1085 results about "Liquid steel" patented technology

This invention exposed the producing method of V-N microalloyed high strength weathering steel which produced with near net shape con-casting technology. It is smelted in electric furnace or converter, refined, con-casted, casted, then directly sent into roller hearth furnace or soaking pit, hot-rolled, laminar cooled, coiled. The liquid steel's chemical elements are (Wt.%): C: <=0.08%, Si: 0.25- 0.75%, Mn: 0.8-2.0%, P: 0.070-0.150%, S: <=0.040%, Cu: 0.25-0.60 %, Cr: 0.30-1.25 wt%, Ni: <=0.65%, V: 0.05-0.20%, N: 0.015-0.030%. This invention can get the high intensity, formation, weathering, joining character stably. The alloying cost is relatively low. So it can be used to produce container, carriage, and other industry facility.

The invention discloses a wear-resisting alloy steel with high boron, high chrome and low carbon and a preparation method thereof, which comprises the following chemical constituents in weight percent: 0.1-0.5% of C, 3-26% of Cr, 0.5-1.2% of Si, 0.5-1.5% of Mn, 0.3-2.8% of B, 0.3-2.6% of Cu, 0.2-0.6% of Ti, 0.02-0.15% of Ca, 0.03-0.25% of Ce, 0.02-0.18% of N, 0.05-0.3% of Nb, 0.04-0.09% of Al, 0.02-0.15% of Mg, 0.04-0.13% of K, less than 0.03% of S, less than 0.04% of P and the balance Fe and unavoidable impurity elements. The method comprises the following steps: melting steel scrap and chromium iron in an electric furnace; adding copper plates, ferrosilicon, ferromanganese into the melted steel scrap and chromium iron, heating the melt to 1560-1620 DEG C after the constituents are adjusted to be qualified in stokehold; adding calcium-silicon alloy and aluminium deoxidation into the melt; and then adding ferrotitanium and ferroboron in sequence, melting and discharging; roasting the compound inoculant composed of granular rare earth magnesium alloy with the diameter being less than 12mm and cerium metal, Si3N4, VN, Nb and K; placing the roasted compound inoculant at the bottom ofa steel ladle; carrying out modification and inoculation processes on the smelted liquid steel by pour-over method in the steel ladle, wherein, the pouring temperature of the liquid steel is 1400-1450DEG C; heating castings to 920-1150 DEG C and preserving heat for 2-4 hours; and air cooling the castings to room temperature to obtain the alloy steel in the invention. The alloy steel of the invention has the advantages of high strength, rigidity and toughness, good thermal fatigue resistance property, wear resistance, and low manufacture cost.

This is about the manufacturing method of cold-rolled non-oriented electrical steel, including the following steps: a) the continuous casting of blanks: the liquid steel is continuously cast into a blank of 120-170mm at a pulling speed of 2-3 m / min; b) hot rolling: the blanks are directly hot-rolled or heated into the hot-rolled plate of 900-1150 deg.C and the thickness of the blank is hot-rolled to 0.8-4mm with finishing temperature 800-900deg.C and coiling temperature 500-900deg.C; c) cold rolling: the hot-rolled band undergoes annealing or non annealing treatment and acidwashing, and then the first cold-rolling or the second cold-rolling with annealing until the goal thickness reaches. When the finishing annealing is carried out, the non-oriented electrical steel is produced.

A process for manufacturing carbon-steel strip having a thickness of less than or equal to 10 mm directly from liquid steel, by casting said liquid steel between the lateral surfaces, made of copper or copper alloy, of two internally cooled rotating horizontal rolls.

The invention discloses an on-line dynamic optimization control method for a converter steelmaking process based on data driving. The method comprises the following steps: building an off-line prediction model database; building a liquid steel temperature prediction model and a carbon content prediction model by use of a data driving method to obtain a corresponding relationship between operating variables and the temperature and carbon content of liquid steel in the converter steelmaking process; selecting a melt data unit matched with the information of the current converter steelmaking production process and determining a control reference curve of the liquid steel temperature and carbon element content; building a real-time dynamic optimization model of the converter steelmaking process and determining an optimized set value unit of each operating variable; and selecting the set value of each operating variable from the optimized set value unit so as to carry out control operation. The method disclosed by the invention can be used for realizing real-time on-line control over the converter steelmaking process and providing convenience for an operator to set selection conditions according to actual working conditions, thus the production efficiency of a steelmaking plant is improved.

