A method is provided for producing a high-strength galvanized steel sheet having a microstructure that contains martensite in an area proportion of 20% or more and 60% or less and ferrite in an area proportion of 40% or more and 80% or less includes, in sequence, hot-rolling a steel slab containing a specific component composition, performing cold rolling, performing primary annealing, performing pickling, performing secondary annealing, and performing galvanizing treatment, in which in the primary annealing, heating is performed at an average heating rate of 0.1 C./sec. or more and less than 3 C./sec. in the temperature range of 600 C. to 750 C., an annealing temperature of 750 C. to 850 C. is maintained for 10 to 500 seconds, and then cooling is performed from the annealing temperature range to a cooling stop temperature of 600 C. or lower at an average cooling rate of 1 to 15 C.,/sec, in which in the pickling, the pickling weight loss of the steel sheet is 0.05 to 5 g/m.sup.2 in terms of Fe, in which in the secondary annealing, an annealing temperature of 750 C. to 850 C. is maintained for 10 to 500 seconds, and then cooling is performed from the annealing temperature at an average cooling rate of 1 to 15 C./s, and in which after the galvanizing treatment, cooling is performed at an average cooling rate of 5 to 100 C./sec.

A high-strength hot-dip galvanized steel sheet containing a main component, the steel sheet having at least 40 wt. % of ferrite as a main phase in terms of the volumetric ratio, and 8-60% inclusive of residual austenite, the remaining structure comprising one or more of bainite, martensite, or pearlite. Austenite particles within a range where the average residual stress (sigmaR) thereof satisfies the expression 400 MPa<=sigmaR<=200 MPa (formula (1)) are present in an amount of 50% or more in the hot-dip galvanized steel sheet. The surface of the steel sheet has a hot-dip galvanized layer containing less than 7 wt. % of Fe, the remainder comprising Zn, Al and inevitable impurities.

To improve the formability of dual phase steels, the martensite phase is tempered. It may form a ferrite-carbide structure. The tempering step occurs after martensite has been formed in the dual phase steel. The tempering step can occur in a box annealing step or it can be performed in a continuous fashion, such as on a continuous annealing, continuous tempering heat treating, or continuous coating line. The tempering step can further comprise a temper rolling on a temper mill after the heating step.

There is provided a high-strength steel sheet having a tensile strength of 1180 MPa or more. The high-strength steel sheet having a component composition containing C: 0.090 mass % or more and 0.390 mass % or less, Si: 0.01 mass % or more and 2.00 mass % or less, Mn: 2.00 mass % or more and 4.00 mass % or less, P: 0.100 mass % or less, S: 0.0200 mass % or less, Al: 1.000 mass % or less, N: 0.0100 mass % or less, and O: 0.0100 mass % or less, with a remaining part consisting of Fe and inevitable impurities; and a microstructure. In the microstructure, an area ratio of martensite is 70% or more, an area ratio of ferrite is 10% or less, an area ratio of retained austenite is 10% or less, and a proportion of the number of martensite blocks in which metastable carbides are present to the number of martensite blocks is 2% or more.

An exemplary embodiment in the present disclosure provides a grain-oriented electrical steel sheet containing, by wt %: 3.0 to 4.5% of Si; 0.05 to 0.2% of Mn; 0.015 to 0.035% of Al; 0.0015% or less (excluding 0%) of C; 0.0015% or less (excluding 0%) of N; 0.0015% or less (excluding 0%) of S; and a balance of Fe and other unavoidable impurities, wherein the grain-oriented electrical steel sheet satisfies the following Relational Expressions 1 and 2:
(W.sub.13/50/W.sub.17/50)0.57[Relational Expression 1]
(W.sub.15/50/W.sub.17/50)0.76[Relational Expression 2] where Wx/y represents a core loss value under conditions in which a magnitude of an applied magnetic field is x/10 T and a frequency is y Hz.

A steel sheet includes, as a chemical composition, by mass %: C: 0.0050% or less; Si: 0.050% or less; Mn: 0.007% to 1.00%; P: 0.020% to 0.200%; S: 0.005% to 0.050%; Al: 0.010% or less; O: 0.0100% to 0.1000%; Cu: 0.010% to 0.060%; N: 0.0050% or less; Cr: 0.010% to 1.00%; one or two of Sn: 0.010% to 1.00% and Sb: 0.010% to 1.00%: 0.11% or more in total; one or more selected from the group consisting of B, Ni, Nb, As, Ti, Mo, Se, Ta, W, La, Ce, Ca, and Mg: 0% to 0.100% in total; and a remainder: Fe and impurities, in which, in a case where a Sn content in mass % is denoted by [Sn], a Sb content in mass % is denoted by [Sb], and a P content in mass % is denoted by [P], Expression (1) is satisfied, and a tensile strength obtained in a tensile test performed in accordance with JIS Z2241:2011 is 340 MPa or more.

A hot-rolled steel sheet has, as a chemical composition, by mass %: C: 0.01% to 0.30%; Si: 0.01% to 3.00%; Mn: 0.20% to 3.00%; P: 0.030% or less; S: 0.030% or less; Al: 0.001% to 2.000%; N: 0.0100% or less; and Ni: 0.02% to 0.50%, in which among measurement points at which elemental analysis is performed at a measurement pitch of 1 m using an EPMA in a region of 250 m250 m on a surface, the percentage of measurement points having a Ni content of 0.5 mass % or more is 10% to 70%.

There is provided a water-based alkaline composition for forming an insulating layer of an annealing separator on a soft magnetic alloy, this composition comprising ceramic particles with a particle size of less than 0.5 m and at least one polymer dispersion as a binding agent, the polymer dispersion comprising one or more mixed polymerisates from the group made up of acrylate polymers, methacrylate polymers, polyvinyl acetate, polystyrene, polyurethane, polyvinyl alcohol, hydroxylated cellulose ether, polyvinyl pyrrolidone, and polyvinyl butyral, and having a pH value of between 8 and 12, preferably between 9 and 11.

Steel part having a chemical composition including, by weight %, 0.18C0.27, 0.18Si0.30, 1.0Mn1.5, 0.14Cr0.25, 0.02Al0.06, 0.02Ti0.06, 0.0020B0.0040, 0S0.008, 0.008N0.020, the remainder of the composition being iron and unavoidable impurities resulting from the elaboration process, having a microstructure including, in surface fraction, 95% or more of martensite, wherein the surface fraction of TIN particles in the skin portion is equal to or greater than 200*10.sup.6 inclusions/mm.sup.2 and the average equivalent diameter of the TiN particles in the skin portion is equal to or smaller than 2.0 microns.

Provided is a grain oriented electrical steel sheet including a base metal steel sheet, an intermediate layer and an insulation coating, wherein: the intermediate layer is an oxide film; an average thickness of the oxide film is 2-500 nm; the insulation coating is a phosphate coating; an average thickness of the insulation coating is 0.1-10 m. When grazing incidence X-ray diffraction is performed on the phosphate coating using a Co-K excitation source, the X-ray diffraction pattern has a diffraction peak originating from cristobalite-type aluminum phosphate at a diffraction angle of 2=24.8; a half value width FWHM.sub.0.5 of the diffraction peak under a diffraction condition with an X-ray incident angle =0.5 and a half value width FWHM.sub.1.0 of the diffraction peak under a diffraction condition with an X-ray incident angle =1.0 satisfy 0.20FWHM.sub.0.52.00, 0.20FWHM.sub.1.02.00, and 0|FWHM.sub.0.5FWHM.sub.1.0|1.00.