Abstract: The present invention has as its object the provision of steel sheet for hot stamping use which is excellent in part strength after hot stamping and delayed fracture resistance comprised of large C content high strength steel sheet in which effective hydrogen traps are formed in the steel material. The steel sheet of the present invention solves this problem by forming Fe—Mn-based composite oxides in the steel sheet and trapping hydrogen at the interfaces of the composite oxides and matrix steel and in the voids around the composite oxides. Specifically, it provides steel sheet for hot stamping use which is comprised of chemical ingredients which contain, by mass %, C: 0.05 to 0.40%, Si: 0.02% or less, Mn: 0.1 to 3%, S: 0.02% or less, P: 0.03% or less, Al: 0.005% or less, Ti: 0.01% or less, N: 0.01% or less, one or both of Cr and Mo in a total of 0.005 to 1%, and O: 0.003 to 0.03% and which have a balance of Fe and unavoidable impurities and which contains average diameter 0.

Abstract: The present invention has as its object the provision of steel sheet for hot stamping use which is excellent in part strength after hot stamping and delayed fracture resistance comprised of large C content high strength steel sheet in which effective hydrogen traps are formed in the steel material. The steel sheet of the present invention solves this problem by forming Fe—Mn-based composite oxides in the steel sheet and trapping hydrogen at the interfaces of the composite oxides and matrix steel and in the voids around the composite oxides. Specifically, it provides steel sheet for hot stamping use which is comprised of chemical ingredients which contain, by mass %, C: 0.05 to 0.40%, Si: 0.02% or less, Mn: 0.1 to 3%, S: 0.02% or less, P: 0.03% or less, Al: 0.005% or less, Ti: 0.01% or less, N: 0.01% or less, one or both of Cr and Mo in a total of 0.005 to 1%, and O: 0.003 to 0.03% and which have a balance of Fe and unavoidable impurities and which contains average diameter 0.

Abstract: The present invention provides a very thin steel sheet and production method thereof that, in a very thin steel sheet of 0.4 mm or less thickness, enable production at low addition of special elements, simultaneous achievement of both good workability and anti-aging property, and stable passing of even wide coil in a continuous annealing process, which very thin steel sheet and production method.

Abstract: A high-strength non-oriented electrical steel sheet contains: in mass %, C: 0.010% or less; Si: not less than 2.0% nor more than 4.0%; Mn: not less than 0.05% nor more than 0.50%; Al: not less than 0.2% nor more than 3.0%; N: 0.005% or less; S: not less than 0.005% nor more than 0.030%; and Cu: not less than 0.5% nor more than 3.0%, a balance being composed of Fe and inevitable impurities. An expression (1) is established where a Mn content is represented as [Mn] and a S content is represented as [S], and not less than 1.0×104 pieces nor more than 1.0×106 pieces of sulfide having a circle-equivalent diameter of not less than 0.1 ?m nor more than 1.0 ?m are contained per 1 mm2 10?[Mn]/[S]?50??(1).

Abstract: The present invention provides a non-aging enameling steel sheet having excellent fishscale resistance characteristics that is suitable for one-coat enameling and a method of producing the same. The enameling steel sheet comprises, in mass %, C: 0.010% or less, Mn: 0.03% to 1.30%, Si: 0.100% or less, Al: 0.010% or less, N: 0.0055% or less, P: 0.035% or less, S: 0.08% or less, O: 0.005% to 0.085%, Nb: 0.055% to 0.250%, and the balance of Fe and unavoidable impurities, in which steel sheet preferably an Fe—Nb—Mn system composite oxide is present, a distribution of Nb mass % concentrations is present in the composite oxide, and the ratio of Nb mass % concentration of a high-concentration portion (Nb max %) to Nb mass % concentration of a low-concentration portion (Nb min %) is Nb max %/Nb min %?1.2.

