This steel sheet has a predetermined chemical composition, the metallurgical structure at a thickness ¼ portion is, by area ratio, martensite: 40% to 97%, ferrite+bainite: 50% or less, residual austenite: 3% to 20% and a remainder in microstructure: 5% or less, the aspect ratio of residual austenite having an aspect ratio of 3 or more is 80% or more with respect to the total area of residual austenite, and the number of carbides having a grain diameter of 8 to 40 nm per square micrometer is five or more in the residual austenite.

The invention relates to a method for rolling a metal product (1), wherein the metal product is subjected to a rolling operation at a first station (2), which rolling operation is controlled by a control device (3), wherein the product (1) is subject to a measurement at a second station (4), wherein the product (1) is subjected to a further processing operation at a third station (6), and wherein the product (1) is in a specified quality at a fourth station (7). In order to increase the quality of the produced strip, the invention provides that the method has the following steps: a) measuring the value of a material property (IW) that the second station (4); b) feeding the value measured at the second station (4) to the control device (3), comparing the measured value with a value (SW) stored in the control device (3), and adjusting a parameter (PPI) if the measured value deviates from the stored value (SW), e) measuring a value of a quality material property (Q) at the fourth station (7); d) comparing the measured value with a stored value, and initiating a measure to influence the quality material property (Q) if the measured value deviates from the stored value beyond a permissible tolerance.

Hot rolling stock (1) made of metal which is rolled in at least one roll stand (2) and then cooled in a cooling section (5) arranged downstream of the at least one roll stand (2). Sound generated by means of a sound generator arrangement (8) is coupled into the rolling stock (1) by a coupling device (1) so that a standing sound wave is formed at least in the region of the rolling stock (1) which is located in the vicinity of the coupling device (10).

A high-strength steel sheet includes a chemical composition including: by mass %, C: 0.080 to 0.500%, Si: 2.50% or less, Mn: 0.50 to 5.00%, P: 0.100% or less, S: 0.0100% or less, Al: 0.001 to 2.500%, N: 0.0150% or less, O: 0.0050% or less, and the balance: Fe and inevitable impurities. The high-strength steel sheet satisfying a predetermined formula has a microstructure in a region from ⅛t to ⅜t from a steel sheet surface. The microstructure includes: by volume %, 20% or more of acicular ferrite, 20% or more of an island-shaped hard structure including residual austenite, 2% to 25% of residual austenite, and 20% or less of aggregated ferrite.

Provided are a hot dip galvanized steel sheet comprising a base steel sheet wherein the base steel sheet has a predetermined chemical composition, and contains ferrite: 50% or less, retained austenite: 30% or less, tempered martensite: 5% or more, fresh martensite: 10% or less, and pearlite and cementite in total: 5% or less, remaining structures consist of bainite, and a number ratio of tempered martensite with a Mn concentration profile satisfying [Mn].sub.b/[Mn].sub.a>1.2 and [Mn].sub.a/[Mn]<2.0 ([Mn] is the Mn content in the base steel sheet, [Mn].sub.a is the average Mn concentration in the tempered martensite, and [Mn].sub.b is the Mn concentration at the interfaces of different phases of the tempered martensite and ferrite phase and bainite phase) is 0.2 or more with respect to the total number of tempered martensite, and a method for producing the same.

A cold rolled and heat-treated steel sheet, the steel including, in weight percentage, 0.17%≤carbon≤0.25%, 2%≤manganese≤3%, 0.9%≤silicon≤2%, 0%≤aluminum≤0.09%, 0.01%≤molybdenum≤0.2%, 0%≤phosphorus≤0.02%, 0%≤sulfur≤0.03%, 0%≤nitrogen≤0.09%, and optionally one or more of the following elements 0%≤chromium≤0.3%, 0%≤niobium≤0.06%, 0%≤titanium≤0.06%, 0%≤vanadium≤0.1%, 0%≤calcium≤0.005%, 0%≤boron≤0.010%, 0%≤Magnesium≤0.05%, 0%≤Zirconium≤0.05%, 0%≤Cerium≤0.1%, and the balance including iron and unavoidable impurities, the steel sheet having a microstructure of—50% to 80% of Bainite, 10% to 30% of residual austenite, 15% to 50% of Partitioned martensite, 0% to 10% of ferrite and 0% to 5% fresh martensite in area fractions, and a ferrite-enriched layer extending up to 50 microns from both surfaces of the steel sheet, such ferrite-enriched layer having a mean ferrite content from 55% to 80% in area fraction.

A hot-pressed member has a predetermined chemical composition. In the hot-pressed member, a steel sheet has a microstructure in which a prior austenite average grain diameter is 8 μm or less, and martensite is present in a volume fraction of 95% or greater in a region within 30 μm of a surface; a Ni diffusion region having a thickness of 0.5 μm or greater exists in a surface layer; a standard deviation of Vickers hardness values is 35 or less; Mndif (mass %) in a sheet thickness direction ≤0.20, where Mndif (mass %) is a degree of Mn segregation; and a tensile strength is 1780 MPa or greater.

A hot-stamping formed body has a predetermined chemical composition, in which an average grain size of prior austenite grains in a microstructure is 5.0 μm or less, and an average Mn concentration at grain boundaries of the prior austenite grains is 1.0 mass % or less. The hot-stamping formed body may be provided with a plating layer on the surface thereof, or may have a softened region in a portion thereof.

The present invention provides: a plated steel sheet for hot press forming having excellent impact properties after hot press forming; a hot press formed member manufactured using the plated steel sheet for hot press forming; and manufacturing methods thereof. The plated steel sheet comprises: a base steel sheet containing, by weight, 0.15-0.4% of C, 0.1-1% of Si, 0.6-8% of Mn, 0.001-0.05% of P, 0.0001-0.02% of S, 0.01-0.1% of Al, 0.001-0.02% of N, and 0.01-0.5% of Cr, with the remainder comprising Fe and miscellaneous impurities; and a plating layer formed on the surface of the base steel sheet and composed of zinc, aluminum, or an alloy containing zinc and aluminum, wherein the ratio (C S/C B) of the content (C S) of C in a surface layer to the content (C B) of C in the base steel sheet is 0.6 or less, and the ratio ((Mn S+Cr S)/(Mn B+Cr B)) of the total content (Mn S+Cr S) of Mn and Cr in the surface layer to the total content (Mn B+Cr B) of Mn and Cr in the base steel sheet is 0.8 or more.

Aluminum alloy sheet for battery lid use excellent in deformation resistance, formability, and heat radiation ability, which aluminum alloy sheet for battery lid use enabling formation of an integrated explosion-proof valve with little variation in operating pressure and excellent in cyclic fatigue resistance, and a method of production of the same are provided, the aluminum alloy sheet for battery lid use for forming an integrated explosion-proof valve having a component composition containing Fe: 0.85 to 1.50 mass %, Mn: 0.30 to 0.70 mass %, Ti: 0.002 to 0.15 mass %, and B: less than 0.05 mass %, having a balance of Al and impurities, having an Fe/Mn ratio restricted to 1.8 to 3.5, restricting, as impurities, Si to less than 0.40 mass %, Cu to less than 0.03 mass %, Mg to less than 0.05 mass %, and V to less than 0.03 mass %, having a 0.2% yield strength of 40 MPa or more, having a value of elongation of 40% or more, having a conductivity of 53.0% IACS or more, having a recrystallized structure, and having a value of elongation after cold rolling by a rolling reduction of 80% of 6.5% or more. Furthermore, an average grain size of the recrystallized grains of the recrystallized structure is preferably 15 to 25 μm.