An ultra-high phosphorus molten iron low-cost smelting method for polar steel includes successively deoxidizing and tapping alloying raw materials including molten iron; performing slag adjusting and refining on the molten steel obtained in the converter smelting step to obtain a refined molten steel; vacuum degassing the refined molten steel; and performing continuous casting on the molten steel obtained after the RH degassing step to obtain a cast billet.

The present disclosure provides a method of making low carbon steel. The method includes tapping the liquid steel out of a primary steelmaking furnace. Deoxidizing the liquid steel. Transferring the deoxidized liquid steel to a ladle metallurgy furnace. Removing sulfur at the ladle metallurgy furnace. Adding fluxes and arcing the liquid steel to prevent sulfur reversion. Transferring the liquid steel from the ladle metallurgy furnace to an RH degasser for carbon removal. 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 sulfur removal.

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.

The present disclosure provides a method for producing a high nitrogen steel by a duplex melting process of a pressurized ladle refining and a pressurized electroslag remelting, which relates to the technical field of high nitrogen steel melting. In the present disclosure, the molten steel is subjected in sequence to a nitrogen alloying, a deep deoxidation and a deep desulfurization by adding a nickel-magnesium alloy and rare earth in the pressurized ladle furnace, and a combination of a blowing nitrogen from the bottom of the pressurized ladle and a pressurized nitriding at the interface of gas and the molten steel is used to achieve a high-efficiency nitrogen alloying, a uniform nitrogen distribution, and a decreased impurity content in the ingot; then the ingot is subjected to a pressurized electroslag remelting to obtain a high nitrogen steel.

The present disclosure provides a method for producing a high nitrogen steel by a duplex melting process of a pressurized ladle refining and a pressurized electroslag remelting, which relates to the technical field of high nitrogen steel melting. In the present disclosure, the molten steel is subjected in sequence to a nitrogen alloying, a deep deoxidation and a deep desulfurization by adding a nickel-magnesium alloy and rare earth in the pressurized ladle furnace, and a combination of a blowing nitrogen from the bottom of the pressurized ladle and a pressurized nitriding at the interface of gas and the molten steel is used to achieve a high-efficiency nitrogen alloying, a uniform nitrogen distribution, and a decreased impurity content in the ingot; then the ingot is subjected to a pressurized electroslag remelting to obtain a high nitrogen 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.

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.

Provided is a method for producing steel including: preparing a first molten steel and a manganese-containing melt; supplying a nitrogen gas into a storage to blow nitrogen into the melt received in the storage and thereby adjusting a nitrogen content (wt %) in the melt to a required nitrogen content (wt %); and mixing the melt and the first molten steel to produce a second molten steel containing manganese and nitrogen. Since nitrogen is not blown while melting large amounts of solid materials, the oxidation of manganese due to a high temperature may be minimized or prevented. In addition, a large amount of solid material is not added, and a small amount of manganese-containing nonferrous metal or a FeMn ferroalloy is added, if necessary, into a produced melt in a molten state, and thus, a problem of temperature drop due to the input of the solid material may be minimized or prevented.

A production method for smelting clean steel from full-scrap steel using duplex electric arc furnaces. Electric arc furnaces located in two positions are connected in series, wherein the electric arc furnace in a first position is dephosphorization electric arc furnace, and the electric arc furnace in a second position is a decarbonization electric arc furnace. The production method includes: performing smelting by combining a decarbonization electric arc furnace and 1-3 dephosphorization electric arc furnaces; a specific process of performing the smelting includes: in a charging period of the 1-3 dephosphorization electric arc furnaces, adding the full-scrap steel for the smelting, lime, slag in the decarbonization electric arc furnace, auxiliary materials and carbon powder or a carbon block into the dephosphorization electric arc furnace.

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.