40results about How to "Reduce the number of inclusions" patented technology

The invention relates to a method for removing non-metallic inclusion in molten steel. The method comprises the following steps that: (1) a ladle filled with the molten steel is hoisted onto a slewing table, argon is blown through an argon blowing hole to stir, and the blowing argon is stopped after 2 minutes at most; (2) one or a plurality of amplitude varying poles are dipped into the molten steel, and an ultrasonic generator is started; (3) after the ultrasonic generator is started for one minute at most, the ultrasonic generator is shut off, and the amplitude varying poles are immediatelydisengaged from the molten steel and are returned to the standby position. The method for removing the non-metallic inclusion in the molten steel can further reduce the inclusion quantity in the molten steel, and can produce the molten steel with adequate small inclusion quantity or adequate small inclusion size, thereby achieving the production requirement of high purity steel.

The invention discloses a method for preparing high-performance high-alumina silicon steel, which belongs to the technical field of powder metallurgy. The invention uses gas-atomized ferrosilicon powder, aluminum powder and ferrophosphorus powder as raw materials, obtains Fe-Si-Al-P mixed powder after full ball milling and mixing, and forms a green thin plate by powder rolling after vacuum annealing , through high-temperature sintering to make it metallurgically bonded, multi-pass hot-rolled to a certain thickness, then cold-rolled 2‑5 times, and finally high-temperature annealed to obtain high-alumina silicon steel sheets with excellent properties. The present invention introduces Al and P elements into the Fe-Si system, which can effectively improve the soft magnetic performance parameters of the material, and use the Al powder with good ductility to improve the formability of the system, ensure powder rolling forming, and have the advantages of operation Simple, high production efficiency, high product precision, no pollution and inclusions, excellent performance and other advantages.

The invention discloses a novel composite modifier for austenitic manganese steel, comprising rare earth alloy, ferrotitanium, calcium silicon and aluminum, wherein the dosage of the Re-containing rare earth alloy accounts for 0.20-0.25 percent of the weight of molten steel; the dosage of the ferrotitanium accounts for 0.02-0.03 percent of the weight of the molten steel; the dosage of the calciumsilicon accounts for 0.20-0.25 percent of the weight of the molten steel; and the dosage of the aluminum accounts for 0.15-0.20 percent of the weight of the molten steel. Treatment inside a furnace is carried out in the alloying adjustment stage for the composition of the molten steel after ferromanganese is added for the fine adjustment of the manganese content of the molten steel; one third of the rare earth alloy is added to a molten pool, and the aluminum is added before the tapping of the molten steel. Treatment outside the furnace is to add the calcium silicon, two thirds of the rare earth alloy and the ferrotitanium to a steel ladle. The adoption of the Re-Ca-Ti-Al multi-element composite modifier prolongs the effective time of the modification process of the molten steel and guarantees good modification effect.

The invention relates to a rolling preheating process for controlling the sizes of titanium inclusions in a hypereutectoid tire cord steel wire rod. The technical scheme of the rolling preheating process is characterized by comprising the following steps of: heating a hypereutectoid tire cord steel continuous casting blank to 1150-1250 DEG C in a steel rolling heating furnace, wherein the heating time is 2-6 hours, the titanium inclusion (TiN or Ti(C,N)) in the casting blank is decomposed (namely solid dissolving) in the heating process, small inclusions disappear, and the sizes of the larger-size titanium inclusions are reduced; cooling the high-temperature-heated hypereutectoid tire cord steel continuous casting blank to the normal rolling temperature of hypereutectoid tire cord steel in a water mist cooling or air mist cooling manner; and carrying out rolling by utilizing a high-speed rolling mill. According to the rolling preheating process for controlling the sizes of the titanium inclusions in the hypereutectoid tire cord steel wire rod, the titanium inclusions in the super-strength hypereutectoid tire cord steel wire rod are diffused and distributed, and the number and the sizes of the titanium inclusions in casting blank are effectively controlled. The rolling preheating process has the characteristics that the titanium inclusions are small in number and sizes and are diffused and distributed, and the process is reliable; and according to the rolling preheating process, the penalty point rate of the titanium inclusions of the hypereutectoid tire cord steel wire rod can be effectively reduced.

