34results about How to "Less organizational defects" patented technology

The invention relates to a quick manufacture method and device for a metal part by a high-energy beam under the action of magnetic field. In the process that the high-energy beam and metal powder act, the metal powder is molten; the electromagnetic force action is applied to the outer part of a molten pool to change the stressed situation of the molten pool; the solidification behavior of the metal molten pool is subjected to directional control; the inner tissue of a metal manufacture part is refined; and the performance of the metal manufacture part is improved. The device comprises a first electrode, a second electrode and a solenoid coil, wherein the first electrode and the second electrode are installed on a workbench; and when the solenoid coil works, the electromagnetic force can be still kept to be enough to act on the molten pool generated by high-energy beam radiation metal powder. According to the invention, the solenoid coil is electrified by the electrodes to generate a magnetic field; and when the high-energy beam acts on the metal powder, the stressed situation of the metal molten pool generated by the metal powder is affected by the electromagnetic force, the magnitude and the direction of the electromagnetic acting force are controlled via the change of the current and the voltage so as to control the stressed behavior of the metal molten pool.

The invention discloses a preparation method of an electrified railway chromium-zirconium-copper contact line. Copper is taken as a substrate, 0.30-0.70% of Cr and 0.10-0.35% of Zr in percentage by weight are added into the substrate, and the total sum of impurities is no greater than 0.05%. The preparation method comprises the following steps: performing vacuum melting and vacuum horizontal continuous casting, thereby obtaining a long-length large cross section chromium-zirconium-copper continuous cast blank; performing full hot continuous rolling and on-line solid solution, thereby obtaining a long-length chromium-zirconium-copper line rod disc; drawing and peeling the disc, and performing cold continuous rolling, thereby reducing the diameter; further performing aging treatment to reinforce the disc; further performing cold continuous rolling by using a Y-type rolling machine, thereby pre-forming the line; and finally performing fine drawing formation once. The chromium-zirconium-copper contact line produced by using the preparation process is fine and uniform in grain, free of defect, high in strength, high in conductivity and high in softening temperature, and applicable to industrialized production.

The invention relates to a 3D printing forming method and device for metal parts under the action of a magnetic field. Under the action of a high-energy beam and metal powder, the metal powder can be melted, electromagnetic force is applied to the outside of a molten pool, the stress state of the molten pool is changed, directional control over the solidification behavior of the metal molten pool is achieved, the internal organization of metal workpieces can be refined, and thus the performance of the metal workpieces is improved. The device comprises a first electrode, a second electrode and an electromagnetic coil which are mounted on a workbench. When the electromagnetic coil works, the electromagnetic force can be kept to act on the high-energy beam to radiate the molten pool generated by the metal powder all the time. According to the 3D printing forming method and device for the metal parts under the action of the magnetic field, the electromagnetic coil is powered up by the electrodes to generate the magnetic field, when the high-energy beam acts on the metal powder, the stress state of the metal molten pool generated by the metal powder can be affected by the electromagnetic force, the size and the direction of the electromagnetic force can be controlled by changing currents and voltages, and therefore the stress behavior of the metal molten pool can be controlled.

The invention discloses a preparation method of a hard alloy bar for a PCB micro drill. The preparation method comprises the following steps: in terms of total weight percent, selecting 4-8% of Co powder, 0.1-0.5% of VC powder, 0.1-1.2% of Cr3C2 powder, 0.005-0.01% of TiN powder and 0.01-0.06% of Y2O3 powder with Fisher particle size of 0.6-1.0 micrometers, and the balance of WC powder with Fisher particle size of 0.3-0.8 micrometer, adding the selected powder into a ball mill, further adding 0.01-0.03% of oleic acid and 1-3% of polyethylene glycol, sufficiently stirring and mixing; adding alcohol according to the proportion of 400ml/kg, further adding mill balls for milling, filtering and drying pulp stock, and then, molding by virtue of mould pressing or extrusion or injection molding, and molding a hard alloy blank by sintering. A PCB micro drill made of the bar prepared by the preparation method is particularly suitable for tools for processing PCB through holes or blind holes with diameter of less than 0.3mm, has less structure defects, high strength, high hardness and good abrasive resistance.