A method of an in situ synthetic steel bond hard alloy casting composite hammerhead adopts a vacuum lost foam casting technology, wherein Ti powder, graphite powder, W powder and metal powder are mixed, and are added with an adhesion agent to produce a powder coating paste, the powder coating paste is filled in a reinforcement groove or a hole of a working part of an expanded poly styrol (EPS) foaming plastic modal of a hammerhead casting, during the pouring process, the high temperature of liquid steel is utilized to initiate the self propagating synthesis reaction, the reactions of Ti plus C->TiC and W plus C->WC are carried out, so the TiC and WC-based hard alloy phases are formed, the liquid steel is filled into the clearance of a hard phase, so an in situ synthetic titanium carbide and tungsten carbide steel bond hard alloy is obtained, and the hard alloy is embedded in the steel base body of the working part of the hammerhead. When the hammerhead which is produced through the method of the in situ synthetic steel bond hard alloy casting composite hammerhead is used, because the hard alloy and the casting are completely, metallurgically and firmly combined together, the hammerhead has high wear resistance and impact resistance during the use, has a simple technological process, low production cost, and is applicable to large-scale industrial production.

The invention discloses a metal complex low-carbon magnesia carbon brick used for ladle slag lines, the weight percentage of the added materials is as following, 50 to 70 percent of magnesia particles, 25 to 35 percent of magnesia powder, and 3 to 6 percent of organic binder, furthermore, the following components are added which are produced by mixing, striating materials, forming and heat-treatment, 0 to 4 percent of flake graphite, 3 to 15 percent of metal powder, and 0.5 to 3 percent of antioxidant containing boron. The antioxidant properties, slag-resistance performance, high temperature strength and the thermal shock resistance of the ladle slag line used metal complex low-carbon magnesia carbon brick are greatly improved, the service life is prolonged, the consumption cost of each ton of refractories is lowered. The preparation method of ladle slag line used metal complex low-carbon magnesia carbon bricks is also disclosed, and the carbon content in the ladle slag line used metal complex low-carbon magnesia carbon bricks produced by the method is less than or equal to 6 percent, little carbon is added so as to reduce the pollution towards liquid steel, and residual strength ratio of the thermal shock resistance is kept at 70 to 80 percent.

The invention provides a real-time dynamic converter steelmaking quality prediction method based on data analysis. The method comprises the following steps: building a converter steelmaking quality off-line prediction model data base; respectively dividing liquid steel temperature and carbon element content into a plurality of stage ranges; building a real-time dynamic converter steelmaking quality prediction model; performing real-time dynamic converter steelmaking quality prediction according to the real-time dynamic converter steelmaking quality prediction model; testing the content of discharged steel components of the liquid steel; periodically updating the history data sets. The method provided by the invention is used for performing real-time dynamic prediction on liquid steel temperature and liquid steel quality during converter steelmaking on the premise of satisfying the technological requirements of converter steelmaking, can be used for tracking the condition inside a furnace in real time, and has the advantages of overcoming the defect of on-site delaying, improving the detection precision of each component content, lowering the production cost, also lowering the demand cost of equipment and providing valuable reference information for control of operators.

The invention provides high-boron high-chromium low-carbon high-temperature-resistant wear-resisting alloy steel and manufacturing method thereof. The chemical content of the alloy steel includes, by weight, 0.10%-0.5% of C, 3%-26% of Cr, 0.5%-4% of W, 0.5%-1.2% of Si, 0.5%-1.5% of Mn, 0.7%-3.5% of B, 0.3%-2.6% of Cu, 1.5%-2.4% of Al, 0.8%-1.6% of Ti, 0.02%-0.15% of Ca, 0.03-0.25% of Ce, 0.02%-0.18% of N, 0.05%-0.3% of Nb, 0.12%-0.25% of Mg, 0.04%-0.13% of K, 0.05%-0.12% of Ca, 0.06%-0.15% of Ba, less than 0.03% of S, less than 0.04% of P and the balance Fe and unavoidable impurity elements. After steel scrap and ferrochromium are melted in an electric furnace, a copper plate, silicon iron and ferromanganese are added to the electric furnace, after content is qualified through pre-furnace adjustment, the temperature of a melt rises to 1560-1620 DEG C, calcium-silicon alloy and deoxidation aluminum are added, ferrotitanium, ferroboron and metal aluminum are sequentially added and poured out of the furnace after being melted, granular rare earth magnesium alloy with a diameter of less than 12mm and a composite inoculant composed of metal cerium, Si3N4, VN, Nb and K are placed at the bottom of a steel ladle after being roasted, metaphoric inoculation processing is carried out on smelt liquid steel in a in-ladle pouring mode, the liquid steel pouring temperature ranges from 1400 DEG C to 1450 DEG C, and a casting piece undergoes air cooling for 2-4 hours at the temperature of 920-1150 DEG C.