Abstract: The present invention provides enamelware and a glaze improving the bondability between the steel substrate and enamel layer and superior in resistance to dew point corrosion by sulfuric acid and hydrochloric acid, that is, a steel substrate of a composition containing, by mass %, Cu: 0.05 to 0.5%, Si: 0.1 to 2.0%, Mn: 0.05 to 2.0%, P: 0.005 to 0.10%, and S: 0.005 to 0.1%, restricting C to C: 0.20% or less, and comprising a balance of Fe and unavoidable impurities on the surface of which an enamel layer of a thickness of 50 to 700 ?m is provided. At that time, the content of Co oxides in the enamel layer is made, converted to Co, 0.01 to 10% and/or the content of Ni oxides is made, converted to Ni, 0.05 to 20% or the total content of Ni in the steel substrate and enamel layer is made 0.005 to 4.5% with respect to the total mass of the enamelware and/or the total content of Co is made 0.008 to 4.0% with respect to the total mass of the enamelware.

Abstract: A high-strength non-oriented electrical steel sheet contains: in mass %, C: 0.010% or less; Si: not less than 2.0% nor more than 4.0%; Mn: not less than 0.05% nor more than 0.50%; Al: not less than 0.2% nor more than 3.0%; N: 0.005% or less; S: not less than 0.005% nor more than 0.030%; and Cu: not less than 0.5% nor more than 3.0%, a balance being composed of Fe and inevitable impurities. An expression (1) is established where a Mn content is represented as [Mn] and a S content is represented as [S], and not less than 1.0×104 pieces nor more than 1.0×106 pieces of sulfide having a circle-equivalent diameter of not less than 0.1 ?m nor more than 1.0 ?m are contained per 1 mm2.

Abstract: The present invention has as its object the provision of steel sheet for hot stamping use which is excellent in part strength after hot stamping and delayed fracture resistance comprised of large C content high strength steel sheet in which effective hydrogen traps are formed in the steel material. The steel sheet of the present invention solves this problem by forming Fe—Mn-based composite oxides in the steel sheet and trapping hydrogen at the interfaces of the composite oxides and matrix steel and in the voids around the composite oxides. Specifically, it provides steel sheet for hot stamping use which is comprised of chemical ingredients which contain, by mass %, C: 0.05 to 0.40%, Si: 0.02% or less, Mn: 0.1 to 3%, S: 0.02% or less, P: 0.03% or less, Al: 0.005% or less, Ti: 0.01% or less, N: 0.01% or less, one or both of Cr and Mo in a total of 0.005 to 1%, and O: 0.003 to 0.03% and which have a balance of Fe and unavoidable impurities and which contains average diameter 0.

Abstract: The invention provides a non-oriented electrical steel sheet excellent in yield strength for use as an iron core material for high rpm motors that does not sacrifice yield or productivity in motor core punching or steel sheet production, which non-oriented electrical steel sheet is given a chemical composition of, in mass %, C: 0.01 to 0.05%, Si: 2.0 to 4.0%, Mn: 0.05 to 0.5%, Al: 3.0% or less and Nb: 0.01 to 0.05%, and optionally Ni at a preferable content of more than 0.5% and less than 3.0%, the balance being Fe and unavoidable impurities, Mn and C contents expressed in mass % are made to satisfy Mn?0.6-10×C, recrystallized portion area fraction is made 50% or greater, yield strength in tensile testing is made 650 MPa or greater, and average-grain diameter viewed in steel sheet cross-section is made 40 ?m or less, and electrical steel sheet production is conducted using a hot-rolled sheet whose transition temperature in impact testing is 70° C. or less.

Abstract: The present invention relates to a steel sheet for Vitreous enameling excellent in enameling properties (bubbling and black spot resistance, enamel adhesiveness and fish scale resistance) and workability, and a method for producing the same, and is characterized in that the steel sheet contains, in mass of, C: 0.010% or less, Mn: 0.03 to 1.3%, Si: 0.03% or less, Al: 0.02% or less, N: 0.0055% or less, P: below 0.035%, and S: over 0.025% to 0.08%; and the density change of the steel sheet from before an annealing to after an annealing at 850° C. for 20 hours, in a hydrogen atmosphere is 0.02% or more.

