A high-strength galvanized steel sheet includes a steel sheet having a chemical composition containing a predetermined component element, a mass ratio of a content of Si to a content of Mn in the steel (Si/Mn) being 0.1 or more and less than 0.2, and the balance: Fe and incidental impurities, and a steel structure in which an average grain size of inclusions containing at least one of Al, Si, Mg, and Ca and existing in an area extending from a surface to a position of ⅓ of a sheet thickness is 50 μm or less, and an average nearest distance between ones of the inclusions is 20 μm or more; and a galvanized layer provided on a surface of the steel sheet, in which an amount of diffusible hydrogen contained in the steel is less than 0.25 mass ppm, and a tensile strength is 1100 MPa or more.

A cold-rolled flat steel product for packaging materials has a thickness of less than 0.6 mm, which has been cold-rolled from steel along a rolling direction (0°) and which has an excellent isotropy with respect to its mechanical properties.

A hot stamped body with high strength and good bendability, comprising a chemical composition consisting of: in mass %, C: 0.06% or more to less than 0.20%, Si: 0.010 to 1.00%, Mn: 1.20 to 3.00%, P: 0.100% or less, S: 0.010% or less, Al: 0.010 to 0.500%, N: 0.010% or less, Nb: 0.0010 to 0.020%, Ti: 0 to 0.10%, V: 0 to 0.10%, Cr: 0 to 0.50%, Mo: 0 to 1.00%, B: 0 to 0.0100%, Ni: 0 to 0.50%, REM: 0 to 0.0100%, Mg: 0 to 0.010%, Ca: 0 to 0.0100%, and Co: 0 to 2.0%, with the balance: Fe and impurities, wherein a microstructure includes martensite: 85% or more, a proportion of regions in the martensite where GAIQ values are 35000 or more to less than 45000 is 30 area % or more, and TS×α, is 105000 or more, and α is 75 or more.

A steel sheet has a predetermined chemical composition and a metal structure represented by, in area fraction, polygonal ferrite: 40% or less, martensite: 20% or less, bainitic ferrite: 50% to 95%, and retained austenite: 5% to 50%. In area fraction, 80% or more of the bainitic ferrite is composed of bainitic ferrite grains that have an aspect ratio of 0.1 to 1.0 and have a dislocation density of 8×10.sup.2 (cm/cm.sup.3) or less in a region surrounded by a grain boundary with a misorientation angle of 15° or more. In area fraction, 80% or more of the retained austenite is composed of retained austenite grains that have an aspect ratio of 0.1 to 1.0, have a major axis length of 1.0 μm to 28.0 μm, and have a minor axis length of 0.1 μm to 2.8 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.

A heat treated and cold rolled steel sheet having a composition including of the following elements 0.09%≤Carbon≤0.15%, 1.8%≤Manganese≤2.5%, 0.2%≤Silicon≤0.7%, 0.01%≤Aluminum≤0.1%, 0%≤Phosphorus≤0.09%, 0%≤Sulfur≤0.09%, 0%≤Nitrogen≤0.09%, 0%≤Niobium≤0.1%, 0%≤Titanium≤0.1%, 0%≤Chromium≤1%, 0%≤Molybdenum≤1%, 0%≤Vanadium≤0.1%, 0%≤Calcium≤0.005%, 0%≤Boron≤0.01%, 0%≤Cerium≤0.1%, 0%≤Magnesium≤0.05%, 0%≤Zirconium≤0.05% the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of said steel sheet comprising in area fraction, 65 to 85% Tempered Martensite, 0% to 5% Residual Austenite and a cumulative presence of Ferrite and Bainite between 15 and 35%.

A packaging sheet metal product from a cold-rolled steel sheet with a thickness of less than 0.6 mm has a specified composition. The packaging sheet metal product during biaxial deformation in a bulge test has a lower yield strength (Sb.sub.eL) of more than 300 MPa and a corresponding elongation at break (Ab) of more than 10% and in the plastic region between the Lüders elongation (Ab.sub.e) and an upper (plastic) elongation limit of ε.sub.max=0.5.Math.Ab.Math.(Sb.sub.eL/Sb.sub.m) has a biaxial stress/strain diagram σ.sub.B(ε) that can be represented by a function ε.sub.B=b.Math.ε.sup.n, with: σ.sub.B is the true biaxial stress in MPa; ε is the amount of true elongation in the thickness direction in %; Sb.sub.m is the absolute strength; b is a proportionality factor; and n is a strain-hardening exponent. A strengthening of the packaging sheet product in the thickness direction is characterized by a strain-hardening exponent of n≥0.353-5.1.Math.Sb.sub.eL/10.sup.4 MPa.

The present invention relates to steel used for a sash component and the like of a vehicle and, more specifically, to a hot-rolled steel sheet for a high-strength electric resistance welded steel pipe having excellent expandability and a method for manufacturing same, the hot-rolled steel sheet having a smaller decrease in the strength of a welding heat-affected zone (HAZ) formed during electric resistance welding, in comparison with a base material.

A rolled steel sheet, for press hardening is provided, having a chemical composition where Ti/N>3.42, and the carbon, manganese, chromium and silicon contents satisfy: $2.6C+\frac{\mathrm{Mn}}{5.3}+\frac{\mathrm{Cr}}{13}+\frac{\mathrm{Si}}{15}\ge 1.1\%.$
The sheet has a nickel content Ni.sub.surf at any point of the steel in the vicinity of the surface over a depth Δ, such that: Ni.sub.surf >Ni.sub.nom, Ni.sub.nom denoting the nominal nickel content of the steel, and such that, Ni.sub.max denoting the maximum nickel content within Δ: $\frac{\left({\mathrm{Ni}}_{\max }+{\mathrm{Ni}}_{\mathrm{nom}}\right)}{2}\times \left(\Delta \right)\ge 0.6,$
and such that: $\frac{\left({\mathrm{Ni}}_{\max }-{\mathrm{Ni}}_{\mathrm{nom}}\right)}{\Delta }\ge 0.01$
and the surface density of all of the particles D.sub.i and the surface density of the particles D.sub.(>2 μm) larger than 2 micrometers satisfy, at least to a depth of 100 micrometers in the vicinity of the surface of said sheet:
D.sub.i+6.75 D.sub.(>2 μm) <270
D.sub.i and D.sub.(>2 μm) being expressed as number of particles per square millimeter, and said particles denoting all the oxides, sulfides, and nitrides, either pure or combined such as oxysulfides and carbonitrides, present in the steel matrix.

A method for producing a cold-rolled flat steel product coated with a metallic anticorrosion layer includes producing a steel melt containing in addition to iron and unavoidable impurities (in % by wt.): C: 0.01-0.35%, Mn: 1-4%, Si: 0.5-2.5%, Nb: to 0.1%, Ti: 0.015-0.1%, P: up to 0.1%, Al: to 0.15%, S: up to 0.01%, N: up to 0.1%, and optionally one or more elements from a group of rare earth metals. The method further includes casting the steel melt to give a preliminary product, hot-rolling the preliminary product to give a hot strip, coiling the hot strip to give a coil, annealing the hot strip, cold-rolling the annealed hot strip to give a cold-rolled flat steel product, finally annealing the cold-rolled flat steel product, and applying a metal anticorrosion layer based on zinc by electrolytic galvanization or hot dip galvanization of the cold-rolled and finally annealed flat steel product.