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. Also disclosed is a method for producing ultra-low phosphorus steel, which includes the above-described slag discharging method in a process of producing ultra-low phosphorus steel, and refining and ingotting after slag discharge.

The present invention relates to steel sheet realizing both formability and weldability. The steel sheet of the present invention is characterized in that at a surface layer part of a region down to 30 μm from the surface of the steel sheet in the sheet thickness direction, Si oxide grains are present in 3000 to 6000/mm.sup.2 in number density, an average of natural logarithms of the particle sizes of the Si oxide grains measured in m units is −2.0 to −1.2, the standard error of the natural logarithms of the particle sizes is 0.6 or less, and the number of Si oxide grains with deviations of the natural logarithms of the particle sizes from the average larger than 2 times the standard error is 5% or less of the total number of Si oxide grains and at a position of ½ of the thickness of the steel sheet, the number density of the Si oxide grains is 1000/mm.sup.2 or less.

A production apparatus and method for electric arc furnace steelmaking with a fully continuous ultra-short process are provided. A continuous adding, melting, smelting and continuous casting of a metal material are integrated, and a metallurgy process is completed in a flowing of a molten steel, to realize a continuous production of ingot blanks. The production apparatus includes four operation sites of an electric arc furnace for melting and primary refining, a sealed tapping chute for molten steel flowing, a refinement storage bed for molten-steel desulfurization and alloying and a conticaster for continuous casting A material flow, an energy flow and a time stream in the four operation sites are in a dynamic equilibrium. The production apparatus and method realize a molten-steel casting is started within 120 minutes after the metal material is started to be continuously added, and an uninterrupted continuous production is maintained for above 80 hours.

The present invention relates to steel sheet realizing both formability and weldability. The steel sheet of the present invention is characterized in that at a surface layer part of a region down to 30 μm from the surface of the steel sheet in the sheet thickness direction, Si oxide grains are present in 3000 to 6000/mm.sup.2 in number density, an average of natural logarithms of the particle sizes of the Si oxide grains measured in μm units is −2.0 to −1.2, the standard error of the natural logarithms of the particle sizes is 0.6 or less, and the number of Si oxide grains with deviations of the natural logarithms of the particle sizes from the average larger than 2 times the standard error is 5% or less of the total number of Si oxide grains and at a position of ½ of the thickness of the steel sheet, the number density of the Si oxide grains is 1000/mm.sup.2 or less.

A production apparatus and method for electric arc furnace steelmaking with a fully continuous ultra-short process are provided. A continuous adding, melting, smelting and continuous casting of a metal material are integrated, and a metallurgy process is completed in a flowing of a molten steel, to realize a continuous production of ingot blanks. The production apparatus includes four operation sites of an electric arc furnace for melting and primary refining, a sealed tapping chute for molten steel flowing, a refinement storage bed for molten-steel desulfurization and alloying and a conticaster for continuous casting A material flow, an energy flow and a time stream in the four operation sites are in a dynamic equilibrium. The production apparatus and method realize a molten-steel casting is started within 120 minutes after the metal material is started to be continuously added, and an uninterrupted continuous production is maintained for above 80 hours.

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.

The invention relates to granules composed of agglomerated reactive bulk material and a binder matrix, the binder matrix comprising as binder an organic or inorganic salt.

The invention relates to granules composed of agglomerated reactive bulk material and a binder matrix, the binder matrix comprising as binder an organic or inorganic salt.

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.

A process and a device are provided that avoid the problems expressed earlier in order to produce a current of alloy particles at temperatures above 400 C. that will ultimately be used to alloy or chemically treat liquid metal streams. The invention that is presented is composed of a chamber heated by one or more gas burners, where a current of alloy particles with the pre-established massic or volumetric flow is input either manually or via the use of a gravimetric or volumetric dosing device that operates at room temperature located in an area above the chamber. These particles are heated by radiation from the walls of the chamber and by the radiation and convection of the flames of the burners that sweep them along during their flight inside the device for the time that they remain inside the chamber. As result of the use of the proposed device and the process, during which a great amount of energy is received during their passage through the device, the alloy particles reach the required temperature prior to their incorporation into a metallic current.