258 results about "Liquid steel" patented technology

The invention relates to a multi-scene self-adaptive intelligent bottom argon blowing control method and system. The method comprises the steps that after a steel ladle reaches a working position, the air permeability is determined, a ladle setting signal is received, argon blowing is started, an infrared thermal imager is started to monitor a picture to judge the liquid steel level, and the liquid level area of the whole steel ladle is completely filled; pLC (Programmable Logic Controller) of all equipment in the whole refining process is intelligently linked, the bottom blowing stirring power is determined, the bottom blowing gas pressure and the bottom blowing gas flow are calculated, and relevant parameters such as the exposed area and the exposed edge slag layer height of molten steel in a continuous video stream are tracked and calculated in real time according to the metallurgical purpose of different stages, so that the bottom blowing control is further optimized; and a flow data instruction is issued to a bottom blowing PLC to control the pressure and flow of bottom blowing gas. According to the requirements of field production, video images of molten steel in the argon blowing state are automatically and continuously received in a zero-delay mode, the argon flow and pressure are automatically distributed through intelligent bottom blowing control, it is guaranteed that each furnace achieves the good bottom blowing stirring effect, field production is guided, and the production labor intensity is reduced.

The invention discloses a steel slag whole-process dry treatment process, and belongs to the technical field of steel slag treatment. Comprising the following steps: S1, a rolling procedure: carrying out rolling crushing on liquid steel slag, and in the process, cooling by adopting an air cooling mode to solidify the liquid steel slag; s2, a cooling procedure, wherein the steel slag obtained in the step S1 is cooled to 100 DEG C or below in a non-air-cooling mode; s3, a grinding procedure; s4, a sorting procedure; and S5, a waste heat recovery process, wherein heat released by the steel slag in the rolling process and the cooling process is recycled. The invention further discloses a steel slag whole-process dry processing system. Through reasonable design, gradient cooling is formed in the rolling procedure and the cooling procedure, meanwhile, heat released by steel slag in the two procedures is recycled, and the problem that the steel slag treatment waste heat recovery rate is low is solved.

The invention relates to a square and round billet continuous casting device and a continuous casting method thereof. The device comprises a tundish, a crystallizer, a separation wall, a molten steel separation layer and a conveying module. The cavity of the tundish is divided into a first cavity body and a second cavity body by the partition wall, the first cavity body is used for bearing base body molten steel, and the second cavity body is used for bearing blank shell molten steel. The molten steel separation layer is arranged in the crystallizer, a spacing space is formed between the edge of the molten steel separation layer and the inner wall of the crystallizer, the molten steel separation layer is provided with a horizontal datum plane, and the horizontal datum plane is arranged in the spacing space. A blank shell casting space is arranged above the horizontal reference surface in the crystallizer; a matrix casting space is arranged below the horizontal reference surface in the crystallizer; at least part of the blank shell casting space and at least part of the base body casting space are located in the interval space. The conveying module comprises a first runner and a second runner; one end of the first runner is communicated with the first cavity and the matrix casting space; and one end of the second runner is communicated with the second cavity and the blank shell casting space, so that two kinds of molten steel are combined for forming.

The application provides a crystallizer protection slag for casting high-hydrogen-content medium-carbon steel liquid steel and application thereof, wherein the chemical composition of the crystallizer protection slag has the following mass percentages: SiO2: 25-32%, CaO: 29-36%, Al2O3: 1-4%, MgO: 3-6%, Na2O: 7-12%, F: 6-10%, C 总 : 3-6%, MnO: 2-4%, Li2O: 0.5-1%, and the rest is other inevitable impurities. The crystallizer protection slag can significantly reduce the occurrence rate of crystallizer sticking alarm emergency speed reduction and the occurrence rate of leakage during continuous casting when used for casting high-hydrogen-content medium-carbon steel liquid steel. Thus, the high-hydrogen-content medium-carbon steel liquid steel can be directly subjected to continuous casting without additional dehydrogenation treatment, the production efficiency is improved, and the production cost is solved.

The present invention relates to the technical field of electromagnetic stirring, and in particular to a flow control method for a roller-type electromagnetic stirring device, comprising symmetrically arranging a plurality of flow control rollers on two wide surfaces of a billet, determining the working modes of a first flow control roller and a third flow control roller, and when molten steel is introduced into the billet at a water inlet, detecting the temperature and the height of the molten steel liquid level at a plurality of detection points arranged in an array on the two wide surfaces of the billet between the first flow control roller and the third flow control roller, further judging whether it is necessary to adjust the flow state of the molten steel, and determining the adjustment method of the flow state of the molten steel and the adjustment parameters of the flow control rollers, judging whether the adjustment of the flow state of the molten steel is qualified based on the change of the height of the molten steel liquid level before and after the adjustment, and continuously monitoring the flow state of the molten steel of the casting. The present invention realizes the control of the flow state of the molten steel during electromagnetic stirring by determining the adjustment object, adjustment timing and adjustment means.