The invention relates to a compact method for producing middle-wide strip steel, which comprises: using melt iron to process pretreatment; smelting liquid steel; refining liquid steel; continuously casting the middle-thin plate blank; step beam heater heats uniformly; high-pressure water scale breaker breaks scale; one-frame four-roller reversible roughing mill mills; hot winding box winds; cutting the head and end of middle blank; the high-pressure water scale breaker breaks scale; the finishing roll machine continuously rolls; cooling the interlayer flow; the underground winder winds; and transporting steel coil. Wherein, all processes are inside one workshop or connected workshops. The invention can be used in middle steel factory with 1-2 million ton / year yields to match the metal flow, temperature flow and time flow effectively, to feed the high-temperature non-defect sheet blank at 920Deg. C into step beam heater, to save energy more than 60%, improve 1-2% of metal yield, reduce the producing cost and reduce the transport cost of middle process.

The invention discloses clay molding sand for cast steel and a preparation method thereof. The clay molding sand is prepared from the following raw materials in parts by weight: 60-80 parts of quartz sand, 20-30 parts of forsterite sand, 8-12 parts of bentonite, 5-8 parts of composite powder, 4-6 parts of talcum powder, 2-3 parts of nanometer aluminum oxide, 3-5 parts of pine sawdust, 2-4 parts of alpha-starch, 1-2 parts of dextrin, 3-6 parts of calcium phosphate, 1.5-2.5 parts of sulfite lye and 4-8 parts of water. The molding sand is high-temperature resistant, high in strength and high in impact resistance, can be used for overcoming the defects on hot spot parts and avoiding sand adhesion, and a phenomenon that the sand mold is broken due to impact force of liquid steel casting is avoided. Moreover, the clay molding sand is low in air release amount, good in air permeability effect and high in liquidity, the defects of air holes, cold shut and shrinkage porosity in the casting can be effectively overcome, and the yield of the casting is improved.

The invention provides a producing method for ultra low steel carbon used in car outer plate, characterized in that liquid steel is cast into plate slab in the pulling speed of 1.5-4m / min; the thickness of plate slab is 100-170mm; casting machine adopts dynamic light pressure and crystallizer electromagnetic braking technology and tundish superheat is 20-45deg.C; the plate slab is installed in heat directly and the charging temperature is more than 800deg.C; the plate slab is heated to 1150-1250deg.C in heating furnace; after the temperature is maintained for 30-90min rough rolling cogging is carried out. By adopting continuous rolling and casting short-flow process of medium-thin plate slab and collocating casting machine and heating furnace compactly quick charging is realized; charging material temperature is improved; problems of large investment and high energy consumption in conventional process are solved; inner limitation generated in continuous casting process of thin plate is eliminated; it is guaranteed that product is provided with good surface quality and stable mechanical property.

The invention provides a wind-crushing water-cooling granulating method of high-temperature liquid steel slag, a granulating device and granulated steel slag and use thereof. The invention belongs to the industrial waste comprehensive utilization filed and particularly relates to the treatment and the utilization of high-temperature liquid steel slag. The wind-crushing water-cooling granulating method of high-temperature liquid steel slag comprises the following steps: liquid steel slag flowing out from a tundish is granulated in the air through the high-speed compressed airflow ejected by a granulator; the granulated steel slag is dropped into a water pool so as to be cooled down; moreover, the pressure of the compressed air is controlled between 0.59 MPa and 0.70 MPa, and the degree of superheat of the liquid steel slag is controlled above 110 DEG C. The granulating device comprises a tundish, a granulator and a water pool, and is characterized in that: a tundish rapid heating-up device is arranged near the granulator; and a compressed air pipe is connected with a compressed air pressure automatic display monitoring device. The final blow rate of steel slag is increased from the 80 percent of the prior art to 95 percent and the steel slag has fine particle diameter; moreover, because unstable phase is eliminated, the steel slag can be directly used in the preparation of cement concrete of various strength grade labels from C30 to C80.

