73results about How to "Reduce macro segregation" patented technology

The invention discloses an electromagnetic semicontinuous casting device and a casting method thereof. The electromagnetic semicontinuous casting device comprises a crucible smelting furnace, a crucible standing furnace, a flow control mechanism, a split-flow device, an electromagnetic crystallizer system and a vertical semicontinuous casting machine, wherein the electromagnetic crystallizer system is a metal inner sleeve crystallizer system in which a group of build-in excitation coil is fixed, and comprises a metal inner sleeve, a cooling water cavity, the excitation coil, an oil supply system, an oil distribution system and a protective gas ring. According to the electromagnetic semicontinuous casting device disclosed by the invention, through a method of adjusting the frequency of electrical current, duty ratio and average current strength, the electrical current in a unique wave shape is formed in the single excitation coil placed in the cooling cavity of a crystallizer, so that desired forced convection or shaking effect is formed in the crystallizer with low current intensity; the grain of ingot blank is significantly refined; and columnar crystals are significantly reduced or eliminated to lower macroscopic segregation and realize the technical effect of low-stress casting. Under the condition of similar functional effects, the size of the electromagnetic crystallizer system is one third to one half of that of an original electromagnetic crystallizer system.

The present disclosure relates to electroslag remelting methods and apparatus for producing metallic ingots, as well as to articles of manufacture made from materials processed according to the methods and/or using the apparatus. One such method includes disposing slag within a withdrawal mold comprising a mold wall and an electrically conductive member disposed through the mold wall, contacting the slag with a consumable electrode, and heating the slag by conducting an electrical current through the consumable electrode into the slag, thereby melting at least a portion of the consumable electrode in contact with the slag. At least a fraction of the melted portion of the consumable electrode is collected in the withdrawal mold to form the ingot. At least a portion of the electrical current is conducted form the slag through the electrically conductive member.

The invention relates to a method for determining the steel belt feeding process parameter of a crystallizer in the thick slab continuous casting process. The method comprises the steps the work condition parameter of the crystallizer in the thick slab continuous casting process is collected, and the feeding quantity of a cold steel belt is determined through the work condition parameter of the crystallizer in the thick slab continuous casting process based on the liquidus congruent melting and phase change heat transfer theory; a continuous casting slab-cold steel belt system phase change heat transfer theoretical model is built through a generalized enthalpy method, namely, a relation model among the melting time and feeding thickness of the cold steel belt, the superheat degree of casting molten steel and the initial temperature of the cold steel belt; the section size and feeding speed of the cold steel belt are determined through the continuous casting slab-cold steel belt system phase change heat transfer theoretical model according to the feeding quantity and melting time of the cold steel belt and the depth of a solidified liquid core; and the cold steel belt with the determined section size and feeding speed is preheated and fed into molten steel in the crystallizer through the position between a water opening and a narrow face of the thick slab crystallizer parallel to the wide face of the crystallizer in a low-amplitude high-vibration manner.

The invention discloses a preparation method of a TiCu50 master alloy material by vacuum consumable arc melting, which mainly comprises the following steps: (1) mixing raw materials: according to theweight percentage content, the percentage contents of raw material are: Cu 50%, and TiO 50%, the required raw materials are weighted according to the proportion, and the raw materials are mixed in a mixer; (2) pressing: the mixed powder is loaded into a rubber sleeve and is subjected to mechanical vibration, rolling and reverse material mounding, and then the cold isostatic pressing method is adopted to press the mixed powder, and then the pressure-keeping treatment is carried out; (3) sintering: the pressed consumable electrode is loaded into a vacuum sintering furnace for sintering, and thesintering temperature, the holding time and the vacuum degree are controlled; Step (4) smelting: the sintered consumable electrode is charged into a vacuum consumable arc smelting furnace for smelting. The TiCu50 master alloy material prepared by the invention has low gas content and less impurities, and is uniform in composition, and has no macroscopic and microscopic defects such as enrichment of Cu and Ti.

