Abstract: Provided is a hot-dip galvanized steel plate which is applicable as a material for a vehicle outer panel and has an excellent bake hardenability and anti-aging property at room temperature, and a method for manufacturing a hot-dip galvanized steel plate, the method comprising a process including the steps of: winding a hot-rolled steel plate, followed by cooling at a speed of 0.002-0.027° C./sec; cold-rolling the cooled steel plate; continuously annealing the cold-rolled steel plate; and cooling the annealed steel plate in the multi-stage manner of primary to third rounds.

Abstract: Provided is a high strength steel sheet having an excellent high-temperature elongation characteristic. The sheet includes, by weight %, 0.4-0.9% of C, 0.01-1.5% of Cr, 0.03% or less (exclusive of 0%) of P, 0.01% or less (exclusive of 0%) of S, 0.01% or less (exclusive of 0%) of N, 0.01% or less (exclusive of 0%) of sol. Al, and a balance of Fe and inevitable impurities, and comprises at least one among 2.1% or less (exclusive of 0%) of Mn and 1.6% or less (exclusive of 0%) of Si; the sheet has a microcrystalline structure including pearlite having an area fraction of 80% or more and ferrite having an area fraction of 20% or less; and the pearlite includes cementite having a major axis length of 200 nm or shorter.

Abstract: Provided are a hot-dip galvanized steel sheet and a hot-dip galvannealed steel sheet with excellent aging-resistance properties and bake hardenability, and a method for manufacturing the same. The hot-dip galvanized steel sheet has a molten zinc plated layer on the surface of a base steel sheet, wherein the base steel sheet comprises: 0.002-0.012 wt % of carbon (C); 1.6-2.7 wt % of manganese (Mn); 0.03 wt % or less (excluding 0 wt %) of phosphorus (P); 0.01 wt % or less (excluding 0 wt %) of sulfur (S); 0.01 wt % or less (excluding 0 wt %) of nitrogen (N); 0.02-0.06 wt % of aluminum (sol.Al); 1.0 wt % or less (excluding 0 wt %) of chromium (Cr), with the remainder being iron and inevitable impurities; the base steel sheet satisfies the relation of 1.3?Mn(wt %)/(1.15×Cr(wt %))?20.5; Mneq defined by relational expression 1 satisfies 1.9?Mneq?3.9.