Posco

Posco Co., Ltd

Chang-Woon Jee

Yong-Hun Kweon

Tae-In Jang

Jung-Kuk Kim

Ki-Cheol Kang

Kwang-Tai Min

Sang-Ho Uhm

Yeon-Chae Jeung

Gun-Young Kim

Yeon-Chae Jeong

A welded member includes: a first steel sheet including a base steel sheet and a zinc-based plating layer formed on a surface of the base steel sheet; and a second steel sheet spot-welded on the first steel sheet and facing the zinc-based plating layer of the first steel sheet, a spot-welded zone being formed between the first steel sheet and the second steel sheet. A surface layer of the base steel sheet has a decarburization ratio of 30% or more. The decarburization ratio is represented by equation: Decarburization ratio (%) of surface layer=(1−average carbon concentration in surface layer/bulk carbon concentration)*100 where the surface layer refers to a region of the base steel sheet from the surface thereof to a depth of 35 μm. A shoulder portion of the spot-welded zone includes a B-type crack having a length of 100 μm or less, and no C-type crack.

Welded member of galvanized steel sheets

An air knife includes: a nozzle main body provided so as to inject gas in response to the width of the steel plate; a nozzle lip installed on at least one of the upper section and the lower section of an outlet of the nozzle main body and extending inclinedly so that the injection cross-sectional area of the gas becomes narrow; and at least one moment generation unit, provided at one side of the nozzle lip, for generating a rotation moment so that the nozzle lip is curved in the width direction of the steel plate and a gap between other nozzle lips varies.

Air knife

There are provided an electromagnetic wiping device, a plated steel sheet wiping apparatus including the electromagnetic wiping device, and a method for manufacturing a plated steel sheet. A portion of a plating layer of a steel sheet having passed through a plating bath is preliminarily removed at least in an edge region of the steel sheet, and a gas wiping operation is performed. Therefore, overplating is prevented at least in the edge region of the steel sheet. In addition, since the load of gas wiping can be reduced while maintaining the line speed of the steel sheet, the quantity of scattered particles and the formation of dross can be reduced for improving the plating quality of the steel sheet and the productivity of a manufacturing process.

Electromagnetic wiping device, plated steel sheet wiping apparatus including same, and method for manufacturing plated steel sheet

Provided is a steel strip stabilizing apparatus which allows shape correction and vibration suppression in a steel strip, particularly, plated steel strip, in a non-contact manner. The steel strip stabilizing apparatus includes an apparatus support body disposed on at least one side of a traveling steel strip and a steel strip stabilizing unit comprising a magnetic field generating pole disposed on the apparatus support body to face the steel strip and a pole expansion part configured to provide steel strip attraction force to a steel strip-side end of the magnetic field generating pole so as to allow shape correction or vibration suppression in the steel strip. The present invention increases the (electro)magnetic attraction force on the plated steel strip that passes through a plating bath, and thereby effectively ensures shape (curvature) correction or vibration suppression (damping) in the plated steel strip and prevents plating variations in the steel strip, and ultimately makes it possible to improve the quality of the plating of the steel strip.

Steel strip stabilization device

Provided is a steel strip stabilizing apparatus which dampens vibrations of a plated steel strip in a non-contact manner or corrects the shape of the plated steel strip. The steel strip stabilizing apparatus comprises: a plurality of steel strip damping means arranged on at least one side of a steel strip undergoing processing in a direction there towards so as to damp vibrations in the steel strip; and a damping means moving unit connected to the steel strip damping means to move at least a portion of each of the steel strip damping means in a widthwise direction with regard to the steel strip corresponding to the width of the steel strip. According to the present invention, (unit) damping means are movable in the widthwise direction with regard to the steel strip, thus improving the vibration damping properties, the steel strip curvature correcting properties and the plated quality of the steel strip.

Steel strip stabilizing apparatus

Provided is an apparatus for efficiently removing a pollutant source in a snout of a steel plating line such as a steel galvanizing line. The pollutant removing apparatus includes at least one pollutant collecting member connecting to a snout between a heating furnace and a plating tank, and a contact-free inducer varying magnetic field within the snout to forcibly guide, without contact, a pollutant source of a steel plate or a processing unit to the pollutant collecting member.

Apparatus for removing pollutant source from snout of galvanizing line

A magnetic bearing device includes a magnet generating a magnetic field at a protrusion formed toward a roll shaft, and a body portion supporting the magnet in one direction. The roll shaft is supported while an air gap is formed between the roll shaft and the protrusion, and both sides of the protrusion are rounded.

Growing community of inventors

Gwangyang-si, South Korea

Chang-Woon Jee