Abstract: The present invention provides a product for enameling and an enameled product that achieve adhesion, bubble/black spot defect resistance and fishscale resistance, even when preprocessing and ground coating are omitted, which product comprise a steel sheet having on the surface thereof an oxide film of 0.10 ?m to 400 ?m thickness comprising oxides of components of the steel sheet, which steel sheet comprises, in mass %, C: 0.0001% to 0.040%, Si: 0.0001% to 0.50%, Mn: 0.001% to 2.00%, P: 0.0001% to 0.10%, S: 0.0001% to 0.060%, Al: 0.0001% to 0.10%, N: 0.0001% to 0.015%, and O: 0.0001% to 0.070%, further comprises one or more of Ni: 0.01% to 2.00%, Co: 0.0005% to 2.00%, Cr: 0.001% to 2.00%, Cu: 0.01% to 2.00%, Mo: 0.0001% to 2.00%, and Ti: 0.0005% to 0.50%, where Ni+Co+Cr/2+Cu+Mo+Ti: 0.010% to 8.0%, the balance being Fe and unavoidable impurities.

Abstract: The present invention provides a very thin steel sheet and production method thereof that, in a very thin steel sheet of 0.4 mm or less thickness, enable production at low addition of special elements, simultaneous achievement of both good workability and anti-aging property, and stable passing of even wide coil in a continuous annealing process, which very thin steel sheet and production method.

Abstract: The present invention has as its object to stably produce a high strength electrical steel sheet and a processed part of the same which is high in strength and has wear resistant and is superior in magnetic flux density and core loss without greatly changing the cold rollability and production processes from those of conventional electrical steel sheet and provides a high strength electrical steel sheet characterized by containing, by mass %, C: 0.06% or less, Si: 0.2 to 6.5%, Mn: 0.05 to 3.0%, P: 0.30% or less, S or Se: 0.040% or less, Al: 2.50% or less, Cu: 0.6 to 8.0%, N: 0.0400% or less, and a balance of Fe and unavoidable impurities and containing in the steel a metal phase composed of Cu of a size of 0.1 ?m or less. The method of production of the same comprises holding in a temperature range of 300° C. to 720° C. for 5 seconds or more for heat treatment.

Abstract: The present invention relates to a steel sheet for Vitreous enameling excellent in enameling properties (bubbling and black spot resistance, enamel adhesiveness and fish scale resistance) and workability, and a method for producing the same, and is characterized in that the steel sheet contains, in mass of, C: 0.010% or less, Mn: 0.03 to 1.3%, Si: 0.03% or less, Al: 0.02% or less, N: 0.0055% or less, P: below 0.035%, and S: over 0.025% to 0.08%; and the density change of the steel sheet from before an annealing to after an annealing at 850° C. for 20 hours, in a hydrogen atmosphere is 0.02% or more.

Abstract: A high-strength non-oriented electrical steel sheet contains: by mass %, C: not less than 0.002% nor more than 0.05%; Si: not less than 2.0% nor more than 4.0%; Mn: not less than 0.05% nor more than 1.0%; N: not less than 0.002% nor more than 0.05%; and Cu: not less than 0.5% nor more than 3.0%. An Al content is 3.0% or less, and when a Nb content (%) is set to [Nb], a Zr content (%) is set to [Zr], a Ti content (%) is set to [Ti], a V content (%) is set to [V], a C content (%) is set to [C], and an N content (%) is set to [N], Formula (1) and Formula (2) are satisfied. A balance is composed of Fe and inevitable impurities, a recrystallization area ratio is 50% or more, yield stress at a tensile test is 700 MPa or more, fracture elongation is 10% or more, and an eddy current loss We10/400 (W/kg) satisfies Formula (3) in relation to a sheet thickness t (mm) of the steel sheet. 2.0×10?4?[Nb]/93+[Zr]/91+[Ti]/48+[V]/51 ??(1) 1.0×10?3?[C]/12+[N]/14?([Nb]/93+[Zr]/91+[Ti]/48+[V]/51)?3.

