61 results about "Calcium handling" patented technology

The utility model provides an efficient sewage treatment system for high-calcium wastewater, which comprises a biological decalcification unit and a biochemical treatment unit, the bottom of a first anaerobic tank of the biological decalcification unit is communicated with the top of a first anoxic tank, the bottom of the first anoxic tank is communicated with a first aerobic tank, and the first aerobic tank is communicated with a first sedimentation tank; the bottom of a second anaerobic tank in the biochemical treatment unit is communicated with the top of a second anoxic tank, and the bottom of the second anoxic tank is communicated with a second aerobic tank; the first sedimentation tank is communicated with the upper part of the second anaerobic tank. The sewage treatment system is based on two-stage A2O, most of calcium ions in water are removed through first-stage A2O, decalcification treatment is carried out, a basis is provided for COD removal, denitrification and other biochemistry through second-stage A2O, the biological treatment effect of high-calcium wastewater is improved, meanwhile, sludge is screened and concentrated through the cyclone device, residual sludge is subjected to resourceful treatment, and the treatment effect of the high-calcium wastewater is improved. And the effects of reducing the cost, improving the efficiency and recycling resources are achieved.

The present application relates to high-temperature alloy smelting technical field, specifically relates to a kind of high-aluminum titanium cast nickel-based high-temperature alloy purification smelting method.The pure smelting method, step one, low calcium nickel alloy preparation;Step two, pure smelting: batching and furnace charging, melting period, refining period, alloying period, calcium treatment purification period and casting period;Pure smelting process is carried out in vacuum induction melting furnace, 2 / 3 low calcium nickel alloy is directly loaded into magnesium oxide crucible when furnace charging, and the remaining 1 / 3 low calcium nickel alloy is added in calcium treatment purification period.The present application prepares a kind of component accurately controllable "low calcium nickel alloy" as master alloy by pre-preparation, is added in key smelting stage, solves the problem of calcium element direct addition, realizes the deep deoxidation denitrogenation desulfurization of alloy melt, significantly reduces the oxygen, nitrogen, sulfur impurity content in alloy, to improve the purity and comprehensive mechanical properties of alloy.

The invention discloses a method for improving castability of aluminum-containing steel in a continuous casting process, which comprises the following steps of: S1, controlling components of molten steel, and accurately controlling the content of acid-soluble aluminum in molten steel of a continuous casting ladle to be 0.020-0.060% according to mass percent; s2, calcium treatment is conducted on the molten steel, and the calcium-aluminum ratio is controlled to range from 0.10 to 0.15; s3, continuous casting process control is conducted, specifically, the superheat degree of tundish molten steel is stably controlled to range from 15 DEG C to 30 DEG C, meanwhile, constant pulling speed operation is adopted, and the pulling speed fluctuation range is controlled within + / -0.1 m / min; and S4, the content of SiO in the casting powder is reduced to be smaller than or equal to 20%, and meanwhile, the alkalinity R of the casting powder is 1.5-2.0. The continuous casting process is ensured to be smooth, nozzle nodulation and casting blank surface defects are effectively prevented, and the production efficiency and the product quality are remarkably improved.

The invention discloses a production method for reducing flaw detection defects of wind power gear steel, and belongs to the technical field of ferrous metallurgy. According to the method, an electric furnace-LF-VD-continuous casting process route is adopted, the mass fraction of an aluminum element Al in molten steel is controlled to be not lower than 0.018% in the LF refining process, and the mass fraction of [Al] is controlled to be higher than 0.010% all the time in the VD vacuum treatment process. And after VD vacuum breaking, aluminum is supplemented in time, the mass fraction of Al is increased to 0.015%-0.020%, calcium treatment is reasonably carried out, and the mass fraction of Ca in molten steel is controlled to be 0.0006%-0.0009%. By accurately controlling the component change of the molten steel in the VD process, the formation of CaO-MgO-Al2O3-SiO2 inclusions with high SiO2 content is effectively inhibited, the large-size ultrasonic flaw detection defects in the wind power gear steel are remarkably reduced, and the internal quality of the steel is improved. The method is simple in process and remarkable in effect, and has a good industrial application prospect.

