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: 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: 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: Provided is a method of manufacturing an HPF part comprising: preparing a steel sheet comprising C: 0.18% to 0.25%, Si: 0.1% to 1.0%, Mn: 0.9% to 1.5%, P: 0.03% or less, S: 0.01% or less, Al: 0.01% to 0.05%, Cr: 0.05% to 0.5%, Ti: 0.01% to 0.05%, B: 0.001% to 0.005%, N: 0.009% or less, and a balance of Fe and impurities; heating the steel sheet at 550° C. to 850° C. followed by maintaining at 640° C. to 680° C., and immersing the steel sheet in a hot dip aluminum plating bath, and a balance of Al and impurities; cooling the plated steel sheet at 15° C./s or faster; heating the cooled hot dip aluminum plated steel sheet at 880° C. to 930° C. followed by maintaining for a certain time; and hot forming the alloyed hot dip aluminum plated steel sheet and quenching at a range of 300° C. or lower at the same time.

Abstract: An HPF molding member having a melted aluminum plating layer formed on the surface of a base steel sheet and excellent delamination resistance. The base steel sheet comprises: 0.18-0.25% by weight of C; 0.1-1.0% by weight of Si; 0.9-1.5% by weight of Mn; 0.03% by weight or less of P; 0.01% by weight or less of S; 0.01-0.05% by weight of Al; 0.05-0.5% by weight of Cr; 0.01-0.05% by weight of Ti; 0.001-0.005% by weight of B; 0.009% by weight or less of N; and the balance Fe and other impurities. The plating layer consists of a soft diffusion layer and a hard alloy layer, the hard alloy layer having a tau layer irregularly and non-continuously dispersed and distributed on the inside thereof at 10% or more of the entire area fraction. The difference in hardness between the alloy layer and the diffusion layer is 400 (Hv) or less.

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: Provided is a method of manufacturing an HPF part comprising: preparing a steel sheet comprising C: 0.18% to 0.25%, Si: 0.1% to 1.0%, Mn: 0.9% to 1.5%, P: 0.03% or less, S: 0.01% or less, Al: 0.01% to 0.05%, Cr: 0.05% to 0.5%, Ti: 0.01% to 0.05%, B: 0.001% to 0.005%, N: 0.009% or less, and a balance of Fe and impurities; heating the steel sheet at 550° C. to 850° C. followed by maintaining at 640° C. to 680° C., and immersing the steel sheet in a hot dip aluminum plating bath, and a balance of Al and impurities; cooling the plated steel sheet at 15° C./s or faster; heating the cooled hot dip aluminum plated steel sheet at 880° C. to 930° C. followed by maintaining for a certain time; and hot forming the alloyed hot dip aluminum plated steel sheet and quenching at a range of 300° C. or lower at the same time.

Abstract: Provided is a hot press-formed (HPF) member with excellent powdering resistance at the time of press forming. The HPF member includes a hot-dip coating layer containing Al on a surface of a base steel sheet. The base steel sheet includes, based on wt %, 0.18-0.25% of C, 0.1-1.0% of Si, 0.9-1.5% of Mn, 0.03% or less of P, 0.01% or less of S, 0.01-0.05% of Al, 0.05-0.5% of Cr, 0.01-0.05% of Ti, 0.001-0.005% of B, 0.009% or less of N, the balance Fe, and the other impurities. The hot-dip coating layer comprises a soft diffusion layer and a hard alloy layer. The alloy layer has a Tau phase in the range of 10-30%, in terms of area percent.

Abstract: An HPF molding member having a melted aluminum plating layer formed on the surface of a base steel sheet and excellent delamination resistance. The base steel sheet comprises: 0.18-0.25% by weight of C; 0.1-1.0% by weight of Si; 0.9-1.5% by weight of Mn; 0.03% by weight or less of P; 0.01% by weight or less of S; 0.01-0.05% by weight of Al; 0.05-0.5% by weight of Cr; 0.01-0.05% by weight of Ti; 0.001-0.005% by weight of B; 0.009% by weight or less of N; and the balance Fe and other impurities. The plating layer consists of a soft diffusion layer and a hard alloy layer, the hard alloy layer having a tau layer irregularly and non-continuously dispersed and distributed on the inside thereof at 10% or more of the entire area fraction. The difference in hardness between the alloy layer and the diffusion layer is 400 (Hv) or less.

