Abstract: The present invention relates to steel used for a sash component and the like of a vehicle and, more specifically, to a hot-rolled steel sheet having excellent durability and a method for manufacturing same, the hot-rolled steel sheet having no cracks formed on a material and a welding heat-affected zone (HAZ) even after pipemaking and molding due to a smaller decrease in the strength of the welding heat-affected zone formed during electric resistance welding in comparison with the strength of the material (base material).

Abstract: The present invention provides a steel sheet plated with aluminum-iron and a preparation method therefor, the steel sheet comprising: a base steel sheet; and a plated layer formed on the surface of the base steel sheet and comprising: an alloyed layer containing at least one of Fe3Al, FeAl(Si), Fe2Al5, and FeAl3; and an aluminum layer formed on the alloyed layer and having a thickness less than 10% of that of the plated layer, wherein the plated layer is 20-35 ?m in thickness and contains 1-20 wt % of Mg as measured by GDS at a position 0.1 ?m deep from the surface of the plated layer and 10 wt % of oxygen as measured by GDS at a position 0.1 ?m deep from the surface of the plated layer.

Abstract: The present invention relates to a grain-oriented electrical steel sheet including 2.0 to 6.0 wt % of Si, 0.01 wt % or less (excluding 0 wt %) of C, 0.01 wt % or less (excluding 0 wt %) of N, and 0.005 to 0.1 wt % of Co, and including a balance of Fe and other inevitable impurities.

Abstract: A preferable aspect of the present invention provides a hot-rolled steel sheet with excellent low-temperature toughness, a steel pipe using the same, and a manufacturing method therefor, wherein the hot-rolled steel sheet contains, by weight, 0.35-0.65% C, 0.01-0.4% Si, 13-26% Mn, 0.01-0.3% Ti, 0.01% or less B, 4% or less Al, 1-6% Cr, 0.05% or less P, 0.02% or less S, 0.01% or less N, 0.01-2% Cu, 0.001-0.015% Nb, and the balance Fe and other unavoidable impurities, the alloy elements satisfying the following relational formulas—[Relational formula 1] 70<[10*(C/12)+(Mn/55)+(Al/27)]*100<95 and [Relational formula 2] 4<100*(Cr/52+100*(Nb/93))<9; wherein a microstructure comprises, by area fraction, 97% or more (including 100%) of austenite and 3% or less (including 0%) of a carbide, the crystal grain size of the austenite being 18-30 ?m or less; and wherein the size of the carbide is 0.5 ?m or less.