The invention provides a method for smelting alloyed oriented silicon steel in a RH furnace. The method includes the steps that converter smelting and tapping are conducted, slag is blocked when converter tapping is finished, and RH refining is conducted; after circulating decarburization is conducted for 3 minutes to 5 minutes, aluminum balls and bauxite are added for deoxidization and slag formation, and when the aluminum balls and the bauxite stop being added, circulation is further conducted for 2 minutes to 3 minutes, and alloying is conducted; and casting is conducted, blanks are formed, and later working procedures are conducted. According to the method, on the one hand, due to the fact that RH refining is conducted, alloying is conducted after residual carbon in molten steel is deoxidized, the number of generated oxide inclusions can be reduced, the total oxygen content in the steel is kept below 15 ppm, the alloy oxidation loss is reduced as well, and the contents of harmful elements such as Nb, V and Ti remaining in the steel are all kept below 20 ppm, and magnetic performance is excellent. Furthermore, due to the fact that decarburization can be conducted in the RH furnace, no converter low-carbon high-oxygen tapping is needed, and corrosion to a converter lining caused by oxygen blast can be relieved remarkably.

The invention discloses a method for controlling inclusion in ultra-low carbon steel based on a straight cylinder type vacuum refining device. The method comprises the following steps that a steel ladle is conveyed to a straight cylinder type vacuum refining station and jacked; a dipping pipe is inserted below the liquid level of molten steel by 50 mm, an argon blowing nozzle, on the same side asa steel ladle eccentric bottom blowing nozzle, of the semi-circumference of the wall of the dipping pipe is adjusted to blow argon strongly, and an argon blowing nozzle on the different size is adjusted to blow argon weakly; the dipping pipe is inserted below the liquid level of the molten steel by 200 mm, and the steel ladle is opened for eccentric bottom argon blowing; the dipping pipe is inserted below the liquid level of the molten steel by 400-500 mm, and rapidly pumped to the limit vacuum degree; the argon blowing flow is adjusted slightly until top slag is pushed to the weak blowing side of the wall of the dipping pipe to the minimum area; after decarbonization treatment is carried out, a molten steel sample is taken for oxygen fixation, then molten steel deoxidization treatment iscarried out, and CaO / Al2O3 in a top slag system is controlled to be equal to 1.2-2.0; and after air breaking, the steel ladle is opened. According to the method, Al2O3 inclusion generated by deep deoxidization is transformed into calcium aluminate low-melting-point inclusion, the amount of the Al2O3 inclusion in the continuous casting molten steel is reduced, thus the adhesion amount of the Al2O3inclusion on the wall of a water opening in the process of the molten steel poured into a crystallizer by passing through a tundish water opening is reduced, and occurrence of flow accumulation of thewater opening is avoided.

A method for controlling oxide inclusions in ultra-low carbon steel produced by LD-RH process, which includes adding lime 2.0-3.5kg / t steel in the early tapping stage of LD converter, and adding 0.5-1.2kg / t Al-based modifier at the end of tapping Steel; then enter the RH furnace for vacuum decarburization; decarburization is completed, deoxidation, adding refining agent 0.3-2kg / t steel, the composition of the refining agent is: CaO: 50-60wt%, Al 2 o 3 : 30~40wt%, MgO: 2~6wt%, SiO 2 ≤3wt%, TiO 2 <0.08wt%, FeO≤1wt%, H 2 O≤0.5wt%; alloying; circulation of molten steel for 3‑12 minutes, and the vacuum refining process ends. The method greatly reduces the amount of oxide inclusions in the slab and the oxygen content of the finished product, reduces the blocking rate of cold rolling, and significantly improves the quality of ultra-low carbon steel products.

A heavy rail steel converter smelting method that can reduce the oxygen content during tapping: the first 350s of converter smelting is the initial smelting period. Two batches are added; from the end of the initial period to 750s is the mid-smelting period, during which the oxygen lance position is still kept at 1.6-1.7m for continuous oxygen blowing, and lime and iron ore are added in sequence when the smelting reaches 450s; The end of the mid-term to 900s is the final stage of smelting. During this period, the position of the oxygen lance is still kept at 1.6-1.7m for continuous oxygen blowing, and lime and lightly burned dolomite are added in sequence. The present invention solves the unstable factors caused by the dynamic control of the lance position and empirical operation by keeping the oxygen lance position fixed; while ensuring effective dephosphorization, the oxygen content at the end of the converter blowing can be kept below 120PPm, thereby enabling Reduce the amount of carburizer by 40% to 60%, and reduce the amount of deoxidized alloy by 10% to 20%, thereby reducing the inclusion of endogenous oxides in the steel and improving the service life and safety of the rail.

