104results about How to "Reduce secondary oxidation" patented technology

The invention relates to a covered argon blowing refining device for a slab continuous casting tundish strip-shaped air brick and an argon control method. The device comprises a turbulent controller (1), a dipping cover (2), the strip-shaped air brick (3), a retainer wall (4) and an inclined hole stop dam (5); the dipping cover (2) is positioned rightly above the strip-shaped air brick (3); the lower end of the dipping cover (2) is dipped below a lowest pouring liquid level (9) of molten steel in a continuous-cast ladle exchange process tundish; an argon blowing control system PLC is adopted to collect and upload a pressure value of a first pressure gauge (22a), a flow value of a special metallurgy mass-flow controller (25) and a pressure value of a second pressure gauge (22b) into a continuous casting foundation automatic system database through ethernet communication; an argon flow automatic control instruction of the argon blowing control system PLC is performed; and the argon flow is automatically adjusted according to the net weight change of the molten steel in the tundish, so that the precise control is realized, and the effect of the tundish removing inclusions in the molten steel is improved.

The invention discloses a water-cooling die casting production process of a plate blank used for a medium plate, which is characterized in that the production process adopts the protective pouring of argon gas in the overall process of the pouring so as to realize that the contact of molten steel with the air is isolated in the pouring process after the molten steel flows out from a water gap; the protective pouring of solid covering slag is adopted to ensure the surface quality of a casting blank; and an ascending hole of flow steel is regulated to enable the molten steel to stably ascend in water-cooling die casting, and the surface quality of the casting blank is ensured. The invention avoids the defects of skull patch, pits and the like of the surface and the defect of slag entrapment when the water-cooling die casting is adopted to produce the blank of the medium plate, and the adopted protective pouring reduces the secondary oxidation of the molten steel in the pouring process, has a certain adsorption function to inclusion and ensure the quality of the blank of the medium plate. The invention is suitable for the production process of the blank of a high-alloy steel medium plate of die steel with high requirement.

The invention relates to a refractory material for a submersed nozzle inner hole body. The refractory material is used for an aluminum-killed steel continuous casting nozzle and particularly for casting of ultra-low-carbon automotive steel with high aluminum content. The refractory material for the submersed nozzle inner hole body is prepared from, by weight, 28%-58% of calcium hexaluminate, 20%-40% of calcium dialuminate, 20%-30% of alumina-magnesia spinel, 4%-6% of additionally added binding agent, namely, phenolic resin and the balance metallic silicon and boron carbide. The refractory material for the inner hole body has excellent alumina clogging resistance, molten steel erosion resistance and thermal shock resistance, can be used for aluminum-killed steel continuous casting and is relatively long in service life, and particularly, when the refractory material is used for casting of the ultra-low-carbon automotive steel with high aluminum content, secondary oxidation caused by the refractory material at the nozzle can be effectively reduced, and nozzle clogging caused by adhesion of alumina in molten steel can be effectively prevented.

The invention discloses a smelting method for high-cleanliness chrome-molybdenum steel. The smelting method comprises the working procedures of electric furnace primary smelting, refining and vacuum treatment. As for the working procedure of refining, calcium carbide is used in refining, foaming slag can be quickly formed at a low temperature, the temperature increasing speed is increased, refining power consumption is lowered, gas suction of molten steel is reduced, and secondary oxidation of the molten steel is relieved; and after vacuuming is finished, a certain quantity of pure calcium lines are fed, the deep deoxidation effect can be enhanced, meanwhile, inclusions in the steel can be modified, and thus harm of the inclusions to the steel is lowered. The cleanliness of the chrome-molybdenum steel is improved through brand-new various novel steel smelting technologies such as earlier compositing weak deoxidation, later aluminum feeding deep deoxidation, prolonging of the vacuum maintenance time and soft blowing time, and calcium treatment after vacuuming, the content of O in the obtained molten steel can reach 10 ppm or below, in analysis on the inclusions in a finished steel product, the thickness of the A, B, C and D types of inclusions is smaller than or equal to 0.5 grade, uniformity of a steel plate structure is improved remarkably, the mechanical property of a steel plate is improved, and thus the smelting method has high application value.