The invention discloses a refining calcium-free treatment process, and belongs to the technical field of refining and smelting of high-carbon aluminum-containing steel. According to the method, various smelting parameters of the whole steelmaking process are adjusted, sulfur entering a converter is guaranteed in a desulfurization area, tapping carbon, tapping temperature, in-place refining component hit rate, deoxidation degree and tapping phosphorus difference are guaranteed in a converter area, refining treatment time, white slag protection time and soft blowing time are guaranteed in a refining area, the content of Al2O3 in molten steel is reduced, the purity of the molten steel is guaranteed, and the quality of the molten steel is improved. Molten steel calcium-free treatment is achieved, and the quality of molten steel is improved.

The application discloses a slag washing desulfurization calcium treatment process, which comprises the following steps: (1) detecting calcium wire for calcium treatment: the method comprises sample preparation, dissection and analysis; the filling of reduced iron powder and the bonding state of calcium particles, the pressure pit of internal iron sheet, the particle size of iron powder and the observation and data information comparison of the weight of the two kinds of powder should be observed from the cross section and the section; the metallurgical effect of calcium treatment is preliminarily judged according to the influencing factors; (2) strictly controlling the particle size of reduced iron powder and the suitable ratio of calcium particles and reduced iron powder, and selecting calcium wire meeting the requirements to be put into the slag washing desulfurization process; the calcium wire selected by the above detection method can make the wire feeding speed stable at 4-4.5 m / s, so that the wire feeding speed is not reduced due to flash explosion and spatter, and the stability of production is ensured.

This invention discloses a method for reducing the refining cost of low-carbon cold heading steel, belonging to the field of iron and steel metallurgical technology. The method includes: recovering molten slag before tapping from the converter; reducing carbon content to below 0.06% in the later stages of smelting; bottom blowing argon after oxygen blowing and measuring oxygen content, dynamically calculating the addition amounts of ferroaluminum and lime; adding ferroaluminum and lime during tapping; adjusting aluminum to 0.050%-0.055% after tapping by feeding aluminum wire; slag breaking and power supply after the molten steel reaches the LF furnace, adding lime at 1.3 times the amount of aluminum added after tapping; raising the temperature to 1600-1605℃ after a second sampling, adding ferromanganese, calculating aluminum loss based on power supply time, and controlling aluminum at 0.035%-0.040%; finally, calcium treatment and soft blowing are performed. This invention achieves low-cost and high-efficiency refining of low-carbon cold heading steel through optimizations such as recovering molten slag, dynamically calculating material addition amounts, moving deoxidation and slag formation forward, reducing material consumption, and replacing large-scale argon agitation for impurity removal.

According to the smelting process, EBT electric arc furnace smelting, LF furnace refining, VD vacuum treatment and continuous casting are adopted, the end point C of an electric arc furnace ranges from 0.08% to 0.25%, and the end point temperature is controlled to range from 1630 DEG C to 1660 DEG C; 5-7 kg / t steel lime and 1.0-2.0 kg / t steel calcium carbide are added into an LF furnace for deoxidation, a staged sulfur adding technology is adopted, the alkalinity of refining slag is controlled to be 2-4, reducing white slag is not produced for desulfurization, the temperature is increased to 1655-1685 DEG C in a submerged arc mode, VOD / VD is converted for vacuum treatment, a vacuum refining technology is adopted in VD, the vacuum degree is smaller than or equal to 67 Pa, the holding time is longer than or equal to 20 min, sulfur line feeding is not conducted after VD, and calcium treatment is not conducted; and when the soft blowing time is greater than or equal to 12 minutes, a continuous casting station is turned, the superheat degree of a continuous casting tundish is controlled to be 20-50 DEG C, and the constant pulling speed is 0.20 + / -0.2 m / The technology is suitable for producing the low-silicon low-aluminum high-sulfur steel through the electric furnace in a short process.

