Provided is a technique that can produce a hot dip Zn—Al—Mg-based alloy coated steel product with a good plating appearance, without the need for heating of a steel product prior to immersion in a hot dip plating bath. Flux (11) for hot dip Zn—Al—Mg-based alloy plating contains: ZnCl.sub.2; and a low-reactive chloride which has low reactivity with respect to Mg in a plating bath and contains at least two chlorides selected from the compound group consisting of alkali metal chlorides and alkaline-earth metal chlorides, and a composition of the ZnCl.sub.2 and the low-reactive chloride is adjusted so that a liquidus temperature of the flux is 450° C. or lower.

Provided is a technique that can produce a hot dip Zn—Al—Mg-based alloy coated steel product with a good plating appearance, without the need for heating of a steel product prior to immersion in a hot dip plating bath. Flux (11) for hot dip Zn—Al—Mg-based alloy plating contains: ZnCl.sub.2; and a low-reactive chloride which has low reactivity with respect to Mg in a plating bath and contains at least two chlorides selected from the compound group consisting of alkali metal chlorides and alkaline-earth metal chlorides, and a composition of the ZnCl.sub.2 and the low-reactive chloride is adjusted so that a liquidus temperature of the flux is 450° C. or lower.

Provided is a plated steel to be used for automobiles, electric home appliances, building materials and the like and, more specifically, to a zinc alloy-plated steel having excellent corrosion resistance and surface smoothness, and a method for manufacturing the same.

Provided is a plated steel to be used for automobiles, electric home appliances, building materials and the like and, more specifically, to a zinc alloy-plated steel having excellent corrosion resistance and surface smoothness, and a method for manufacturing the same.

A hot pressed member disclosed herein includes: a base steel sheet; a Fe—Zn—Al—Mg-based alloy coated layer containing an α-Fe phase and a Γ phase and formed on at least one surface of the base steel sheet; and an oxide layer containing Zn, Al, and Mg and formed on the Fe—Zn—Al—Mg-based alloy coated layer, in which a ratio of I.sub.Γ/I.sub.α is 0.5 or less when measured by X-ray diffraction using a Co-Kα (wavelength: 1.79021 Å) radiation source at an incident angle of 25°, where IF is an intensity of a diffraction peak of (411) plane of the Γ phase present in an angular range of 41.5°≤2θ≤43.0° and I.sub.α is an intensity of a diffraction peak of (110) plane of the α-Fe phase present in an angular range of 51.0°≤2θ≤52.0°, and a sum of Al and Mg concentrations in the oxide layer is 28 atomic % or more.

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 hot stamped body comprising a steel base material and an Al—Zn—Mg-based plating layer formed on a surface of the steel base material, wherein the plating layer has a predetermined chemical composition, the plating layer comprises an interfacial layer positioned at an interface with the steel base material and containing Fe and Al and a main layer positioned on the interfacial layer, the main layer comprises, by area ratio, 10.0 to 90.0% of an Mg—Zn containing phase, 5.0 to less than 30.0% of an Fe—Al containing phase, and 2.0 to 25.0% of an Al—Si containing oxide phase, the Mg—Zn containing phase comprises at least one selected from the group consisting of an MgZn phase, Mg.sub.2 Zn.sub.3 phase, and MgZn.sub.2 phase, and the Fe—Al containing phase comprises at least one of an FeAl phase and Fe—Al—Zn phase.

A hot stamped body comprising a steel base material and an Al—Zn—Mg-based plating layer formed on a surface of the steel base material, wherein the plating layer has a predetermined chemical composition, the plating layer comprises an interfacial layer positioned at an interface with the steel base material and containing Fe and Al and a main layer positioned on the interfacial layer, the main layer comprises, by area ratio, 10.0 to 90.0% of an Mg—Zn containing phase, 5.0 to less than 30.0% of an Fe—Al containing phase, and 2.0 to 25.0% of an Al—Si containing oxide phase, the Mg—Zn containing phase comprises at least one selected from the group consisting of an MgZn phase, Mg.sub.2 Zn.sub.3 phase, and MgZn.sub.2 phase, and the Fe—Al containing phase comprises at least one of an FeAl phase and Fe—Al—Zn phase.