The invention relates to an iron-making method with low grade refractory iron ore, particularly to an iron-making method for low grade refractory iron core and equipment thereof to solve the problems of long procedures and high energy consumption in an existing iron-making method with low grade refractory iron ore. The iron-making method with the low grade refractory iron ore comprises the steps of mixing the low grade refractory iron ore with reduction coal and crushing the iron core and the reduction coal, adding flux, catalyst and water and performing stirring, molding the materials into cuboid blocks, conveying the dried cuboid blocks into a tunnel reduction furnace for solid-state initial reduction; and then conveying the cuboid blocks into a three-phase arc furnace. The low grade refractory iron core and the reduction coal are mixed on the base of calculating coal blending according to C/O=1.2 and further 2-4% carbon is blended in an excess mode; the catalyst is dolomite powder or limestone powder, and the addition amount of the flux is calculated according to the formula of CaO+MgO/SiO2=0.8; the catalyst is salt materials containing sodion and the utilization amount is 3-5% of that of the coal blending amount. The iron-making equipment is additionally provided with a loading section based on an original tunnel reduction furnace and further provided with a conveyer belt and a three-phase arc furnace.

The invention discloses a method used for tapping through deflecting the bottom of a convertor, which is characterized in that the tapping opening of the converter is designed at the lower part of the converter; the position at the upper end of the tapping opening is arranged below a molten liquid surface; the lower end is higher than the slag surface after tapping in the convertor only with the slag left by 10 to 20cm; the diameter of the tapping opening is between 10 and 20cm; when the smelting reaches the end point, the converter is deflected by 20 to 60 degrees; the rotated angle leads the position of the tapping opening to be arranged at the lowest side of the converter; then the tapping opening is opened, the molten steel flows into a ladle arranged below the tapping opening; after the molten steel flows out, the converter is resumed to the normal vertical position and the ladle is removed, then the liquid surface of slag is lower than the lowest position of the tapping opening of the converter; then the ladle is arranged below the converter and the converter is deflected to lead the opening of the converter to face the lower side; and then the slag is spilled out from the opening of the converter. The method used for tapping through deflecting the bottom of a convertor solves the problem of slag during the tapping of the converter, ensures the slag amount of the converter to be lower than 0.5kg/t. Not only the rephosphorization of the molten steel can be reduced and the alloy recycling rate is improved, but also the occluded foreignsubstance in the steel can be reduced and the cleanness of the molten steel can be improved. Besides, the refining time can be shortened and the desulfurization degree can be improved.

The invention discloses a process for performing casting under a negative pressure condition. In the method, the advantages of investment casting and lost foam casting are combined, the high-quality casting mould of investment casting is used, and pouring is performed under a thermal condition; by using a negative pressure technology of a lost foam, the negative pressure environment is formed around the investment casting mould, and the secondary oxidation of metal is reduced; and metal filling is promoted and the feeding capacity of molten metal is improved by using the pressure difference between the casting mould and a pouring gate, so that a high-quality casting is obtained, and a large-sized casting can be cast.

A control method for vortex slag entrainment in converter tapping. When the molten steel in the furnace reaches two-half and the slag on the liquid surface rotates, the electromagnetic stirrer around the tapping hole is started, and continuous and pulsed slag are adopted respectively according to specific conditions. Type and alternate stirring mode, the power adjustment range of the agitator is 30-200kW, the power frequency adjustment range is 5-10Hz, when the molten steel is about to be discharged, the taphole is blocked with a slag stopper. The invention can reduce the amount of slag in the converter, increase the alloy yield, reduce the burning loss of deoxidized aluminum, reduce the secondary oxidation of molten steel, improve the cleanliness and refining effect of molten steel, reduce the amount of modifier used, and shorten the treatment cycle , and reduce the amount of residual steel in the furnace, effectively prevent the occurrence of steel sticking when the oxygen lance is splashing slag to protect the furnace, and improve the service life of the oxygen lance.

