Abstract: The reduced iron manufacturing method of the present invention includes preparing an agglomerate by agglomerating a mixture containing an iron oxide-containing substance and a carbonaceous reducing agent, and preparing reduced iron by heating the agglomerate to reduce iron oxide in the agglomerate, characterized in that Expression (I) as follows is satisfied: Cfix×Xunder105/OFeO?51??(I) where OFeO is the mass percentage of oxygen contained in the iron oxide in the agglomerate, Cfix is the mass percentage of total fixed carbon contained in the agglomerate, and Xunder105 is the mass percentage of particles having a particle diameter of 105 ?m or less with respect to the total mass of particles configuring the carbonaceous reducing agent.

Abstract: Disclosed herein is a duplex stainless steel material including a ferrite phase and an austenite phase, wherein the steel material contains, as metal component composition, at least one X-group element selected from 0.01 to 0.50 mass % of V, 0.0001 to 0.0500 mass % of Ti, 0.0005 to 0.0500 mass % of Nb, and 0.01 to 0.50 mass % of Ta. The steel material has composite inclusions or has composite inclusions and inclusions, in which each of the inclusions includes at least one of an oxide, a sulfide, and an oxysulfide; each of the composite inclusions includes one of the inclusions as a nucleus and includes an outer shell existing around the nucleus and having a carbide or a nitride containing Cr and the at least one X-group element, and the proportion of the number of the composite inclusions with respect to the total number of the inclusions is 30% or more.

Abstract: A flux-cored wire for gas-shielded arc welding, contains, based on the total mass of the wire: C: from 0.03 to 0.12 mass %; Si in terms of Si in Si alloy and Si compound: from 0.10 to 0.50 mass %; Mn: from 1.0 to 4.0 mass %; Ti in terms of Ti in Ti alloy and Ti compound: from 2.4 to 4.5 mass %; Al: from 0.005 to 0.050 mass %; at least one of Ni: from 0.30 to 3.50 mass % and B: from 0.0008 to 0.012 mass %; and Fe: 80 mass % or more, and satisfies (Ti+Mn+Al)/Si?15.

Abstract: Disclosed herein is a flux-cored wire for gas-shielded arc welding containing, based on total mass of the wire: C: from 0.03 to 0.12 mass %; Si in terms of Si in Si alloy and Si compound: from 0.20 to 0.70 mass %; Mn: from 1.0 to 4.0 mass %; Ti in terms of Ti in Ti alloy and Ti compound: from 2.4 to 4.5 mass %; Al: from 0.005 to 0.050 mass %; Ca: from 0.03 to 1.0 mass %; at least one of Ni: from 0.30 to 3.50 mass % and B: from 0.0008 to 0.012 mass %; and Fe: 80 mass % or more, and satisfies: (Ti+Mn+Al+Ca)/Si?12; and Ca/Si: from 0.07 to 0.35.

Abstract: A Ni based alloy flux cored wire including a Ni based alloy as a sheath is provided, wherein the sheath contains predetermined ranges of Ni, Cr, Mo, Ti, Al, and Mg relative to the total mass of the sheath, control is made to ensure predetermined C and Si, the composition of the whole wire, which is the sum total of the sheath components and flux components enveloped in the sheath, contains predetermined ranges of Ni, Cr, Mo, Mn, W, Fe, Ti, Al, and Mg relative to the total mass of the wire, and control is made to ensure predetermined C, Si, Nb, P, and S.

Abstract: A steel wire rod for a spring includes: C: 0.2 to 1.2%, Si: 1.0 to 3%, Mn: 0.1 to 2%, Cr: 3% or less (not inclusive of 0%), Al: 0.0002 to 0.005%, Ca: 0.0002 to 0.002%, Ti: 0.0003 to 0.010%, and balance: iron and unavoidable impurities. An average composition of oxide-based inclusions having a minor axis of 1 ?m or more which are present in a cross section satisfies CaO: 35% or less, Al2O3: 40% or less, SiO2: 30 to 95%, MgO: 8% or less, MnO: 5% or less, TiO2: 3 to 10%, and CaO+Al2O3+SiO2+MgO+MnO+TiO2?80%. The number of oxide-based inclusions having a minor axis of 2 ?m or more which are present in the cross section is more than 0.002 inclusions/mm2.

Abstract: The reduced iron manufacturing method of the present invention includes preparing an agglomerate by agglomerating a mixture containing an iron oxide-containing substance and a carbonaceous reducing agent, and preparing reduced iron by heating the agglomerate to reduce iron oxide in the agglomerate, characterized in that Expression (I) as follows is satisfied: Cfix×Xunder105/OFeO?51??(I) where OFeO is the mass percentage of oxygen contained in the iron oxide in the agglomerate, Cfix is the mass percentage of total fixed carbon contained in the agglomerate, and Xunder105 is the mass percentage of particles having a particle diameter of 105 ?m or less with respect to the total mass of particles configuring the carbonaceous reducing agent.

