43results about How to "Near net shape" patented technology

The invention relates to a novel degradable medical magnesium alloy composite material. The medical magnesium alloy composite material provided by the invention has the characteristics of high strength, good temperature memory and controllable degradation velocity and can be used in the field of orthopedic implantation. The composite material is characterized in that the composite material contains Mg-Al-Zn magnesium alloys, wherein the content of Al is 0.5-3.5wt% and the content of Zn is 0.5-1.8wt%; besides, the magnesium alloy material can contain a few impurities including Fe, Mn, Cu and Ni, wherein the total of the impurities is not greater than 0.3wt%; and a medical biology degradable material exists on the surface layer of the composite material and can be a pure carbon dioxide copolymer, pure polyhydroxyalkanoate or a blend of the carbon dioxide copolymer and polyhydroxyalkanoate, which has to be medically purified before use.

The invention discloses an iron-based gradient structure gear and a manufacturing method thereof; to realized high surface layer hardness and high core/shell layer bonding strength, Fe2Ni is adopted as a core layer and the Fe2Ni added with an alloying element Cr is adopted as a shell layer; through strengthening effect of Cr, sintering/heat treatment is adopted to facilitate surface layer hardness to exceed 40 HRC and realize the metallurgical bonding of the core layer and the shell layer; sintering time is adjusted to realized homogeneous diffusion of Cr outside the interface and core/shell layer bonding strength is higher than 280 MPa.

The invention relates to a vacuum impregnation and hot-press curing molding method for a carbon fiber composite material. The vacuum impregnation and hot-press curing molding method comprises vacuum heating and pre-dipping and hot-pressing dipping and curing forming, heating and dipping and extrusion forming of the composite material are achieved through a vacuum heating dipping device and a pressing and dipping and curing device, so that the gas impurities in the carbon fiber cloth laminated layer can be discharged in time, the defect of vacuum impregnation can be made up, so that the curingsolution can be better filled into the gap of the carbon fiber cloth, the defects of pores, shrinkage cavities and shrinkage porosity of the extruded composite material can be obviously reduced, the density is obviously improved, and then the performance of the composite material is improved. According to the vacuum impregnation and hot-press curing molding method, the composite materials with different shapes and sizes can be formed in a near-net mode according to the shape matched with the upper die and the lower die.

The invention relates to a liquid die forging/rolling composite forming method for a magnesium alloy irregular-section large-size ring piece, which comprises the following steps: smelting, liquid die forging, homogenizing, excess heat isothermal rolling, heat treatment and finishing, wherein in the liquid die forging process, after a liquid die forging die is fixed onto an indirect extrusion casting machine, the smelted magnesium alloy solution is quantitatively cast into the liquid die forging die, and kept under the specific pressure of 140-200 MPa for 35-150 seconds to obtain the similar end-section ring blank, wherein the casting temperature is 680-740 DEG C, the pressurization speed is 50-100 mm/s, and the cavity filling time is 1-6 seconds; and in the excess heat isothermal rolling process, when the homogenized similar end-section ring blank is cooled to 300-400 DEG C, isothermal rolling is carried out on a radial/axial composite ring rolling machine. The method provided by the invention can simplify the blank making process of the alloy ring piece, lower the cost, enhance the production efficiency, effectively improve the microstructure state of the liquid die forging die magnesium alloy ring piece, and enhance the comprehensive mechanical properties.

The invention provides a green preparation method and a filter for a lightweight high-strength cordierite porous ceramic. The preparation method comprises the following steps: step S10, mixing magnesium oxide, aluminum oxide and silicon dioxide according to a cordierite stoichiometric ratio to obtain mixed powder, adding the mixed powder into deionized water with a certain volume, ball milling andmixing to prepare slurry; step S20, foaming the slurry to obtain foam slurry; step S30, injecting the foam slurry into a mold for freeze drying; step S40, sintering the dried green body to obtain thelightweight high-strength cordierite porous ceramic. According to the invention, the green preparation method is small in additive dosage used and environment-friendly, the size change from injectionmolding to sintering is less than 2% (the bus shrinkage range is-1.87% to 0.45%), and the method accords with the technical characteristic of green preparation.

The invention discloses a pulse discharge flash sintering metal-based part near-net forming technology method, and belongs to the technical field of powder metallurgy. The problems that a traditionalpowder metallurgy part production process is high in power consumption, tedious and complex in process flow and low in production efficiency are solved. The method mainly comprises the steps of pushing metal powder into a mold, and forming the metal powder through stamping; enabling the inner wall, making contact with the metal powder, of the mold to have the insulation property; and enabling stamping to serve as an electrode of a pulse discharge body, and enabling stamping to synchronously carry out pulse discharge in the metal powder forming process. According to the method, the process flowis greatly simplified, large-scale industrialized application is easily achieved, the near-net forming advantage is achieved, the product quality is high, porosity adjusting control is convenient, practicality is high, and the method has the important significance in the powder metallurgy industry manufacturing field.