The invention discloses a multi-source solid waste-based cementing material and a preparation method thereof, and relates to the technical field of solidified organic matter soft soil cementing materials. The cementing material is prepared from the following raw materials: carbide slag, desulfurized fly ash, yellow phosphorus slag, high-activity and high-stability steel slag, modified red mud, alkaline residues, desulfurized gypsum, mineral slag and calcium sulphoaluminate; the high-activity and high-stability steel slag is prepared by carrying out steel slag preliminary stabilization treatment and steel slag excitation activation on liquid steel slag; exciting and activating the steel slag: preparing high-activity and high-stability steel slag from the stabilized steel slag, the modified ettringite particles, aluminum sulfate, a polycarboxylate superplasticizer, hexadecyl triethyl ammonium bromide and potassium hydroxide; the modified red mud is prepared from red mud, magnesium hydroxide, N-methyldiethanolamine, desulfurized fly ash, calcium oxide and a ferric chloride solution; the modified ettringite particles are prepared from polyvinyl alcohol and N-beta-aminoethyl-gamma-aminopropyl trimethoxy silane as a modifying agent. The preparation method comprises the following steps: preparing the modified ettringite particles; according to the multi-source solid waste-based cementing material, the compressive strength and the water stability coefficient of the solidified organic matter soft soil are effectively improved.

The invention relates to a method and device for preventing longitudinal cracks of a slab continuous casting head slab, and belongs to the technical field of continuous casting methods and devices. According to the technical scheme, the method comprises the following steps: calculating a function relational expression between a solidification shrinkage coefficient of molten steel and a casting blank temperature and between a linear expansion coefficient of a blank shell and the casting blank temperature; predicting the temperature of a billet shell and molten steel of the continuous casting billet discharged from the crystallizer; calculating the casting blank width of the continuous casting blank at the lower opening of the crystallizer and the actual casting blank width at high temperature; the ratio of the blank shell width to the lower opening width of the crystallizer is calculated and set according to actual conditions, and when the ratio is smaller than a threshold value, an operation interface gives an alarm for adjustment. The method has the beneficial effects that the longitudinal cracks of the head blank of the continuous casting blank are prevented on line, the flame cleaning work of the casting blank due to the longitudinal cracks is avoided, the time for offline casting blank cooling and manual cold detection is shortened, the temperature loss and turnover time of the casting blank are reduced, and the labor intensity of workers and the production cost loss are reduced.

The invention discloses a sodium-based desulfurization ash resource utilization method which comprises the following steps: S1, accurately weighing a certain amount of sodium-based desulfurization ash and circulating water after steel slag braising treatment, and controlling the temperature of the circulating water to be higher than 40 DEG C; s2, pouring the sodium-based desulfurization ash weighed in the step S1 into circulating water, uniformly stirring to obtain a mixed solution, precipitating and filtering the mixed solution, taking supernate, and measuring the hardness of the supernate; and S3, uniformly spraying the mixed solution obtained in the step S2 to the surface of the liquid steel slag for cooling and / or adding water to braise the slag in the steel slag hot braising process. The method has the beneficial effect that the advantage of effectively recycling the sodium-based desulfurized fly ash is achieved.

The invention discloses a variable-flow submersed nozzle based on continuous cast steel production, and relates to the technical field of submersed nozzles, the variable-flow submersed nozzle comprises a base, the top surface of the base is provided with a flow control mechanism used for controlling the flow of cast steel liquid, and the top surface of the base is provided with an auxiliary flow mechanism used for assisting the flow of the liquid steel; the flow control mechanism can be blocked in the submersed nozzle, so that the flowing space of molten steel in the nozzle is reduced, the flow of the molten steel is controlled, a stop block is relatively simple to use, a complex flow control system and related equipment are not needed, the complexity and cost of the system are reduced, potential fault points are reduced, and the service life of the system is prolonged. The auxiliary flowing mechanism can knock the isolation plate, impurities attached to the isolation plate can be shaken off by knocking the isolation plate, the cleaning effect is achieved, blockage of a water gap can be reduced by cleaning the blocked isolation net, the fluidity of molten metal is improved, and therefore the production efficiency is improved, and the rejection rate can be reduced and the product quality can be improved by cleaning the blocked isolation net.