The invention provides high-strength fire resistant steel with the room-temperature yield strength being more than 460 MPa, the yield ratio being smaller than 0.80, the high-temperature yield strength at 600 DEG C being more than two thirds of the room-temperature yield strength (i.e. more than 307 MPa) and favorable impact flexibility, which comprises the following components by weight percent: 0.05 to 0.14 percent of C, 0.15 to 0.50 percent of Si, 0.5 to 1.2 percent of Mn, equal to or less than 0.025 percent of P, equal to or less than 0.015 percent of S, 0.10 to 0.40 percent of Cu, 0.10 to0.50 percent of Ni, 0.015 to 0.050 percent of Nb, 0.005 to 0.040 percent of Ti, 0.010 to 0.050 percent of V, 0.10 to 0.50 percent of Cr, 0.20 to 0.50 percent of Mo, 0.015 to 0.05 percent of Al, Fe and foreign matters. The invention also provides a production method of the fire resistant steel, which comprises the following steps: liquid steel is obtained through vacuum melting, and the liquid steel is cast to form a billet; after the billet is heated to 1150 to 1250 DEG C and is maintained for 1.5 to 2.5 hours, the billet is controlled to be rolled to the thickness of a finished product plate, the final rolling temperature is controlled about 820 to 950 DEG C, and the steel plate is air cooled or is air cooled after being fast water cooled to 450 to 650 DEC C after the rolling.

The invention discloses a roughing roll made of a graphitizable steel material and a manufacturing method thereof. The roughing roll comprises the following alloy components by weight percent: 1.20-2.30% of C, 1.00-2.20% of Si, 0.50-1.20% of Mn, less than or equal to 0.03% of P, less than or equal to 0.03% of S, 0.40-3.50% of Cr, 0.20-2.00% of Ni, 0.20-1.00% of Mo, and the balance of Fe and inevitable impurities. The manufacturing method of the roughing roll comprises the steps of smelting, inoculation and spheroidization, casting and heat treatment, wherein in inoculation and spheroidization, an inoculator of aluminum and rare-earth silicon iron magnesium alloy is adopted, the inoculator is added by 1-3 Kg per one ton of liquid steel, and Fe-Si particles and Si-Ca particles are rushed into along with a steel flow in the steel tapping process; after the completion of steel tapping, argon blowing treatment is performed on the liquid steel in a steel ladle, and then standing is carried out for more than 10 minutes so that the temperature of the liquid steel reaches a casting temperature 50 DEG C higher than the melting point of the liquid steel; then casting is carried out. The roughing roll made of the graphitizable steel material provided by the invention has high abrasive resistance, and also has excellent thermal crack resistance and excellent accidental impact resistance.

The invention discloses steel for a saw blade substrate, comprising the chemical components in percentage by weight: 0.68-0.80% of C, 0.30-0.70% of Cr, 0.50-1.00% of Mn, 0.10-0.50% of Si, 0.03-0.15% of V, 0-0.0050% of Ca, 0.0050-0.010% of N, 0.005-0.04% of Alt, P less than or equal to 0.02%, S less than or equal to 0.01% and the balance of Fe and unavoidable impurities. The manufacturing method of the steel comprises the steps of: carrying out continuous casting or die casting on the smelted liquid steel and carrying out blooming after the die casting to obtain steel billet; carrying out slowcooling on the continuously cast billet or the bloomed steel billet after die casting; heating the continuously cast billet or the bloomed steel billet in a temperature range of 1100-1250DEG C, wherein the outlet temperature of a rough mill is greater than or equal to 1050DEG C, the final rolling temperature is 870-950DEG C and the rolled steel plate adopts natural cooling; or carrying out hot rolling to obtain strip steel, wherein the final rolling temperature is 870-950DEG C and coiling temperature is 720-820DEG C; and controlling within 0.1-5DEG C / s for cooling after the coiling. After thesteel is made into a saw blade and undergoes quenching and annealing, the section rigidity of whole saw blade body can be above HRC43, is distributed evenly and can satisfy the usability requirementsof the saw blades with larger diameters.