The invention discloses a preparation process of a low-thermal-expansion wear resistant shaft sleeve. The preparation process comprises the following steps: 1) the surface treatment is performed for SiC powder and carbon fiber short filaments; 2) the SiC powder and the carbon fiber short filaments are mixed with Al powder; 3) the vacuum hot isostatic pressing sintering is performed; and 4) the thermal spinning is performed for a sintered blank. A bearing sleeve, prepared by the preparation process, has such advantages as low thermal expansion coefficient, high wear resistance and excellent lubricity to play an important role on guarantee of the size precision and the surface quality of a rolled piece.

The invention belongs to the technical field of metal pipe manufacturing, and specifically, relates to a manufacturing method of a large-diameter complex-shaped metal special section pipe through an additive manufacturing method. The method comprises the following steps: performing solid modeling of a pipe through a computer three-dimensional modeling software, and considering enough allowance for subsequent processing during design; making a pipe blank according to the obtained three-dimensional computer model through adoption of an additive manufacturing method (also called 3D printing), such as laser melting deposition (LMD) or laser engineered net shaping (LENS), suitable for metal materials; and carrying out proper precision machining of the pipe blank through conventional methods such as machining or grinding. Compared with a traditional technical method, such as casting, forging, and machining, the method has the advantages that a metal structure and mechanical properties of a pipe become more uniform and stable, the machining difficulty is greatly reduced, the manufacturing process is quickened, and massive raw materials are saved.

The invention provides a degradable antibacterial magnesium alloy and a preparation method of the degradable antibacterial magnesium alloy, and relates to the field of metal biomedical materials. Thedegradable antibacterial magnesium alloy comprises main active elements of Ag, Cu, Zn and Sr, and by means of composition optimization design of the magnesium alloy, the components comprise, by mass,1.35-1.65% of Ag, 0.9-1.1% of Cu, 3.6-4.4% of Zn, 0.9-1.1% of Sr, 0.36-0.44% of Ca and the balance Mg and other inevitable impurities. After the magnesium alloy material implant finishes the action, the magnesium alloy material implant can be completely degraded to avoid secondary operation removal, the medical cost and the pain of patients are reduced, the antibacterial property of the implant isimproved, and the magnesium alloy material implant has the functions of promoting osteoblast formation and inhibiting osteoclast bone absorption; the degradable antibacterial magnesium alloy adopts asemi-solid rheological die casting process, the microstructure of the product is uniformly distributed, the internal structure is compact, the defects of pores, segregation and the like are few, andthe requirements for high quality and high precision of implant products can be met.

The invention discloses a liquid die forging and rolling compound formation method for an aluminum alloy irregular-section large ring piece. The method comprises the following steps of: smelting, performing liquid die forging, homogenizing, performing afterheat isothermal rolling, performing thermal treatment and finishing, wherein the step of performing liquid die forging comprises the following substeps of: fixing a liquid die forging mold on an indirect extrusion casting machine, pouring a quantitative amount of aluminum alloy solution obtained through smelting into the liquid die forging mold at the pouring temperature of between 650 and 730 DEG C, pressurizing at the speed of 35 to 40 mm/s, filling for 1 to 6 seconds at the specific pressure of 100 to 200 MPa, keeping the pressure for 35 to 60 seconds, and thus obtaining a similarly final section ring blank; and the step of performing afterheat isothermal rolling comprises the following substeps of: cooling the homogenized similarly final section ring blank to the temperature of between 430 and 480 DEG C, and performing afterheat isothermal rolling on a radial shaft compound ring rolling machine. According to the liquid die forging and rolling compound formation method for the stainless steel irregular-section large ring piece, the flow of a blank preparation process for an aluminum alloy ring piece can be simplified, the cost can be reduced, and the production efficiency can be improved; and furthermore, the microstructure state of the aluminum alloy ring piece can be effectively improved, and the comprehensive mechanical performance is improved.

The invention discloses a liquid die forging rolling compound forming method for a 2A70 aluminium alloy large ring member with different cross sections. The liquid die forging rolling compound forming method comprises the following steps of: 1), smelting; 2), liquid die forging: fixing a forged die on an indirect extrusion casting machine; pouring alloy solution in the forged die for mold-filling for 1-5s at the pouring temperature between 700 and 720 DEG C and specific pressure between 180 and 200 MPa in the pressurizing speed of 35-40mm/s; and keeping the pressure for 40-60s under the pressure to obtain a ring blank with a nearly end cross section; 3) homogenization: cooling the ring blank with the nearly end cross section to 495 DEG C for keep the temperature for 16h; 4) afterheat isothermy rolling: reducing the temperature of the homogenized ring blank with the nearly end cross section to 430-450 DEG C, and performing isothermy rolling on a radial-shaft compound ring rolling machine; 5) thermal treatment: raising the temperature of the ring blank to 535 DEG C, keeping the temperature for 3 hours and performing water quenching; and then, raising the temperature to 190 DEG C and keeping the temperature for 12h; and 6) finishing.