Provided is a steel sheet comprising a sheet thickness center part and a first surface layer part and a second surface layer part respectively arranged at two sides of the sheet thickness center part, wherein the first surface layer part and second surface layer part respectively independently have thicknesses of more than 10 μm to 30% or less of the sheet thickness, the first surface layer part and second surface layer part have average Vickers hardnesses different from the average Vickers hardness of a sheet thickness ½ position, and a first hardness cumulative value at a region from a surface of the first surface layer part side to 30% of the sheet thickness is 1.05 times or more of a second hardness cumulative value at a region from a surface of the second surface layer part side to 30% of the sheet thickness.

The method of producing composite material with a high complex of mechanical properties, consisting of vanadium alloy inner layer V—3-11 wt % Ti—3-6 wt % Cr and two outer layers of stainless steel of ferritic grade with chromium content of not less than 13 wt %, includes preparation of a composite workpiece consisting of said inner layer and outer layers, hot treatment by pressure and subsequent exposure in furnace. Prepared composite workpiece, thickness of inner layer of which is 1.5-2 times more than total thickness of outer layers of stainless steel, hot working is performed with pressure of the workpiece in the temperature range of 1,050-1,150° C. with degree of reduction from 30 to 40% and with subsequent exposure for 1-3 hours with temperature reduction to 500-700° C., then annealing workpiece by heating to temperature of 850-950° C., holding for 2-4 hours and subsequent cooling in furnace.

The present disclosure provides cladding in which at least two layers of alloys are joined, the cladding having high wear resistance, high workability, and excellent strength at the joining interface of the alloys. The cladding is composed of two or more layers including a first alloy and a second alloy joined to the first alloy. The hardness of the second alloy of the cladding is greater than that of the first alloy, and the difference in hardness between the first alloy and the second alloy is at least HRC 44. When a shearing test based on JIS G 0601 is performed on the cladding, the breakage is on the first alloy side.

Provided is a low-density clad steel sheet having excellent formability and fatigue properties, including a base material; and cladding materials provided on both side surfaces of the base material, wherein the base material is a lightweight steel sheet including, by weight, C: 0.3 to 1.0%, Mn: 4.0 to 16.0%, Al: 4.5 to 9.0%, and a remainder of Fe and inevitable impurities, and each of the cladding materials is martensitic carbon steel including, by weight, C: 0.1 to 0.45%, Mn: 1.0 to 3.0%, and a remainder of Fe and inevitable impurities.

An embodiment of the present invention provides: an adhesive coating composition capable of attaching (coupling) an electrical steel sheet without using an existing coupling method, such as welding, clamping, or interlocking; an electrical steel sheet laminate employing the same; and a manufacturing method therefor. The adhesive coating composition according to an embodiment of the present invention comprises: 40-95 wt % of a first component comprising an organic/inorganic composite in which inorganic nanoparticles are substituted in a water-soluble resin; 1-50 wt % of a second component comprising a composite metal phosphate; and 1-10 wt % of an additive.

A method of manufacturing a press-formed product includes: a heating step; a transportation step; and a pressing step. The transportation step includes: using claws of a pair of first arms to support the lower surface, at both ends, of a first heated workpiece and lift the workpiece; using claws of a pair of second arms to support the lower surface, at both ends, of a second heated workpiece and lift the workpiece; transporting the first heated workpiece with the lower surface supported, at both ends, by the claws of the pair of first arms and the second heated workpiece with the lower surface supported, at both ends, by the claws of the pair of second arms, where the first and second heated workpieces overlap each other in the direction normal to the sheet surfaces; driving the pair of first arms to lower the first heated workpiece to a pressing location on a press machine; and driving the pair of second arms to lower the second heated workpiece to a pressing location on the press machine.

A low-strength steel sheet for hot stamping according to an aspect of the present invention satisfies a predetermined chemical composition, the Ac.sub.3 point (° C.) represented by Equation (1) is 890° C. or more, and an area ratio of ferrite at a depth to be ¼ of a steel sheet thickness is 80% or more. Ac.sub.3 point (° C.)=910−203×[C].sup.1/2+44.7×[Si]−30×[Mn]+700×[P]+400×[Al]+400×[Ti] . . . (1) In Equation (1), [C], [Si], [Mn], [P], [Al], and [Ti] are values denoting the percentage contents of C, Si, Mn, P, Al, and Ti in terms of % by mass, respectively.

There is provided a steel sheet including an inner layer and a hard layer formed on one or both surfaces of the inner layer, wherein each content of C and Mn in the hard layer is more than each content of C and Mn in the inner layer, a thickness of the hard layer is 20 μm or more and a total of the thickness of the hard layer is ⅖ or less of the entire sheet thickness, an average micro-Vickers hardness of the hard layer is 400 HV or more and less than 800 HV, an average micro-Vickers hardness of the inner layer is 350 HV or more and is 50 HV or more smaller than a hardness of the hard layer, and a screw dislocation density of the inner layer is 2.0×10.sup.13 m/m.sup.3 or more.

Clad steel plate of super duplex stainless steel and manufacturing method thereof. The clad steel plate of super duplex stainless steel which has a two-layer structure wherein one layer is duplex stainless steel, and the other layer is carbon steel, wherein said duplex stainless steel comprises the following components by weight: C≤0.03%, Mn≤1.20%, Si≤0.80%, Cr: 24.0-26.0%, Ni: 6.0-8.0%, Mo: 3.0-5.0%, N: 0.24-0.32% and the balance being Fe and inevitable impurities; and said carbon steel comprises the following components by weight: C: 0.03˜0.12%, Si: 0.10˜0.45%, Mn: 0.70-1.60%, P<0.020%, S<0.025%, Cu: 0˜0.35%, Cr 0˜0.40%, Ni 0˜0.40%, Nb 0˜0.05%, Mo 0˜0.40%, Ti 0˜0.018%, Al 0.015˜0.045% and the balance being Fe and inevitable impurities. The clad steel plate of the disclosure has good structure strength and corrosion resistance; the clad steel plate is a rolled cladding steel plate and is capable of realizing the metallurgical bonding of cladding and base layer materials, thereby yielding good bonding capability.

Disclosed are a corrosion-resistant marine composite steel plate and a manufacturing method therefor. The corrosion-resistant composite steel plate has a two-layer structure, wherein one layer is duplex stainless steel, and the other layer is marine carbon steel; said duplex stainless steel comprises the following components by weight: C≤0.03%, Mn≤2.00%, Si≤1.00%, Cr: 21.0-23.0%, Ni: 4.5-6.5%, Mo: 2.5-3.5%, N: 0.08-0.20%, P≤0.02%, S≤0.025%, and the balance being Fe and inevitable impurities; and said marine carbon steel comprises the following components by weight: 0.03%≤C≤0.13%, Si≤0.50%, Mn: 0.90-1.60%, P≤0.020%, S≤0.025%, Cu≤0.035%, Cr≤0.20%, Ni≤0.40%, Nb: 0.02-0.05%, Ti≤0.02%, Mo≤0.08%, Al≥0.015%, and the balance being Fe and inevitable impurities. A rolled composite steel plate is produced by using a double-barrier vacuum assembly method, so that a reduction in structure weight is achieved while a good structural strength and an excellent corrosion resistance are obtained