This invention discloses a multi-element low alloy abrasion-resisting cast steel, which is composed of C 0.20-0.45 wt.%, Mn 1.1-1.8 wt.%, Si 0.8-1.5 wt.%, Cr 0.3-1.2 wt.%, B 0.05-0.20 wt.%, Ti 0.08-0.30 wt.%, N 0.03-0.20 wt.%, Ca 0.05-0.15 wt.%, K 0.04-0.15 wt.%, and the rest is Fe and inavoidable impurities. The cast steel is manufactured by: (1) mixing scrapped steel, silicon iron, chromium iron and manganese iron, (2) carrying out carburization by using scrapped graphite electrode or pig iron, (3) melting to obtain liquid steel and adjusting the components until being qualified, (4) heating the liquid steel to 1620-1660 deg.C, (5) adding Si-Ca alloy, boron iron, titanium iron and nitrogen-containing chromium iron, and then pouring out of the furnace, (6) pulverizing Y-based rare earth magnesium alloy and potassium-containing substances to granules whose sizes are less than 15 mm, (7) drying at 130-180 deg.C, (8) placing at the bottom of the ladle, (9) carrying out modification treatment by pour-over process, and casting at 1480-1520 deg.C, (10) austenitizing at 830-1050 deg.C for 0.5-4 h, (11) rapidly cooling, (12) keeping the temperature at 150-300 deg.C, and (13) cooling in a furnace or in the air.

In a method for manufacture of electrical steel a liquid steel mixture is created with a specified mixture chemistry. A continuous casting is performed to convert the liquid steel mixture to a slab. Hot roll steel band is created from the slab which is then pickled and hot band annealed, and then a cold rolled steel strip is formed. In a continuous annealing line, the cold rolled strip is annealed to achieve a partial recrystallization with a smaller grain size than would be the grain size with a complete recrystallization. Electrical steel created by the method is used for rotors and matching stators of a motor with properties at high strength and low electrical losses.

The invention provides a high-strength hot rolled steel plate roll for automobile wheels as well as a preparation method thereof. The method comprises the following steps of: smelting target liquid steel comprising the following components of 0.05-0.10% of C, less than or equal to 0.15% of Si, 1.30-1.50% of Mn, less than or equal to 0.15% of P, less than or equal to 0.002% of S, 0.02-0.10% of Ti, 0.025-0.045% of Nb as well as the balance of Fe and unavoidable impurities; casting into a plate blank continuously: heating the plate blank to 1,180-1,250 DEG C; rolling in a mode of 5 gates, wherein the single-gate rolling rate is not less than 20%; controlling the start rolling temperature of precision rolling to be not greater than 1,030 DEG C, and controlling the final rolling temperature of precision rolling to be 820-870 DEG C; firstly cooling rolling elements obtained through precision rolling at 12 DEG C / s-24 DEG C / s to 620-690 DEG C; then carrying out air cooling for 5-9 seconds; and then carrying out water cooling to the coiling temperature, and coiling, thereby obtaining the high-intensity hot rolled steel plate roll. According to the invention, the high-intensity hot rolled steel plate roll for the automobile wheels, which has the yield strength of being not less than 685MPa, the tensile strength of 750-950 MPa, and the ductility of 25-41%, can be prepared.

