The present invention relates to an apparatus for removing top dross of a plating pot where a snout and an air knife are arranged, the snout being arranged between the front end region and the rear end region of a plating pot. The present invention provides an apparatus for removing top dross of a plating pot, the apparatus comprising: a first wiping means which is mounted on the plating pot and is arranged between the snout and the air knife so as to be movable in the width direction of the plating pot; a second wiping means which is mounted on the plating pot and is rotatably arranged between the air knife and the first wiping means so as to transfer, to the rear end region, the top dross transferred by the first wiping means; and a third wiping means which is mounted on the plating pot and is rotatably arranged between the air knife and the front end region so as to transfer the top dross to the front end region. Thereby, the present invention provides an advantageous effect of effectively removing dross.

A hot-rolled strip steel product having a chemical composition consisting of, in terms of weight percentages (wt. %): 0.025%-0.070% C, 0%-1.10% Si, 0.50%-2.0% Mn, <0.020% P, <0.050% S, <0.010% N, 0%-0.60% Cr, 0%-0.20% Ni, 0%-0.25% Cu, 0%-0.20% Mo, 0%-0.15% Al, 0%-0.050% Nb, 0.020%-0.20-% V, 0.020%-0.15% Ti, 0%-0.0010% B, remainder Fe and inevitable impurities, wherein the strip steel product has a microstructure comprising of, in terms of volume percentages (vol. %), ferrite ≥90%, wherein the ferrite structure comprises 10%-50% quasi-polygonal ferrite and a reminder of ferrite structure is polygonal ferrite and/or bainite: and wherein the steel strip product has an average ferrite grain size of <10 μm, an average hole expansion ratio of ≥50%, a yield strength (Rp0.2%) longitudinal to rolling direction of ≥660 MPa and a tensile strength of ≥760 MPa.

A hot-rolled strip steel product having a chemical composition consisting of, in terms of weight percentages (wt. %): 0.025%-0.070% C, 0%-1.10% Si, 0.50%-2.0% Mn, <0.020% P, <0.050% S, <0.010% N, 0%-0.60% Cr, 0%-0.20% Ni, 0%-0.25% Cu, 0%-0.20% Mo, 0%-0.15% Al, 0%-0.050% Nb, 0.020%-0.20-% V, 0.020%-0.15% Ti, 0%-0.0010% B, remainder Fe and inevitable impurities, wherein the strip steel product has a microstructure comprising of, in terms of volume percentages (vol. %), ferrite ≥90%, wherein the ferrite structure comprises 10%-50% quasi-polygonal ferrite and a reminder of ferrite structure is polygonal ferrite and/or bainite: and wherein the steel strip product has an average ferrite grain size of <10 μm, an average hole expansion ratio of ≥50%, a yield strength (Rp0.2%) longitudinal to rolling direction of ≥660 MPa and a tensile strength of ≥760 MPa.

A hot-rolled strip steel product is described having a chemical composition consisting of, in terms of weight percentages (wt. %): 0.030%-0.10% C, 0%-1.10% Si, 0.50%-2.0% Mn, <0.020% P, <0.010% S,<0.010% N, 0%-0.60% Cr, 0%-0.20% Ni, 0%-0.25% Cu, 0%-0.30% Mo, 0%-0.15% Al, 0%-0.10% Nb, 0.10%-0.30% V, <0.020% Ti, 0%-0.0010% B, remainder being Fe and inevitable impurities, wherein the hot rolled strip steel product has a a microstructure comprising, in terms of volume percentages (vol. %), ferrite≥90, wherein the ferrite structure comprises bainite, at least 50% of polygonal ferrite and at most 10% quasi-polygonal ferrite, and wherein the steel strip product has an average hole expansion ratio≥50%, a yield strength (Rp0.2%) longitudinal to rolling direction of ≥660 MPa and a tensile strength≥760 MPa.

