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1693 results about "Vacuum furnace" patented technology

A vacuum furnace is a type of furnace in which the product in the furnace is surrounded by a vacuum during processing. The absence of air or other gases prevents oxidation, heat loss from the product through convection, and removes a source of contamination. This enables the furnace to heat materials (typically metals and ceramics) to temperatures as high as 3,000 °C (5,432 °F) with select materials. Maximum furnace temperatures and vacuum levels depend on melting points and vapor pressures of heated materials. Vacuum furnaces are used to carry out processes such as annealing, brazing, sintering and heat treatment with high consistency and low contamination.

Preparation method for silicon carbide ceramic tube or rod

The invention relates to a preparation method for a silicon carbide ceramic tube or rod. An extrusion moulding method is adopted to form a blank body; a normal pressure sintering method is adopted for sintering; and submicron level silicon carbide powder and additives are taken as main raw materials. The preparation method comprises the following steps: 1) carrying out ball milling on the main raw materials by a dry method, adding water, a dispersant, a plasticizer, a lubricant and a liquid state binder, and then carrying out ball milling by a wet method; 2) adopting a spray granulation process to granulate silicon carbide slurry; 3) extruding the blank body by a one-shot direct extrusion moulding method after vacuum pug, corrosion, and vacuum pug; 4) drying the molded blank body by a stage drying mechanism; and 5) placing the blank body of the silicon carbide ceramic tube or rod in a vacuum furnace and carrying out sintering for two times by taking argon gas as protective gas. The high temperature resisting strength and the corrosion resistance of the silicon carbide ceramic tube or rod prepared by the method are both better than those of a reactive sintered product. Compared with a hot press sintering method, the method has lower limit on the product shape and size, and lower cost. The method is suitable for the industrialized production.
Owner:宁波欧翔精细陶瓷技术有限公司

Process for manufacturing low-silicon low-carbon deep punching/drawing steel

The invention discloses a production method of low-silicon and low-carbon deep punching/drawing steel, bottom-blowing argon is performed in the whole process of converter smelting, and a single slag/double slag technique is adopted to pour out the dephosphorized slag, high-basicity slag is produced in later period, the dualistic basicity of final slag R is more than 3.5, the terminal temperature of molten steel is 1620 DEG C to 1650 DEG C, and tapping ( P ) is less than 0.012 percent. The molten steel is refined by adopting low-silicon and low-carbon high-basicity reductive slag in a LF furnace refining station, thus to manufacture reductive slag for desulphurisation, and the ( Al ) in the molten steel is less than 0.005 percent. The molten steel refined by the LF furnace is vacuum-treated by a RH vacuum furnace, the carbon and the silicon in the molten steel is circularly removed, the molten steel is continuously casted into a casting blank through a CSP sheet bar conticaster, the casting blank is sent into CSP sheet bar heat continuous rolling mill and rolled into a coiled sheet after being heated in a roller hearth soaking furnace, a hot rolled coiled sheet is coldrolled into cold rolled coiled sheet through a cold tandem mill or a single mill after being acidwashed, and leveled through a leveling machine after being annealed by a cover furnace, and a leveling divided coil is stretched and divided. The production method has the advantages that the production cost of the working procedure is saved, the consumption of the refractory consumption of the converter is reduced, the equipment investment is saved, the process of the production technique is steady and smooth, the n value of the cold rolled plate is bigger than 0.23, the r value thereof is bigger than 2.1, and the deep punching performance and the extensibility are good.
Owner:湖南华菱涟钢特种新材料有限公司 +1

Preparation method of silicon carbide fiber reinforced silicon carbide composite material