The invention discloses submerged arc refining slag, which is prepared from the following raw materials in part by weight: 35 to 40 parts of sintered bauxite, 1 to 2 parts of metal aluminum powder, 8 to 12 parts of silicon carbide, 2 to 4 parts of high carbon powder, 40 to 45 parts of limestone, 1 to 3 parts of blast furnace grain slag and 2 to 4 parts of lignin. In the invention, deoxygenation, submerged arc foaming and refining are integrated, production process is simplified, working environment is improved, the stability of ingredients of molten steel is improved, smelting cost is lowered, refining time is reduced, yield of expensive metal is increased, secondary oxidization of molten steel is relieved, the recovery rate of molten steel is increased, arc and noise pollution are reduced and the service life of refractory materials is prolonged.

The invention discloses a method and system for treating iron vitriol slag. The method for treating the iron vitriol slag comprises the steps that the iron vitriol slag containing water, reducing agents and additives are mixed so that wet mixed materials can be obtained; the wet mixed materials are treated in an annular furnace, specifically, the wet mixed materials are subjected to drying treatment in a drying area to obtain dried materials, vapor produced through drying treatment is discharged through a first flue and is recycled; the dried materials are subjected to decomposition treatment in a decomposition area to obtain decomposition products, flue gas which contains sulfur oxide and is produced through decomposition treatment is discharged through a second flue and collected; and the decomposition products are subjected to reduction treatment in a reduction area to obtain reduced products, flue gas which contains lead and zinc and is produced through reduction treatment is discharged through a third flue and collected, and the reduced products are subjected to ball milling and magnetic separation treatment so that metal iron powder and tailings can be obtained. By means of the method, the flue gas containing the sulfur oxide and the flue gas containing the lead and the zinc can be collected correspondingly, and high-grade fine iron powder is obtained.

The invention relates to an auxiliary steelmaking material, in particular to an environment-friendly material and a preparing method thereof. The environment-friendly material is characterized in that a submerged arc heat accumulation agent comprises, by weight, 63-71 parts of limestone, 8-16 parts of magnesite, 7-9 parts of light calcined magnesia, 1-5 parts of barium carbonate, 1-5 parts of metallic aluminum, 1-3 parts of silicon carbide, 0.5-1.5 parts of metallic silicon and 3.5-4.5 parts of water. Material decomposition is achieved at the high temperature, gas is continuously generated under the condition that 0.7-1.0 Kg/ton of steel is added, slag liquid is foamed, the slag liquid is emulsified in the gas-slag mixing state, the slag liquid level rises, and electrode arc light is continuously and more effectively embedded. In the steel refining process, the purposes that the extremely high noise generated by electrode arcing in an LF furnace is lowered, the noise in an operation room of the LF furnace is reduced to 74-85 decibels from 87-97 decibels, and the environment-friendly steel making is achieved are achieved.

The invention relates to the technical field of double steelmaking tundish continuous casting heat number study, and discloses a double steelmaking tundish continuous casting heat number in-depth study method. The method comprises the following steps that 1) firstly, a reasonable and effective tundish baking system is formulated, the tundish baking time is controlled to be 2 h to 3 h, a capping production mode is adopted on a tundish, and therefore when baking is needed, the casting waiting time is effectively shortened through capping, a cover plate can be pulled to be open when the tundish needs to be stopped, the tundish cooling waiting time and the temperature drop are shortened, and the tundish baking temperature during casting is ensured to be higher than or equal 900 DEG C. By meansof the double steelmaking tundish continuous casting heat number in-depth study method, the double steelmaking tundish continuous casting heat number is wholly and effectively improved, the overall double steelmaking tundish continuous casting heat number in-depth study method is clear and explicit in step, operation is simple, the service life of the tundish can be effectively prolonged, meanwhile, the double steelmaking tundish continuous casting heat number is greater than or equal to 90 furnaces, the production cost of steelmaking is reduced, and implementation by a user is facilitated.

