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 for a high-strength electric resistance welded steel pipe having excellent expandability and a method for manufacturing same, the hot-rolled steel sheet having a smaller decrease in the strength of a welding heat-affected zone (HAZ) formed during electric resistance welding, in comparison with a base material.

Abstract: A steel material showing excellent hydrogen-induced cracking resistance according to an aspect of the present invention comprises, in weight %, 0.10-0.25% of C, 0.05-0.50% of Si, 1.0-2.0% of Mn, 0.005-0.1% of Al, 0.010% or less of P, 0.0015% or less of S, 0.001-0.03% of Nb, 0.001-0.03% of V, 0.01-0.15% of Mo, 0.01-0.50% of Cu, 0.05-0.50% of Ni, and the remainder being Fe and unavoidable impurities, and has a thickness of 100-300 mm. The maximum size of pores formed inside can be 1 ?m or less.

Abstract: A surface treatment solution composition for forming an inorganic film, comprising: 10 to 30% by weight of a trivalent chromium compound containing chromium phosphate (A) and chromium nitrate (B) and satisfying a content ratio A/(A+B) of 0.3 to 0.6; 5 to 50% by weight of a silane compound; 0.2 to 3% by weight of a vanadium-based rust-inhibiting and corrosion-resisting agent; 0.5 to 5% by weight of a cobalt-based rust-inhibiting and corrosion-resisting agent; and 12 to 84.3% by weight of water, an alloyed hot-dip galvanized steel sheet surface-treated using the composition, and a method for manufacturing the alloyed hot-dip galvanized steel sheet, are provided, and the surface treatment solution composition containing the trivalent chromium compound has an excellent effect on corrosion resistance, blackening resistance, fuel resistance, weldability, and alkali resistance.

Abstract: A high-strength austenite-based high-manganese steel material and a manufacturing method for the same, the steel material comprising: manganese (Mn): 20 to 23 wt %, carbon (C): 0.3 to 0.5 wt %, silicon (Si): 0.05 to 0.50 wt %, phosphorus (P): 0.03 wt % or less, sulfur (S): 0.005 wt % or less, aluminum (Al): 0.050 wt % or less, chromium (Cr): 2.5 wt % or less, boron (B): 0.0005 to 0.01 wt %, nitrogen (N): 0.03 wt % or less, and a balance of iron (Fe) and other inevitable impurities, wherein stacked defect energy (SFE) represented by the following relationship 1 is 3.05 mJ/m2 or more, and a microstructure comprises 95 area % or more (including 100 area %) of austenite, and comprises 6 area % or more of strain grain boundaries in an austenite recrystallized grain, is provided. SFE(mJ/m2)=?24.2+0.950*Mn+39.0*C?2.53*Si?5.50*Al?0.765*Cr??[Relationship 1] where Mn, C, Cr, Si, and Al denote weight percent of respective components.

Abstract: Provided is a ferritic stainless steel for an exhaust system heat exchanger and a method of manufacturing the same. The ferritic stainless steel includes, in percent (%) by weight of the entire composition, 0.003 to 0.1% of carbon (C), 0.01 to 2.0% of silicon (Si), 0.01 to 1.5% of manganese (Mn), 0.05% or less of phosphorus (P), 0.005% or less of sulfur (S), 10 to 30% of chromium (Cr), 0.001 to 0.10% of titanium (Ti), 0.001 to 0.15% of aluminum (Al), 0.003 to 0.03% of nitrogen (N), 0.3 to 0.6% of niobium (Nb), 0.01 to 2.5% of molybdenum (Mo), and the remainder of iron (Fe) and other inevitable impurities, wherein TiN precipitates having a size of 0.1 ?m or more are distributed in a surface layer of a ferrite matrix at a concentration of 2.5*104 ea/mm2 or less.

Abstract: Disclosed are a high-strength ultra-thick steel material and a method for manufacturing same. The high-strength ultra-thick steel material comprises in weight % 0.04-0.1% of C, 1.2-2.0% of Mn, 0.2-0.9% of Ni, 0.005-0.04% of Nb, 0.005-0.03% of Ti and 0.1-0.4% of Cu, 100 ppm or less of P and 40 ppm or less of S with a balance of Fe, and inevitable impurities, and comprises, in a subsurface area up to t/10 (t hereafter being referred to as the thickness of the steel material), polygonal ferrite of 50 area % or greater (including 100 area %) and bainite of 50 area % or less (including 0 area %) as microstructures.

