Shin-Hwan Kang

Ju-Seung Lee

Ki-Jang Oh

Sang-Woo Choi

Il-Ryoung Sohn

Seong-Ho Han

Chang-Hyun Park

Ho-Moon Bae

Geon Shin

Se-Ho Choi

Jong-Pil Yun

Min-Ki Seun

An aspect of the present disclosure may provide a defect detection apparatus and method for a steel plate, in which a defect in a steel plate may be detected, and particularly, only an inner defect in the steel plate may be detected, even with a relatively low amplification rate.

Apparatus and method of detecting defect of steel plate

Provided is a defect inspection device of a steel plate. The defect inspection device according to the present invention includes a plurality of inspection units arranged in a width direction of the steel plate, wherein each of the plurality of inspection units includes a first magnetized pole and a second magnetized pole corresponding to each other. Also, the inspection unit includes: a magnetizing part generating a magnetic flux for magnetizing the steel plate in a direction inclined at a predetermined angle with respect to a rolling direction through the first magnetized pole and the second magnetized pole; and a detection part detecting a leakage flux that leaks due to defects existing in or on the steel plate by using the flux generated by the magnetizing part. Thus, the defects may be correctly detected through the defect inspection device.

Defect inspection device of steel plate

Provided are a bake hardening steel having a crystalline grain size of ASTM No. 9 or more and a method for preparing the bake hardening steel by controlling the winding, rolling and cooling conditions. The bake hardening steel includes: C:0.0016&#x2dc;0.0025%, Si:0.02% or less, P:0.01&#x2dc;0.05%, S:0.01% or less, sol.Al:0.08&#x2dc;0.12%, N:0.0025% or less, Ti:0.003% or less, Nb:0.003&#x2dc;0.011%, Mo:0.01&#x2dc;0.1%, B:0.0005&#x2dc;0.0015% or less, balance Fe and other inevitable impurities, wherein % is weight %, and Mn and P satisfy the relation of &#x2212;30(&#xb0; C.)&#x2267;803P&#x2212;24.4Mn&#x2212;58.

Bake hardening steel with excellent surface properties and resistance to secondary work embrittlement, and preparation method thereof

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Gwangyang-si, South Korea

Shin-Hwan Kang