The invention belongs to the technical field of metallurgy and particularly relates to a preparation method of sheet billet continuous casting and rolling easy-acid washing hot rolling strip steel. The preparation method comprises the steps of: smelting liquid steel and continuously casting to form a sheet billet; heating the sheet billet; descaling the sheet billet by using high pressure water and finish-rolling the sheet billet, wherein during the finish rolling process, the water amount of cooling water between a first rack and a second rack is greater than or equal to 60%; the water amount of cooling water between the second rack and a third rack is 50%-60%; the water amount of cooling water between the third rack and a fourth rack and between the fourth rack and a fifth rack is 30-50%; and water amount of cooling water between the fifth rack and a sixth rack and between the sixth rack and a seventh rack is 10-20%; performing ultrafast cooling and laminar flow cooling on the finish-rolled sheet billet to finally obtain iron scale with the content of FeO lower than 10 wt%; and thinning the iron scale for 5-10 microns to obtain the easy-acid washing hot rolling strip steel in a uniform structure. According to the easy-acid washing hot rolling strip steel produced by the preparation method, the iron scale has a rational structure and good uniformity and the surface of the iron scale is provided with a plenty of micro-cracks; in the subsequent acid washing process, the acid washing efficiency of the strip steel is improved, acid consumption is reduced and acid washing efficiency is improved efficiently while the acid washing quality of the sheet steel is guaranteed.

The invention relates to a ferrite stainless steel cold-rolled steel band and a manufacturing method thereof. The ferrite stainless steel cold-rolled steel band comprises the following chemical ingredients in percentage by weight: 0.02%-0.04% of C, 0.10%-0.50% of Si, 0.10%-1.00% of Mn, 14.0%-19.0% of Cr, less than or equal to 0.030% of P, less than or equal to 0.010% of S, more than 0% while lessthan or equal to 0.030% of N, more than 0% while less than or equal to 0.60% of Ni, and the balance of Fe and unavoidable impurities. The manufacturing method comprises the following steps: (1) smelting, i.e. smelting liquid steel according to the requirement of the steel band; (2) continuous casting, i.e. casting into a continuous casting billet; (3) casting billet hot rolling, i.e. rolling the casting billet into a hot rolled coil; (4) hot coiling annealing, i.e. preserving the temperature at 800 DEG C-880 DEG C for the temperature preserving time of 10-13 hours, freely reducing the temperature to 600 DEG C after the temperature preservation is completed; (5) cold rolling, i.e. adopting once cold rolling or twice cold rolling among cold rolled finished products; and (6) cold coiling annealing, i.e. controlling annealing temperature at 860+ / -20 DEG C, and controlling annealing time according to 2-5 minutes / mm. The ferrite stainless steel cold-rolled steel band has good cold processingforming property and excellent crinkling and breaking resistance.

The invention provides an aluminum-calcium-magnesium-cerium composite alloy used for strong desulfurization, final desoxidation, and microalloying quenching and tempering of liquid steel, belonging to the technical field of ferroalloy used for steelmaking. Based on aluminum deoxidization, the aluminum-calcium-magnesium-cerium composite alloy is added with alkaline-earth metal calcium and magnesium to conduct the strong desulphurization and the final desoxidation on the liquid steel so as to reduce inclusions in steel, and adopts rare earth-cerium and alloy elements such as titanium, niobium, vanadium and the like to conduct quenching and tempering, and microalloying on the liquid steel so as to change the morphology of the inclusions, lead the steel to be solidified, crystallized and refined, and optimize the steel performance. The aluminum-calcium-magnesium-cerium composite alloy contains the following chemical compositions (mass percent): 10-60% of aluminum, 10-30% of calcium, 10-30% of magnesium, 0.5-10% of cerium, less than or equal to 1% of impurities (carbon + silicon + phosphorus + sulphur), and the balance of ferrum; and for the purpose of achieving different microalloying, the composite alloy also can contain one or more microalloying elements of titanium, niobium, molybdenum, vanadium, tungsten and boron, and the weight percentage content of the microalloying elements is 0.1-10%. In the invention, the final desoxidation, the strong desulfurization, the microalloying and the quenching and tempering of the liquid steel is completed in one step, thus improving the refining efficiency and effect, and greatly improving the steel quality.

