Abstract: A continuous annealing apparatus includes: a pre-treatment device to prepare a strip unwound from a coil; a heating device to heat the strip prepared by the pre-treatment device; a heat holding device to isothermally maintain the strip heated by the heating device; a first cooling device to cool the strip heat-maintained by the heat holding device; an annealing device including a first annealing device for annealing the strip, which, is cooled by the first cooling device, for a first time, and a second annealing device for winding the strip, which is cooled by the first cooling device, into a coil and then unwinding the coil into the strip again after annealing for a second time; a second cooling device to cool the strip annealed by the first annealing device or the second annealing device; and a post-treatment device to wind the strip cooled by the second cooling device into the coil.

Abstract: Disclosed is a steel composition for hot stamping that comprises carbon (C) in an amount of about 0.22 to about 0.25 wt %, silicon (Si) in an amount of about 0.2 to about 0.3 wt %, manganese (Mn) in an amount of about 1.2 to about 1.4 wt %, titanium (Ti) in an amount of about 0.02 to about 0.05 wt %, chromium (Cr) in an amount of about 0.11 to about 0.2 wt %, boron (B) in an amount of about 0.005 to about 0.01 wt %, zinc (Zr) in an amount of about 0.005 to about 0.02 wt %, niobium (Nb) in an amount of about 0.01 to about 0.05 wt %, tungsten (W) in an amount of about 0.1 to about 0.5 wt %, iron (Fe) constituting the remaining balance of the steel composition, all the wt % based on the total amount of the steel composition.

Abstract: A continuous annealing apparatus includes: a pre-treatment device to prepare a strip unwound from a coil; a heating device to heat the strip prepared by the pre-treatment device; a heat holding device to isothermally maintain the strip heated by the heating device; a first cooling device to cool the strip heat-maintained by the heat holding device; an annealing device including a first annealing device for annealing the strip, which, is cooled by the first cooling device, for a first time, and a second annealing device for winding the strip, which is cooled by the first cooling device, into a coil and then unwinding the coil into the strip again after annealing for a second time; a second cooling device to cool the strip annealed by the first annealing device or the second annealing device; and a post-treatment device to wind the strip cooled by the second cooling device into the coil.

Abstract: A bearing steel includes 1.0 to 1.3 wt % carbon; 0.9 to 1.6 wt % silicon; 0.5 to 1.0 wt % manganese; 1.5 to 2.5 wt % nickel; 1.5 to 2.5 wt % chromium; 0.2 to 0.5 wt % molybdenum; 0.01 to 0.06 wt % aluminum; 0.01 to 0.1 wt % copper; at least one selected from the group consisting of more than 0 wt % and less than 0.38 wt % vanadium and more than 0 wt % and less than 0.02 wt % niobium; and a balance of iron.

Abstract: A carburized alloy steel includes, based on a total weight of the carburized alloy steel, 0.1 to 0.35 wt % carbon, 0.1 to 2.0 wt % silicon, 0.1 to 1.5 wt % manganese, 1.5 to 3.0 wt % chromium, 0.2 to 0.5 wt % molybdenum, greater than 0 to 0.07 wt % niobium, and a balance of iron.

Abstract: Disclosed is a steel composition for hot stamping that comprises carbon (C) in an amount of about 0.22 to about 0.25 wt %, silicon (Si) in an amount of about 0.2 to about 0.3 wt %, manganese (Mn) in an amount of about 1.2 to about 1.4 wt %, titanium (Ti) in an amount of about 0.02 to about 0.05 wt %, chromium (Cr) in an amount of about 0.11 to about 0.2 wt %, boron (B) in an amount of about 0.005 to about 0.01 wt %, zinc (Zr) in an amount of about 0.005 to about 0.02 wt %, niobium (Nb) in an amount of about 0.01 to about 0.05 wt %, tungsten (W) in an amount of about 0.1 to about 0.5 wt %, iron (Fe) constituting the remaining balance of the steel composition, all the wt % based on the total amount of the steel composition.

Abstract: A carburized alloy steel includes, based on a total weight of the carburized alloy steel, 0.1 to 0.35 wt % carbon, 0.1 to 2.0 wt % silicon, 0.1 to 1.5 wt % manganese, 1.5 to 3.0 wt % chromium, 0.2 to 0.5 wt % molybdenum, greater than 0 to 0.07 wt % niobium, and a balance of iron.

Abstract: A bearing steel includes 1.0 to 1.3 wt % carbon; 0.9 to 1.6 wt % silicon; 0.5 to 1.0 wt % manganese; 1.5 to 2.5 wt % nickel; 1.5 to 2.5 wt % chromium; 0.2 to 0.5 wt % molybdenum; 0.01 to 0.06 wt % aluminum; 0.01 to 0.1 wt % copper; at least one selected from the group consisting of more than 0 wt % and less than 0.38 wt % vanadium and more than 0 wt % and less than 0.02 wt % niobium; and a balance of iron.

Abstract: Disclosed herein is a method for warm forming of a super high tensile strength steel sheet. The method may improve productivity and simultaneously maintain accurate strength by securing thermal structure stability and dimensional stability during heating and forming the super high tensile strength steel sheet. According to an exemplary embodiment of the present invention, the method for warm forming of a super high tensile strength steel sheet includes: heating a steel sheet having a single-phase structure at Al transformation temperature or less; pressing, in a mold, the heated steel sheet to be formed in a predetermined shape; and extracting and cooling the pressed steel sheet.

Abstract: Disclosed are a coating layer having excellent low-friction ability at a high temperature and a method of forming the coating layer. The high-temperature low-fiction coating layer may improve heat resistance, fatigue resistance, low-friction ability, and seizure resistance of the turbine wheel of a turbocharger and the parts sliding at a high temperature in the exhaust system of an engine, improve turbo-lag, and improve durability of the high-temperature parts in the exhaust system of an engine.