The invention discloses a molten steel component online detection method based on an LIBS technology and deep learning, and relates to the technical field of component online detection in the casting metallurgy process. The method comprises the following steps: acquiring one-dimensional spectral data of target molten steel through an LIBS-based light path excitation collection system, and preprocessing the one-dimensional spectral data to obtain a corresponding two-dimensional grey-scale map; inputting the two-dimensional grey-scale map into a trained molten steel component detection model, and outputting a multi-element content predicted value of the target molten steel; the molten steel component detection model is constructed based on an improved ResNet50 network. According to the invention, the light path excitation collection system is arranged based on the LIBS technology, and the light path excitation collection system is combined with the improved ResNet50 network, so that the detection efficiency and the detection precision of the molten steel components are effectively improved.

Method for producing liquid steel in an electric arc furnace with final decarburization The invention relates to a method for producing liquid steel in an electric arc furnace (2) comprising successively: - melting a metal load in the electric arc furnace (2) for generating a steel bath (10); - denitrogenating the steel bath (10) to reach a nitrogen content %N below a targeted nitrogen content %Ntarg, wherein the carbon content %C remains greater than a targeted carbon content %Ntarg; - applying a final decarburization treatment to reach a carbon content %C ≤ %%Ntarg, to reach an oxygen content %Op greater than 200 ppm, wherein oxygen is injected at a flow rate above 0.3 Nm3 / min / ton, the ambient air being at a pressure of above 90% of the atmospheric pressure; - tapping the steel bath (10), the oxygen content %Op reached by the final decarburization treatment being maintained up to the tapping.

The invention relates to a method for producing liquid steel in an electric arc furnace (2) comprising successively: - defining a targeted nitrogen content wt. %Ntarg of the produced liquid steel, - introducing a metal load in the electric arc furnace (2) and - melting it for generating a steel bath (10) and a slag (12); - carburizing the steel bath (10) by adding a carbon amount equal to or greater than a minimum denitrogenation carbon amount CdeN said amount CdeN being defined as a function of the nitrogen content in excess to wt. %Ntarg at the beginning of the step (E4), - injecting a flow of oxygen to reach a nitrogen content wt. %N such that wt. %N ≤ wt. %Ntarg, - tapping the steel bath (10) to obtain the produced liquid steel.

The invention discloses a casting mold for special-shaped steel castings, and the invention relates to the technical field of casting processing of special-shaped steel castings. The casting mold for special-shaped steel castings comprises a base and a mounting through hole opened in the middle of the base, a plurality of quick-disassembly mold mechanisms are arranged equidistantly in the circumferential direction on the upper part of the base for quick demoulding after casting, a synchronous closing and disassembling mold control mechanism is arranged in the mounting through hole and between the quick-disassembly mold mechanism, the quick-disassembly mold mechanism is arranged vertically to enhance the fluidity of molten steel during casting, and ensure that the molten steel is quickly poured and filled into the quick-disassembly mold mechanism, the invention uses gravity to enhance the fluidity of molten steel through the vertically arranged main mold base and supporting mold base, ensures uniform filling of the casting mold cavity, and at the same time allows the surface around the mold to be more fully in contact with air or cooling medium, significantly increases the contact area between the mold and the outside world, improves the heat transfer efficiency, and uniformly accelerates the cooling speed of the special-shaped steel casting.

This invention discloses a method for controlling surface weld scar defects in large square billets of high-carbon chromium bearing steel, belonging to the field of metallurgical technology. For GCr15 steel, the method for controlling surface weld scar defects includes the following steps: molten steel enters the crystallizer, forming a solidified billet shell, and leaves the crystallizer under the action of a straightening machine. In the secondary cooling chamber, the molten steel is cooled by water spray, gradually solidifying into a large square billet. The protective slag addition rate is controlled at 58-60 g / min, the large billet drawing speed is 0.9-1.1 m / min, and the crystallizer cooling water flow rate is 142-144 m³ / min. 3 The above controls various parameters during the continuous casting process of high-carbon chromium bearing steel GCr15, ultimately reducing the surface weld scar defect rate of large billets to less than 1%. Compared with existing control methods, this significantly reduces the weld scar defect on the surface of GCr15 steel.

