In a hot-rolled steel sheet having a predetermined chemical composition and having a metallographic structure including 90 vol % or greater of martensite and 0 vol % to 10 vol % of a residual structure, the residual structure includes one or both of bainite and ferrite, the average prior austenite grain size in an L-section parallel to a rolling direction and an average prior austenite grain size in a C-section parallel to a direction orthogonal to the rolling direction are 1.0 μm to 10.0 μm the aspect ratio associated with the prior austenite grain size is 1.8 or less, the average grain size of the residual structure in the L-section and the average grain size of the residual structure in the C-section are 5.0 μm or less, and the aspect ratio associated with the average grain size of the residual structure is 2.0 or less.

A shock absorbing member which can increase impact absorption energy and also enables thinning of a steel sheet that is a starting material, a method for producing the shock absorbing member, and a method for producing a steel sheet for cold plastic working are provided. The shock absorbing member includes a ridge portion formed in a curved shape as viewed from a longitudinal direction, and a wall portion extending from the ridge portion. In the wall portion, a ratio σ.sub.5/τ.sub.5 between a tensile stress σ.sub.5 when an elongation in a tensile test is 5% and a shear stress τ.sub.5 when a shear strain in a shear test is 5√3% is 1.70 or less, or a ratio σ.sub.10/τ.sub.10 between a tensile stress σ.sub.10 when an elongation in a tensile test is 10% and a shear stress τ.sub.10 when a shear strain in a shear test is 10√3% is 1.70 or less.

An alloy includes: an average Ni concentration of 1.5 at.% or more and 15.5 at.% or less; an average Co concentration of 0 at.% or more and 10.0 at.% or less; an average B concentration of 3.0 at.% or more and 16.0 at.% or less; an average P concentration of 0.5 at.% or more and 10.0 at.% or less; an average Cu concentration of 0 at.% or more and 2.0 at.% or less; an average Si concentration of 0 at.% or more and 6.0 at.% or less; an average C concentration of 0 at.% or more and 6.0 at.% or less; a total of average concentrations of Nb, Mo, Zr, W, V, Hf, Ta, Al, Ti, and Cr of 0 at.% or more and 6.0 at.% or less; and a total of an average Fe concentration, the average Ni concentration, and the average Co concentration of 78.0 at.% or more and 88.0 at.% or less.

A method for manufacturing a non-oriented electrical steel sheet includes a step of obtaining a hot-rolled steel sheet by performing hot rolling on a steel material having a predetermined chemical composition, a step of performing first cold rolling on the hot-rolled steel sheet, and a step of performing first annealing after the first cold rolling. A final pass of finish rolling is performed in a temperature range equal to or higher than an Ar1 temperature, and cooling of which an average cooling rate is in a range of 50 to 500° C./sec is started in 0.1 sec from completion of rolling of the final pass of the finish rolling and is performed up to a temperature range higher than 250° C. and equal to or lower than 700° C.

This hot-stamping formed body has a predetermined chemical composition and has a metallographic structure consisting of, by area ratio, a total of 10% to 30% of ferrite and granular bainite and a remainder in microstructure consisting of one or more of martensite, bainite, and tempered martensite, and, in textures of a surface layer region and an inside region, ratios between a pole density of an orientation group consisting of {001}<1-10> to {001}<−1-10> and a pole density of an orientation group consisting of {111}<1-10> to {111}<−1-12> are controlled.

A high-strength cold-rolled steel sheet having a high yield ratio and excellent stretch flangeability and a method for manufacturing the steel sheet. The high-strength cold-rolled steel sheet has a chemical composition including, by mass %, C: 0.10 to 0.30%, Si: 0.50 to 2.00%, Mn: 2.5 to 4.0%, P: 0.050% or less, S: 0.020% or less, Al: 0.10% or less, N: 0.01% or less, Ti: 0.100% or less, and B: 0.0003 to 0.0030%, with the balance being Fe and incidental impurities. N and Ti satisfy a specified formula, and the total area fraction of martensite and bainite is 95% or more. The number density of bainite grains having an area of 3 μm.sup.2 or more and a carbon concentration of less than 0.7C is 1200 grains/mm.sup.2 or less.

Provided are a cryogenic steel plate and a method for manufacturing the same, the cryogenic steel plate comprising, in wt %, 0.04 to 0.08% carbon (C), 8.9 to 9.3% nickel (Ni), 0.6 to 0.7% manganese (Mn), and 0.2 to 0.3% silicon (Si), and 50 ppm or less of P, 10 ppm or less of S, and the remainder in iron (Fe) and various unavoidable impurities, and the microstructure at a ¼t location of the steel plate, where t is a thickness of the steel plate, comprising, in % surface area, 10% or more of tempered bainite, 10% or less of residual austenite, and the remainder of tempered martensite.

An electric resistance welded steel pipe or tube comprises: a base metal being a steel sheet having a specific chemical composition and an electric resistance weld portion having a bond width of 40×10.sup.−6 m or more and 120×10.sup.−6 m or less, wherein C.sub.0-C.sub.1 is 0.05 mass % or less, where C.sub.0-C.sub.1 is a difference between C.sub.1 in mass % which is a minimum C content of the electric resistance weld portion and Co in mass % which is a C content of the steel sheet, and a depth of a total decarburized layer in each of an inner surface layer and an outer surface layer of the electric resistance welded steel pipe or tube is 50×10.sup.−6 m or less.

The invention relates to sheet metal packaging products, in particular tinplate or electrolytically chrome-plated sheet steel (ECCS), consisting of a sheet steel substrate (S) with a thickness in the region of 0.1 mm to 0.6 mm and a coating (B), in particular made of tin and/or chromium or chromium and chromium oxide, that is electrolytically deposited on at least one side of the sheet metal substrate. In addition, at least one surface of the sheet metal packaging product provided with the coating (B) has a surface profile with periodically repeating structure elements in at least one direction, wherein an autocorrelation function resulting from the surface profile has a plurality of side lobes with a height of at least 20%, preferably at least 30% of the height of the main lobe. These sheet metal packaging products have improved and novel surface properties.

A method for producing a steel strip with a multiphase structure by which the production of complex geometries with a high energy-absorption capacity and high resistance to edge cracking is provided achieving a high yield strength or high yield-strength ratio and a high elongation at break, comprising producing a rolled steel strip of particular elements, and first annealing the steel strip at a temperature of between 750° C. and 950° C., and subsequently first cooling of the steel strip to a temperature of between 200° C. and 500° C. at an average cooling rate of 2 K/s to 150 K/s, further cooling of the steel strip to a supercooling temperature below 100° C. at an average cooling rate of 1 K/s to 50 K/s, final annealing of the steel strip with a Hollomon-Jaffe parameter, and final cooling of the steel strip to room temperature at an average cooling rate of 1 K/s to 160 K/s.