A coating weight control apparatus includes: a strip passing position movement amount estimate part configured to estimate an movement amount of a strip passing position, in response to any of activation factors for movement of a strip passing position, that is, a welding point passing, a change in tension, and an operation of a correcting roll; and a nozzle position control part configured to shift each of positions of a front side nozzle and a back side nozzle by an amount corresponding to the movement amount of the strip passing position estimated by the strip passing position movement amount estimate part.

A stabilization apparatus for stabilizing a metal strip rising from a molten metal bath along a theoretical feeding plane, comprising at least one pair of air knives, each being arranged in a mutually specular manner with respect to said plane; at least one pair of electromagnetic stabilizing devices, each being arranged in a mutually specular manner with respect to said plane; a pair of first support beams, each supporting a respective air knife; a pair of second support beams, each supporting a respective electromagnetic stabilizer device; wherein the pair of second support beams is distinct from the pair of first support beams, and wherein the first support beams are distal from the plane, while the second support beams are proximal to said plane and arranged in an innermost position with respect to the pair of first support beams.

A stabilization apparatus for stabilizing a metal strip rising from a molten metal bath along a theoretical feeding plane, comprising at least one pair of air knives, each being arranged in a mutually specular manner with respect to said plane; at least one pair of electromagnetic stabilizing devices, each being arranged in a mutually specular manner with respect to said plane; a pair of first support beams, each supporting a respective air knife; a pair of second support beams, each supporting a respective electromagnetic stabilizer device; wherein the pair of second support beams is distinct from the pair of first support beams, and wherein the first support beams are distal from the plane, while the second support beams are proximal to said plane and arranged in an innermost position with respect to the pair of first support beams.

Embodiments of the present disclosure provides an aluminum alloy-plated steel sheet having high surface quality and weldability, a hot-formed member, and methods for manufacturing the aluminum alloy-plated steel sheet and the hot-formed member. The aluminum alloy-plated steel sheet includes: a base steel sheet; and an aluminum alloy plating layer formed on the base steel sheet, wherein the aluminum alloy plating layer includes, by weight %, Zn: 21% to 35%, Si: 1% to 6.9%, Fe: 2% to 12%, and the balance of Al and inevitable impurities.

A steel part includes a steel sheet substrate and a coating on at least one surface of the steel sheet substrate. The coating includes between 0.2 and 0.7% by weight of Al, with a remainder of the metal coating being Zn and inevitable impurities. The steel sheet substrate and the coating have at least one deformation. An outer surface of the coating has a waviness Wa.sub.0.8 of less than or equal to 0.43 μm.

A steel part includes a steel sheet substrate and a coating on at least one surface of the steel sheet substrate. The coating includes between 0.2 and 0.7% by weight of Al, with a remainder of the metal coating being Zn and inevitable impurities. The steel sheet substrate and the coating have at least one deformation. An outer surface of the coating has a waviness Wa.sub.0.8 of less than or equal to 0.43 μm.

An embodiment of the present disclosure provides a hot dip alloy coated steel material having high corrosion resistance, the hot dip alloy coated steel material including: a base steel sheet; and a hot dip alloy coating layer formed on the base steel sheet, wherein the hot dip alloy coating layer includes, by wt %, Al: from greater than 8% to 25%, Mg: from greater than 4% to 12%, and a balance of Zn and other inevitable impurities, wherein a surface of the hot dip alloy coating layer has a surface X-ray diffraction intensity satisfying Condition 1 below: [Condition 1] 2000 cps≤X-ray diffraction intensity≤20000 cps where the X-ray diffraction intensity refers to M−N, M refers to a greatest peak intensity within a 2θ range of 20.00° to lower than 21°, and N refers to a peak intensity at 2θ=20.00°.

A method of forming a coating of an Al—Zn—Si—Mg alloy on a steel strip to form an Al—Zn—Mg—Si coated steel strip is disclosed. The method includes the steps of dipping steel strip into a bath of molten Al—Zn—Si—Mg alloy and forming a coating of the alloy on exposed surfaces of the steel strip and cooling the coated strip with cooling water. The cooling step includes controlling the p H of cooling water to be in a range of pH 5-9. Particular embodiments focus on Al—Zn—Si—Mg alloys that contain the following elements in % by weight: Zn: 2 to 19, Si: 0.01 to 2, Mg: 1 to 10, and Balance Al and unavoidable impurities.

A method of forming a coating of an Al—Zn—Si—Mg alloy on a steel strip to form an Al—Zn—Mg—Si coated steel strip is disclosed. The method includes the steps of dipping steel strip into a bath of molten Al—Zn—Si—Mg alloy and forming a coating of the alloy on exposed surfaces of the steel strip and cooling the coated strip with cooling water. The cooling step includes controlling the p H of cooling water to be in a range of pH 5-9. Particular embodiments focus on Al—Zn—Si—Mg alloys that contain the following elements in % by weight: Zn: 2 to 19, Si: 0.01 to 2, Mg: 1 to 10, and Balance Al and unavoidable impurities.

A crossbow correction device 16 for correcting crossbow of a steel strip S by a magnetic force during conveyance includes a plurality of electromagnets 57a to 57d, 67a to 67d arranged in a strip width direction of the steel strip S and facing each other so as to sandwich the steel strip S in a strip thickness direction, a moving mechanism 51 to 54, 61 to 64 capable of moving the electromagnets 57a to 57d, 67a to 67d relative to the steel strip S, and a controller 17 configured to operate the moving mechanism 51 to 54, 61 to 64, based on a current value flowing through the electromagnets 57a to 57d, 67a to 67d.