31results about How to "Prevent resulfurization" patented technology

A high PH value ball type hollow coating agent comprises burnt lime, silica dioxide, and alumind, with the former two taking 30%-60% of the total weight and their rate 8:12, alunind taking 20%-50% of the total weight, with pre smelt, high PH value, carbon free material and spraying grain making process, enjoying fine heat preserving capacity, retaining three layer structure, without crustization, with improved capability in avoiding secondary oxidization of steel liquid and impurities adhesion.

The invention discloses an RH refining desulphurization process of non-oriented electrical steel, belonging to the technical field of steel making. The process comprises the following steps: setting the lift gas flowrate to 1200 NL/min after the entering of the RH, and enhancing the lift gas flowrate to 1600 NL/min 3 minutes later; blowing oxygen to perform the forced decarburization when the vacuum degree is reduced to 2.0 mba, and when the oxygen blowing is finished and the vacuum degree is lower than 2.0 mba, performing the natural decarburization for 20 minutes; adding the aluminum for deoxidation when the vacuum decarburization is finished; and performing the silicon alloying by using the low carbon ferrosilicon, and adding the desulfurizing agent into the vacuum chamber in two timesthrough the RH alloy bin. The circulation time of the test furnace batch is from 10 minutes to 15 minutes. The process provided by the invention has the advantages that the RH device needs no reconstruction, and the operation is simple. The average RH desulphurization degree is 36.7%, and the desulphurization effect is better. The contents of the FeO and the MnO of the ladle slag have significantinfluence on the desulphurization effect, and the enhancing of the alkalinity of the ladle slag can increase the RH desulphurization efficiency as well as reduce the corrosion of the RH device.

The invention relates to a casting process of a nodular cast iron planet carrier, which comprises the following procedures of modeling, iron melt melting, spheroidizing, modifying, casting and stress relieving and annealing. The design of a casting system adopts a step casting method which takes consideration of both bottom casting and top casting to improve the finished product rate of castings, and also adopts technical schemes of placing chill iron at the position of thick walls, adding Sn element in the iron melt, optimizing, spheroidizing, modifying, casting and the like, so that the produced planet carrier not only meets the high demands on property, but also achieves great improvement in production cost and efficiency.

A high PH value ball type hollow coating agent comprises burnt lime, silica dioxide, and alumind, with the former two taking 35%-65% of the total weight and their rate 5:8, alunind taking 18%-45% of the total weight, with pre smelt, high PH value, carbon free material and spraying grain making process, enjoying fine heat preserving capacity, retaining three layer structure, without crustization, with improved capability in avoiding secondary oxidization of steel liquid and impurities adhesion.

The invention relates to the technical field of steel rolling, and relates to steel for heavy-truck super-thick steel-made spokes and a manufacturing method of steel. The steel comprises the following trace elements in percent by mass: carbon, 0.07~0.12%; silicon, 0.05-0.15%; manganese, 0.7-1.1%; niobium, 0.01-0.03%; titanium, 0.01-0.03%; phosphor, <=0.015%; sulfur, <=0.005%; aluminium, 0.02-0.05%; and nitrogen, <=0.006%. The manufacturing method comprises: performing KR desulphurization and LF-method processing to obtain casting blanks, performing rough rolling and finish rolling, and performing laminar flow cooling and reeling to obtain the needed steel. By utilizing smelting to obtain the casting blanks with the above trace-element mass percentages and employing the technologies of low-temperature heating, low-temperature rolling and high-temperature reeling, the demands of heavy-truck spokes on easy spinning property, surface quality and performance stability are satisfied, and the collapsing crushing rate of heavy-truck wheels is substantially reduced.

The invention discloses a double-layer tundish covering agent for an ultrathin belt, and relates to the technical field of metallurgy. The upper covering agent and the lower covering agent are hollowgranular products which are subjected to spray granulation. The upper covering agent comprises the following chemical components of, in percentage by weight, 45%-55 wt% of CaO, 18.0-24.0 wt% of SiO2,14.0-18.0 wt% of MgO, less than or equal to 1.9 wt% of Al2O3, 7.5-11.5 wt% of C-solid and the balance inevitable impurities, and the melting point of the upper covering agent is greater than 1450 DEGC. The lower covering agent comprises the following chemical components of, in percentage by weight, 25.0-31.0 wt% of CaO, 27.0-37.0 wt% of SiO2, 13.0-18.0 wt% of MgO, less than or equal to 1.9 wt% ofAl2O3, 13.0-17.0 wt% of (Li2O + Na2O), less than or equal to 0.5 wt% of C-solid and the inevitable balance impurities, and the melting point of the lower covering agent is 1150-1250 DEG C. The product has the advantages that the specific gravity is light, the upper layer is carbon-containing and the lower layer is extremely few in carbon-containing, carbon-increasing is prevented and heat preservation is achieved, the content of Al2O3 in the upper layer and the lower layer is low, the impurities are fully absorbed, the melting point of the upper layer is high, the insulation of the air is isolated, the melting point of the lower layer is low, and rapid melting can be achieved so as to prevent the carbon-containing upper layer from being in contact with the molten steel to increase the carbon.