The application belongs to the technical field of wastewater treatment and recycling, and particularly relates to a desulfurization wastewater resource treatment method. The application can remove calcium ions to the maximum extent without reducing the concentration of magnesium ions in the first-stage calcium removal process by selecting a composite calcium removal agent with a specific composition, that is, effectively separating calcium ions and magnesium ions without introducing impurity ions, the concentration of calcium ions can be reduced to below 60 mg / L, and the removal rate of magnesium ions is below 10%; then the concentration of calcium ions is further reduced to below 10 mg / L through secondary calcium removal treatment; finally, through steps such as nanofiltration salt separation and concentration crystallization, sodium chloride with a purity of above 98% and magnesium sulfate heptahydrate with a purity of above 98.5% are obtained.

The invention provides a method for preparing nickel-cobalt-manganese ternary regenerated liquid through multi-metal co-extraction and application, and the method comprises the following steps: firstly, carrying out calcium extraction treatment on a leaching solution obtained by removing iron, aluminum and copper from battery positive electrode black powder by adopting a first extraction organic phase to obtain a calcium-loaded organic phase and a calcium-removed raffinate; carrying out nickel-cobalt-manganese co-extraction on the calcium-removed raffinate by adopting a second extraction organic phase to obtain a nickel-cobalt-manganese-loaded organic phase, and carrying out reverse extraction treatment on the nickel-cobalt-manganese-loaded organic phase to obtain a nickel-cobalt-manganese mixed solution; and finally, the nickel-cobalt-manganese mixed solution is subjected to purification and impurity extraction treatment through a third extraction organic phase, and the nickel-cobalt-manganese ternary regenerated liquid is obtained. According to the preparation method provided by the invention, synchronous extraction of nickel, cobalt and manganese is realized, and the nickel-cobalt-manganese ternary regenerated liquid obtained by co-extraction can be directly used for in-situ preparation of the ternary positive electrode material, so that the regeneration period of the ternary positive electrode material is greatly shortened, the operation complexity and the production energy consumption are reduced, and the overall recovery cost is greatly reduced.

The invention belongs to the technical field of metallurgy, and particularly relates to a cleanliness control method for medium-carbon aluminum-containing and sulfur-containing structural steel for an automobile transmission shaft. According to the medium-carbon aluminum-containing sulfur-containing structural steel, the technological process of converter-LF refining furnace-RH vacuum treatment furnace-continuous casting is adopted, the alkalinity of refining slag is controlled by determining the type of deoxidation materials in the converter tapping and LF process, the binary alkalinity of refining final slag is controlled to be 3.5-4.0, and the slag deoxidation and inclusion adsorption capacity is enhanced; in the LF process, through a calcium treatment process, aluminum oxide and other impurities difficult to float upwards are subjected to denaturation treatment, and the situation that a large number of calcium sulfide impurities more difficult to remove are generated due to improper calcium treatment is avoided; in the continuous casting process, nozzle nodulation is controlled through nozzle argon blowing, slow pulling speed and other operations. And finally, the castability of the molten steel is improved, meanwhile, non-metallic inclusions of rolled metal are effectively controlled, the flaw detection qualification rate is increased, and meanwhile the product crack occurrence rate of a user is effectively reduced.

The invention discloses an anti-flocculating-flow smelting method for a beam blank continuous casting machine, which comprises the following steps of: LF (ladle furnace) refining and calcium treatment process: when the temperature of molten steel reaches 1550-1580 DEG C at an LF station, feeding an iron-calcium core-spun yarn or a high-calcium yarn into the molten steel, and carrying out calcium treatment; during calcium treatment, the mass ratio of calcium to aluminum in molten steel is controlled to be 0.09-0.12; soft argon blowing treatment is carried out after calcium treatment, and the soft argon blowing time is not shorter than 10 minutes; a continuous casting protective pouring procedure: sealing from a steel ladle to a tundish by adopting a long nozzle matched with argon, wherein the argon flow at the sealing part is 5-15L / min; an alkaline covering agent is used in the tundish, and the alkalinity of the alkaline covering agent is controlled to be 1.8-2.5; and the superheat degree of the tundish molten steel is stably controlled to be 25-35 DEG C. Through systematic process design, the form and the number of inclusions in the molten steel are controlled, and stable high-quality molten steel is provided for a casting machine.