The utility model belongs to the technical field of steel slag treatment, and particularly relates to a device for recovering metal from steel slag through reduction. The device for recovering metal through steel slag reduction comprises a reaction tank and a vibration generating device, liquid steel slag to be subjected to reduction reaction is contained in the reaction tank, the reaction tank is arranged on the vibration generating device, and the vibration generating device drives the reaction tank to vibrate. According to the utility model, the reaction tank is arranged on the vibration generation device, so that fine iron powder obtained by a reduction reaction can be gathered into iron particles by adopting vibration treatment after the reduction reaction of liquid steel slag, and the larger the particles are, the lower the oxidation degree is, so that the reduction effect is guaranteed; the problem that the recovery rate is reduced due to the fact that metal iron is oxidized again in the follow-up treatment process is solved.

The application discloses a preparation method of a medium-high carbon steel hot-rolled coil and the medium-high carbon steel. The preparation method of the medium-high carbon steel hot-rolled coil comprises the following steps: slab continuous casting: medium-high carbon steel liquid steel is cast and drawn to obtain a slab, and a pre-descaling treatment is performed on the slab to reduce oxides on the surface of the slab, thereby obtaining a pretreated slab; slab heating: the pretreated slab is subjected to a heating treatment, and after the heating treatment, a high-pressure water descaling treatment is performed, thereby obtaining a to-be-processed slab; rolling: the to-be-processed slab is rolled to obtain a strip steel. According to the embodiment of the application, the slab after the slab continuous casting is subjected to the pre-descaling treatment before the slab is heated in a furnace, and after the heating treatment, the high-pressure water descaling treatment is performed before rolling, thereby removing the initial thick iron oxide scale on the surface of the slab and ensuring that the uniformity of the iron oxide scale formed on the surface of the slab during hot rolling is good.

This invention relates to a method for producing support roll steel, belonging to the field of metallurgical industry, and solves the problems of high cost and severe shrinkage porosity in existing support roll steel. The method for producing support roll steel includes: smelting, deoxidizing, desulfurizing, and refining the support roll steel ingot raw material, adjusting the alloy composition to obtain a first portion of support roll steel molten steel, tapping the steel, vacuum casting, and solidifying to obtain a solidified billet shell and liquid steel inside the billet shell; smelting, deoxidizing, desulfurizing, and refining the support roll steel ingot raw material, adjusting the alloy composition to obtain a second portion of support roll steel molten steel, tapping the steel, mixing the second portion of support roll steel molten steel with the liquid steel inside the billet shell within the solidified billet shell of the first portion of support roll steel, vacuum casting, solidifying to obtain a complete support roll steel ingot, demolding, removing the sprue, forging, removing the riser, heat treating, and machining to obtain the support roll steel; the composition of the first portion of support roll steel and the second portion of support roll steel molten steel differs.

The invention relates to a method for RH magnesium treatment of molten steel, which comprises the following steps: smelting initial molten steel through RH to obtain intermediate molten steel; magnesium alloy is added into the intermediate molten steel under the RH vacuum condition for magnesium treatment, and magnesium-treated molten steel is obtained; continuously casting the magnesium-treated molten steel to obtain a steel billet; feO + MnO in the steel ladle top slag above the initial molten steel is less than or equal to 4% by mass; the content of acid-soluble aluminum Als in the intermediate molten steel is 0.02%-Alb1, and the Alb1 is the upper limit value of the aluminum content of the intermediate molten steel before magnesium treatment. The adding position of the magnesium alloy is limited in the upper area of the RH descending pipe, so that the magnesium alloy enters the deep position of a steel ladle along with descending initial molten steel flow, and the acting time of the alloy and intermediate molten steel is prolonged. Magnesium steam is inhibited and an alloy structure is protected by utilizing a vacuum environment, and nodulizing and dispersion of inclusions can be realized only by adding a small amount of the alloy. According to the method, secondary oxidation of the magnesium treatment molten steel is effectively inhibited, the cleanliness is improved, the continuous casting nozzle nodulation risk is eliminated, and stable continuous casting operation is guaranteed.