The invention relates to a filtering device for magnesium alloy casting and pouring. The lower portion of a sprue is communicated with a casting die through a cross gate, a metal liquid filtering pool is arranged in the cross gate and comprises a left filtering pool box and a right filtering pool box which are buckled, the left filtering pool box is in a shape of a circular truncated cone, a metal liquid inlet is formed in the smaller bottom face of the left filtering pool box, the right filtering pool box is in a shape of a right trapezoid, and a magnesium alloy metal liquid outlet is formed in the smaller bottom face of the right filtering pool box; and a conic foamed ceramic filtering block is arranged in the left filtering pool box, the outer conic face of the conic foamed ceramic filtering block is matched with the conic face of the left filtering pool box, and the ceramic filtering block is made of magnesium oxide foamed ceramic. The foamed ceramic filtering block in the shape of the circular truncated cone is arranged in the filtering pool, influences on casting of an overall structure are avoided, the effective filtering area is large, and blockage can be avoided; and as the foamed ceramic is an efficient and stable alloy melt filtering medium, various impurities in the metal liquid in the pouring process can be effectively removed, the impurity content is obviously reduced, and the quality of a cast magnesium alloy is improved.

The invention relates to a refining cover for a continuous casting tundish and a manufacturing method of the refining cover. The refining cover comprises an outer arc plate, an inner arc plate and a dipping cover. A circulation seam is reserved between the outer arc plate and the inner arc plate, and communicated with a gap between a tundish cover and a steel slag layer inside the tundish. Air exhaust holes penetrating through the dipping cover are formed in the dipping cover, through holes opposite to the air exhaust holes are formed in the inner arc plate, the air exhaust holes are communicated with the circulation seam through the through holes, argon is blown in through air curtain ventilation bricks, an air curtain barrier with the large continuous intensity is formed between the air curtain ventilation bricks and the dipping cover, the inclusions are captured and are adsorbed and removed by the steel slag layer, the argon breaks through the steel slag layer below the dipping cover to move upwards continuously and enters the circulation seam through the air exhaust holes and the through holes, the argon enters the position above the steel slag layer of the tundish through the circulation seam, and argon seal is formed in the space between the steel slag layer inside the tundish and the tundish cover. The steel slag face is protected, secondary oxidation of liquid steel is avoided, the 0.5 level of the four kinds of inclusions in LHG2 steel reaches more than 90%, and the cleanliness of the liquid steel is greatly improved.

The invention discloses a method for solving blockage of a pouring nozzle of a billet caster producing high carbon chromium bearing steel. The method includes LF refining, RH refining and a casting process. According to the method, calcium treatment operation is carried out in the middle of the LF refining. Calcium line addition is 0.10-0.35 kg/t steel. The content of molten steel Ca is controlledwithin 0.0010-0.0025 wt %. The sulfur content of the molten steel is less than or equal to 0.010 wt % before calcium treatment, otherwise the calcium treatment is delayed. Aluminum products are not added into the molten steel in the later period of the LF refining and the RH process. A slab section of the billet caster is less than or equal to 260mm*260mm. A tundish nozzle is an immersion nozzle,and an argon blowing stopper with holes is not needed to be used. The method solves the technical problems troubling the billet caster producing high carbon chromium bearing steel for a long time that the immersion nozzle is likely to be plugged, causing the billet caster to have accidents to stop pouring, the molten steel to return to a furnace or falls to the ground. The method reduces the production cost, improves the benefit of an enterprise and has excellent promotion and application value.

The invention discloses a method and a device for filling a continuous casting tundish with argon, and belongs to the technical field of steelmaking and continuous casting. The device for filling the continuous casting tundish with the argon comprises a first closed mechanism, a second closed mechanism and an argon filling pipeline, wherein the first closed mechanism is arranged in the tundish and positioned between a first stick plug hole and a pouring hole of a tundish cover; a plurality of holes are formed in the lower part of the first closed mechanism; the second closed mechanism is arranged in the tundish and positioned between a second stick plug hole and the pouring hole of the tundish cover; a plurality of holes are formed in the lower part of the second closed mechanism; the argon filling pipeline is arranged in the tundish cover; and a plurality of argon blowing openings are formed in the argon filling pipeline. According to the method and the device for filling the continuous casting tundish with the argon, the blowing-in amount of the argon is reduced, the argon filling efficiency is improved, and the intake amount of external air is reduced; and furthermore, the rated aim of reducing secondary oxidization of molten steel is fulfilled, so that the comprehensive control effect for the first slab quality is better.