A steel sheet includes a predetermined chemical composition and a metal structure represented by, in area fraction, ferrite: 50% to 95%, granular bainite: 5% to 48%, martensite: 2% to 30%, and upper bainite, lower bainite, tempered martensite, retained austenite, and pearlite: 5% or less in total.

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 steel sheet has a tensile strength of 1310 MPa or higher, a specified chemical composition, and a steel microstructure containing martensite at an area ratio of 70% or more, bainite at an area ratio of 30% or less, and ferrite and retained austenite at a total area ratio of 10% or less, in which, at a ¼ thickness position of the steel sheet, a number density of carbides having long axes of 0.5 μm or more is 60000 carbides/mm.sup.2 or less, in a ¼-to-¾ thickness region of the steel sheet, a number density of inclusion grains having equivalent circle diameters of 4.0 μm or more is 10 grains/mm.sup.2 or more and 30 grains/mm.sup.2 or less, and, in a surface-to-¼ thickness region of the steel sheet, a number density of inclusion grains having equivalent circle diameters of 4.0 μm or more is 27 grains/mm.sup.2 or less.

There is provided a metal member capable of effectively preventing a coating layer from peeling off from a base. The metal member in an embodiment is a metal member that is used in a solid-oxide type electrochemical stack, and includes: a base formed of ferritic stainless steel; and a metal film provided on the base, in which the metal film includes a first metal layer containing Co and a second metal layer made of Mn, and is a stack in which the first metal layer and the second metal layer are sequentially stacked from the side of the base.

The present disclosure relates to a zinc-based coated steel material having excellent corrosion resistance and spot weldability and, more particularly, to a zinc-based coated steel material plated with a multilayer zinc alloy, which has two or more layers, and having excellent corrosion resistance and spot weldability. A zinc-based coated steel material according to an aspect of the present disclosure includes: a base steel; and a multilayer zinc-based plating layer composed of two or more discriminated plating layers, in which the multilayer zinc-based plating layer may include Mg of 0.12˜0.64 percent by weight.

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 shaped steel object is provided. The method includes cutting a blank from an alloy composition including 0.05-0.5 wt. % carbon, 4-12 wt. % manganese, 1-8 wt. % aluminum, 0-0.4 wt. % vanadium, and a remainder balance of iron. The method also includes heating the blank until the blank is austenitized to form a heated blank, transferring the heated blank to a press, forming the heating blank into a predetermined shape to form a stamped object, and decreasing the temperature of the stamped object to a temperature between a martensite start (Ms) temperature of the alloy composition and a martensite final (Mf) temperature of the alloy composition to form a shaped steel object comprising martensite and retained austenite.

A device including a hard shield material; a layer including aluminum or copper; and a silicon layer having a first thickness is disclosed. The device can also include a silicon layer having a second thickness. A method of making the device is also disclosed.

Provided is a method capable of producing a plated black heart malleable cast iron member having a plating layer with excellent adhesiveness to a black heart malleable cast iron member, while having less burden on the environment, compared to conventional methods.