A steel sheet having a tensile strength of 1100 MPa or more and excellent in crash resistance, having a micro-structure containing tempered martensite: 95 vol. % or more, wherein in a cross section parallel to a sheet-thickness direction of the steel sheet, when a sheet thickness is denoted by t, in a 300-μm-square region centered about a t/2 point, a standard deviation of Vickers hardnesses that are measured under a load of 9.8 N at 30 points is 30 or less, wherein when a 100-μm-square region centered about a t/2 point is divided into 10×10, 100 subregions, and at a center of each of the subregions, a nano hardness is measured under a maximum load of 1 mN, out of the subregions, the number of subregions each of which makes a difference in nano hardness of 3 GPa or more from any one of eight surrounding subregions is 10 or less.

Disclosed is a hot-pressed member that can exhibit very high tensile strength after hot pressing as high as TS: 1780 MPa or more, and excellent indentation peeling strength at projection welds by properly adjusting its chemical composition and its microstructure such that a prior austenite average grain size is 7 μm or less within a range of 50 μm or less in a thickness direction from a surface of the member, a volume fraction of martensite is 90% or more, and an average intergrain distance of Nb and Ti carbonitrides having a grain size of less than 0.10 μm within a depth range of 20 μm to 100 μm in the thickness direction from the surface of the member is 5 μm or less.

The metal plate includes a plurality of pits located on the surface of the metal plate. The manufacturing method for a metal plate for use in manufacturing of a deposition mask includes an inspection step of determining a quality of the metal plate based on a sum of volumes of a plurality of pits located at a portion of the surface of the metal plate.

Conventional Fe-based soft magnetic alloy ribbons each containing Co and Ni have a problem that magnetic anisotropy that is neatly arranged in one direction cannot be induced easily even by a magnetic field annealing treatment and, therefore, a wound magnetic cores, a problem that a residual magnetic flux density Br is high, a problem that the hysteresis of the B—H curve becomes large (coercivity Hc becomes large), a problem that the change in incremental permeability relative to superimposed magnetic field becomes large, and others. In order to solve the problems, provided is an Fe-based soft magnetic alloy ribbon including a Cu-concentrated region present directly below a surface of the ribbon, and a Co-concentrated region present directly below the Cu-concentrated region. Also provided is a magnetic core including the Fe-based soft magnetic alloy ribbon.

A step of, while a powder of an RLM alloy (where RL is Nd and/or Pr; M is one or more elements selected from among Cu, Fe, Ga, Co, Ni and Al) which is produced through atomization and a powder of an RH compound (where RH is Dy and/or Tb) are present on the surface of a sintered R-T-B based magnet, performing a heat treatment at a sintering temperature of the sintered R-T-B based magnet or lower is included. The RLM alloy contains RL in an amount of 65 at % or more, and the melting point of the RLM alloy is equal to or less than the temperature of the heat treatment. The heat treatment is performed while the RLM alloy powder and the RH compound powder are present on the surface of the sintered R-T-B based magnet at a mass ratio of RLM alloy:RH compound=9.6:0.4 to 5:5.

A ferritic heat-resistant steel includes, by mass: from 0.06 to 0.11% of C; from 0.15 to 0.35% of Si; from 0.35 to 0.65% of Mn; from 0 to 0.02% of P; from 0 to 0.003% of S; from 0.005 to 0.25% of Ni; from 0.005 to 0.25% of Cu; from 2.7 to 3.3% of Co; from 8.3 to 9.7% of Cr; from 2.5 to 3.5% of W; from 0.15 to 0.25% of V; from 0.03 to 0.08% of Nb; from 0.002 to 0.04% of Ta; from 0.01 to 0.06% of Nd; from 0.006 to 0.016% of B; from 0.005 to 0.015% of N; from 0 to 0.02% of Al; and from 0 to 0.02% of O, with a balance consisting of Fe and impurities, and an amount of W, which is analyzed as an electrolytically extracted residue, [% W].sub.ER, satisfying: −10×[% B]+0.26≤[% W].sub.ER≤10×[% B]+0.54.

The invention is intended to provide a duplex stainless steel and a method for manufacturing same. A duplex stainless steel pipe is also provided. A duplex stainless steel of the present invention has a specific composition, and has a microstructure containing an austenitic phase and a ferrite phase. The duplex stainless steel satisfies the following contents for C, Si, Mn, Cr, Mo, Ni, N, Cu, and W in the formula (1) below, and has a yield strength YS of 655 MPa or more, and an absorption energy vE.sub.−10 of 40 J or more as measured by a Charpy impact test at a test temperature of −10° C.

0.55[% C]−0.056[% Si]+0.018[% Mn]−0.020[% Cr]−0.087[% Mo]+0.16[% Ni]+0.28[% N]−0.506[% Cu]−0.035[% W]+[% Cu*F]≤0.94  (1)

A nanostructured bainitic steel of low carbon comprising of the following components in percentage by mass: Carbon—(0.24-0.28%), Manganese—(1.8-2%), Silicon—(2-2.5%), Nickel—(1.5-1.8%), Molybdenum—(0.2-0.25%), Chromium—(0.2-0.25%), Aluminium—(0.2-0.25%), and Cobalt—(0.45-0.5%) and the balance being Iron and unavoidable impurities and a method for preparation thereof.

[PROBLEM] The invention provides a roll for hot rolling process having various types of more excellent durability performances than conventional rolls, and provides also a method for manufacturing the same. [SOLUTION] A cladding layer 4 is formed on an outer circumference portion of a roll for hot rolling process 1, where the cladding layer 4 comprises: 0.5 to 0.7% by mass of C, 2.8 to 4.0% by mass of Si, 0.9 to 1.1% by mass of Cu, 1.4 to 1.6% by mass of Mn, 2.7 to 3.3% by mass of Ni, 13.5 to 14.5% by mass of Cr, 0.8 to 1.1% by mass of Mo, 0.9 to 1.1% by mass of Co, and 0.2 to 0.4% by mass of Nb, with a balance being Fe and inevitable impurities, and has a thickness of 5 mm or more.

This hot-rolled steel sheet has a predetermined chemical composition, in which in a case where the thickness is denoted by t, a metallographic structure at a t/4 position from the surface includes, by area fraction, 77.0% to 97.0% of bainite or tempered martensite, 0% to 5.0% of ferrite, 0% to 5.0% of pearlite, 3.0% or more of residual austenite, and 0% to 10.0% of martensite, in the metallographic structure, the average grain size excluding the residual austenite is 7.0 μm or less, the average number density of iron-based carbides having a diameter of 20 nm or more is 1.0×10.sup.6 carbides/mm.sup.2 or more, a tensile strength is 980 MPa or more, and an average Ni concentration on the surface is 7.0% or more.