The invention provides a continuous casting bloom soft press technology based on tail end electromagnetic stirring and belongs to the field of metal casting. The continuous casting bloom soft press technology based on the tail end electromagnetic stirring is characterized in that after a tail end electromagnetic stirring device is arranged on a second cooling area, a previous air cooling area is straightened. The thickness of a liquid core controlling the position of the stirring device occupies 30% to 55% of the thickness of a casting blank through a solidification heat transmission mathematical model. Stirring current of the tail end electromagnetic stirring device is 350A to 750A and stirring frequency is 3Hz to 8Hz. When soft press and straightening are conducted simultaneously, complete solidification of liquid phase among columnar crystals is guaranteed and meanwhile total press amount of a press intersection is controlled to be 10mm to 25mm, liquid steel superheat degree of a tundish is 20 DEG C to 30DEG C, dragging speed of a continuous casting machine is 0.35m / min to 0.75m / min, and therefore internal quality of a continuous casting bloom is remarkably improved and high quality rolled metal is guaranteed. Continuous casting bloom bearing steel manufactured through the technology is continuously manufactured for over 10 boilers, occurrence of internal cracks is avoided, a central organization is dense and even, the rate that a center contracting hole <=1.0 reaches 97.54%, center C segregation is controlled to be under 1.06 and thus the internal quality of the bearing steel is remarkably improved.

The invention discloses a process for smelting ultra clean steel by a single-nozzle refining furnace, belonging to the technical field of ferrous metallurgy. The process comprises the followings steps of: blowing in argon gas from the bottom of steel ladle with the blowing gas flow quantity of 1-10 NL / min per ton of steel, and inserting a suction nozzle into the steel ladle; carrying out a vacuum natural decarburization technology when the initial carbon content in liquid steel is smaller than 0.035%, and carrying out a vacuum forced decarburization technology when the initial carbon content in the liquid steel is greater than 0.035%, wherein the time for decarburization is 12-22 min; after decarburization, maintaining the pressure of a vacuum chamber to be les than 100-200 Pa, adding 1-6 kg of deoxidizer per ton of steel, and adding 0.5-8 kg of desulfurizer per ton of steel in 1-2 min after the deoxidizer is added, wherein the flow quantity of argon gas is 1-10 NL / min per ton of steel, and the time for desulfurization is 5-15 min; and deoxidizing and removing impurities after desulfurization. The process can simultaneously reduce the content of impurity elements comprising carbon, sulfur, nitrogen, hydrogen and oxygen and impurities in the liquid steel to an extremely low level within limited refining time, and the refining efficiency is obviously superior to that of an RH refining furnace.

The invention provides a high-toughness wear-resisting medium manganese steel hot rolled plate and a manufacturing method thereof. The high-toughness wear-resisting medium manganese steel hot rolled plate is prepared from the following chemical components in percentage by mass: 0.8-1.2% of C, less than or equal to 0.8% of Si, 7.0-9.0% of Mn, less than or equal to 0.030% of P, less than or equal to 0.005% of S, 1.5-2.0% of Cr, 0.2-1.0% of Mo, 0.2-1.0% of Mo, 0.2-1.0% of V, less than or equal to 0.2% of Nb, less than or equal to 0.05% of Ti, less than or equal to 0.04% of Al, less than or equal to 0.003 of B and the balance of Fe and inevitable residual impurity elements. The manufacturing method of the hot rolled steel plate comprises the following steps: smelting liquid steel according to set element components, after performing vacuum degassing treatment (external refining) on the liquid steel, performing continuous casting to form a continuous casting blank or die casting and initial rolling to form a steel billet, heating the steel billet at 1250 DEG C and then performing multi-pass rolling with the total reduction rate of not lower than 65% and the pass deformation rate of 10-20% at a final rolling temperature not lower than 1050 DEG C; next, performing solution treatment on the rolled steel plate at a solution temperature not lower than 1050 DEG C, controlling the surface temperature of the steel plate after coming out of water not to be lower than 300 DEG C, and finally obtaining the steel plate, wherein the tensile strength of the obtained steel plate is 700-900MPa, the normal-temperature impact toughness Akv of the steel plate is greater than or equal to 90J, and the hardness of the steel plate after water toughening treatment is less than or equal to 250HBW. The obtained steel plate is suitable for scraper conveyor middle grooves, self-discharging truck compartment plates, ball mill lining plates, feed bin lining plates and the like applicable under the conditions of medium and low loads.

