A method for producing metal powders by gas atomization is provided, including providing a metal charge; melting the metal charge inside an electric-arc furnace, controlling its composition until a molten metal bath having a desired composition is obtained; tapping the bath from the furnace, collecting it inside a ladle; refining the bath under controlled atmosphere, vacuum, or overpressure condition; atomizing the refined bath by feeding it into a gas atomizer, inside which a molten metal bath flow is produced, and impinging the molten metal bath flow with an atomization inert gas stream for the atomization of the molten metal bath into metal powders; and extracting the obtained metal powders from the gas atomizer.

A method for producing metal powders by gas atomization is provided, including providing a metal charge; melting the metal charge inside an electric-arc furnace, controlling its composition until a molten metal bath having a desired composition is obtained; tapping the bath from the furnace, collecting it inside a ladle; refining the bath under controlled atmosphere, vacuum, or overpressure condition; atomizing the refined bath by feeding it into a gas atomizer, inside which a molten metal bath flow is produced, and impinging the molten metal bath flow with an atomization inert gas stream for the atomization of the molten metal bath into metal powders; and extracting the obtained metal powders from the gas atomizer.

A CrMnN austenitic heat-resistant steel is provided. The heat-resistant steel comprises, in weight percentage, carbon 0.20% to 0.50%, silicon 0.50% to 2.00%, manganese 2.00% to 5.00%, phosphorus less than 0.04%, sulphur less than 0.03%, chromium 20.00% to 27.00%, nickel 6.00% to 8.00%, molybdenum less than 0.50%, niobium less than 0.60%, tungsten less than 0.60%, vanadium less than 0.15%, nitrogen 0.30% to 0.60%, zirconium less than 0.10%, cobalt less than 0.10%, yttrium less than 0.10%, boron less than 0.20%, with the balance iron. The heat-resistant steel has high temperature strength, high thermal conductivity, low thermal expansion coefficient, good dimensional stability, good ductility, heat resistance, impact resistance, and low production costs, and meets the requirements for high performance engines.

Disclosed is a slag discharging method in a process of producing ultra-low phosphorus steel, which relates to the technical field of iron and steel smelting, and in which molten steel is mixed with lime first to produce basic slag; then converting is performed with oxygen to increase the oxidizability of the basic slag; and a carbon-containing reducing agent is finally added, so that in the process that the carbon is oxidized to release a large amount of carbon monoxide gas, phosphates are captured, and the basic slag is rapidly foamed and overflows from the opening of the steel ladle, so that conditions are no longer available for rephosphorization. The slag discharging method is simple and convenient to operate, does not have high requirements on the equipment, has relatively good dephosphorization effect, and can be used to prepare an ultra-low phosphorus steel containing less than 0.003% phosphorus. Also disclosed is a method for producing ultra-low phosphorus steel, which comprises the above-described slag discharging method in a process of producing ultra-low phosphorus steel, and refining and ingotting after slag discharge. The production method has good dephosphorization effect, has a low production cost, and can high-efficiently produce an ultra-low phosphorus steel containing less than 0.003% phosphorus.

When performing dephosphorization treatment of hot metal by adding a refining agent as a lime source and an oxygen source (dephosphorizing agent(s) and a gaseous oxygen source into the hot metal accommodated in a hot metal holding container, the refining agent used is a refining agent having an Ig-loss value of from 4.0% by mass to 35.0% by mass and including 60% by mass or more of quicklime.

When storing a molten ferroalloy or molten nonferrous metal, the molten ferroalloy or molten nonferrous metal is denitrified or prevented from absorbing nitrogen, and thus post processing such as a denitrification process may not be performed. For this, there is provided a method of producing molten manganese-containing steel, the method including: preparing a molten ferroalloy or a molten nonferrous metal; maintaining the molten ferroalloy or the molten nonferrous metal at a temperature equal to or higher than a melting point thereof; and pouring the molten ferroalloy or the molten nonferrous metal into prepared molten steel, wherein in the maintaining of the molten ferroalloy or the molten nonferrous metal, the molten ferroalloy or the molten nonferrous metal is subjected to a nitrogen-absorption prevention process or a denitrification process.

An inoculant for the manufacture of cast iron with spheroidal graphite is disclosed, the inoculant has a particulate ferrosilicon alloy having

between 40 and 80% by weight of Si;
0.02-8% by weight of Ca;
0-5% by weight of Sr;
0-12% by weight of Ba;
0-15% by weight of rare earth metal;
0-5% by weight of Mg;
0.05-5% by weight of Al;
0-10% by weight of Mn;
0-10% by weight of Ti;
0-10 by weight of Zr;
the balance being Fe and incidental impurities in the ordinary amount,
wherein the inoculant additionally contains, by weight, based on the total weight of inoculant: 0.1 to 15% of particulate Sb.sub.2S.sub.3, and optionally between 0.1 and 15% of particulate Bi.sub.2O.sub.3, and/or between 0.1 and 15% of particulate Sb.sub.2O.sub.3, and/or between 0.1 and 15% of particulate Bi.sub.2S.sub.3, and/or between 0.1 and 5% of one or more of particulate Fe.sub.3O.sub.4, Fe.sub.2O.sub.3, FeO, or a mixture thereof, and/or between 0.1 and 5% of one or more of particulate FeS, FeS.sub.2, Fe.sub.3S.sub.4, or a mixture thereof, a method for producing such inoculant and use of such inoculant.

A steel for induction hardening according to the present invention includes a chemical composition consisting of, in mass percent: C: 0.58 to 0.68%, Si: 0.70 to 1.40%, Mn: 0.20 to 1.40%, P: less than 0.020%, S: less than 0.020%, Al: 0.005 to 0.060%, N: 0.0020 to 0.0080%, O: 0.0015% or less, V: 0.01 to 0.25%, B: 0.0003 to 0.0040%, Ti: 0.010 to 0.050%, and Ca: 0.0005 to 0.005%, with the balance being Fe and impurities, and satisfies Formulae (1) to (3). The steel microstructure is made up of ferrite and pearlite. A ratio of a number of composite inclusions is 20% or more.
C+Si/7+Mn/5+Cr/9+Mo/2.51.05(1)
C+Si/10+Mn/20+Cr/250.70(2)
Cr/Si0.20(3)

A method for forming a protective antioxidative barrier on the furnace electrodes using a chemically altered cooling liquid containing an antioxidant additive. This method can be applied to electrodes used in electric arc furnaces and ladle metallurgy furnaces. The method can involve spraying the cooling liquid onto the electrode, thereby forming the protective antioxidative barrier and reducing the oxidation of the electrode.

A method for forming a protective antioxidative barrier on the furnace electrodes using a chemically altered cooling liquid containing an antioxidant additive. This method can be applied to electrodes used in electric arc furnaces and ladle metallurgy furnaces. The method can involve spraying the cooling liquid onto the electrode, thereby forming the protective antioxidative barrier and reducing the oxidation of the electrode.