Abstract: Provided is a hot press-formed (HPF) member with excellent powdering resistance at the time of press forming. The HPF member includes a hot-dip coating layer containing Al on a surface of a base steel sheet. The base steel sheet includes, based on wt %, 0.18-0.25% of C, 0.1-1.0% of Si, 0.9-1.5% of Mn, 0.03% or less of P, 0.01% or less of S, 0.01-0.05% of Al, 0.05-0.5% of Cr, 0.01-0.05% of Ti, 0.001-0.005% of B, 0.009% or less of N, the balance Fe, and the other impurities. The hot-dip coating layer comprises a soft diffusion layer and a hard alloy layer. The alloy layer has a Tau phase in the range of 10-30%, in terms of area percent.

Abstract: The present invention relates to an insulating adhesive composition for metal printed circuit board, an adhesive-coated metal plate using the same, and a method for manufacturing the adhesive-coated metal plate. The adhesive composition according to the present invention forms an adhesive layer that is excellent in terms of adhesion to a copper foil, electrical insulating properties, and thermal resistance. The composition contains a specific epoxy resin, a curing agent and alumina. According to the present invention, in coating the metal plate with the solvent type adhesive, a roll coating method is used to perform a continuous coating process on the metal plate, thereby improving productivity when compared to the general method using a sheet type adhesive film.

Abstract: Provided is an aluminum coated steel sheet having excellent oxidation and heat resistance. The aluminum coated steel sheet includes an aluminum coating layer and an alloy layer. The aluminum coating layer is formed on a surface of a steel sheet which includes 0.001 to 0.015 wt % of carbon (C), 0.05 to 0.3 wt % of silicon (Si), 0.1 to 0.6 wt % of manganese (Mn), 0.01 to 0.05 wt % niobium (Nb), 0.01 wt % or less of phosphorus (P), 0.01 wt % or less of sulfur (S), 0.1 wt % or less of soluble aluminum (Al), 0.05 to 0.5 wt % of copper (Cu), 0.05 to 0.5 wt % nickel (Ni), 0.001 to 0.01 wt % of nitrogen (N), and the balance of Fe and inevitable impurities. The alloy layer includes an intermetallic compound at an interface between the steel sheet and the aluminum coating layer.

Abstract: Provided is an aluminum coated steel sheet having excellent oxidation and heat resistance. The aluminum coated steel sheet includes an aluminum coating layer and an alloy layer. The aluminum coating layer is formed on a surface of a steel sheet which includes 0.001 to 0.015 wt % of carbon (C), 0.05 to 0.3 wt % of silicon (Si), 0.1 to 0.6 wt % of manganese (Mn), 0.01 to 0.05 wt % niobium (Nb), 0.01 wt % or less of phosphorus (P), 0.01 wt % or less of sulfur (S), 0.1 wt % or less of soluble aluminum (Al), 0.05 to 0.5 wt % of copper (Cu), 0.05 to 0.5 wt % nickel (Ni), 0.001 to 0.01 wt % of nitrogen (N), and the balance of Fe and inevitable impurities. The alloy layer includes an intermetallic compound at an interface between the steel sheet and the aluminum coating layer.

Abstract: Disclosed is a steel sheet that exhibits an ultra-high strength after hot press forming followed by rapid cooling, and an enhanced yield strength after painting. The steel sheet has a composition comprising 0.1% to 0.5% by weight of C, 0.01% to 1.0% by weight of Si, 0.5% to 4.0% by weight of Mn, 0.1% by weight or less of P, 0.03% by weight or less of S, 0.1% by weight of soluble Al, 0.01% to 0.1% by weight of N, 0.3% by weight or less of W, and the balance Fe and other inevitable impurities. Further disclosed are a hot-pressed part made of the steel sheet and a method for manufacturing the hot-pressed part. The hot-pressed part achieves a high increment in yield strength after heat treatment for painting while ensuring an ultra-high tensile strength. Furthermore, the hot-pressed part exhibits superior adhesion to a coating layer, good surface appearance and improved corrosion resistance after painting.