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 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.

A steel for machine structural use according to the present embodiment has a chemical composition which consists of, in mass %, C: 0.15 to less than 0.30%, Si: 0.01 to 0.80%, Mn: 0.20 to 2.00%, P: 0.030% or less, S: 0.010 to 0.100%, Pb: 0.010 to 0.100%, Al: 0.010 to 0.050%, N: 0.015% or less, O: 0.0005 to 0.0030% and Cr: 0.50 to 2.00%, with the balance being Fe and impurities, the chemical composition satisfying Formula (1). The total number of specific inclusions included in the steel which are any of MnS inclusions, Pb inclusions and composite inclusions containing MnS and Pb and which have an equivalent circular diameter of 5 m or more is 40 per mm.sup.2 or more.

Mn/S8.0(1)

Where, a content (mass %) of a corresponding element is substituted for each symbol of an element in Formula (1).

A valve spring includes a nitrided layer, and a core portion that is further inward than the nitrided layer. A chemical composition of the core portion consists of, in mass %, C: 0.53 to 0.59%, Si: 2.51 to 2.90%, Mn: 0.70 to 0.85%, P: 0.020% or less, S: 0.020% or less, Cr: 1.40 to 1.70%, Mo: 0.17 to 0.53%, V: 0.23 to 0.33%, Ca: 0.0001 to 0.0050%, Cu: 0.050% or less, Ni: 0.050% or less, Al: 0.0050% or less, Ti: 0.050% or less, and N: 0.0070% or less, with the balance being Fe and impurities. In the core portion, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 500 to 8000 per ?m.sup.2, and in the core portion, a numerical proportion of Ca sulfides with respect to a total number of oxide-based inclusions and sulfide-based inclusions is 0.20% or less.

A cored wire for refining molten metal includes a reactive core material that is in the form of a solid rod. A non-reactive particulate material radially surrounds the solid core material, and an exterior metal jacket radially surrounds the particulate material. The particulate material may include wood or other material that when introduced into the molten metal, undergoes thermal decomposition to release carbon dioxide, hydrocarbons, or combinations thereof as a shroud around the core material.

A method for desulfurizing molten steel comprising taking a sample out from molten steel after tapping from a converter or during secondary refining and analyzing the sample rapidly with high accuracy by a method comprising a high frequency induction heating step wherein the sample is combusted and oxidized under the high frequency induction heating in an oxygen atmosphere having an oxygen purity of 99.5 vol % or more to convert S in the sample into SO.sub.2 and an analyzing step wherein SO.sub.2-containing gas produced in the high frequency induction heating step is analyzed through an ultraviolet fluorescence method to quantify S concentration of the sample.

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 method by which an extremely low nitrogen concentration range can be stably reached in a short time without use of a top-blown gas is proposed. A molten steel denitrification method is a denitrification process in which CaO-and-Al.sub.2O.sub.3-containing slag formed by a combination of an Al addition step of adding a metal-Al-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. It is preferable that, in the denitrification process, a surface of the molten steel or the slag is subjected to an atmosphere of 1.0?10.sup.5 Pa or lower. In a steel production method, the obtained molten steel is cast after the components are adjusted.

Devices, systems, and methods are directed at spreading sequential layers of powder across a powder bed and applying energy to each layer to form a three-dimensional object. The powder can include granules including agglomerations of metallic particles to facilitate spreading the metallic particles in each layer. The energy can be directed to the powder to reflow the granules in each layer to bind the metallic particles in the layer to one another and to one or more adjacent layers to form the three-dimensional object. Thus, in general, the agglomeration of the metallic particles in the granules can overcome constraints associated with metallic particles that are of a size ordinarily unsuitable for flowing and/or a size that presents safety risks. By overcoming these constraints, the granules can improve formation of dense finished parts from a powder and can result in formation of unique microstructures in finished parts.

A method for smelting low-phosphorus high-manganese steel based on reduction dephosphorization of ferromanganese is provided in the present application, relating to the technical field of high-manganese steel smelting, where the dephosphorization of ferromanganese is carried out under reducing atmosphere conditions through mediate-frequency induction furnace to obtain molten ferromanganese with lower phosphorus content, which is subsequently mixed with low phosphorus molten steel obtained by smelting in oxidative period of electric arc furnace in LF ladle refining furnace to make the Mn content of steel reach the requirement of high-manganese steel, and smelting is carried out under the condition of reducing atmosphere by adjusting the composition and temperature of the molten steel to meet the requirements of the target composition of the steel grade before tapping the steel.