Abstract: Provided is a solution composition for steel sheet surface treatment, comprising 30 wt % to 60 wt % of a trivalent chromium compound containing chromium phosphate (A) and chromium nitrate (B); 0.2 wt % to 0.4 wt % of a rust-inhibiting and corrosion-resisting agent; 0.1 wt % to 0.3 wt % of a molybdenum-based compound; 5 wt % to 10 wt % of a water-soluble cationic urethane resin; 0.5 wt % to 2.0 wt % of a silane coupling agent; and 27.3 wt % to 64.2 wt % of water, a zinc-based plated steel sheet surface-treated with the same, and a manufacturing method therefor, the zinc-based plated steel sheet surface-treated with the solution composition for steel sheet surface treatment containing trivalent chromium may have an excellent effect on corrosion resistance, blackening resistance, fingerprint resistance, oil resistance, and alkali resistance.

Abstract: A non-oriented electrical steel sheet according to an exemplary embodiment of the present invention includes, by weight, Si: 2.0 to 3.5%, Al: 0.3 to 2.5%, Mn: 0.3 to 3.5%, Sn: 0.0030 to 0.2%, Sb: 0.0030 to 0.15%, P: 0.0040 to 0.18%, individually or in a total amount of 0.0005 to 0.03% of at least one of Ga and Ge, and a remainder including Fe and unavoidable impurities, and satisfies Equation 1 below. 0.05?([Sn]+[Sb])/[P]?25??[Equation 1] ([Sn], [Sb], and [P] respectively represent the content (% by weight) of Sn, Sb, and P.

Abstract: Provided are an apparatus and a method for reaction for use in a co-precipitation reaction for preparing a catalyst or a cathode active material for a lithium secondary battery, which injects a raw material (a solution) at least between impellers according to the solution level in a vessel, thereby making a stirring speed uniform and, in particular, minimizing a concentration difference between solutions. The apparatus for the reaction may comprise: a reaction vessel; a stirring means provided inside the reaction vessel and having multistage impellers; and a raw material injecting means, comprising at least one injection nozzle connected to the reaction vessel, for injecting a raw material at least between impellers.

Abstract: An aspect of the present invention relates to a cold-rolled steel plate for hot forming, which is excellent in corrosion-resistance and spot-weldability, contains, by weight %, C: 0.1-0.4%, Si: 0.5-2.0%, Mn: 0.01-4.0%, Al: 0.001-0.4%, P: 0.001-0.05%, S: 0.0001-0.02%, Cr: 0.5% to less than 3.0%, N: 0.001-0.02%, and a balance of Fe and inevitable impurities, satisfying formula (1) below, and includes an Si amorphous oxidation layer continuously or discontinuously formed at a thickness of 1 nm-100 nm on the surface thereof. Formula (1): 1.4?0.4*Cr+Si?3.2 (wherein element symbols denote measurements of respective element contents by weight %).

Abstract: An aspect of the present invention provides: a steel for a pressure vessel, the steel having excellent surface quality while having excellent strength and toughness even after a long-term post-weld heat treatment (PWHT); and a method for manufacturing same.

Abstract: Disclosed is a highly anticorrosive martensitic stainless steel having uniformly distributed fine chromium carbide so as to have improved corrosion resistance and being applicable as tableware with suitable hardness when strengthened by heat treatment, and a manufacturing metho therefor. The highly anticorrosive martensitic stainless steel according to an embodiment of the present disclosure includes, in percent by weight (wt%), 0.14 to 0.21% of C, 0.05 to 0.11% of N, 0.1 to 0.6% of Si, 0.4 to 1.2% of Mn, 14.0 to 17.0% of Cr, 0.2 to 0.32% of C+N, and the balance of Fe and inevitable impurities, has a PREN value, represented by Formula (1), of 16 or more, and has a precipitation temperature of chromium carbide of 950° C. or lower.

