There is provided a method for manufacturing a duplex stainless steel sheet having reduced inclusions through argon oxygen decarburization (AOD), ladle treatment (LT), and twin roll strip casting. The method includes deoxidizing molten steel using silicon (Si) during the AOD, wherein the molten steel has a silicon (Si) content of 0.55 wt % to 0.75 wt % at the end of the AOD.

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.

The application provides a method for controlling nitrogen in steelmaking by spraying hydrogen containing plasma, including: using a mixture of hydrogen rich gas and argon gas to generate hydrogen plasma for denitrification of molten steel during at least one of arc furnace smelting, ladle refining, VOD refining, and RH refining. The method for controlling nitrogen in steelmaking by spraying hydrogen containing plasma provided in the application can effectively remove nitrogen from the molten steel by spraying a mixture of argon gas and hydrogen rich gas into the molten steel through a hollow electrode and plasma torch, reducing electrode consumption and electricity consumption per ton steel, and also reducing arc radiation heat loss, improving heating rate, thereby shortening smelting time and reducing production costs.

A method for preparing low-cost clean steel includes steps of: preliminarily desulfurizing iron melt: preliminarily desulfurizing in an iron melt channel during blast furnace tapping and during iron folding in an iron folding room, adding a desulfurizing ball into the iron melt during the blast furnace tapping or the iron folding; dephosphorizing and controlling sulfur: dephosphorizing and controlling sulfur during converter steelmaking, in such a manner that P0.014% and S0.004% during tapping; rapidly dephosphorizing by slag-forming: rapidly dephosphorizing by slag-forming during converter tapping, at a converter end point, controlling a C content at 0.020.10%, adding a dephosphorizing ball through an alloy chute during the converter tapping, blowing argon and stirring at the same time; purifying steel melt during RH refining: adding a purifying ball at a late stage of the RH refining when a vacuum degree is at 66.7500 Pa; and continuously casting with whole-process protection.

The application provides a method for controlling nitrogen in steelmaking by spraying hydrogen containing plasma, including: using a mixture of hydrogen rich gas and argon gas to generate hydrogen plasma for denitrification of molten steel during at least one of arc furnace smelting, ladle refining, VOD refining, and RH refining. The method for controlling nitrogen in steelmaking by spraying hydrogen containing plasma provided in the application can effectively remove nitrogen from the molten steel by spraying a mixture of argon gas and hydrogen rich gas into the molten steel through a hollow electrode and plasma torch, reducing electrode consumption and electricity consumption per ton steel, and also reducing arc radiation heat loss, improving heating rate, thereby shortening smelting time and reducing production costs.

A method of making non-grain oriented (NGO) electrical steel is disclosed. The method includes tapping 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 deoxidized liquid steel from the ladle metallurgy furnace to an RH degasser for carbon removal by blowing oxygen, and adding fluxes at the RH degasser 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. Oxygen blowing at the RH also lowers titanium pickup. The ultra low levels of carbon, nitrogen, sulfur, and titanium in the NGO steel provide excellent magnetic properties.

Improved casting powders and improved casting slags enable production of steels having high aluminum contents of greater than or equal to 1% by weight and, in some cases, high manganese content of greater than or equal to 15% by weight. In some examples, such steels may also or alternatively include greater than or equal to 0.2% by weight titanium. The casting slag may result from a casting powder that comprises CaO and Al.sub.2O.sub.3 components essentially in the form of prefused calcium aluminate. Methods for casting steel, including methods for continuously casting steel, are also disclosed based on the use of the disclosed casting powders or casting slags.

This slag-supplying container of an electric furnace for reduction processing of steel-making slag includes: a container body that causes hot steel-making slag to flow to the electric furnace; a slag discharging portion connected with an electric-furnace-side slag-supplying port; a slag receiving portion that receives the hot steel-making slag supplied; a lid that opens and closes the slag receiving portion; an exhausting portion that discharges exhaust gas from the electric furnace; and, a tilting unit that tilts the container body to adjust the amount of inflow of the hot steel-making slag to the electric-furnace-side slag-supplying port.

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.