Abstract: To provide a non-aging steel sheet for vitreous enameling, the steel sheet being excellent in resistance to bubbles and black spots, without the employment of decarbonization and denitrification annealing that raises the cost of production and also without the addition of expensive elements such as Nb, Ti, etc. that raise the cost of alloys. The steel sheet comprises, in mass, to C: 0.0050% or less, Si: 0.50% or less, Mn: 0.005 to 1.0%, P: 10×(B?11/14×N) to 0.10%, S: 0.080% or less, Al: 0.050% or less, N: 0.0005 to 0.020%, B: 0.60×N to 0.020%, and O: 0.002 to 0.0800%, and the shape of B nitrides is controlled mainly by adjusting hot-rolling conditions.

Abstract: The present invention has as its object the production of high strength electrical steel sheet, having a high strength of a tensile strength TS of for example 500 MPa or more, having wear resistance, and having superior magnetic properties of magnetic flux density and iron loss, that is, provides a method of production of high strength electrical steel sheet containing, by mass %, C: 0.060% or less, Si: 0.2 to 6.5%, Mn: 0.05 to 3.0%, P: 0.30% or less, S or Se: 0.040% or less, Al: 2.50% or less, N: 0.020% or less, and further one or more of Cu: 0.001 to 30.0% and Nb: 0.03 to 8.

Abstract: The present invention stably provides a high-strength hot-dip galvanized steel sheet having a high tensile strength and no non-plated portions and being excellent in workability and surface properties even when the employed equipment has only a reduction annealing furnace and a steel sheet containing relatively large amounts of Si, Mn and Al that are regarded as likely to cause non-plated portions is used as the substrate.

Abstract: The present invention provides a non-aging enameling steel sheet having excellent fishscale resistance characteristics that is suitable for one-coat enameling and a method of producing the same. The enameling steel sheet comprises, in mass %, C: 0.010% or less, Mn: 0.03% to 1.30%, Si: 0.100% or less, Al: 0.010% or less, N: 0.0055% or less, P: 0.035% or less, S: 0.08% or less, O: 0.005% to 0.085%, Nb: 0.055% to 0.250%, and the balance of Fe and unavoidable impurities, in which steel sheet preferably an Fe—Nb—Mn system composite oxide is present, a distribution of Nb mass % concentrations is present in the composite oxide, and the ratio of Nb mass % concentration of a high-concentration portion (Nb max %) to Nb mass % concentration of a low-concentration portion (Nb min %) is Nb max %/Nb min % ?1.2.

Abstract: The present invention provides a product for enameling and an enameled product that achieve adhesion, bubble/black spot defect resistance and fishscale resistance, even when preprocessing and ground coating are omitted, which product comprise a steel sheet having on the surface thereof an oxide film of 0.10 ?m to 400 ?m thickness comprising oxides of components of the steel sheet, which steel sheet comprises, in mass %, C: 0.0001% to 0.040%, Si: 0.0001% to 0.50%, Mn: 0.001% to 2.00%, P: 0.0001% to 0.10%, S: 0.0001% to 0.060%, Al: 0.0001% to 0.10%, N: 0.0001% to 0.015%, and O: 0.0001% to 0.070%, further comprises one or more of Ni:0.01% to 2.00%, Co: 0.0005% to 2.00%, Cr: 0.001% to 2.00%, Cu: 0.01% to 2.00%, Mo: 0.0001% to 2.00%, and Ti: 0.0005% to 0.50%, where Ni+Co+Cr/2+Cu+Mo+Ti: 0.010% to 8.0%, the balance being Fe and unavoidable impurities.