Posco

Posco Co., Ltd

Sang-Ho Uhm

Ki-Cheol Kang

Chang-Woon Jee

Kwang-Tai Min

Chung-Hwan Lee

Won-Seog Bong

Chung-Ha Kim

Ji-Hyun 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

The present invention relates to a zinc plated steel sheet having excellent surface quality and spot weldability, and a manufacturing method therefore. A zinc plated steel sheet according to one aspect of the present invention comprises a base steel sheet and a zinc-based plating layer formed on the surface of the base steel sheet, wherein the GDOES profile of oxygen, which is measured in the depth direction from the surface of the base steel sheet, has a form in which a local minimum point and a local maximum point alternately appear in the depth direction from the surface, and the difference (a local maximum value−a local minimum value) between the oxygen concentration (a local minimum value) at the local minimum point and the oxygen concentration (a local maximum value) at the local maximum point can be 0.1 wt % or more.

Zinc plated steel sheet having excellent surface quality and spot weldability, and manufacturing method therefor

There are provided a method for manufacturing an electrical steel sheet laminated core having reduced core loss and improved strength, and a laminated core produced by the manufacturing method. The method includes: stacking electrical steel sheets to obtain a lamination; and welding an outer surface of the lamination, wherein during the welding, a welding wire having a resistivity of 6.5&#xd7;10&#x3a9;m or greater, a relative permeability of less than 1.02, and a melting point lower than that of the electrical steel sheets is used as a welding material.

Method for manufacturing electrical steel sheet laminated core having reduced core loss and increased strength, and laminated core produced by the same

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Incheon, South Korea

Sang-Ho Uhm