In a steel sheet according to the present embodiment, a Ti content and a N content satisfy Ti−3.5×N≥0.003, at a sheet thickness ¼ position, a metallographic structure includes 90% or more of martensite in terms of volume fraction, at the sheet thickness ¼ position, a number density of TiC having a circle equivalent diameter of 1 to 500 nm is 3.5×10.sup.4 particles/mm.sup.2 or more, at the sheet, thickness ¼ position, a value of a median value of a Mn concentration+3σ is 5.00% or less, and a hardness measured at the sheet thickness ¼ position is 1.30 times or more a hardness measured at a position 50 μm deep from a surface of the steel sheet.

There is provided an alloy that has sufficient creep strength in a high temperature environment, and that is capable of achieving both excellent stress relaxation cracking resistance and excellent weld hot cracking resistance. An alloy according to the present disclosure consists of, in mass %, C: 0.050 to 0.100%, Si: 1.00% or less, Mn: 1.50% or less, P: 0.035% or less, S: 0.0015% or less, Cr: 19.00 to 23.00%, Ni: 30.00 to 35.00%, N: 0.100% or less, Al: 0.15 to 0.70%, Ti: 0.15 to 0.70%, and B: 0.0010 to 0.0050%, with the balance being Fe and impurities, and satisfies Formula (1) and Formula (2).

[00001]$\begin{array}{cc}0.6<A1+\mathrm{Ti}<1.2& \left(1\right)\end{array}$$\begin{array}{cc}1.12\mathrm{Ti}/A1& \left(2\right)\end{array}$

This steel sheet has a predetermined chemical composition, in which a steel structure of an inside of the steel sheet contains, by volume fraction, soft ferrite: 0% to 30%, retained austenite: 3% to 40%, fresh martensite: 0% to 30%, a sum of pearlite and cementite: 0% to 10%, and a remainder includes hard ferrite, a number proportion of the retained austenite having an aspect ratio of 2.0 or more in the total retained austenite is 50% or more, a soft layer having a thickness of 1 to 100 μm from a surface in a sheet thickness direction is present, in ferrite contained in the soft layer, a volume fraction of grains having an aspect ratio of 3.0 or more is 50% or more, a volume fraction of retained austenite in the soft layer is 80% or less of the volume fraction of the retained austenite in the inside of the steel sheet, and a peak of an emission intensity at a wavelength indicating Si appears in a range of more than 0.2 μm and 10.0 μm or less from the surface.

A high-strength steel having a yield strength at a level of 800 MPa and a method of manufacturing the same, with the components and amounts thereof by weight percentage being: C:0.06-0.14%, Si: 0.1-0.30%, Mn: 0.8-1.60%, Cr: 0.2-0.70%, Mo: 0.1-0.40%, Ni: 0-0.30%, Nb: 0.01-0.030%, Ti: 0.01-0.030%, V: 0.01-0.05%, B: 0.0005-0.0030%, Al: 0.02-0.06%, Ca: 0.001-0.004%, N: 0.002-0.005%, P≦0.02%, S≦0.01%, O≦0.008%, the balance of Fe and unavoidable impurities; wherein the above elements meet the following relationships: 0.40%<Ceq<0.50%, Ceq=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15; 0.7%≦Mo+0.8Ni+0.4Cr+6V≦1.1%; 3.7≦Ti/N≦7.0; 1.0≦Ca/S≦3.0.

A hot-rolled steel sheet includes a specific chemical composition, and includes a microstructure represented by, in vol %: retained austenite: 2% to 30%; ferrite: 20% to 85%; bainite: 10% to 60%; pearlite: 5% or less; and martensite: 10% or less. A proportion of grains having an intragranular misorientation of 5° to 14° in all grains is 5% to 50% by area ratio, the grain being defined as an area which is surrounded by a boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 μm or more.

An aspect of the present invention provides an Fe—Ni alloy metal foil having excellent heat resilience, where the Fe—Ni alloy metal foil is prepared by an electroforming (EF) method and has a thickness of 100 μm or less (except O μm), wherein the Fe—Ni alloy metal foil comprises, by wt %, Ni: 34-46 %, a remainder of Fe and inevitable impurities, and wherein the Fe—Ni metal foil has a degree of heat resilience in an amount of 30 ppm or less.

This molded steel alloy includes the following elements in weight percent: carbon (C) between 0.08% and 0.4%, silicon (Si) between 0.15% and 2%, nickel (Ni) between 24% and 31%, cobalt (Co) between 15% and 30%, and niobium (Nb) between 0.01% and 2.5%.

The composition also includes an additional element selected from a group consisting of: molybdenum (Mo) at a content of less than or equal to 3% by weight, manganese (Mn) at a content of less than or equal to 1.5% by weight, chromium (Cr) at a content of less than or equal to 1.5% by weight, phosphorus (P) at a content of less than or equal to 0.04% by weight, sulfur (S) at a content of less than or equal to 0.03% by weight, copper (Cu) at a content of less than or equal to 0.5% by weight, iron, and unavoidable impurities.

The object of the present invention is to provide a metal plate capable of manufacturing a deposition mask in which dispersion of positions of through-holes is restrained. A thermal recovery rate is defined as parts per million of a difference a distance between to measurement points on a sample before a heat treatment and a distance therebetween after the heat treatment, relative to the distance therebetween before the heat treatment. In this case, an average value of the thermal recovery rates of the respective samples is not less than −10 ppm and not more than +10 ppm, and (2) a dispersion of the thermal recovery rates of the respective samples is not more than 20 ppm.

In the present invention, a steel plate contains specific alloy components, has a steel structure that contains specific proportions of retained austenite and ferrite, with the remainder comprising one or more types selected from among bainite, martensite, tempered bainite and tempered martensite, and has a specific average carbon concentration and carbon concentration distribution in the retained austenite.

Provided are high-strength steel having superior brittle crack arrestability and a production method therefor. The structural ultra-thick steel comprises 0.05-0.1 wt % of C, 0.9-1.5 wt % of Mn, 0.8-1.5 wt % of Ni, 0.005-0.1 wt % of Nb, 0.005-0.1 wt % of Ti, 0.1-0.6 wt % of Cu, 0.1-0.4 wt % of Si, at most 100 ppm of P, and at most 40 ppm of S with the remainder being Fe and other inevitable impurities, has microstructures including one structure selected from the group consisting of a single-phase structure of ferrite, a single-phase structure of bainite, a complex-phase structure of ferrite and bainite, a complex-phase structure of ferrite and pearlite, and a complex-phase structure of ferrite, bainite, and pearlite, and has a thickness of at least 50 mm. The high-strength steel has high yield strength and superior brittle crack arrestability.