The invention belongs to the field of light alloy machining, and particularly relates to a variable frequency ultrasonic semi-continuous casting method for magnesium alloy. The method comprises the steps of alloy smelting, melt delivery and consolidation forming under ultrasonic treatment. Magnesium alloy melt is treated in a real-time variable frequency ultrasonic field introduced in the semi-continuous casting process, and the quasi real-time tracking of the resonant frequency of metal melt is achieved; and liquid cave melt is subjected to the ultrasonic resonance treatment continuously in the whole semi-continuous casting process, so that the continuous ultrasonic high-efficiency treatment of the magnesium alloy melt is achieved in the solidification process. In the method provided by the invention, an ultrasonic radiation rod is extended into the magnesium alloy melt in the magnesium alloy semi-continuous casting process, so that the cavitation effect and acoustic streaming effect produced by the variable frequency ultrasonic field directly act on the magnesium alloy melt solidifying. With the method provided by the invention, the magnesium alloy solidification behavior can be changed obviously, the structure is refined, and the uniformity of the billet solidification structure as well as the mechanical property of magnesium alloy billets are improved; and the billet casting defects are reduced obviously, and the quality of the magnesium alloy billets is improved greatly.

The invention discloses a method for high purification preparation for nickel-base superalloy through an electron beam coating induced solidification technology. The method comprises the following steps of 1, raw material preparing, 2, preparing before smelting, and 3, electron beam coating smelting. Nickel-base superalloy cast ingots are prepared by adopting the method, and macrosegregation of the cast ingots is reduced; under the electron beam induced solidification technology, the degree of purity and the metallurgical quality of the cast ingots are improved by a large margin; and engineering preparation of the large-scale cast ingots can be achieved, and the yield of primary product is improved from being less than 70% of a traditional technology to being above 85%.

The invention discloses a method and device for homogenizing a large ingot solidification structure by combining a static magnetic field with a rotating magnetic field. Through the electromagnetic oscillation effect generated by a combined magnetic field and the rotational flow induction stirring effect of the rotating magnetic field, nucleation is promoted, dendritic crystal tips are crushed, crystal grains are refined, the solidification structure is homogenized, macroscopic segregation is reduced, and therefore the method and the device are used for the large ingot casting process. When metal melt is solidified, the static magnetic field and the rotating magnetic field are exerted to a heat preservation riser in a combined mode according to the characteristics that metal liquid at an ingot mould riser is solidified lastly, the riser wall and the metal liquid surface are easy to nucleate first, and the rotating magnetic field and the static magnetic field can easily permeate a riser material, the metal liquid in the heat preservation riser is effectively oscillated and stirred, and the metal liquid in the riser is delivered into the metal liquid at the center of an ingot mould through oscillating and rotational flow stirring; the dendritic crystal tips are crushed, the crystal grains are refined, the solidification structure is homogenized, macroscopic segregation is reduced, a compact, homogenized and crystal grain-refined large ingot is obtained, and therefore the subsequent machining performance and service performance of the large ingot are improved.

The invention discloses a discrete casting method for preparing a homogenized ingot, which comprises the following steps: step 1, numerically simulating the discrete pouring process, obtaining the relationship between the solid phase ratio and solidification time in the solidification process as the numerical simulation result; step 2, After smelting, degassing, and slag removal of the molten metal, the alloy liquid is obtained and ready for casting; step 3, adopt the top pouring casting method, use the alloy liquid to cast to a predetermined thickness, and stop pouring; step 4, track and measure the temperature in real time, refer to step 1 According to the numerical simulation results, when the solid phase ratio of the poured metal liquid reaches 70%-80%, the next casting is carried out; step 5, repeat steps 3 and 4 until the casting and solidification of the ingot is completed; step 6, heat treat the ingot To eliminate casting stress. Compared with the ordinary casting process, in the discrete casting method of the present invention, more metal surfaces are in contact with the environment, and the cooling rate is faster, which is helpful for grain refinement.