Abstract: This steel material for bearings includes prescribed components in the steel, the oxide inclusions in the steel that have a minor axis of 1 ?m or greater satisfying the following conditions (1) and (2). (1) The average composition contains specific respective amounts of CaO, Al2O3, SiO2, and TiO2, and CaO+Al2O3+SiO2+TiO2?60%. (2) The proportion of oxide inclusions in which TiN occurs at the interface of the oxide inclusions and the steel is 30% or more of the total of the oxide inclusions.

Abstract: A method for producing granular metallic iron of the present invention includes: an agglomeration step of obtaining agglomerates through agglomeration of a mixture that contains an iron oxide-containing material and a carbonaceous reducing agent; and a granulation step of obtaining granular metallic iron by heating the agglomerates, reducing iron oxides in the agglomerates, aggregating generated metallic iron to be granular while separating the metallic iron from slag generated as a by-product, and thereafter cooling and solidifying the metallic iron, wherein agglomerates satisfying all the conditions given by formulas (1) to (3) below are used as the agglomerates: (1) [(total CaO amount+total SiO2 amount+total Al2O3 amount)/total Fe amount]?0.250; (2) (total CaO amount/total SiO2 amount)?0.9; (3) [total Al2O3 amount/(total CaO amount+total SiO2 amount+total Al2O3 amount)]×100?9.7.

Abstract: Disclosed is a method for controlling a Ti concentration in a steel when manufacturing a silicon-deoxidized steel comprising 0.1 to 3% by mass of Si and 0.0001 to 0.005% by mass of Al by ladle refining of a molten steel, the method including the step of: adding an oxide including TiO2 to a slag in a ladle during the ladle refining, wherein the slag produced at end of the ladle refining satisfies formulas (1) to (7) below: 0.5?CaO/SiO2?1.8??(1) 4% by mass?Al2O3?20% by mass??(2) MgO?15% by mass??(3) 1.5% by mass?TiO2?10% by mass??(4) CaO+SiO2+Al2O3+MgO+TiO2?90% by mass??(5) 0.4?TiO2/MnO?5??(6) 1?TiO2/T.Fe?10??(7) where a compound represented by a chemical formula represents the content of the compound in percent by mass; and T.Fe represents the total concentration, in mass ratio, of Fe contained in Fe oxides in the slag.

Abstract: A steel wire rod for a spring includes: C: 0.2 to 1.2%, Si: 1.0 to 3%, Mn: 0.1 to 2%, Cr: 3% or less (not inclusive of 0%), Al: 0.0002 to 0.005%, Ca: 0.0002 to 0.002%, Ti: 0.0003 to 0.010%, and balance: iron and unavoidable impurities. An average composition of oxide-based inclusions having a minor axis of 1 ?m or more which are present in a cross section satisfies CaO: 35% or less, Al2O3: 40% or less, SiO2: 30 to 95%, MgO: 8% or less, MnO: 5% or less, TiO2: 3 to 10%, and CaO+Al2O3+SiO2+MgO+MnO+TiO2?80%. The number of oxide-based inclusions having a minor axis of 2 ?m or more which are present in the cross section is more than 0.002 inclusions/mm2.

Abstract: Bearing steel material according to the present invention has: a properly adjusted chemical composition; an average chemical composition of oxide-inclusions which comprises 10 to 45% of CaO, 20 to 45% of Al2O3, 30 to 50% of SiO2, up to 15% (exclusive of 0) of MnO, and 3 to 10% of MgO, with the balance being unavoidable impurities; a maximum major axis diameter of the oxide inclusions in a longitudinal section of the steel material of 20 ?m or less; and a spheroidal cementite structure.

Abstract: A bearing steel material which contains 0.8-1.1 mass % C, 0.15-0.8 mass % Si, 0.1-1.0 mass % Mn, 1.3-1.8 mass % Cr, up to 0.05 mass % P (0 mass % is excluded), up to 0.015 mass % S (0 mass % excluded), 0.0002-0.005 mass % Al, 0.0002-0.0020 mass % Ca, 0.0005-0.010 mass % Ti, up to 0.0080 mass % N (0 mass % is excluded), and up to 0.0025 mass % O (0 mass % is excluded). The steel material contains oxide inclusions which have an average composition that comprises, in terms of mass %, 20-50% CaO, 20-50% Al2O3, 20-70% SiO2, and 3-10% TiO2.

Abstract: A bearing steel material which contains 0.8-1.1 mass % C, 0.15-0.8 mass % Si, 0.1-1.0 mass % Mn, 1.3-1.8 mass % Cr, up to 0.05 mass % P (0 mass % is excluded), up to 0.015 mass % S (0 mass % excluded), 0.0002-0.005 mass % Al, 0.0002-0.0020 mass % Ca, 0.0005-0.010 mass % Ti, up to 0.0080 mass % N (0 mass % is excluded), and up to 0.0025 mass % O (0 mass % is excluded). The steel material contains oxide inclusions which have an average composition that comprises, in terms of mass %, 20-50% CaO, 20-50% Al2O3, 20-70% SiO2, and 3-10% TiO2.

