Provided is a high-strength hot-dip galvanized steel sheet having good surface quality and spot weldability. The high-strength hot-dip galvanized steel sheet includes a base steel sheet and a zinc plating layer formed on the base steel sheet. The base steel sheet includes carbon (C): 0.1% to 0.3%, silicon (Si): 0.5% to 2.5%, manganese (Mn): 2.0% to 8.0%, soluble aluminum (sol.Al): 0.001% to 0.5%, phosphorus (P): 0.04% or less (excluding 0%), sulfur (S): 0.015% or less, nitrogen (N): 0.02% or less, chromium (Cr): 0.01% to 0.7%, titanium (Ti): (48/14)*[N] % to 0.1%, and a balance of iron (Fe) and inevitable impurities. The base steel sheet has a microstructure comprising ferrite in an area fraction of 5% to 30%, austenite in an area fraction of 5% to 20%, bainite and martensite in an area fraction of 50% to 80%, and precipitates in an area fraction of 2% or less.

A hot dip galvanized steel sheet and hot dip galvannealed steel sheet improved in uniform ductility and local ductility, yield strength and tensile strength, and low temperature impact property, characterized by having a predetermined chemical composition, having a metal structure containing, by volume %, retained austenite: over 5.0% and tempered martensite: over 5.0%, having retained austenite containing C: 0.85 mass % or more, and having a ratio [C].sub.gb/[P].sub.gb of an amount of segregation of C (number of atoms/nm.sup.2): [C].sub.gb to an amount of segregation of P (number of atoms/nm.sup.2): [P].sub.gb at prior austenite grain boundaries of 4.0 or more.

In one aspect of the present invention, a hot-dip galvannealed steel sheet includes a steel sheet and a hot-dip galvannealed layer on the surface of the steel sheet. The steel sheet has a predetermined composition and has an average oxygen concentration of 0.10 mass % or less in the region of 1 m from the interface between the steel sheet and the hot-dip galvannealed layer toward the steel sheet. The metal microstructure of the steel sheet at a position of t/4 where t represents the sheet thickness of the hot-dip galvannealed steel sheet includes 50 to 85 area % of martensite, 15 to 50 area % of bainite, and 5 area % or less of ferrite.

The present invention relates to a tubular element for a gas pressure container of an airbag system of a motor vehicle, wherein the tubular element (10) has at least one first length section (100, 101) and at least one recess (11) extending in the circumferential direction, characterized in that the tubular element (10) has at least one second length section (102), formed by the recess (11) extending over at least a part of the circumference of the tubular element (10), that the second length section (102) lies between two first length sections (100, 101), that in at least one first length section (100, 101) the outer radius (A1) of the tubular element (10) is greater than the smallest outer radius (A2) of the at least one second length section (102), that the tubular element (10) has a tensile strength of >920 MPa, that the wall thickness (W2) of the tubular element (10) in the at least one second length section (102) is thicker than or equal to the wall thickness (W1) in at least one first length section (100, 101) of the tubular element (10), that the degree of reduction of the outer radius (A2) in the recess (11) lies in the range of 5 to 35% relative to the outer radius (A1) of at least one first length section (100, 101), and that the tubular element (10) consists of a material which, in addition to iron and impurities due to melting, comprises the following alloying elements in the ranges indicated in percent by weight: C 0.05-0.2% Si0.9% Mn 0.2-2.0% Cr 0.05-2% Mo<0.5% Ni<1.0% Nb 0.005-0.10% Al<0.07% Ti<0.035% and B<0.004%.

A zinc-plated steel sheet for hot stamping according to an aspect of the present invention includes a steel substrate and a plated layer provided on a surface of the steel substrate, in which the steel substrate contains, in % by mass, C: 0.10 to 0.5%, Si: 0.7 to 2.5%, Mn: 1.0 to 3%, and Al: 0.01 to 0.5%, with the balance being iron and inevitable impurities, and the steel substrate has, in the inside thereof, an internal oxide layer consists of an oxide containing at least one of Si and Mn having a thickness of 1 m or more, and a decarburized layer having a thickness of 20 m or less from an interface with the plated layer toward an internal direction of the steel substrate.

