37results about How to "Repressive" patented technology

The invention relates to a preparation method of a powder-metallurgy refrigeration compressor valve sheet. The preparation method is characterized by comprising the following steps of: mixing iron powder, high-alloy main powder, graphite powder, manganese sulfide powder and zinc stearate powder according to certain proportion, leading the weight percentage of all elements in the total components to be as follows: 0.5-2.0% of carbon, 3.0-6.5% of cobalt, 2.5-4.5% of chromium, 2.5-4.5% of molybdenum, 0.5-2.0% of nickel, 0.2-1.0% of vanadium, less than 3% of impurities and the balance of iron; using a mold to press and form the mixture to obtain a powder-metallurgy green blank; putting the green blank in a sintering furnace to sinter for more than 5 minutes with the sintering temperature being 1150-1250 DEG C; carrying out repressing and finishing on the sintered blank; carrying out quenching and annealing under the protective atmosphere; and carrying out grinding on the valve sheet. In the preparation method, the problems of the adding mode and effective alloying of the powder-metallurgy high alloy are solved, and higher forming density needed by the powder-metallurgy valve sheet material under higher alloy content is realized, so that the powder-metallurgy refrigeration compressor valve sheet achieves the needed wear resistance. The prepared powder-metallurgy refrigeration compressor valve sheet has the advantages of low material cost, high material utilization ratio and suitability for large-batch production.

The invention relates to a powder metallurgy production method of an internal helical gear. The powder metallurgy production method comprises the following steps: 1) preparing metal powder raw materials in proportion; 2) putting the prepared metal powder raw materials into a mould of a powder extrusion moulding machine for moulding by rotary extrusion to form a mould green compact; 3) putting the mould green compact into a high temperature mesh belt furnace for sintering treatment; and 4) putting a sintered product into a carburizing furnace for carburizing treatment. The powder metallurgy production method helps produce the internal helical gear with easy production and operation, less cost, high production efficiency, high material utilization rate and high product accuracy.

An anti-oxidation iron-based superalloy and a preparation method thereof, which belong to superalloys and a preparation method thereof, solve the problem of unsatisfactory oxidation resistance of existing iron-based superalloys under high-temperature conditions, so as to improve serviceability and broaden high-temperature application fields. The anti-oxidation iron-based superalloy of the present invention has the composition mass percentages of: 12%≤Cr≤14%, 2%≤W≤3%, 0.3%≤Ti≤0.4%, 0.2%≤Si≤2%, 0.25%≤ Y2O3≤0.3%, the balance is Fe; it is made by mechanical alloying, molding and vacuum sintering, and the matrix of the final sintered body is α-(Fe, Cr) single-phase solid solution with uniformly distributed oxides in the matrix. The invention has high production efficiency and low cost, and the prepared anti-oxidation iron-based superalloy has reduced oxidation weight gain and improved anti-oxidation ability under the atmospheric condition of 850°C; the tensile strength at room temperature is ≥600MPa, and the elongation rate is ≥25%, which meets the requirements of automobiles. Requirements for the use of high-temperature structural parts such as engines and gas turbines, nuclear fission fuel cladding tubes, and first wall structural materials of nuclear fusion reactors.

The invention discloses iron-silicon-chromium soft magnetic powder, a preparation method and application thereof. The preparation method comprises the following steps: 1) iron-silicon-chromium soft magnetic alloy powder raw materials are added in a medium-frequency induction furnace for atmospheric smelting to obtain alloy liquid; and 2) under the condition of nitrogen protection, the alloy liquid is fed in an atomization tower; in the feeding process, two atomization mediums of ultrahigh-pressure atomization water and low-pressure vortex gas synchronously acts on the alloy liquid; and the alloy liquid is strongly crushed as a lot of fine metal molten drops, and is cooled and condensed as the iron-silicon-chromium soft magnetic alloy powder. The iron-silicon-chromium soft magnetic powder with high loose packing density, high tap density, low oxygen content and higher inductance value and magnetic conductivity can be prepared; and the iron-silicon-chromium soft magnetic powder can serve as a raw material of a micro inductor, and is widely applied.