The invention discloses a laser additive and laser shock synchronous composite manufacturing method and system. The system comprises a laser additive manufacturing module and a laser shock module; inthe laser additive manufacturing process, a beam of focused laser generated by the laser shock module acts on the surface of a molten pool, a pasty area of the rear edge of the molten pool and the surface of a high-temperature solidification area in real time; and shock waves generated by plasma induction are used for stirring the molten pool, destroying thick dendrites in the paste area and inducing residual stress in the high-temperature solidification area, so that convection of the molten pool is intensified, the temperature gradient is improved, the nucleation rate of the paste area is increased, and defects such as cracks in the high-temperature solidification area are relieved. Therefore, efficient laser additive manufacturing of high-performance metal parts can be achieved throughthe force-heat coupling effect of laser additive and laser shock synchronous compounding.

A technology for welding high-C steel rail and high-Mn steel switch fork of railway includes such steps as build-up welding of Cr-Ni-Mo alloy transition layer on the steel rail, build-up welding of Mn-Cr-Ni alloy transition layer on the switch fork and solid dissolving, matching their U-shaped bevel joint surfaces, and manual arc welding. Its advantages are high welding quality and stability and low cost.

The invention relates to a magnesium-aluminum-zinc wrought magnesium alloy containing calcium and rare-earth samarium. The wrought magnesium alloy comprises the following components by mass percent: 5.3% to 6.0% of Al (aluminum), 0.7% to 1.0% of Zn (zinc), 0.4% to 0.5% of Ca (calcium), 0.2% to 1.5% of Sm (samarium), less than or equal to 0.15% of inevitable impurities and the balance of Mg (magnesium), wherein all the components taken as raw materials in proportion are fused and rapidly cooled in a salt bath; an obtained alloy spindle is annealed in a homogenization manner at 400 DEG C and air-cooled to reach a room temperature; then the hot extrusion is carried out on the alloy spindle at 360 DEG C according to the extrusion ratio being 25:1, so that the magnesium-aluminum-zinc wrought magnesium alloy containing the calcium and the rare-earth samarium is obtained. After the thermal deformation is carried out on the magnesium alloy, the tensile strength and the yield strength of the magnesium alloy are improved. Thus, the foundation for actual production applications of the wrought magnesium alloy is laid.

The invention discloses a ferroelectric polymer electric card material and a preparation method thereof, wherein the ferroelectric polymer electric card material is a polyvinylidene fluoride (PVDF) based ferroelectric polymer electric card nanowire array; the PVDF based ferroelectric polymer electric card nanowire array is also embedded into a porous anodic aluminum oxide (AAO) template. Accordingto the preparation method, a PVDF based ferroelectric polymer electric card material is controlled to form the nanowire array; the nanowire array is also embedded into the porous anodic aluminum oxide AAO template; the ferroelectric polymer nanowire array is prepared in the porous anodic aluminum oxide AAO template through a solution infiltration method, and through improving the morphology, structure, internal microscopic joint construction and the like of a key ferroelectric polymer, in comparison with the prior art, the problems that the strength of a ferroelectric polymer electric card islow, the heat conduction in the electric card material is difficult and the refrigeration power density of an electric card device is low and the like are effectively solved.

The invention relates to an aluminum matrix composite, in particular to high-strength anti-fatigue in-situ nano strengthening aluminum alloy and a die casting method thereof. In-situ nano strengthening and alloy component control are conducted, and an optimized nonlinear high-pressure die casting process is combined, so that the die casting is obtained. With the help of the scale effect, the interface effect and the heterogeneous nucleation effect of an in-situ nano ZrB2 reinforcement and a nano Al3Er precipitated phase, the strength, the anti-fatigue performance and the damping performance of the alloy are significantly improved; at the same time, the content of the elements Mg, Zn and Fe is increased, the elements Mn and Ni are introduced, the strengthening phase content is increased, the high strength is obtained, meanwhile, Al-Fe and other harmful coarse precipitated phases are effectively refined and rounded, and the good die casting performance of the alloy is ensured; and thus, a component produced through the high-strength anti-fatigue in-situ nano strengthening aluminum alloy and the die casting method thereof has the characteristics of being high in strength, plasticity, anti-fatigue performance and damping performance, and good in die casting performance.