Abstract: One embodiment of the present invention relates to a welded member obtained by overlapping portions of two sheets of base metal and performing fillet welding thereon using weld material, and provides a welded member having excellent fatigue strength of welded portion, and a method for manufacturing same, the welded member comprising base metal, a weld bead and root-reinforcing weld metal, wherein the base metal has a tensile strength of 780 MPa, the weld bead has a toe angle of 160 degrees or greater and the weld bead and the root-reinforcing weld metal have a Vicker's hardness of 280-320 Hv and a fatigue strength of 350 MPa or higher.

Abstract: Provided is a galvanized steel sheet having excellent plating adhesion, having a plated layer with improved friction characteristics by means of a predetermined level of Fe elution, and having excellent corrosion resistance; and a manufacturing method therefor.

Abstract: An upconversion nanoparticle includes at least one host selected from LiYF4, NaY, NaYF4, NaGdF4, and CaF3, at least one sensitizer selected from Sm3+, Nd3+, Dy3+, Ho3+, and Yb3+ doped in the at least one host, and at least one activator selected from Er3+, Ho3+, Tm3+, and Eu3+ doped in the at least one host. The upconversion nanoparticle is designed using a calculation from first principles to absorb light in the near-infrared wavelength range whose stability is ensured. Further, a hyaluronic acid-upconversion nanoparticle conjugate, in which the upconversion nanoparticle as described above is bonded to hyaluronic acid, is provided to be used in various internal sites with a hyaluronic acid receptor, particularly enables targeting, and increases an internal retention period and biocompatibility thereof.

Abstract: An electrical steel sheet adhesive coating composition according to an exemplary embodiment of the present invention includes, based on 100 wt % of the total solids: a resin at 20 to 40 wt % and having an average particle diameter of 10 to 300 nm; an inorganic nanoparticle at 10 to 35 wt % bonded with the resin; a metal phosphoric acid salt at 10 to 30 wt %; and phosphoric acid at 10 to 40 wt %. An electrical steel sheet product according to an exemplary embodiment of the present invention includes a plurality of electrical steel sheets; and an adhesive layer disposed between the plurality of electrical steel sheets, wherein the adhesive layer includes a metal of one or more kinds among Al, Mg, Ca, Co, Zn, Zr, and Fe at 0.5 to 30 wt %, N at 0.1 to 10 wt %, C at 0.1 to 5 wt %, P at 1 to 30 wt %, a metal of one or more kinds among Si and Ti at 10 to 30 wt %, and a balance of O.

Abstract: Provided are a high-carbon steel sheet having good surface quality and a manufacturing method therefor. The present invention provides a high-carbon pickled steel sheet having good surface quality, the steel sheet containing, in weight %, 0.4% or more and less than 1.2% of carbon (C), 0.5% or less (excluding 0%) of silicon (Si), 0.05% or less of phosphorus (P), 0.03% or less of sulfur (S), 0.1 to 2.5% of at least one of manganese (Mn) and chromium (Cr), and the balance of iron (Fe) and inevitable impurities, wherein the average thickness of an internal oxide layer and/or a decarburized layer formed in a surface layer portion of the steel sheet is 1 to 10 ?m and the standard deviation of the thickness of the internal oxide layer and/or the decarburized layer in the length direction of the steel sheet is 2 ?m or less.

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: A steel sheet with excellent surface quality, and a manufacturing method therefor are provided. The present invention provides a pickled steel sheet with excellent surface quality, comprising, by wt %, carbon (C) in an amount greater than or equal to 0.05% and less than 0.4%, 0.5% or less of silicon (Si) (excluding 0%), 0.05% or less of phosphorus (P), 0.03% or less of sulfur (S), 0.01% or less of boron (B), 0.1-2.5% of manganese (Mn) and/or chromium (Cr), and the balance of iron (Fe) and inevitable impurities, wherein the average thickness of an internal oxide layer and/or a tantalum layer, which are formed on the surface layer of the steel sheet, is 1-10 ?m, and the standard deviation of the thickness of the internal oxide layer and/or the tantalum layer in the length direction of the steel sheet is 2 ?m or less.

Abstract: An adhesive coating composition according to an embodiment of the present invention comprises polyethylene acrylate including a repeating unit represented by chemical formula 1 below and a repeating unit represented by chemical formula 2 below, wherein the polyethylene acrylate includes 65-90 wt % of the repeating unit represented by chemical formula 1 below and 10-35 wt % of the repeating unit represented by chemical formula 2 below.