Abstract: A spring steel includes a predetermined chemical composition and a composite inclusion having a maximum diameter of 2 ?m or more that TiN is adhered to an inclusion containing REM, O and Al, in which the number of the composite inclusion is 0.004 pieces/mm2 to 10 pieces/mm2, the maximum diameter of the composite inclusion is 40 ?m or less, the sum of the number density of an alumina cluster having the maximum diameter of 10 ?m or more, MnS having the maximum diameter of 10 ?m or more and TiN having the maximum diameter of 1 ?m to 10 pieces/mm2.

Abstract: A steel for induction hardening includes as a chemical composition, by mass %, C: 0.45% to 0.85%, Si: 0.01% to 0.80%, Mn: 0.1% to 1.5%, Al: 0.01% to 0.05%, REM: 0.0001% to 0.050%, O: 0.0001% to 0.0030%. Ca: 0.0050% or less as necessary, Ti: less than 0.005%, N: 0.015% or less, P: 0.03% or less, S: 0.01% or less, and the balance consists of Fe and impurities. The steel for induction hardening also includes a composition inclusion which is an inclusion containing REM, O, S, and Al, or an inclusion containing REM, Ca, O, S, and Al, to which TiN is adhered.

Abstract: A case hardening steel includes as a chemical composition, by mass %, C: 0.10% to 0.40%, Si: 0.01% to 0.80%, Mn: 0.1% to 1.5%, Cr: 0.35% to 2.0%, Al: 0.01% to 0.05%, REM: 0.0001% to 0.050%, O: 0.0001% to 0.0030%, Ca: 0.0050% or less as necessary, Ti: less than 0.005%, N: 0.015% or less, P: 0.03% or less, S: 0.01% or less, and the balance consists of Fe and impurities. The case hardening steel also includes a composition inclusion which is an inclusion containing REM, O, S, and Al, or an inclusion containing REM, Ca, O, S, and Al, to which TiN is adhered.

Abstract: A bearing steel includes, as a metallographic structure, inclusions which contain complex oxysulfides including Rare Earth Metal, Ca, O, S, and Al, TiN, MnS, Al2O3, and complex oxides including Al and Ca, wherein, a number fraction of the complex oxysulfides in a total number of the inclusions is 50% to less than 100% and a number of complex oxysulfides having a major axis of 5 ?m or more is 0.001 pieces to 2 pieces in an observed section of 1 mm2, and a number of TiN existing independently from the complex oxysulfides and having a major axis of 5 ?m or more is 0.001 pieces to less than 1.0 piece in an observed section of 1 mm2.

Abstract: A high-strength steel sheet includes: 0.03 to 0.20% of C, 0.08 to 1.5% of Si, 0.5 to 3.0% of Mn, 0.05% or less of P, 0.0005% or more of S, 0.008 to 0.20% of acid-soluble Ti, 0.0005 to 0.01% of N, more than 0.01% of acid-soluble Al, and 0.001 to 0.04% of one or both of Ce and La in terms of mass %; and the balance including Fe and inevitable impurities. The ratio of (Ce+La)/acid-soluble Al is equal to or more than 0.1 and the ratio of (Ce+La)/S is in the range of 0.4 to 50 in a mass base, and the density of the number of inclusions, having a circle equivalent diameter of 2 ?m or less, which are present in the steel sheet is equal to or more than 15/mm2.

Abstract: The present invention provides a high-strength steel sheet including: C: 0.03 to 0.25 mass %, Si: 0.1 to 2.0 mass %, Mn: 0.5 to 3.0 mass %, P: not more than 0.05 mass %, T.O: not more than 0.0050 mass %, S: 0.0001 to 0.01 mass %, N: 0.0005 to 0.01 mass %, acid-soluble Al: more than 0.01 mass %, Ca: 0.0005 to 0.0050 mass %, and a total of at least one element of Ce, La, Nd, and Pr: 0.001 to 0.01 mass %, with a balance including iron and inevitable impurities, in which the steel sheet contains a chemical component on a basis of mass that satisfies 0.7<100×([Ce]+[La]+[Nd]+[Pr])/[acid-soluble Al]?70 and 0.