The invention discloses a method for preparing copper or nickel powder and an electrolysis device based on the same, so as to achieve continuous large-scale production. The method comprises the steps of: preparing electrolyte; clearing metal particles or turning scraps to be powdered to obtain a metal raw material; putting the metal raw material as a sacrificial anode into an electrolysis basket for electrolysis; continuously sending a suspension solution of the metal powder and the electrolyte out to filter and separate the metal powder; cleaning the filtered metal powder with deionized water; vacuum drying the metal powder; mechanically grinding the dried metal powder; and examining a finished product. The electrolysis device comprises an electrolysis tank, a cathode assembly plate, a conductive spindle, a ceramic bearing, a collector, an insulating coupling, a speed reduction motor, the anode basket, a bracket, a scraping brush, a separation tank, an acid-resistant pump and an overhead tank. The device has a compact structure, and the effective cathode area is enlarged by more than five times compared with the roller type electrolysis tank with the equal capacity, so that the working efficiency is greatly improved, and the labor intensity is reduced.

The invention provides a hard alloy large pipe drawing mold and a preparation method. The hard alloy large pipe drawing mold comprises the following raw material ingredients in percentage by weight: 14 to 20 percent of cobalt with a particle size of 1.0 to 3.0mu m, and the balance of tungsten carbide with a particle size of 4 to 5mu m. The preparation method comprises: raw material preparation, wet milling, drying, pressing, forming agent removal and sintering, wherein in the drying step, wax or butadiene rubber is used as the forming agent; the drying with the wax as the forming agent is spray drying; the forming agent remove is performed in a dewaxing and sintering integrated furnace or bell-type furnace; and the sintering is pressure sintering, and during the sintering, the temperature is raised within 11 to 13 hours till a liquid phase of the product appears, then about 40 mbars of high-purity argon is introduced into the furnace till the final sintering temperature of 1,390 to 1,400 DEG C, the temperature is kept for 50 to 60 minutes, then about 50 to 60 bars of high-purity argon is introduced, the temperature is kept continuously for 50 to 60 minutes, and the product is cooled to room temperature. The Rockwell hardness of the hard alloy large pipe drawing mold of the invention is more than or equal to 83HRA, the bending strength of the hard alloy large pipe drawing mold is more than or equal to 2,200MPa, and the density of the hard alloy large pipe drawing mold is 13.40 to 14.20g/cm<3>. And the hard alloy large pipe drawing mold has the advantages of high hardness, high wear resistance, uniform product performance, fragmentation resistance and long service life.

The invention discloses a high speed steel precursor powder mixture used for preparing a cBN-high speed steel composite material. The high speed steel precursor powder mixture comprises, by mass, 3%-15% of Co powder, 32%-75% of Fe powder, 20%-50% of carbide powder selected from Group 4 metal, Group 5 metal and Group 6 metal of the periodic table of the elements, and 0-2% of C powder. The cBN-high speed steel composite material comprises, by mass, 1%-30% of cBN, 2.7%-13.5% of Co, 1.7%-5.4% of C, 14%-45% of Group 4 metal, Group 5 metal and Group 6 metal selected from the periodic table of the elements, and 40.6%-67.5% of Fe. Non-atomized powder is adopted to replace atomized powder, a local eutectic liquid phase can be avoided, erosion to cBN by the local eutectic liquid phase is prevented, the cBN can be kept stable, and therefore usability of the final cBN-high speed steel composite material is improved.

The invention discloses a novel isotropic nuclear-grade graphite material and a preparation method thereof. The novel isotropic nuclear-grade graphite material is prepared by using spheroidized natural crystalline flake graphite as an aggregate, and the proportion of the spheroidized natural crystalline flake graphite in the aggregate is 50-100 wt%. The preparation method comprises the following steps: spheroidizing treatment, purification, mixing kneading, secondary crushing and screening, forming, primary roasting, dipping, secondary roasting, and graphitizing treatment. The isotropic nuclear-grade graphite material is prepared by spheroidizing natural crystalline flake graphite, has the characteristics of high density, high thermal conductivity, low expansion coefficient and excellent isotropy, and shows good application prospects in the fields of nuclear energy, thermal management, machinery, chemical engineering and the like.

The invention relates to a high-performance self-lubricating copper-based pantograph pan material and a preparation method thereof, and belongs to the technical field of high-speed carrying equipmentdevelopment. The self-lubricating copper-based pantograph pan material is prepared from, by mass, 40-70 parts of copper-tin alloy powder, 10-30 parts of pure copper powder, 4-12 parts of iron-copper alloy powder, 2-6 parts of copper-chromium alloy powder, 5-9 parts of lead powder, 1-4 parts of graphite powder and 1-3 parts of molybdenum disulfide. According to the preparation method, the copper-tin alloy powder, the iron-copper alloy powder and the copper-chromium alloy powder are adopted to replace elemental tin powder, iron powder, chromium powder and the like to serve as a reinforcing phase, the sintering temperature can be effectively reduced, and the problem of loss of the low-melting-point elemental tin powder in the sintering process is avoided. Through reinforcement, the high-temperature stability and anti-ablation capability of a copper matrix are improved, the deformation and adhesion of a pan in a high-temperature environment caused by friction are suppressed, the loss of the pan is reduced, and the friction resistance of the pan is improved.

