Described are solid agglomerates of fine metal particles and methods for manufacturing same. A liquid oily lubricant is used in the manufacture of the solid agglomerates. The manufacturing comprises blending fine metal particles with the liquid oily lubricant and compacting the oily metallic mixture obtained to desired solid form. Advantageously, the solid agglomerates possess a desirable density, a suitable resistance to crumbling and dusting during handling, and they can resist to high temperature and to humidity. Solid agglomerated metal products, according to the invention, may be useful for different purposes such as quality charge material for steel plants, blast furnaces and foundries.

A composite additive for forming inclusions with a core-shell structure, a preparation method and a smelting method are provided. The composite additive includes the following chemical components by mass percentage: Fe: 41-59%, Zr: 5-11%, Ti: 14-26%, Mg: 11-19%, and RE: 4-10%, in which the mass percentage content of Zr element, Ti element, Mg element and RE element satisfies a formula: (Ti+Mg+RE)/Zr=4-8. The composite additive for forming inclusions with a core-shell structure has the characteristics of fineness, spheroidization and obvious dispersion effect. This type of inclusions has a bulk modulus similar to that of the iron matrix, which can significantly improve the plasticity, toughness, fatigue resistance, local corrosion resistance, welding performance, cold bending performance, etc. of steel materials, suitable for steel types with strict requirements on the shape of inclusions, such as marine steel, pipeline steel, container steel, cold heading steel, tool and die steel, etc.

The invention provides a maraging steel production method in which an oxide is added during an Mg oxide formation step, the production method including: the Mg oxide formation step in which Mg is added to molten steel and MgO is formed in the molten steel, during primary melting; a consumable electrode production step in which, after the Mg oxide formation step, the molten steel is solidified and a consumable electrode having residual MgO is obtained; and a vacuum arc re-melting step in which the consumable electrode is used and vacuum arc re-melting is performed.

An apparatus of adding high vapor pressure magnesium to a steel liquid, includes a magnesium additive device and a tube furnace. The magnesium additive device includes a storage barrel, a conveying pipe, a control valve, and an insertion tube. A method of adding high vapor pressure magnesium to a steel liquid, includes placing the magnesium additive device in the tube furnace, and delivering pure magnesium particles into the storage barrel. When the temperature at the mediate lower position of the conveying pipe is increased to reach a preset value, the control valve is opened to pour the pure magnesium particles into the conveying pipe to form a magnesium vapor, and an argon regulating valve is opened to introduce the argon into the conveying pipe so as to add the magnesium vapor to a steel liquid by carrying of the argon.

Described are solid agglomerates of fine metal particles and methods for manufacturing same. A liquid oily lubricant is used in the manufacture of the solid agglomerates. The manufacturing comprises blending fine metal particles with the liquid oily lubricant and compacting the oily metallic mixture obtained to desired solid form. Advantageously, the solid agglomerates possess a desirable density, a suitable resistance to crumbling and dusting during handling, and they can resist to high temperature and to humidity. Solid agglomerated metal products, according to the invention, may be useful for different purposes such as quality charge material for steel plants, blast furnaces and foundries.

The present invention has as its object the provision of hot rolled steel sheet (hot coil) for line pipe use in which API5L-X80 standard or better high strength and low temperature toughness and ductile fracture arrest performance are achieved and a method of production of the same. For this purpose, the hot rolled steel sheet of the present invention comprises C, Si, Mn, Al, N, Nb, Ti, Ca, V, Mo, Cr, Cu, and Ni in predetermined ranges and a balance of Fe and unavoidable impurities, in which the microstructure is a continuously cooled transformed structure, in which continuously cooled transformed structure, precipitates containing Nb have an average size of 1 to 3 nm and are included dispersed at an average density of 3 to 3010.sup.22/m.sup.3, granular bainitic ferrite and/or quasi-polygonal ferrite are included in 50% or more in terms of fraction, furthermore, precipitates containing Ti nitrides are included, and they have an average circle equivalent diameter of 0.1 to 3 m and include complex oxides including Ca, Ti, and Al in 50% or more in terms of number.

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/mm.sup.2.

An H-section steel has a predetermined chemical composition, in which a Mg-containing oxide having an equivalent circle diameter of 0.005 m to 0.5 m is contained at a total number density of 100 pieces/mm.sup.2 to 5000 pieces/mm.sup.2, a thickness of a flange is 100 mm to 150 mm, at a strength evaluation portion which is at a position from a surface of the flange in a length direction and at a position from the surface in a thickness direction, a fraction of bainite in a steel structure is 80% or more, and the average prior austenite grain size is 70 m or more, and at a toughness evaluation portion which is at a position from the surface of the flange in the length direction and at a position from the surface of the flange in the thickness direction, the average prior austenite grain size in a steel structure is 200 m or less.

A molten steel denitrification method, wherein an extremely low nitrogen concentration range is stably reached in a short time without use of a top-blown gas, is a denitrification process wherein CaOandAl.sub.2O.sub.3-containing slag formed by a combination of an Al addition step of adding a metalAl-containing substance to molten steel to deoxidize and turn the molten steel into Al-containing molten steel and a CaO addition step of adding a CaO-containing substance to the molten steel is brought into contact with the Al-containing molten steel to remove nitrogen in the molten steel, in which the molten steel is stirred at a stirring power density of 60 W/t or higher. In the denitrification process, a surface of the molten steel or the slag is subjected to an atmosphere of 1.010.sup.5 Pa or lower. In a steel production method, the obtained molten steel is cast after the components are adjusted.

Torpedo cars for use with granulated iron production, and associated systems, devices, and methods are disclosed herein. In some embodiments of the present technology, a torpedo car includes a tilting mechanism, a body rotatably coupled to the tilting mechanism, and a controller operably coupled to the tilting mechanism to control tilting of the body. The body can include (i) an inner surface defining a cavity and a channel, and (ii) an outer surface defining an opening to the cavity and a channel outlet of the channel spaced apart from the opening. The channel can extend between the channel outlet and a channel inlet interfacing the cavity. The inner surface can include a slag dam configured to prevent slag from exiting the opening while the torpedo car tilts. The controller can control the tilting mechanism to control molten metal flow out of the cavity through the channel.