The invention relates to the technical field of steelmaking, in particular to a method for deoxidizing low-silicon steel using silicon alloys. In the production process route of converter-RH vacuum refining-slab continuous casting, add Silicon alloy is used as a deoxidizer to remove the excess oxygen in the ultra-low carbon steel in the converter area and the excess oxygen after RH decarburization. The specific implementation steps are as follows: 1) The converter process requires boiling tapping, and ferrosilicon is added during the tapping process for deoxidation; 2) During RH treatment, ferrosilicon is used for pre-deoxidation; 3) After RH decarburization, aluminum is added for final deoxidation. The critical oxygen content can be calculated as 0.045%, and the composition is adjusted. Compared with the prior art, the beneficial effect of the present invention is that the silicon alloy (ferrosilicon) is used to remove excess oxygen, the silicon content of molten steel can be controlled below 0.030%, and the Al in the slab can be reduced while achieving the same deoxidation effect. 2 o 3 Increase the number of inclusions while reducing the cost of deoxidized alloys.

The invention relates to an aluminum alloy welding wire for a high speed train and a preparation method of the aluminum alloy welding wire for the high speed train. The aluminum alloy welding wire for the high speed train is characterized by comprising the following chemical components in percentages by mass: 4.0-6.5% of Mg, 0.06-0.2% of Ti, 0.1-0.3% of Cr, 0.05-0.2% of Mn, 0.05-0.2% of La, 0.05-0.2% of Te, 0.01-0.05% of Bi, less than or equal to 0.25% of Si, less than or equal to 0.2% of Fe, less than or equal to 0.20% of Zn, less than or equal to 0.05% of single content of other impurity elements, less than or equal to 0.15% of total content of other impurity elements and the balance of Al. The preparation method of the aluminum alloy welding wire for the high speed train comprises the following steps: smelting, refining, casting, homogenization, extrusion, drawing, and surface treatment. The aluminum alloy welding wire for the high speed train provided by the invention is fine in weld microstructure and good in crack resistance; the tensile strength, the plasticity and the toughness of welded joints are remarkably higher than those of common ER5356 and ER5183 welding wires.

The invention provides a method for smelting nanoparticle dispersion strengthened steel, comprising the following steps: S100: placing the material to be smelted in a smelting container, and then placing the smelting container in a magnetic levitation furnace for smelting treatment to obtain molten steel, In the smelting process, the temperature of the magnetic levitation furnace is above 1500°C, and the smelting time is greater than or equal to 0.5 minutes; wherein the material to be smelted contains large particle inclusions, and the material to be smelted contains titanium; S200: The nano particle dispersion strengthened steel can be obtained by cooling the molten steel. The invention realizes the use of a smelting method to obtain nanoscale (10nm) particle dispersion-strengthened super steel, and provides a new feasible process for the industrial-scale mass production of oxide dispersion-strengthened steel (ODS), which can greatly improve the strength of ODS steel Improve production efficiency and reduce the production cost of ODS steel.

The invention discloses a method for reducing segregation in the pouring process of continuous casting billets for gears, which comprises the following steps: before the end of LF refining, the temperature of molten steel is raised until the superheat of continuous casting molten steel is 20-30°C, and continuous casting of 150×150mm billets The first cooling and the second cooling use a large amount of water, and the proportion of water in the foot roll section reaches 40%. Turn off the electromagnetic stirring of the crystallizer, use a lower current for the electromagnetic stirring at the end, and use a casting speed of 2.00m / min. The present invention avoids excessive stirring in the mold during pouring of molten steel by not using electromagnetic stirring of the crystallizer, resulting in slag entanglement affecting the purity of molten steel, increasing the amount of cooling water, improving the cooling intensity, reducing the casting speed, and fully cooling the slab to achieve the promotion of columnar The effect of crystal growth and reduction of central equiaxed crystal ratio can avoid the accumulation of solute elements to the intergranular and center, reduce the segregation of slab elements, and enable the gear to be used on the diagonal of the continuous casting billet from the surface to the 3 / 8 diagonal. The carbon range is controlled within 0.015%, and the central carbon segregation index is within 1.05, which improves the stability of steel performance.