A casting method by continuous directional solidifying includes extending one end of drawing line or plate in crystallizing mouth, extending its another end is cooling liquid, preheating the crystallizer, pouring fluid material in the crystallizer, insulating for directional solidifying, and drawing said drawing line or plate to draw the solidified material in cooling liquid. Its apparatus is composed of crystallizer, drawing line or plate, cooling unit, drawing unit and check unit. Its product (wire or plate) features high quality and uniformity, and excellent performance.

The invention discloses a method for preparing high wear-resistant cemented carbide. The parts by weight of each component in the raw material are: 83-90 parts of WC powder with a Fisher particle size of 1.2-2.0 μm, and a Fisher particle size of 0.6-1.0 μm Co powder 10-17 parts, B powder 0.7-1.0 parts, C powder 0.2-1.0 parts; the process steps of the high wear-resistant cemented carbide are: (1) select each material component; First add B powder, C powder and Co powder for stirring and grinding; (3) Then add tungsten carbide for grinding; (4) Filtration and drying; (5) Molding or extrusion or injection molding; (6) Sintering molding The sintering temperature is 1400-1425° C., the Ar pressure is 8-10 MPa, and the sintering time is 30-100 min. Practice has proved that the service life of the high wear-resistant cemented carbide of the present invention is 2 to 3 times that of ordinary cemented carbide.

The invention provides a powder material for 3D printing. The powder comprises a wear-resistant phase and a binding phase, wherein a mixture of sintered WC-Co hard alloy spherical particles and tungsten carbide particles serves as the wear-resistant phase, and Co-based alloy serves as the bonding phase. The weight percentage of the wear-resisting phase is 20-60%, the weight percentage of the bonding phase is 40-80%, the weight percentage of the sintered WC-Co hard alloy spherical particles is 5-15%, and the weight percentage of the coarse-grained or monocrystalline tungsten carbide particles is 15-45%. The failure period can be effectively avoided or delayed, and the wear resistance and working efficiency of the material are improved.

The invention belongs to the technical field of metal pressure machining processes, and particularly discloses a forging production process of a 30Cr15MoN high-nitrogen martensitic stainless steel bar, which comprises the steps of electroslag remelting, heating, forging preparation, forging and red annealing. According to the method, the problems that 30Cr15MoN steel in an existing forging processis prone to cracking and uneven in structure are effectively solved by combining the optimized forging mode that drawing is directly conducted without upsetting and an eight-edge four-method is adopted for drawing with strict temperature control, meanwhile, the forging heating number is reduced, and the production efficiency is improved; The steel bar forged through the method is excellent in performance in all aspects and can meet the material requirements of high-precision sharp-end projects.

The invention relates to an aluminum alloy surface modification technology, in particular to a production method of a high-performance cladding coating on the surface of an aluminum alloy. The production method of the high-performance cladding coating on the surface of the aluminum alloy comprises the following steps: conducting ball milling on Ni60, SiC and La2O3 with certain mass fractions to produce cladding powder; and blending the mixed powder obtained after ball milling into paste, coating the surface of the aluminum alloy with the paste, conducting drying, conducting cold pressing on a coating layer to form a prefabricated block, conducting induction cladding on the prefabricated block, subjecting a test piece obtained after cladding to heat-preservation aging standing treatment, and then making the test piece stand in air in a room temperature state. According to the production method of the high-performance cladding coating on the surface of the aluminum alloy, the problem of interface bonding of an aluminum alloy matrix and a cladding layer is solved, so that a polymorphic microstructure is generated in a transition area; and the service life of an aluminum alloy component is prolonged, and the aluminum alloy component adapts to severe environments.

The invention discloses a crystal orientation template for BaTiO3-based lead-free piezoelectric ceramics represented by formula 1: Ba(Ti1-xAx)O3 (wherein, A is Zr or Sn, 0<x<1). According to the crystal orientation template for BaTiO3-based lead-free piezoelectric ceramics, zirconium or tin is melted, so that the composition ratio is similar to base material for preparing the BaTiO3-based lead-free piezoelectric ceramics, and the structural defects can be reduced. The BaTiO3-based lead-free piezoelectric ceramics with high displacement properties can be manufactured through crystal orientation.