The invention relates to the technical field of metallurgy, in particular to a production process for reducing oxide inclusions of 20CrMnTiH gear steel. The process sequentially comprises the steps of electric furnace primary smelting, LF refining, RH vacuum treatment, continuous casting and rolling. The core of the method is that through whole-process systematic cooperative control, key process parameters such as an electric furnace end point, LF white slag refining, RH calcium treatment and continuous casting electromagnetic stirring and pulling speed are accurately regulated and controlled, and a set of complete inclusion prevention and treatment system is formed. According to the method, the total oxygen content in the steel can be stably controlled to be smaller than or equal to 15 ppm, and the grades of B-class and D-class inclusions are both smaller than or equal to 1.5, so that the fatigue life and the mechanical property consistency of the steel are remarkably prolonged, and the harsh requirement of high-end gear manufacturing for the material cleanliness is met.

The invention discloses a method for improving cracks of a 9SiCr casting blank, which comprises the following steps of: feeding a pure calcium line into molten steel to carry out calcium treatment on the molten steel, controlling the pure calcium line fed into the first furnace of molten steel to be 1.2-1.4 m / t, and controlling the pure calcium line fed into the second furnace of molten steel to be 0.7-0.9 m / t; the total aluminum content Alt in the steel is controlled to range from 0.020% to 0.035%; controlling the superheat degree of the molten steel to be 20-35 DEG C; the pulling speed of a 160mm * 160mm casting blank is controlled to be 1.75 m / min; the water flow of the crystallizer is controlled to be 1800 L / min; a secondary cooling water dynamic water distribution mode is weak cooling, and the water inlet temperature of secondary cooling water and crystallizer water is controlled to be 25-35 DEG C; special high-carbon high-alloy steel crystallizer casting powder is used; the casting blank with the surface temperature of 700-800 DEG C is off-line hoisted into a heat preservation pit for heat preservation, and the heat preservation pit is preheated to 200 DEG C or above in advance; according to the method, it can be guaranteed that the surface quality of the casting blank of the steel grade is stable, embrittlement does not occur in the cooling process of the casting blank, cracking does not occur in the rolling process, and the method has the advantages of being controllable, high in quality, efficient and low in cost and is suitable for large-scale industrial production of the high-carbon alloy tool steel 9SiCr.

Embodiments of the present disclosure disclose a method, device, electronic and medium for determining the composition-mass ratio of alumina inclusions. A specific embodiment of the method comprises: in response to determining that alumina inclusions are detected in a smelting process of calcium-treated steel, obtaining smelting data; determining a shape factor of the alumina inclusions according to the smelting data; and determining a composition-mass ratio of the alumina inclusions according to the shape factor and a pre-determined composition-mass ratio prediction formula. The embodiment associates the shape factor with the composition-mass ratio of the alumina inclusions, effectively improves the efficiency and effect of the calcium treatment process, reduces the experimental detection cost, and facilitates the modification of the alumina inclusions into spherical inclusions, which will not be deformed or broken during the steel processing process, thereby improving the plasticity, toughness and fatigue resistance of the steel product.

The invention relates to a large heat input welding steel manufacturing method for realizing full-process oxide metallurgy, which comprises the following steps: 1) controlling the end point carbon content and tapping temperature in converter smelting, and carrying out deoxidation alloying by adopting a composite deoxidizer; 2) controlling the mass ratio of calcium to aluminum in molten steel in the LF refining and calcium treatment process; (3) whole-course protection pouring is adopted for continuous casting, and the superheat degree and the pulling speed of tundish molten steel are controlled; (4) the heating temperature and the heat preservation time of the plate blank, the initial rolling temperature of a recrystallization area and the final rolling temperature and the accumulated reduction rate of a non-recrystallization area are controlled; and (5) a two-stage accelerated cooling system is adopted, through systematic control over technological parameters of the whole process of converter smelting, refining, continuous casting, rolling and cooling, accurate regulation and control over the types, the sizes, the distribution and the number of oxides in steel are achieved, and therefore stable production of thick plate steel products with excellent large heat input welding heat affected zone toughness is achieved.