The invention discloses a preparation method of a silicon carbide fiber reinforced silicon carbide composite material. The preparation method comprises the following steps of preparing a SiC fiber knitted piece, placing the SiC fiber knitted piece into a vacuum furnace to carry out chemical vapor deposition through adopting methane or propylene as feed gas and a pressure difference method to deposit a carbon coating on the surface of the SiC fiber knitted piece, carrying out a vacuum impregnation process on the SiC fiber knitted piece deposited with the carbon coating through adopting a liquid SiC ceramic precursor as impregnation liquid, putting the impregnated SiC fiber knitted piece into a mold, carrying out thermal molding crosslinking in a dynamic nitrogen atmosphere, putting the crosslinked SiC fiber knitted piece into a cracking furnace to carry out high temperature cracking in a dynamic nitrogen atmosphere, repeating a vacuum impregnation-thermal molding crosslinking-high temperature cracking cycle so as to finish preparation until the weight increment of a sample obtained after the vacuum impregnation-thermal molding crosslinking-high temperature cracking cycle is less than 1% of the weight increment of the sample obtained after the previous cycle. The preparation method has the advantages of short period, low cost, low pollution and toxic effects, etc.
Owner:NAT UNIV OF DEFENSE TECH

Grain boundary diffusion method for improving properties of sintered NdFeB magnets

The invention relates to a grain boundary diffusion method for improving properties of sintered NdFeB magnets. The grain boundary diffusion method comprises the following steps of stacking sintered NdFeB magnets and diffusion alloy sheets together and placing in a hot-pressing furnace; vacuumizing the hot-pressing furnace until the vacuum degree reaches a set value, heating the hot-pressing furnace, and when the temperature of the hot-pressing furnace reaches a set value, beginning to exert a pressure and maintaining the pressure and putting the diffused sample into a high-vacuum furnace for annealing, wherein the diffusion alloy sheets are low-melting-point eutectic diffusion alloys and are represented by R-TM, R is one or more of Sc, Y, La, Ce, Pr or Nd and TM is one or more of Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn. Compared with the prior art, the sintered NdFeB magnets modified by the pressure diffusion method, which is provided by the invention, have the advantages of large diffusion depth of a diffusion agent, uniform distribution of grain boundary phases, high coercivity and the like, especially, low-melting-point diffusion alloys designed by the invention are free of expensive heavy rare earth element dysprosium and thus the cost of the raw materials is relatively low, the diffusion temperature is low and the energy consumption in the diffusion process is small.
Owner:SHANGHAI JIAO TONG UNIV

High-temperature fused salt synchrotron radiation in-situ research device

InactiveCN102590253AEliminate phenomena that introduce artifactsExpand the detection angleMaterial analysis using wave/particle radiationFluorescenceIonization chamber
The invention discloses a high-temperature synchrotron radiation in-situ research device. The high-temperature fused salt synchrotron radiation in-situ research device comprises a fused salt test tube, a vacuum furnace, a heating device, a first ionization chamber, a second ionization chamber or a charge coupled device (CCD) detector and an external fluorescence detector, wherein a cavity is formed in the vacuum furnace; an incident window, a transmission window and a fluorescence window are arranged on the furnace wall of the vacuum furnace; the incident window and the transmission window are arranged coaxially and collinearly; the axial line of the fluorescence window is vertical to that of the incident window and/or the transmission window; the heating device is arranged in the cavity of the vacuum furnace and is used for heating the fused salt test tube arranged in the heating device; an incident hole, a transmission hole and a fluorescence hole corresponding to the incident window, the transmission window and the fluorescence window respectively are formed on the heating device; the first ionization chamber corresponding to the incident window is arranged outside the vacuum furnace; the second ionization chamber or the CCD detector corresponding to the transmission window is arranged outside the vacuum furnace; and the external fluorescence detector corresponding to the fluorescence window is arranged outside the vacuum furnace.
Owner:SHANGHAI INST OF APPLIED PHYSICS - CHINESE ACAD OF SCI

Method for preparing magnesium metal and by-product by vacuum carbothermic reduction with serpentine minerals

