A steel part includes a steel sheet substrate and a coating on at least one surface of the steel sheet substrate. The coating includes between 0.2 and 0.7% by weight of Al, with a remainder of the metal coating being Zn and inevitable impurities. The steel sheet substrate and the coating have at least one deformation. An outer surface of the coating has a waviness Wa.sub.0.8 of less than or equal to 0.43 μm.

Provided is a method for manufacturing a grain-oriented electrical steel sheet. The method comprises: hot rolling a slab to obtain a hot rolled sheet; subjecting the hot rolled sheet to hot band annealing as necessary; subjecting the hot rolled sheet to cold rolling; subjecting the cold rolled sheet to decarburization annealing; applying an annealing separator having MgO as a main component onto a surface of the decarburization annealed sheet and subjecting the decarburization annealed sheet to final annealing to form the forsterite film; and applying an insulating coating treatment liquid onto the final annealed sheet and subjecting the final annealed sheet to flattening annealing to form a tension-applying insulating coating. A difference in total tensions between one and opposite surfaces of the sheet is less than 0.5 MPa. A difference in tensions between the forsterite films in one and opposite surfaces of the sheet is 0.5 MPa or more.

A structural steel having excellent brittle crack propagation resistance, according to one aspect of the present invention, comprises, by wt %, 0.02-0.12% of C, 0.01-0.8% of Si, 1.7-2.5% of Mn, 0.005-0.5% of Al, and the balance of Fe and inevitable impurities, wherein an outer surface part and an inner center part thereof are microstructurally distinguished in the thickness direction, and the surface part comprises tempered bainite as a base structure, comprises fresh martensite as a second structure and can comprise austenite as a residual structure.

The present disclosure provides rare earth die steel. Mg and B elements are added on the basis of adding rare earth element Y, so that the rare earth element purifies a matrix, and grain boundary occupation by Mg and B is fully utilized to regulate grain network chromium carbides. In addition, the B element can fully improve hardenability of austenite and ensure that non-martensite such as bainite does not appear during the cooling process, and therefore rare earth die steel with high impact toughness and high isotropy is obtained.

A heat treated and cold rolled steel sheet having a composition including of the following elements 0.09%≤Carbon≤0.15%, 1.8%≤Manganese≤2.5%, 0.2%≤Silicon≤0.7%, 0.01%≤Aluminum≤0.1%, 0%≤Phosphorus≤0.09%, 0%≤Sulfur≤0.09%, 0%≤Nitrogen≤0.09%, 0%≤Niobium≤0.1%, 0%≤Titanium≤0.1%, 0%≤Chromium≤1%, 0%≤Molybdenum≤1%, 0%≤Vanadium≤0.1%, 0%≤Calcium≤0.005%, 0%≤Boron≤0.01%, 0%≤Cerium≤0.1%, 0%≤Magnesium≤0.05%, 0%≤Zirconium≤0.05% the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of said steel sheet comprising in area fraction, 65 to 85% Tempered Martensite, 0% to 5% Residual Austenite and a cumulative presence of Ferrite and Bainite between 15 and 35%.

A non-oriented electrical steel sheet according to an embodiment of the present invention includes, in wt %, Si: 2.1 to 3.8%, Mn: 0.001 to 0.6%, Al: 0.001 to 0.6%, Bi: 0.0005 to 0.003%, and Ge: 0.0003 to 0.001%, and the balance of Fe and inevitable 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.

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.

The present invention relates to a non-oriented electrical steel sheet including 1.5 to 4.0 wt % of Si, 0.1 to 1.5 wt % of Al, 0.1 to 1.5 wt % of Mn, 0.005 wt % or less (excluding 0%) of C, 0.005 wt % or less (excluding 0%) of N, 0.005 wt % or less (excluding 0%) of Ti, 0.001 to 0.005 wt % of S, 0.1 wt % or less (excluding 0%) of P, 0.02 to 0.2 wt % of at least one of Sn and Sb, and a balance of Fe and other inevitable impurities; and satisfying the following Formulas 1, 2, and 3.
0.9≤[Al]+[Mn]≤2.1  [Formula 1]
0.2≤([Si]+[Al]+[Mn]/2)*([P]+[Sn]+[Sb])≤0.4  [Formula 2]
(Gs.sub.center−Gs.sub.surface)/(Gs.sub.center*t)≤0.5  [Formula 3] (In Formula 1 and Formula 2, [Al], [Mn], [Si], [P], [Sn], and [Sb] represent the content (weight %) of Al, Mn, Si, P, Sn, and Sb, respectively, and in Formula 3, t represents the thickness (mm) of the non-oriented electrical steel sheet, Gs.sub.surface represents the average grain size (μm) from 0 to t/4 or 3t/4 to t based on the thickness direction of the non-oriented steel sheet, Gs.sub.center represents the average grain size (μm) from more than t/4 to less than 3t/4 based on the thickness direction of the non-oriented steel sheet.)

A grain oriented electrical steel sheet includes a base steel sheet, a glass film, and a tension-insulation coating. When a glow discharge emission spectroscopy is conducted from a surface of the glass film toward a depth direction, an analysis starting time Ts, a time T.sup.Al.sub.p at which Al shows a maximum emission intensity, an Al emission intensity F(T.sup.Al.sub.p) at the T.sup.Al.sub.p, a time T.sup.Si.sub.p at which Si shows a maximum emission intensity, and an Al emission intensity F(T.sup.Si.sub.p) at the T.sup.Si.sub.p satisfy 0.05≤F(T.sup.Si.sub.p)/F(T.sup.Al.sub.p)≤0.50 and 2.0≤(T.sup.Al.sub.p−Ts)/(T.sup.Si.sub.p−Ts)≤5.0.