The present application relates to a kind of low-silicon high-aluminum welding wire steel and its production method, its production method is according to the flow production of converter smelting, LF refining, VD vacuum treatment and continuous casting;When converter smelting, control C, Si component when tapping, add aluminum cake, lime and calcium aluminate slagging material;When LF refining, adopt aluminum bean and calcium carbide mixed deoxidation, adopt low-carbon ferromanganese and ferromolybdenum to carry out alloy component adjustment, feed aluminum wire before refining and carry out high-aluminum content pre-adjustment, after detecting that the aluminum content is ≥0.050% 10~20min, feed pure calcium line and carry out first calcium treatment;When VD vacuum treatment, feed aluminum wire after breaking empty to the Al component control target of welding wire steel, feed pure calcium line before outlet and carry out second calcium treatment;Can effectively control low-carbon, low-silicon, high Al, low nitrogen, low Ca steel grade component, balance Ca content and molten steel castability control, realize the efficient, high-quality, low-cost continuous stable production of welding wire steel used in low temperature weak corrosion environment.

The application relates to the technical field of steelmaking secondary refining process, in particular to a method for RH vacuum calcium treatment. The method comprises the following steps: according to the content of sulfur in molten steel, setting the adding amount of high-efficiency calcium-iron alloy; under the condition of setting the vacuum degree, adding the high-efficiency calcium-iron alloy with the set adding amount into the molten steel, and controlling the total argon flow of the vacuum chamber to carry out homogenization calcium treatment operation; under the condition of setting the time, carrying out soft blowing operation on the molten steel after calcium treatment, and controlling the argon flow of the ladle bottom blowing to promote the floating of inclusions. The application solves the technical problem of smoking in the existing RH vacuum calcium treatment process.

The application provides a production method of a hot-rolled strip steel for a 700MPa-grade high-frequency welded pipe, which comprises the following steps of steelmaking, continuous casting, heating, rolling, cooling, coiling and flattening. A secondary calcium treatment process is adopted in the steelmaking stage, and the contents of nitrogen, sulfur and calcium in the refined molten steel and the mass ratio of calcium to sulfur are controlled; the subsequent continuous casting process, multi-stage heating process, rolling process and three-stage cooling process are combined, and finally the obtained hot-rolled strip steel has excellent strength and plasticity and good overall strength and plasticity stability. The yield strength of the hot-rolled strip steel is 740-780MPa, the tensile strength is 820-850MPa, the elongation is 22-25%, and the product of strength and plasticity is 18-23GPa·%. Meanwhile, the elongation of the steel pipe prepared by high-frequency welding of the hot-rolled strip steel can also reach more than 20%, the flattening performance and flaring are good without cracking phenomenon, the internal stress of the steel pipe is low, the welding performance is good, and the right angle is not greater than 2mm / 10m.

The invention belongs to the field of steel for low-alloy oil cylinder pipes, and discloses a continuous casting round billet for low-alloy oil cylinder pipes and a continuous casting production method thereof.The continuous casting round billet for low-alloy oil cylinder pipes comprises, by weight, 0.14%-0.18% of C, 0.30%-0.50% of Si, 1.50%-1.60% of Mn, 0.10%-0.20% of Cr, 0.020%-0.040% of Al, 0.03%-0.07% of RE, smaller than or equal to 0.020% of P, smaller than or equal to 0.010% of S, smaller than or equal to 0.0015% of O, smaller than or equal to 0.00020% of H and the balance Fe and inevitable impurity elements; through a converter deep deoxidation large-slag-amount process, LF diffusion deoxidation combined with white slag refining, RH high-vacuum calcium treatment and trace rare earth modification, fine diffusion and floating of inclusions are promoted, the uniformity of solidification structures is remarkably improved, center looseness and shrinkage cavities are eliminated, surface cracks and sunken defects are completely eradicated, and the cleanliness and compactness of the interior of a casting blank are improved.