Abstract: A non-oriented electrical steel sheet comprising, Si: not less than 1.0 mass % nor more than 3.5 mass %, Al: not less than 0.1 mass % nor more than 3.0 mass %, Ti: not less than 0.001 mass % nor more than 0.01 mass %, Bi: not less than 0.001 mass % nor more than 0.01 mass %, wherein Expression (1) is satisfied when a Ti content (mass %) is represented as [Ti] and a Bi content (mass %) is represented as [Bi]: [Ti]?0.8×[Bi]+0.002 . . . (1).

Abstract: A spring steel includes a predetermined chemical composition and a composite inclusion having a maximum diameter of 2 ?m or more that TiN is adhered to an inclusion containing REM, O and Al, in which the number of the composite inclusion is 0.004 pieces/mm2 to 10 pieces/mm2, the maximum diameter of the composite inclusion is 40 ?m or less, the sum of the number density of an alumina cluster having the maximum diameter of 10 ?m or more, MnS having the maximum diameter of 10 ?m or more and TiN having the maximum diameter of 1 ?m to 10 pieces/mm2.

Abstract: A low-carbon steel slab producing method includes: adding Ti to a molten steel decarbonized to have a carbon concentration of 0.05 mass % or less, and subsequently adding at least one of La and Ce to adjust a constitution, and producing a smelted molten steel; and pouring the smelted molten steel into a casting mold via a tundish; wherein at least one of La and Ce in a total amount of 0.2 to 1.2 times an increased amount of oxygen in the smelted molten steel during contained in the tundish is added to the smelted molten steel in the tundish, so as to obtain a steel slab having inclusions which contain oxides of Ti and at least one of La and Ce as chief components, and so as to make a composition of each of the inclusions have a mass ratio of 0.1 to 0.7, in terms of (La2O3+Ce2O3)÷TiOn (n=1˜2).

Abstract: A non-oriented electrical steel sheet comprising, Si: not less than 1.0 mass % nor more than 3.5 mass %, Al: not less than 0.1 mass % nor more than 3.0 mass %, Ti: not less than 0.001 mass % nor more than 0.01 mass %, Bi: not less than 0.001 mass % nor more than 0.01 mass %, wherein Expression (1) is satisfied when a Ti content (mass %) is represented as [Ti] and a Bi content (mass %) is represented as [Bi]: [Ti]?0.8×[Bi]+0.002 . . . (1).

Abstract: A steel for induction hardening includes as a chemical composition, by mass %, C: 0.45% to 0.85%, Si: 0.01% to 0.80%, Mn: 0.1% to 1.5%, Al: 0.01% to 0.05%, REM: 0.0001% to 0.050%, O: 0.0001% to 0.0030%. Ca: 0.0050% or less as necessary, Ti: less than 0.005%, N: 0.015% or less, P: 0.03% or less, S: 0.01% or less, and the balance consists of Fe and impurities. The steel for induction hardening also includes a composition inclusion which is an inclusion containing REM, O, S, and Al, or an inclusion containing REM, Ca, O, S, and Al, to which TiN is adhered.

Abstract: In a non-oriented electrical steel sheet, Si: not less than 1.0 mass % nor more than 3.5 mass %, Al: not less than 0.1 mass % nor more than 3.0 mass %, Ti: not less than 0.001 mass % nor more than 0.01 mass %, Bi: not less than 0.001 mass % nor more than 0.01 mass %, and so on are contained. (1) expression described below is satisfied when a Ti content (mass %) is represented as [Ti] and a Bi content (mass %) is represented as [Bi]. [Ti]?0.8×[Bi]+0.

Abstract: A case hardening steel includes as a chemical composition, by mass %, C: 0.10% to 0.40%, Si: 0.01% to 0.80%, Mn: 0.1% to 1.5%, Cr: 0.35% to 2.0%, Al: 0.01% to 0.05%, REM: 0.0001% to 0.050%, O: 0.0001% to 0.0030%, Ca: 0.0050% or less as necessary, Ti: less than 0.005%, N: 0.015% or less, P: 0.03% or less, S: 0.01% or less, and the balance consists of Fe and impurities. The case hardening steel also includes a composition inclusion which is an inclusion containing REM, O, S, and Al, or an inclusion containing REM, Ca, O, S, and Al, to which TiN is adhered.