Abstract: Provided is a steel for machine structural use which has excellent machinability (particularly, with respect to tool life) for both intermittent cutting with a high-speed steel tool and continuous cutting with a cemented carbide tool while maintaining strength properties required of the steel for machine structural use. Specifically, the steel for machine structural use contains C: 0.05-0.9 mass %, Si: 0.03-2 mass %, Mn: 0.2-1.8 mass %, P: 0.03 mass % or less, S: 0.03 mass % or less, Al: 0.1-0.5 mass %, N: 0.002-0.017 mass %, and O: 0.003 mass % or less, and contains one or more selected from a group consisting of Ti: 0.05 mass % or less (excluding 0 mass %) and B: 0.008 mass % or less (excluding 0 mass %), with the remainder being iron and unavoidable impurities, and satisfies all of the following inequalities (1)-(3) below: (1): [N]?0.3[Ti]?1.4[B]<(0.0004/[Al])?0.002; (2): [Ti]?[N]/0.3<0.005; and (3): [B]?([N]?0.3[Ti])/1.4<0.003 when [Ti]?[N]/0.3<0 and [B]<0.003 when [Ti]?[N]/0.3?0.

Abstract: A bearing steel material which contains 0.8-1.1 mass % C, 0.15-0.8 mass % Si, 0.1-1.0 mass % Mn, 1.3-1.8 mass % Cr, up to 0.05 mass % P (0 mass % is excluded), up to 0.015 mass % S (0 mass % excluded), 0.0002-0.005 mass % Al, 0.0002-0.0020 mass % Ca, 0.0005-0.010 mass % Ti, up to 0.0080 mass % N (0 mass % is excluded), and up to 0.0025 mass % O (0 mass % is excluded). The steel material contains oxide inclusions which have an average composition that comprises, in terms of mass %, 20-50% CaO, 20-50% Al2O3, 20-70% SiO2, and 3-10% TiO2.

Abstract: A Ni based alloy flux cored wire including a Ni based alloy as a sheath is provided, wherein the sheath contains predetermined ranges of Ni, Cr, Mo, Ti, Al, and Mg relative to the total mass of the sheath, control is made to ensure predetermined C and Si, the composition of the whole wire, which is the sum total of the sheath components and flux components enveloped in the sheath, contains predetermined ranges of Ni, Cr, Mo, Mn, W, Fe, Ti, Al, and Mg relative to the total mass of the wire, and control is made to ensure predetermined C, Si, Nb, P, and S.

Abstract: Bearing steel material according to the present invention has: a properly adjusted chemical composition; an average chemical composition of oxide-inclusions which comprises 10 to 45% of CaO, 20 to 45% of Al2O3, 30 to 50% of SiO2, up to 15% (exclusive of 0) of MnO, and 3 to 10% of MgO, with the balance being unavoidable impurities; a maximum major axis diameter of the oxide inclusions in a longitudinal section of the steel material of 20 ?m or less; and a spheroidal cementite structure.

Abstract: An object of the present invention is to provide a Ni base alloy solid wire for welding, which has excellent cracking resistance to ductility dip cracking in weld metal, can increase the tensile strength of the weld metal to not less than the tensile strength of the base material, and has excellent weldability. The present invention provides a solid wire which has a composition containing Cr: 27.0 to 31.5 mass %, Ti: 0.50 to 0.90 mass %, Nb: 0.40 to 0.70 mass %, Ta: 0.10 to 0.30 mass %, C: 0.010 to 0.030 mass %, and Fe: 5.0 to 11.0 mass %, and is regulated to Al: 0.10 mass % or less, N: 0.020 mass % or less, Zr 0.005 mass % or less, P:0.010 mass % or less, S: 0.0050 mass % or less, Si: 0.50 mass % or less, and Mn: 1.00 mass % or less, with the balance including Ni and inevitable impurities.

Abstract: The present invention provides a steel for machine and structural use which is capable of maintaining mechanical characteristics such as strength by reducing a S content as well as of exhibiting excellent machinability (particularly tool life) in intermittent cutting (such as hobbing) with the high speed tool, and a method useful for producing the steel for machine and structural use. The steel for machine and structural use according to the invention secures 0.002% or more of solute N in the steel and has a chemical composition which is appropriately adjusted and satisfies a relationship of the following expression (1): (0.1×[Cr]+[Al])/[O]?150 . . . (1), in which [Cr], [Al], and [0] represent a Cr content (mass %), an Al content (mass %), and an O content (mass %), respectively.