InactiveCN101560603AHigh in magnesiumNo need for calcination to remove carbonProcess efficiency improvementMagnetic separationSlagMassicot
The invention discloses a method for preparing a magnesium metal and a by-product by vacuum carbothermic reduction with serpentine minerals. The method comprises the following steps: using serpentine mineral powder as a raw material; adding a carbonaceous reducing agent which is 1 to 2 times of the theoretical quantity of carbon required for completely reducing magnesium silicate in the serpentine; adding a catalyst, and mixing the materials evenly to obtain a mixed raw material; pressing the mixed raw material into spherical or blocky ball agglomerations and drying the ball agglomerations; putting the dried ball agglomerations into a vacuum furnace, controlling the vacuum degree in the furnace to between 10 and 500 Pa, raising the temperature to between 500 and 700 DEG C, and keeping the temperature for 20 to 60 minutes to remove crystal water and clinker the materials; keeping the vacuum degree in the furnace, raising the temperature to between 1,200 and 1,500 DEG C, and reducing the magnesium silicate and oxides of metallic iron and nickel at a constant temperature for 30 to 60 minutes; and condensing magnesium vapor obtained from the reduction on a magnesium condenser into crystallized magnesium, recycling the metallic iron and the metallic nickel in the slag through magnetic separation, and preparing the slag after the magnetic separation into industrial silicon carbide through decarburization and purification.
Owner:北京华夏建龙矿业科技有限公司

Method for separating tin from tin-lead-stibium-arsenic alloy by vacuum distillation

The invention relates to a method for separating tin from tin-lead-stibium-arsenic alloy by vacuum distillation, belonging to the technical field of vacuum metallurgy of non-ferrous metals. The method comprises the following steps: melting the tin-lead-stibium-arsenic alloy to obtain tin-lead-stibium-arsenic alloy liquid at first; and continuously and uniformly feeding the obtained tin-lead-stibium-arsenic alloy liquid into a continuous vacuum furnace by adopting a constant-current feeding method to carry out vacuum distillation so as to obtain residues, namely crude tin or tin-lead-stibium alloy and tin-lead-stibium-arsenic metal vapor entering a condenser, and controlling the temperature of the condenser and the condensation section number according to the concentration of tin vapor in the tin-lead-stibium-arsenic metal vapor, thereby obtaining tin-lead-stibium alloy, lead-stibium alloy and crude arsenic. According to the method, a tin-lead-stibium-arsenic alloy raw material is directly separated by adopting the continuous vacuum furnace; the universality to raw materials is higher; the lead-stibium alloy with the tin content less than 0.2wt%, the crude tin with the tin content above 98wt% and crude arsenic with the arsenic content above 90wt% can be obtained; and therefore, high-efficiency separation of the tin-lead-stibium-arsenic alloy is realized.
Owner:KUNMING DIBOO TECH

Biomedical beta-titanium alloy material and preparation method thereof

The invention relates to a biomedical beta-titanium alloy material with low elastic modulus. The preparation method for the material comprises the steps of raw material preparation, raw material smelting, cogging, forging and the like, namely the method comprises the following steps: preparing a raw material alloy of Nb, Zr, Sn, Ta, Mo and Ti according to a certain proportion, mechanically stirring and mixing the alloy, then pressing the alloy on a hydraulic press to form electrodes, and later smelting the electrodes in a vacuum consumable electro-arc furnace to obtain cast ingots of the beta-titanium alloy material; taking out the cast ingots with certain diameter, heating the cast ingots in a vacuum furnace and then preserving the heat, upsetting and drawing out the heated cast ingots on the hydraulic press or a forging device, and repeating the step twice to thrice to obtain a forging stock of the beta-titanium alloy material; heating the forging stock in the vacuum furnace and then preserving the heat, drawing out the heated forging stock on the hydraulic press or the forging device to obtain the biomedical beta-titanium alloy material with the elastic modulus E of 50 to 80GPa. The alloy has the characteristic of low elastic modulus, has good combination properties such as tensile strength, yield strength, corrosion resistance and the like, and does not contain toxic elements to human body.
Owner:UNIV OF SHANGHAI FOR SCI & TECH