Abstract: A non-oriented electrical steel sheet, containing: C: 0.01 mass % or less; Si: 1.0 mass % or more and 3.5 mass % or less; Al: 0.1 mass % or more and 3.0 mass % or less; Mn: 0.1 mass % or more and 2.0 mass % or less; P: 0.1 mass % or less; S: 0.005 mass % or less; Ti: 0.001 mass % or more and 0.01 mass % or less; N: 0.005 mass % or less; and Y: more than 0.05 mass % and 0.2 mass % or less, with the balance being iron and inevitable impurities.

Abstract: A bearing steel includes, as a metallographic structure, inclusions which contain complex oxysulfides including Rare Earth Metal, Ca, O, S, and Al, TiN, MnS, Al2O3, and complex oxides including Al and Ca, wherein, a number fraction of the complex oxysulfides in a total number of the inclusions is 50% to less than 100% and a number of complex oxysulfides having a major axis of 5 ?m or more is 0.001 pieces to 2 pieces in an observed section of 1 mm2, and a number of TiN existing independently from the complex oxysulfides and having a major axis of 5 ?m or more is 0.001 pieces to less than 1.0 piece in an observed section of 1 mm2.

Abstract: A non-oriented electrical steel sheet, containing: C: 0.01 mass % or less; Si: 1.0 mass % or more and 3.5 mass % or less; Al: 0.1 mass % or more and 3.0 mass % or less; Mn: 0.1 mass % or more and 2.0 mass % or less; P: 0.1 mass % or less; S: 0.005 mass % or less; Ti: 0.001 mass % or more and 0.01 mass % or less; N: 0.005 mass % or less; and Y: more than 0.05 mass % and 0.2 mass % or less, with the balance being iron and inevitable impurities.

Abstract: The present invention provides a high-strength steel sheet including: C: 0.03 to 0.25 mass %, Si: 0.1 to 2.0 mass %, Mn: 0.5 to 3.0 mass %, P: not more than 0.05 mass %, T.O: not more than 0.0050 mass %, S: 0.0001 to 0.01 mass %, N: 0.0005 to 0.01 mass %, acid-soluble Al: more than 0.01 mass %, Ca: 0.0005 to 0.0050 mass %, and a total of at least one element of Ce, La, Nd, and Pr: 0.001 to 0.01 mass %, with a balance including iron and inevitable impurities, in which the steel sheet contains a chemical component on a basis of mass that satisfies 0.7<100×([Ce]+[La]+[Nd]+[Pr])/[acid-soluble Al]?70 and 0.

Abstract: A continuous casting device for steel of the present invention includes a casting mold for casting a molten steel, a submerged entry nozzle, an electromagnetic stirring device, and an electromagnetic brake device. Further, a curved portion which is curved toward the electromagnetic stirring device is formed at least at a position where the curved portion faces the submerged entry nozzle, on each of the long side walls. Moreover, the horizontal distance between a top of the curved portion and the submerged entry nozzle in plan view is equal to or more than 35 mm and less than 50 mm.

Abstract: A low-carbon steel slab producing method includes: adding Ti to a molten steel decarbonized to have a carbon concentration of 0.05 mass % or less, and subsequently adding at least one of La and Ce to adjust a constitution, and producing a smelted molten steel; and pouring the smelted molten steel into a casting mold via a tundish; wherein at least one of La and Ce in a total amount of 0.2 to 1.2 times an increased amount of oxygen in the smelted molten steel during contained in the tundish is added to the smelted molten steel in the tundish, so as to obtain a steel slab having inclusions which contain oxides of Ti and at least one of La and Ce as chief components, and so as to make a composition of each of the inclusions have a mass ratio of 0.1 to 0.7, in terms of (La2O3+Ce2O3)÷TiOn (n=1˜2).

Abstract: The present invention provides tough cast iron and cast iron semi-finished products excellent in workability without heat treatment requiring massive heat energy and long time and a method of production enabling these to be efficiently produced, that is, cast iron of ingredients of white cast iron where particles of spheroidal graphite or flattened graphite are dispersed, cast iron where the ingredients of the white cast iron satisfy, by wt %, (% C)?4.3?(% Si)÷3 and C?1.7% and where the particles of spheroidal graphite are dispersed at a density of 50 particles/mm2 or more, or cast iron where the particles of flattened graphite have a width of 0.4 mm or less and a length of 50 mm or less.