The invention discloses a preparation method of high pressed compact strength tungsten powder by ammonium metatungstate (AMT) direct hydrogen reduction. The tungsten powder prepared by the invention is directly formed into high-intensity pressed compacts without adding any forming agents, and the transverse rupture strength of the pressed compacts reaches 2.5 to 4.0MPa. The tungsten powder prepared by the invention can be widely used for preparing large tungsten products and tungsten alloy products. In the method, ammonium metatungstate is used for direct reduction, and calcination and other intermediate processes are not necessary, thereby process is simple and energy consumption is low. The granularity of the tungsten powder prepared by the method is controlled to be homogeneous and the sintering activity is high, thereby being benefit for the preparation of high-performance tungsten products.

The invention relates to a method for improving the fluidity of spray powder particles of a hard alloy mixture. Raw materials are prepared into the hard alloy mixture, a wet milling medium, an alloy bar and a forming agent are added for ball milling, and fatty acid diethanolamide and oleamide are added in the ball milling process; and mixture slurry obtained after wet milling is screened, spray-dried and pelletized, and the hard alloy spray particles smooth in surface and good in fluidity are prepared. The fatty acid diethanolamide and the oleamide are added, and in combination with ball milling and spray production processes matched with the fatty acid diethanolamide and the oleamide, the fatty acid diethanolamide can be fully fused with paraffin and ethyl alcohol; polar groups and non-polar groups in the fatty acid diethanolamide are combined with a ball milling medium and the paraffin correspondingly, and stable suspension is formed; the prepared mixture slurry is uniform and is notlikely to precipitate, the spraying efficiency is high, and the spray powder particles are good in uniformity; the spray powder particles are regular in morphology, smooth in surface and good in fluidity; and the prepared powder is good in pressing performance, and cracks and other defects are not likely to be generated.

The invention relates to a preparation method of diffusion bonding titanium powders, in particular to a method for producing powders for high performance powder metallurgy titanium alloys. The preparation method comprises the following steps that coarse particle titanium powders and elemental powders or alloy powders are used as raw materials to be mixed according to the proportion of required components, obtained mixed powders are subjected to diffusion bonding treatment, and hydrogen is introduced to form titanium hydride; and then the titanium hydride is taken out of a furnace, ball millingand crushing are carried out to obtain powders with the required particle size, and finally dehydrogenating is carried out to obtain the diffusion bonding titanium alloy powders. According to the preparation method, the cost of titanium alloy powders is obviously reduced, and the cost is only 1/10-1/2 that of the prior art; the preparation method has the advantages of low equipment requirement, less fixed asset investment, high production efficiency and simple and controllable production process; obtained products have low oxygen content and few impurities; and products obtained after sintering have stable performance, low oxygen content and uniform component structures.

The invention discloses a mixture preparation process. Rapid and continuous stirring is carried out in the state that the vacuum degree of a vacuum drying stirrer ranges from -0.06- -0.08 so that the drying speed can be increased and oxidation and/or excessive hardness of a mixture can be prevented; when stirring enables the temperature in the vacuum drying stirrer has an obvious rising process and the mixture is in a half-dry state, continuous stirring is stopped, the vacuum degree of the vacuum drying stirrer is reduced to 0- -0.05, the mixture is prevented from being broken, so that follow-up pelletizing is facilitated; and the mixture particles produced and discharged in such a way are soft, fragile and good in pressing performance, holes of sintered products can reach A02 or below, WC grows completely, and metallographic structures are uniform.

The invention discloses an ultraviolet absorber for an ultraviolet excitation LED device. The ultraviolet absorber comprises, by weight, 6 to 9 parts of mineral pressed powder, 5 to 8 parts of film-forming agent, 12 to 18 parts of nano aluminum hydroxide, 3 to 5 parts of nano zinc oxide, 4.5 to 7 parts of nano titanium dioxide, 2 to 3.5 parts of aminobenzoate, 1 to 3 parts of benzophenone derivatives, and 2 to 4 parts of methoxycinnamate. The formula of the ultraviolet absorber can be produced through a pressing process, the material is easy to obtain, the ultraviolet absorber is simple and efficient, and can be used for ultraviolet excitation light sources with wide ranges.