Method of hot press forming an article from zinc or zinc alloy coated steel, wherein the steel is a product obtained by: casting the molten steel into slabs; reheating the slabs; hot rolling the steel into a strip, preferably with an FRT above Ar3; coiling the hot rolled steel strip; pickling the hot rolled steel strip; continuous annealing the strip; hot dip coating the steel strip with the zinc or zinc alloy whilst: using a dipping time of 3 seconds or more; maintaining in the hot dip bath a bath temperature of 420° C. to 500° C.; wherein the zinc bath contains essentially zinc, at least 0.1% Al, and optionally up to 5% Al and optionally up to 4% Mg, the rest of the bath including further elements all individually less than 0.3%, and unavoidable impurities; hot press forming the article.

Method of hot press forming an article from zinc or zinc alloy coated steel, wherein the steel is a product obtained by: casting the molten steel into slabs; reheating the slabs; hot rolling the steel into a strip, preferably with an FRT above Ar3; coiling the hot rolled steel strip; pickling the hot rolled steel strip; continuous annealing the strip; hot dip coating the steel strip with the zinc or zinc alloy whilst: using a dipping time of 3 seconds or more; maintaining in the hot dip bath a bath temperature of 420° C. to 500° C.; wherein the zinc bath contains essentially zinc, at least 0.1% Al, and optionally up to 5% Al and optionally up to 4% Mg, the rest of the bath including further elements all individually less than 0.3%, and unavoidable impurities; hot press forming the article.

This hot-dip Zn—Al—Mg-based plated steel includes: a steel; and a plating layer formed on a surface of the steel, in which the plating layer contains, as an average composition, Mg: 1 to 10 mass %, Al: 4 to 22 mass %, and a remainder consisting of Zn and impurities, the plating layer includes an (Al—Zn mixed structure) in an area ratio of 10% to 70% in a cross section of the plating layer in a matrix of an (Al/Zn/MgZn.sub.2 ternary eutectic structure), the (Al—Zn mixed structure) includes a first region that has a Zn concentration in a range of 75 mass % or more and less than 85 mass % and a second region that is present inside the first region and has a Zn concentration in a range of 67 mass % or more and less than 75 mass %, and an area ratio of the second region in the (Al—Zn mixed structure) in the cross section of the plating layer is more than 0% and 40% or less.

This hot-dip Zn—Al—Mg-based plated steel includes: a steel; and a plating layer formed on a surface of the steel, in which the plating layer contains, as an average composition, Mg: 1 to 10 mass %, Al: 4 to 22 mass %, and a remainder consisting of Zn and impurities, the plating layer includes an (Al—Zn mixed structure) in an area ratio of 10% to 70% in a cross section of the plating layer in a matrix of an (Al/Zn/MgZn.sub.2 ternary eutectic structure), the (Al—Zn mixed structure) includes a first region that has a Zn concentration in a range of 75 mass % or more and less than 85 mass % and a second region that is present inside the first region and has a Zn concentration in a range of 67 mass % or more and less than 75 mass %, and an area ratio of the second region in the (Al—Zn mixed structure) in the cross section of the plating layer is more than 0% and 40% or less.

Provided are a plated steel sheet and a method for manufacturing same, the plated steel sheet comprising: a base steel sheet; a Zn—Mg—Al based steel sheet plating layer provided on at least one surface of the base steel sheet; and an Fe—Al based inhibition layer provided between the base steel sheet and the Zn—Mg—Al based plating layer, wherein the plating layer comprises, in wt %: 4% or more of Mg; 2.1 times or more of Mg content and 14.2% or less of Al; 0.2% or less (including 0%) of Si; 0.1% or less (including 0%) of Sn; the remainder Zn; and unavoidable impurities.

Provided are a plated steel sheet and a method for manufacturing same, the plated steel sheet comprising: a base steel sheet; a Zn—Mg—Al based steel sheet plating layer provided on at least one surface of the base steel sheet; and an Fe—Al based inhibition layer provided between the base steel sheet and the Zn—Mg—Al based plating layer, wherein the plating layer comprises, in wt %: 4% or more of Mg; 2.1 times or more of Mg content and 14.2% or less of Al; 0.2% or less (including 0%) of Si; 0.1% or less (including 0%) of Sn; the remainder Zn; and unavoidable impurities.