The utility model discloses a device for synchronously controlling a withdrawal and straightening machine and a dummy bar of a continuous casting machine. The device comprises a potentiometer, a PLC (Programmable Logic Controller) control system, a signal isolation module, a withdrawal and straightening machine frequency converter, a dummy bar frequency converter and a digital display instrument. The potentiometer is connected to an analog quantity input port of the PLC control system through the one-input one-output optoelectronic isolator and is used for inputting an initial control signal; the output end of the PLC control system is connected with the withdrawal and straightening machine frequency converter and the dummy bar frequency converter to drive the two frequency converters to operate. A feedback signal of the withdrawal and straightening machine frequency converter is divided into two paths to be transmitted to the PLC control system and the withdrawal and straightening machine digital display instrument through the one-input two-output isolator, and a feedback signal of the dummy bar frequency converter is directly accessed to the dummy bar digital display instrument. The device eliminates electromagnetic interference through a photoelectric isolation module, integrates a water distribution model and a molten steel temperature data interface, adopts a standardized interface design for hardware, is adaptive to different continuous casting machine models, has the characteristics of strong anti-interference capability, stable signal transmission and visual real-time monitoring, and effectively improves the operation reliability of equipment.

The invention provides a method for reducing content of MnS inclusions in steel, including: (1) placing raw materials of other elements than manganese in a smelting furnace according to components of steel to perform smelting to obtain liquid steel; (2) first adding a first rare earth element and sulfur to the liquid steel, to form rare earth sulphide, then adding a raw material containing manganese to perform smelting, performing tapping after smelting is completed, and performing pouring and cooling to obtain a cast ingot. A rare earth element and sulfur are first added to liquid steel before manganese is added to generate tiny, round rare earth sulphide, and subsequently manganese is added to make it difficult to generate MnS, so that MnS and rare earth / manganese / sulfur composite inclusions are reduced, and content of MnS inclusions at a parting plane of a workpiece is reduced, thereby improving the reliability of the workpiece.

The invention relates to a metal mold extrusion imbedding method, which is specially used for an imbedding casting which cannot be used for imbedding a large-proportion insert in gravity casting, and comprises the following steps of: fixing all inserts on an insert assembly which is made of a thin steel plate, can be put into a metal mold, has a casting appearance, is provided with an opening at the upper end and is used for isolating molten steel from directly contacting with the metal mold; the method comprises the following steps: putting an insert assembly into a furnace, heating to 600-1000 DEG C, putting into a metal mold, closing and locking the mold, quantitatively pouring molten steel at an upper end opening, starting a press, carrying out closed extrusion on the molten steel by an upper mold, enabling the molten steel to enter a small space between inserts, and wetting the surfaces of the inserts at a certain temperature under pressure to form metallurgical bonding.

The invention discloses a tundish water nozzle flow control system and method, which can adjust the current of the electromagnetic flow control mechanism coil in real time according to the liquid level of the molten steel in the crystallizer, thereby adjusting the electromagnetic field in real time, and realizing the precise control of the flow rate of the molten steel in the water nozzle. This structure and control method are not limited by the size of the water nozzle, and can be applicable to water nozzles of different sizes. At the same time, the adjustment of the flow rate of the molten steel in the water nozzle is realized through electrical signals, and there is no mechanical structure, and the advantages of fast response speed, high control accuracy, no material loss, continuous production, energy saving and environmental protection can be realized.

The invention discloses a method for co-processing electrolytic aluminum overhaul slag with converter steel slag. First, carbon blocks in the overhaul slag produced by the electrolytic aluminum enterprise are crushed to less than 5 cm, the carbon blocks and waste refractory materials are mixed in a mass percentage of 20:80, and the mixture is processed to less than 1 mm by a rod mill and a Raymond mill, and then transported to a pelletizing production line for use as an overhaul slag powder material; converter sludge is added to the overhaul slag powder material as a binder, and the added amount of converter sludge is 5% to 10% of the mass of the overhaul slag powder material, and a high-pressure dry powder pelletizing machine is used to press it into pellets with a diameter of 30 to 50 mm, and then the pellets are transported to a converter production line and a hot slag production line for use; the pellets are used as a defoaming agent for converter foam slag or as a slag pressing defoaming agent for a slag pot or added to a slag pot filled with converter liquid steel slag, and the pellets are treated according to normal hot slag pouring or hot slag stuffing process.

The utility model provides a converter steel slag waste heat recovery system, and particularly relates to the technical field of solid waste treatment, the converter steel slag waste heat recovery system uses a phase change ball tank and a slag tank to respectively add phase change balls and the slag tank into a mixing stock bin, and the phase change balls and steel slag are mixed in the mixing stock bin; conveying and heat exchange are synchronously achieved in the rotary conveying device, phase-change core metal in the phase-change balls is gradually converted into a liquid state from a solid state, the steel slag is gradually reduced to the target temperature, then the steel slag and the phase-change balls are conveyed into the solid-solid separation device to be separated, and finally the phase-change balls enter the waste heat recovery device to conduct heat exchange with a medium to release heat. Meanwhile, the internal phase change core metal is gradually converted into a solid state from a liquid state and is conveyed into the mixing bin again through the conveyor, and due to the fact that the phase change balls have good stability, high energy storage density and high heat conductivity, a large amount of heat energy can be efficiently and stably stored; the problem that high-grade waste heat of converter steel slag cannot be efficiently and stably recycled is solved.

