C21C7/0075

DEGASSING METHOD FOR MANUFACTURING STEEL

The present disclosure provides a method of making non-grain oriented (NGO) electrical steel. The method includes tapping the liquid steel out of a primary steelmaking furnace. Deoxidizing the liquid steel before or after transferring the deoxidized liquid steel to a ladle metallurgy furnace. Removing sulfur at the ladle metallurgy furnace (LMF). Adding fluxes and deoxidizer to the ladle slag and/or skimming off ladle slag to prevent sulfur reversion. Transferring the liquid steel from the ladle metallurgy furnace to an RH degasser for carbon removal by blowing oxygen. Adding fluxes at the RH before oxygen blowing to fortify the bottom layer of the ladle slag to prevent sulfur reversion. The removal of oxygen and sulfur prior to transferring the liquid steel to the RH degasser facilitates nitrogen removal and prevents carbon pick up during the step of adding fluxes and arcing for sulfur removal if sulfur removal is carried out at the LMF after carbon removal at the RH degasser in the conventional process. Oxygen blowing at the RH also lowered the titanium pickup from the earlier desulfurization process. The ultra low levels of carbon, nitrogen, sulfur, and titanium in the NGO steel made using this method enabled the excellent magnetic properties achieved in the finishing NGO products.

Methods of protecting furnace electrodes with cooling liquid that contains an additive

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.

SYSTEMS AND METHODS FOR CONTINUOUS PRODUCTION OF GAS ATOMIZED METAL POWDERS
20230356298 · 2023-11-09 ·

Raw material feed into an electric arc furnace (“EAF”) is melted into heated liquid metal at a controlled temperature with impurities and inclusions removed as a separate liquid slag layer. The heated liquid metal is removed from the EAF into a passively heatable ladle wherein it is moved into a refining station where they are placed into a inductively heated refining holding vessel and wherein vacuum oxygen decarburization is applied to remove carbon, hydrogen, oxygen, nitrogen and other undesirable impurities from the liquid metal. The ladle and liquid metal is then transferred to a refining station/gas atomizer having a controlled vacuum and inert atmosphere wherein the liquid metal is poured from an inductively heated atomizing holder vessel into a heated tundish at a controlled rate wherein high pressure inert gas is applied through a nozzle to create a spray of metal droplets forming spherical shapes as the droplets cool.

Metallurgical furnace having an integrated off-gas hood

An apparatus is disclosed for a metallurgical furnace having a roof with an integrated off-gas hood. The roof has a hollow metal roof. The hollow metal roof has a top, a bottom, an outer sidewall and an inner sidewall. An opening extends from the top to the bottom and is defined by the inner sidewall. The opening is configured for one or more electrodes to pass therethrough. An enclosed space is defined between the top, the bottom, the inner sidewall and the outer sidewall. A spray-cooled system is disposed in the enclosed space and configured to spray coolant in the enclosed space on the bottom surface of the hollow metal roof. A channel having walls is disposed through the enclosed space, wherein the spray-cooled system extends between the top of the hollow metal roof and the wall of the channel.

CORED WIRE FOR OUT-OF-FURNACE TREATMENT OF METALLURGICAL MELTS

A wire for out-of-furnace treatment of metallurgical melts comprises a metallic sheath which encloses a core comprising at least one element selected from the group consisting of Ca, Ba, Sr, Mg, Si and Al, wherein at least one layer of a composite coating is applied to an inner and/or outer surface of said sheath, which coating consists of a lacquer paint material and contains high-melting ultrafine particles selected from compounds of metal carbides and/or nitrides and/or carbonitrides and/or silicides and/or borides. The composite coating comprises a protector material, for which ferroalloys and/or flux agents are used. The metals contained in the high-melting compounds are titanium and/or tungsten and/or silicon and/or magnesium and/or niobium and/or vanadium. Said coating is applied evenly onto the surface of the sheath.

Method for producing metal powders by means of gas atomization and production plant of metal powders according to such method
11389873 · 2022-07-19 · ·

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.

Method for producing metal powders by means of gas atomization and production plant of metal powders according to such method
11389873 · 2022-07-19 · ·

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.

Methods of protecting furnace electrodes with cooling liquid that contains an additive

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.

Molten steel desulfurization method, molten steel secondary refining method, and molten steel manufacturing method

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.

Manufacture of low carbon steel
11047015 · 2021-06-29 · ·

Embodiments include a method of making steel with low carbon content which includes preparing a heat of molten steel composition in a steelmaking furnace to a tapping temperature ranging from 2912 to 3060 degrees F. and tapping into a ladle the molten steel composition having an oxygen level is about 700 to 1000 ppm. The molten steel composition is then transported to a ladle metallurgy furnace, where the molten steel composition is further heated and one or more elements are added to the molten steel composition. The molten steel composition is then transported from the ladle metallurgy furnace to a vacuum tank degasser. The molten steel composition is then decarburized and one or more elements are added to the molten steel composition at the vacuum tank degasser for deoxidization and desulphurization. The molten steel composition is then transported to a ladle metallurgy furnace to further adjust chemistry and temperature.