The method of applying electric field energy on molten steel to improve quality of silicon steel billet is to introduce electric field energy with the electric field energy generator and the electrodes into molten steel, the electric field energy waveform is duty ratio variable square wave of energy 1000 J-180 MJ, voltage 100-1800V, current 100A-8KA, frequency not higher than 25 Hz and duty ratio of 5-90 %. The electric field energy generator is suitable for use in industrial production and controllable in electric field energy parameters. The treated molten steel results in refined billet structure with obviously increased global crystal, less defaults and high quality.

The invention provides an indium gallium antimonide crystal growing furnace with a traveling wave magnetic field. The indium gallium antimonide crystal growing furnace comprises a magnetic field generation mechanism, a vertical lifting mechanism and a furnace body supporting mechanism. The magnetic field generation mechanism is composed of an iron core, a three-phase conduction insulated wire, andan insulated protective shell; the three-phase conduction insulated wire is connected to a power supply; the power supply generates electric current, and the electric current generates a travelling wave magnetic field in a horizontal coil. By applying a travelling wave magnetic field in the crystal growing furnace, when the direction of the lorentz force caused by the travelling wave magnetic field is downward, the melted material of indium gallium antimonide in a crucible is conveyed under the action of the lorentz force so that the convection process of the melted material can be accelerated and cold and hot area distribution in a furnace hearth can be more uniform. Meanwhile, a rectangular wave current generator is used for periodically controlling phase displacement signals of the three-phase current in the coil, so that uniform distribution of the melted material is facilitated, macrosegregation is obviously weakened, and indium gallium antimonide crystal ingots with lower dislocation and better crystal quality are obtained.

The invention discloses a device and method for preparing large cast ingot through slag protection based multi-layer casting magnetic field current compound treatment. The device comprises a steel ingot mould, a dead head, a slag ladle and a tundish, wherein movable type parallel electrodes and a movable type magnetic field coil are further separately arranged on the upper part of the steel ingotmould; during casting, amount of needed molten steel is firstly determined according to the specification of the large cast ingot, and the amount of the molten steel is divided into a plurality of parts according to the property of easily segregating elements in the molten steel; content of elements which are easily segregated in each part is regulated, so that casting powder is added before the first part of the molten steel is cast, tapping in a slag layer is guaranteed, and impurities are adsorbed; under action of magnetic fields and/or current, the next part of the molten steel is added while the first part of the molten steel is gradually solidified till a molten pool is relatively small, and protective slag is supplemented till all of the molten steel is cast to prepare the cast ingot. The casting method disclosed by the invention can purify the molten steel, relieves and even eliminates gross segregation, and alleviates shrinkage cavity and porosity.

The invention discloses a method for preparing a copper and stainless steel in-situ composite material through vacuum consumable arc melting. The method comprises the following steps that S1, raw materials are prepared, wherein 2 wt%-98 wt% of electrolytic copper powder and 98 wt%-2 wt% of gas atomization stainless steel powder are prepared; s2, raw material mixing, wherein the electrolytic copper powder and the gas atomization stainless steel powder are weighed according to the proportion and stirred and mixed in a mixer; s3, heading powder: filling the mixture into a rubber sleeve for heading powder; s4, pressing is conducted, specifically, the rubber sleeve subjected to powder upsetting is put into a cold isostatic press to be pressed into a blank; s5, sintering: putting the pressed green body into a vacuum sintering furnace for sintering; and S6, smelting is conducted, specifically, the sintered blank serves as a consumable electrode and is put into a vacuum consumable arc smelting furnace to be smelted. The copper stainless steel in-situ composite material prepared through the method is uniform in element distribution, less in macrosegregation, free of macroscopic and microcosmic defects such as element enrichment and good in structure uniformity.