The application discloses a RH furnace calcium treatment process and relates to the technical field of molten steel calcium treatment. The process comprises the following steps: S1, molten steel is kept circulating in vacuum; S2, silicon calcium barium alloy is added after first-stage wire feeding and second-stage wire feeding; S3, nitrogen is introduced again; S4, normal pressure is restored, and molten steel after calcium treatment is obtained, the silicon calcium barium alloy is added in an amount of 40-47 kg per ton of molten steel, the first-stage wire feeding time is 3-5 min, the vacuum degree of the first-stage wire feeding is 55-67 Pa, the mass ratio of the silicon calcium barium alloy to the molten steel added in the first-stage wire feeding is 22-26 kg / t, the second-stage wire feeding time is 2-4 min, and the vacuum degree of the second-stage wire feeding is 50-55 Pa. The two-stage wire feeding mode is matched with multiple wire feeding ports, the wire feeding time and the vacuum degree are adjusted, the silicon calcium barium alloy is uniformly distributed in the molten steel, segregation is avoided, the calcium treatment effect is good, and the steel performance is greatly improved.

This invention relates to the field of wastewater treatment technology, specifically to a papermaking wastewater treatment process based on mitigating sludge calcification, comprising the following steps: S1: pretreatment, S2: calcium separation treatment, S3: deep decalcification treatment, S4: deep treatment, S5: anaerobic biological treatment, and S6: recovery treatment. In this invention, the treatment agent added during the calcium separation treatment process achieves large-scale separation of calcium ions from the water in a gentle manner. Subsequently, in the deep decalcification treatment, a weakly acidic cation exchange resin is used for fine treatment. These two processes work synergistically to fundamentally and significantly reduce the calcium ion load entering the subsequent anaerobic biological treatment system, completely changing the conditions under which calcium carbonate deposits on the sludge surface in the biological treatment tank. This effectively solves the fundamental technical problem of reduced activity, decreased fluidity, and equipment scaling and clogging caused by sludge calcification.

This invention discloses a method for smelting high-purity rare earth steel, belonging to the field of iron and steel smelting technology. This invention reduces inclusions and improves purity by sequentially subjecting vacuum-treated molten steel to calcium and rare earth treatments. Calcium treatment transforms inclusions into liquid inclusions, promoting polymerization and growth, which are then removed by flotation during soft argon blowing, thus reducing the purity of the molten steel. Based on this, rare earth treatment further deoxidizes the steel, improving its purity and modifying inclusions. This invention fully considers the aluminum reduction in actual production processes. It utilizes the total aluminum, sulfur, and total oxygen content in the molten steel after vacuum degassing to limit the amount of solid pure calcium wire and rare earth added, thereby improving the purity of the molten steel while avoiding nozzle clogging or nodule formation during continuous casting.

The invention provides a method for inhibiting blockage of a rare earth steel casting nozzle, which comprises the following steps of: before rare earth steel is cast, casting calcium treatment molten steel, and starting to cast the rare earth steel after the calcium treatment molten steel is cast; the molten steel subjected to calcium treatment comprises the following components in percentage by weight: 0.0020 to 0.0040 percent of Ca, 0.025 to 0.035 percent of Als, less than or equal to 0.0015 percent of T.O and less than or equal to 0.0020 percent of S; the rare earth steel is characterized in that T.O is less than or equal to 0.0015 wt%, S is less than or equal to 0.0010 wt%, Als is 0.030-0.050 wt%, and RE is 0.003-0.006 wt%. According to the method, a CaO-Al2O3-RE2O3 stable corrosion-resistant protective layer is generated on the inner wall of the nozzle through calcium treatment in the first furnace before rare earth steel casting and rare earth molten steel casting, direct contact and erosion reaction of rare earth elements and nozzle refractory are blocked, the generation condition of a chemical deposition layer on the inner wall of the nozzle is eliminated, and the nozzle nodulation and blockage risks are remarkably reduced.

The invention discloses a pure steel calcium treatment spherical bomb feeding device which comprises a steel platform, a bomb dropping mechanism and a controller electrically connected with the bomb dropping mechanism, the steel platform is located above a steel ladle, a heat insulation fireproof layer is arranged at the lower end of the steel platform, and a plurality of vertical through holes which are distributed in rows and columns and used for allowing spherical bombs to pass through are formed in the steel platform; the horizontal positions of the vertical through holes are all within the range of the horizontal position of the inner ladle cavity of the steel ladle, and the bomb dropping mechanism is provided with a plurality of bomb dropping ends which are used for dropping bombs to the vertical through holes synchronously. According to the invention, after the bomb dropping mechanism is controlled, a plurality of spherical bombs are synchronously and uniformly dropped into a steel ladle through a plurality of vertical through holes which are distributed in rows and columns, so that the time of a calcium treatment process can be shortened, calcium absorption is promoted, and automation, high efficiency and large scale of calcium treatment can be realized; the heat insulation and fire prevention layer can insulate heat and prevent fire, so that the bomb dropping mechanism is not exposed in molten steel heat radiation baking any more, the bomb dropping mechanism does not deform for a long time, and then reliability is improved.