A method for the post-combustion of exhaust gases comprising carbon monoxide from metallurgical processes includes conditioning the exhaust gas prior to post-combustion by metering a combustion gas and / or one additional gas in feedback-controlled fashion. The feedback control depends on the composition of the exhaust gas dependent on the exhaust gas volume flow. A device for post-combustion of exhaust gas during vacuum treatment of liquid steel comprises a flare stack at an exhaust outlet, means for feeding combustion gas to the flare stack, means for feeding an inert gas into the exhaust gas channel of the vacuum pump, means for ascertaining the exhaust gas volume flow and / or for measuring the exhaust gas velocity within the exhaust gas channel, means for analyzing the exhaust gas composition, means for metering the combustion gas and the inert gas, and means for feedback control of the metering of the combustion gas and / or the inert gas dependent on the exhaust gas composition.

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.

The application relates to the technical field of tail gas treatment, in particular to a method and system for carbon neutralization in lime kiln tail gas; the method comprises the following steps: obtaining liquid steel slag after a converter and lime kiln tail gas respectively; performing pressure swing adsorption on the lime kiln tail gas to obtain first CO2 gas; introducing the first CO2 gas into the first treated steel slag to perform an oxidation-reduction reaction, then performing second heat exchange and post-treatment to obtain second CO2 gas and CO gas respectively; returning the second CO2 gas to the blowing to realize carbon cycle; collecting and storing the CO gas to realize carbon neutralization; the system comprises a lime kiln tail gas collecting part, a steel slag reaction part, a gas treatment part and a control part; the utilization of CO2 in the lime kiln tail gas can improve the heat energy utilization rate of the steel slag.

The invention discloses a method for smelting ultra-clean Cr-Ni-Mo-V steel liquid using CO2-Ar, and belongs to the technical field of steelmaking process. A medium-frequency furnace smelting system is used in the smelting process, including four stages: an early melting stage, a mid-term mixed bottom blowing stage, a mid-term feeding bottom blowing stage, and a late feeding bottom blowing stage. The present invention is applicable to the process of smelting high-alloy special steel in a 10kg-50t medium-frequency furnace; CO2-Ar is used as a bottom blowing stirring gas, and alloy smelting is added to the molten pool in the order of alloy element content and oxidation property strength. According to the different alloy element contents in the molten steel predicted by the computer and control system, the mixing ratio and flow rate of the bottom blowing CO2-Ar are adjusted in real time, and a large number of CO bubbles are generated by the reaction of CO2 with the carbon element in the molten steel, so as to strengthen the stirring of the molten pool, make the composition and temperature of the molten steel more uniform, shorten the smelting time, avoid alloy element burnout, and improve the alloy yield.

Method of producing steel with using an electric arc furnace The method of producing steel comprises the steps of loading a metal load (L) in the EAF, the metal load containing steel scrap, melting the metal load in the EAF and generating liquid steel (LS),tapping the liquid steel (LS) into a ladle (42) and refining the chemical composition of the liquid steel (LS) in a secondary metallurgy reactor with addition of a slagging material with nitrogen affinity in the liquid steel (LS) such as to lower the nitrogen content of the liquid steel (LS) in the secondary metallurgy reactor.

The invention discloses a simulated liquid level dynamic control method based on a Fluent continuous casting tundish, which comprises the following steps: S1, establishing a geometric model of the tundish and a long nozzle, and carrying out grid division; s2, importing the geometric model of the tundish and the long nozzle subjected to grid division into Fluent software, and setting calculation parameters; s3, developing a Fluent user self-defined function, and importing the Fluent user self-defined function into Fluent compiling; and S4, after the user-defined function is imported into Fluent to be compiled, analog calculation is started, and dynamic control over the liquid steel level in the tundish is achieved. The method has the advantages that real-time dynamic control of the liquid level of the molten steel in the tundish in the simulation process is achieved, the liquid level is accurately controlled, the limitation of single-phase flow or constant flow assumption adopted in a traditional simulation method is overcome, the actual production working condition is met, and the consistency of the simulation result and the actual production process is remarkably improved.