The present disclosure provides systems and methods that employ slurries to form layers adjacent to substrates. Such layers can include, for example, one or more of iron, chromium, nickel, silicon, vanadium, titanium, boron, tungsten, aluminum, molybdenum, cobalt, manganese, zirconium, and niobium, oxides thereof, nitrides thereof, sulfides thereof, or combinations thereof. In some examples, such layers are stainless steel layers.

A nickel-plated heat-treated steel sheet for a battery can, having a nickel layer with a nickel amount of 4.4 to 26.7 g/m.sup.2 on a steel sheet. When the Fe intensity and the Ni intensity are continuously measured along the depth direction from the surface of the nickel-plated heat-treated steel sheet for a battery can, by using a high frequency glow discharge optical emission spectrometric analyzer, the difference between the depth at which the Fe intensity exhibits a first predetermined value and the depth at which the Ni intensity exhibits a second predetermined value is less than 0.04 m.

The invention relates to a method for producing a hot-rolled strip composed of a bainitic multi-phase steel and having a ZnMgAl coating, comprising the following steps: melting a steel melt containing (in weight percent): C: 0.04-0.11, Si: <=0.7, Mn: 1.4-2.2, Mo: 0.05-0.5, Al: 0.015-0.1, P: up to 0.02, S: up to 0.01, B: up to 0.006, and at least one element from the group Nb, V, Ti in accordance with the following condition: 0.02<=Nb+V+Ti<=0.20, the remainder being iron including unavoidable steel-accompanying elements resulting from the melting process, casting the steel melt into a preliminary material, in particular a slab or a block or a thin slab, hot rolling the preliminary material into a hot-rolled strip having a final rolling temperature in the range of 800 to 950 C., cooling the hot-rolled strip to a winding temperature less than 650 C., winding the hot-rolled strip at a winding temperature less than 650 C., cooling the wound hot-rolled strip to room temperature in still air, wherein the microstructure of the wound hot-rolled strip then has a bainite fraction greater than 50% after the hot rolling, heating the hot-rolled strip to a temperature greater than 650 C. and less than Ac3, in particular less than Ac1+50 C., cooling the hot-rolled strip to zinc bath temperature, hot-dip coating the heated hot-rolled strip in a zinc alloy molten bath containing (in weight percent): Al: 1.0-2.0, Mg: 1.0-2.0, the remainder being zinc and unavoidable impurities. The invention further relates to the hot-rolled strip produced in accordance with the method above and to shaped, dynamically highly loadable components, in particular motor vehicle parts, that are produced from said hot-roiled strip and that are resistant to corrosive and abrasive influences.

A dual hardness steel article comprises a first air hardenable steel alloy having a first hardness metallurgically bonded to a second air hardenable steel alloy having a second hardness. A method of manufacturing a dual hard steel article comprises providing a first air hardenable steel alloy part comprising a first mating surface and having a first part hardness, and providing a second air hardenable steel alloy part comprising a second mating surface and having a second part hardness. The first air hardenable steel alloy part is metallurgically secured to the second air hardenable steel alloy part to form a metallurgically secured assembly, and the metallurgically secured assembly is hot rolled to provide a metallurgical bond between the first mating surface and the second mating surface.

A steel sheet including an inner layer and a hard layer at one or both surfaces of the inner layer wherein the hard layer and the inner layer have predetermined compositions, each hard layer has a thickness of 20 m or more and of the total sheet thickness or less, the hard layer has an average micro-Vickers hardness of 400 HV or more and less than 700 HV, the hard layer has an N amount of 0.02% or less, the inner layer has an average micro-Vickers hardness of 80 HV or more and less than 400 HV, the inner layer has a carbide volume ratio of less than 2.00%, and the hard layer has a nanohardness standard deviation of 2.00 or less is provided.