The invention relates to a low-nickel austenitic stainless steel, which comprises the following chemical components by weight percent: no less than 0.05% and no more than 0.15% of C, less than 1.00% of Si, more than 9.00% and less than 10.00% of Mn, no less than 14.00% and no more than 16.00% of Cr, no less than 0.50% and less than 1.00%, more than 0.15% and no more than 0.25% of N, more than 1.50% and no more than 2.00% of Cu, no less than 10*10<-4>% and no more than 30*10<-4>% of B, no less than 1*10<-4> and no more than 50*10<-4>% of Ca, less than 0.030% of P, no less than 0.020% of S and the balance of Fe and inevitable impurities. For the stainless steel, heat processing performance of materials is improved through B alloying treatment on premise of further reducing the content of precious metal of nickel, and the purity of the liquid steel is enhanced through Ca treatment. The formability of stainless steel is enhanced through the reasonable alloy system design and a micro-alloy treatment method, the defects of sand buckle, sand holes, and the like are avoided in the forming process, the delayed rupture phenomenon is lightened, and the application scope of the festival nickel austenitic stainless steel is further broadened.

The invention provides a method for quickly replacing a tundish at a low liquid level of a medium thin plate blank continuous casting machine crystallizer. The method comprises the following steps of: (1) reducing the tonnage of liquid steel in an old tundish to 20 tons and reducing the pull speed at the same time; (2) reducing the tonnage of the old tundish to 8 to 10 tons, switching a crystallizer liquid level control mode from an automatic control mode into a manual control mode, and closing a plug stick; (3) rising the old tundish to a high-level removal pouring position, and starting a new tundish to move to the pouring position; (4) pulling the liquid level in the crystallizer to a position 550mm away from the upper edge of a copper plate of the crystallizer, and stopping pulling and straightening; (5) moving the new tundish to the pouring position; (6) pouring until the tonnage of the tundish is 4 tons, performing high-flow pouring, adding protection slag, and performing pulling and straightening; (7) increasing the pull speed to 1.30 m / min, and changing the manual control mode into the automatic control mode; and (8) increasing the pull speed to a target pouring speed, thus finishing the replacement of the tundish.

The invention belongs to the field of metal smelting, and mainly relates to smelting manufacturing technology of low-carbon TWIP steel through an AOD (argon oxygen decarburization) furnace. The smelted TWIP steel comprises the following components in percentage by weight: 0%-0.06% of C, 20%-30% of Mn, 2.0%-3.0% of Si, 2.5%-3.5% of Al, and the balance of Fe. The particular technology procedures comprises the following steps: 1), the AOD furnace is adopted for oxygen decarburization process, once the carbon in the liquid steel is lower than 0.03%, the liquid steel is subject to alloying; 2), after the TWIP steel is subject to manganese alloying, ferrosilicon or / and metal aluminium is adopted to perform reduction reaction on manganese oxide, so that the yield of metal manganese is increased; the oxidation heat of silicon or / and aluminium is adopted to regulate the temperature of the liquid steel and compensate temperature drop of the liquid steel generated by the manganese alloying of the TWIP steel. The method is high in manufacturing efficiency, low in cost, stable in operation and easily-mastered in technology; the main raw material is easily accessible, and no specific requirement is needed; the realization of large-scaled industrialized production is facilitated.

The invention discloses high-strength cast steel for a coupler of a railway vehicle and a manufacturing method thereof. The high-strength cast steel comprises the following chemical compositions by weight percentage: 0.22 to 0.28 of C, 0.20 to 0.40 of Si, 1.20 to 1.50 of Mn, 0.40 to 0.60 of Cr, 0.90 to 1.10 of Ni, 0.20 to 0.30 of Mo, 0.030 to 0.080 of Al, less than or equal to 0.30 of Cu, less than or equal to 0.030 of P, less than or equal to 0.030 of S, the balance Fe and unavoidable impurities. The key technology of the manufacturing method is that: the temperature of the tapping liquid steel is controlled to be 1,590 to 1,610 DEG C, the casting temperature is controlled to be 1,560 to 1,580 DEG C, the quenching temperature for the thermal refining of casting is controlled to be 850 to 890 DEG C, and the temper temperature is controlled to be 530 to 590 DEG C. the test indicates that the failure load of the manufactured high-strength cast steel is larger than or equal to 950 MPa, the tensile strength is larger than or equal to 800 MPa, the percentage elongation after fracture is larger than or equal to 10 percent, the reduction of cross section is larger than or equal to 24 percent, and the work done by impact is larger than or equal to 20 J, so the high-strength cast steel can completely meet the requirement on the material of the draft gear for the heavy load transportation of the railway.