The invention belongs to the technical field of metallurgy, and particularly discloses a smelting method for producing cold heading steel through a refining furnace. A staged slagging and heating step; forming and maintaining white slag; a dynamic argon stirring step; a calcium treatment step; and a soft blowing purification step. By means of the smelting method for producing the cold pier steel through the refining furnace, the temperature, components and purification effect of the molten steel can be effectively controlled, and the performance and production efficiency of the cold pier steel are improved.

The invention relates to a method for increasing the number of continuous casting furnaces of medium-carbon bearing steel, in order to refine grains, the mass percentage of Al in the medium-carbon bearing steel is generally required to be 0.020-0.050%, and calcium treatment is not allowed. As secondary oxidation of a casting furnace is serious, inclusions at a tundish nozzle bowl part and a stopper rod head are easy to gather, the stopper rod rises, and the continuous casting castability is influenced. According to the technical scheme, when the medium-carbon bearing steel is poured, calcium-treatable medium-carbon steel is adopted for casting a first furnace, the first furnace is subjected to Ca treatment, the second furnace is not subjected to calcium treatment, the medium-carbon bearing steel is produced after a third furnace, and the steel must contain common components of C, Si, Mn, P, S and Cr elements with the medium-carbon bearing steel. The production efficiency is improved; the production cost is reduced.

This invention relates to the field of road materials technology, specifically to a desulfurized gypsum-fly ash-based high-durability road base inorganic cementitious material and its preparation method. The material comprises, by weight, 6200-7100 parts modified fly ash, 200-500 parts silicate cement, 800-1200 parts calcium hydroxide, and 1500-2500 parts flue gas desulfurization gypsum. The modified fly ash is pre-activated by a composite activation solution, then sequentially treated with calcium hydroxide, sodium hexametaphosphate, and calcium nitrate tetrahydrate to construct calcium-phosphorus reaction sites. A sodium silicate solution is then added dropwise to form a hydrated calcium silicate nucleation coating. Finally, sodium tripolyphosphate is added, followed by aging and drying to obtain the final product. This invention effectively improves the surface activity and nucleation efficiency of fly ash, giving the material the advantages of high early strength, strong water resistance, and good freeze-thaw stability, making it particularly suitable for high-humidity areas and heavy-load road bases.

The invention relates to a preparation method of an ultra-fine grain high-performance high-speed rail wheel, which comprises the following steps: smelting, LF (ladle furnace) refining, RH (relative humidity) vacuum refining, soft blowing and calcium treatment, continuous casting forming to obtain a continuous casting blank and other steelmaking operations, in the steelmaking process, wheel steel comprises the following chemical components in percentage by weight: 0.52-0.77% of C, 0.60-1.00% of Si, 0.60-1.00% of Mn, less than or equal to 0.010% of P, less than or equal to 0.006% and less than or equal to 0.015% of S, 0.20-0.40% of Cr, 0.020-0.050% of Al, 0.0080-0.0150% of N and less than or equal to 0.0010% of Ti; heating a continuous casting blank formed by continuous casting, and enabling the continuous casting blank to deform in a rolling or forging manner; the rolled blank or the forged blank is subjected to ingot cutting and then subjected to heating, dephosphorization, preforming, rolling and punching procedures in sequence to be subjected to thermal forming to form the high-speed rail wheel; the high-speed rail wheel is subjected to complete austenitizing treatment and normalizing; carrying out incomplete austenitizing treatment and rim quenching on the high-speed rail wheel; and tempering after quenching. According to the method, the grain structure state and the obdurability level of the wheel rim are systematically and comprehensively optimized, the wear and fatigue performance of the wheel is improved, and the use performance of the wheel is improved.