The invention relates to a method for preventing sulphur from flowing back into liquid steel tank after steel tapping. The melting point of top slag is lowered during smelting, the temperature of thetop slag is controlled after casting is finished, the quantity of slag in the liquid steel tank is reduced after casting is finished, and a steel tapping process when liquid steel is contained in theliquid steel tank is selected according to the conditions of liquid steel desulfuration conditions. By means of the method, sulphur is prevented from flowing back into liquid steel tank after steel tapping, the effect that the content of sulphur in the liquid steel is in a controlled state is guaranteed, and thus the stability of the product quality is guaranteed.

The invention discloses a HG hot metal desulfurization device and desulfurization method thereof, and a desulfurizer and a slag remover. A nozzle of the desulfurizer is formed in a support, the nozzle of the desulfurizer is fixed inside a sleeve, the sleeve is movably connected to the support in up and down direction, the lower part of the sleeve is rotationally connected with a stirred tube, one end of the nozzle of communicates with desulfurizer a stock bin of the desulfurizer, the other end of the nozzle of the desulfurizer communicates with the lower nozzle of the stirred tube, a nitrogen gas tube is in connection with the nozzle of the desulfurizer, the outlet direction of the nitrogen gas tube points to the lower nozzle of the stirred tube, a stirred tube is located at outside of the tube wall under the position of the lower part of the nozzle and fixed with a stirred rod , and the stirred tube is connected to a rotating motor fixed on the outside wall of the sleeve in a transmission mode. According to the structure of the HG hot metal desulfurization device, not only the dynamic property conditions of desulfurization is strengthened, but also a deep, complete, and full mixing of the desulfurizer with the hot mental can be made and desulfurization by reaction, thus utilization ratio of desulfurizer is improved, waste of desulfurizer is avoided, and in addition, nodulation of the stirring device is prevented.

The invention discloses a desulfurizing agent for pipeline steel smelting. The desulfurizing agent is composed of the following components in parts by weight: 70-80 parts of rare earth and passivated magnesium composite material, 10-12 parts of calcium fluoride, 5-8 parts of barium carbonate and 15-18 parts of attapulgite, wherein the rare earth and passivated magnesium composite material comprises 60-70 parts of Mg, 3-5 parts of CeO and 15-25 parts of MgO. The preparation method of the rare earth and passivated magnesium composite material comprises the steps of firstly, carrying out dry mixing on Mg, CeO and MgO to prepare a mixed material; then, heating the mixed material, and controlling the temperature at 60-70 DEG C; next, mixing oxalic acid, magnesium chloride and water to prepare a passivation solution; then, pouring the passivation solution into the mixed material, stirring until the material is dry, and naturally cooling to prepare the rare earth and passivated magnesium composite material, wherein the weight ratio of the passivant, namely oxalic acid to magnesium chloride is 1: (3-4), the concentration of the passivation solution is 40-50g/L, and the weight ratio of the passivation solution to the mixed material subjected to dry mixing is 1: (20-25).

The invention relates to a low-carbon ultralow-sulfur pure iron smelting method. The process route comprises the steps of molten iron pretreatment, converter double-slag smelting, RH decarburization, LF dephosphorization, molten steel slagging-off, LF desulfurization and continuous casting. The method specifically comprises the following steps: 1) molten iron pretreatment desulfurization: the S content of molten iron before pretreatment is less than or equal to 0.040%; s is required to be less than or equal to 0.002% after molten iron pretreatment desulfurization; (2) converter double-slag smelting is carried out to control resulfurization, specifically, special pure iron waste steel is added into a converter, oxygen blowing is started, a slagging material is added after oxygen blowing is carried out for 40-50 s, oxygen blowing is carried out for 4-5 min, the oxygen accumulation amount of oxygen blowing is 3500-4500 standard cubic meters, and a gun is lifted to discharge slag; 3) LF desulfurization: after molten steel slagging-off is finished and argon blowing is confirmed to be normal, carrying out oxygen determination operation; the top slag is strongly modified and desulfurized, and it is guaranteed that the outbound S is controlled to be 10 ppm or below; atomized aluminum powder is used in the middle and later periods of LF desulfurization, so that it is guaranteed that outbound Alt is not higher than 0.010%; and 4) controlling the resulfurization by a casting machine. According to the invention, after RH decarburization, LF desulfurization is carried out, and then the desulfurization is directly carried out on a machine, so that the resulfurization in the RH treatment process is avoided, and the ultralow sulfur control that the sulfur content of a finished product is less than or equal to 0.001% is ensured.

The invention discloses an efficient desulfurizer and preparation and use methods thereof. The desulfurizer is prepared from the following raw materials in percentage by weight: 20-30% of Mg3N2, 40-55% of CaO, 1-4% of a binder and the balance iron. Aiming at the defects of the existing magnesium-based desulfurizer, the invention provides the efficient desulfurizer which is prepared from magnesium nitride as a raw material and a reaction promoter, so that the problem of low utilization rate of pure magnesium is solved, and the desulfurization efficiency is remarkably improved. Therefore, the desulfurizer has the advantages of convenience in use, high utilization rate, high desulfurization efficiency and the like.