Method and device for preparing uniform solidified particles by orifice injection

The invention relates to a method and a device for preparing uniform solidified particles by orifice injection, which belong to the technical field of high-melting-point micro-particles and particularly relates to a method for preparing uniform solidified particles by orifice injection. The method comprises the following steps of: smelting a raw material in a crucible with a central hole by using a heater; inputting a pulse signal with a certain waveform to piezoelectric ceramics; driving a piston rod to move downwards and extrude a melt by the piezoelectric ceramics; injecting the melt from an orifice of a bolt with an injection orifice to form liquid drops; and freezing the liquid drops in an annular descending pipe to form the uniform solidified particles. A vacuum furnace and a collecting cabin in the device are fixedly connected with each other through a left bracket and a right bracket; the vacuum furnace is communicated with the middle of the collecting cabin through the annular descending pipe; and the vacuum furnace consists of a furnace body and a furnace door. Various micro-particle materials which have uniform sizes, accordant textures, high sphericity and controllable sizes and meet requirements can be prepared skillfully for materials with different high melting points. The method has the advantages of high efficiency, simple device and energy conservation.
Owner:DALIAN UNIV OF TECH

Preparation method of normal pressure-sintered silicon carbide ceramics

The invention discloses a preparation method of normal pressure-sintered silicon carbide ceramics, which adopts a solid normal pressure sintering method and takes submicro silicon carbide powder, graphite powder and boron carbide powder as main materials. The method comprises the following steps: 1) material grinding is carried out by adopting a staged ball milling mode, firstly, the main raw materials are ball-milled by adding water under the environment of the pH value being 10-12 to lead the agglomerated silicon carbide micro powder and other main raw materials to be evenly dispersed; then a plasticiser, a lubricant and water soluble phenol resin are added and ball-milled for a period of time; and finally a caking agent is added for ball milling; 2) spray granulation technology is adopted for carrying out granulation on the silicon carbide slurry; (3) the materials after granulation are maintained under constant temperature and humidity; (4) double-sided compression moulding is carried out on the maintained materials; (5) a staged drying mechanism is adopted for drying the molded body; and (6) the silicon carbide body is put in a vacuum firing furnace for being subjected to two times of sintering by taking the argon as protective gas. The silicon carbide ceramics prepared by the method have superior performance, corrosion resistance and long service life, and are applicable to commercial process.
Owner:宁波欧翔精细陶瓷技术有限公司

Preparation technology of TC17 titanium alloy wire

ActiveCN102451862ASolve the problem that cannot meet the current requirements of titanium alloy wire for aerospaceWire rodTitanium alloy
The invention discloses a preparation technology of a TC17 titanium alloy wire. The preparation technology is characterized by comprising the following steps of: rolling the TC17 titanium alloy into a disk with specification of (Phi)12mm; performing three times of grinding on the (Phi)12mm disk; after the grinding and when the total working rate reaches 30%, performing heat treatment and stress relief annealing in an electric furnace or a vacuum furnace; when the diameter of the wire is greater than or equal to (Phi)10mm, controlling the stretching temperature at 780+/20 DEG C; when the diameter of the wire is less than (Phi)10mm, controlling the stretching temperature at 730+/-20 DEG C; repeatedly performing annealing-stretching-grinding-annealing of the wire after the heat treatment until the diameter of the wire is greater than or equal to (Phi)5.5mm, and performing vacuum heat treatment; before obtaining the finished product and after performing the vacuum heat treatment, removing the lubricant and scale impurity layer on the material surface by use of a round-blade mould with 0-5 degrees of internal and external taper angles according to the diameter of the finished product, stretching to obtain a bright wire with diameter of less than or equal to (Phi)5.0mm, and checking the finished product; and if the finished product is qualified, delivering as the finished product. The preparation technology disclosed by the invention makes up for the shortcoming that the TC17 titanium alloy wire cannot be produced domestically.
Owner:SHENYANG HANRUIDA TITANIUM
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