61results about How to "Uniform microstructure" patented technology

The preparation process comprises the following steps: dissolving ammonium dimolybdate, ammonium rhenate and water at a high temperature, then adding zirconium hydroxide, uniformly mixing, carrying out vacuum drying, carrying out two-stage hydrogen reduction on the obtained precursor composite powder, and carrying out vacuum drying to obtain the zirconium dioxide reinforced phase-containing molybdenum-rhenium alloy capable of inhibiting abnormal growth of crystal grains, thereby obtaining the zirconium dioxide reinforced phase-containing molybdenum-rhenium alloy capable of inhibiting abnormal growth of crystal grains. Zirconium oxide reinforced molybdenum-rhenium composite powder obtained after reduction is subjected to cold isostatic pressing, pressureless sintering and hot isostatic pressing to obtain zirconium oxide reinforced molybdenum-rhenium alloy, and then the zirconium oxide reinforced molybdenum-rhenium alloy is obtained through high-temperature rolling and recrystallization annealing treatment. According to the method, atomic-level mixing of molybdenum and rhenium is achieved through liquid-phase doping, the microstructure of the molybdenum-rhenium alloy is more uniform and fine due to addition of ZrO2, the recrystallization temperature is increased, and the phenomenon that sintered grains of the molybdenum-rhenium alloy grow abnormally is relieved. And by optimizing the annealing process and regulating and controlling the annealing mode, grains are rearranged to form a more uniform microstructure, abnormal growth of the grains is further inhibited, and the high-temperature tensile strength and the ductility of the molybdenum-rhenium alloy are improved.

The invention discloses a high-strength TC4 titanium alloy wire and a preparation method thereof, and belongs to the technical field of titanium alloy wire materials. The method comprises the following steps: carrying out multi-pass roller die drawing on a TC4 titanium alloy hot-rolled wire blank in a high-temperature two-phase region, and then carrying out annealing treatment to obtain a wire material; then the annealed wire is subjected to multi-pass roller die drawing again, and the temperature is gradually reduced in the drawing process; and finally, the wire obtained after roller die drawing is subjected to multi-pass fixed die drawing in a low-temperature two-phase region, the temperature is not changed in the drawing process, and finally secondary annealing treatment is conducted to obtain the high-strength TC4 titanium alloy wire. The TC4 alloy wire prepared through the roller die and fixed die drawing method is high in strength and uniform and fine in microstructure, and the room-temperature tensile property of the TC4 alloy wire far exceeds the performance requirements of relevant standards such as GB / T 13810-2017 on medical instrument materials.

The invention discloses a heat treatment processing method for grain refinement of a large steel forge piece. The heat treatment processing method comprises the following steps: S1, selecting steel suitable for grain refinement; s2, the forge piece is heated to be lower than 700 DEG C at a certain heating speed; s3, the forge piece continues to be heated to the austenitizing temperature; s4, normalizing treatment is conducted on the forge piece; s5, the normalized forge piece is subjected to multiple times of heat treatment cycle operation; s6, the forge piece is heated to the temperature higher than Ac3; s7, tempering treatment is conducted according to requirements; and S8, after heat treatment is completed, ultrasonic flaw detection and other necessary quality detection are conducted on the forge piece. The strength and toughness of the forge piece are remarkably improved, so that the overall mechanical performance of the forge piece is improved, fine crystal grains can more effectively hinder dislocation movement, the material is more difficult to deform when bearing external force, thick and uneven structures and widmannstatten structures generated in the forging process can be eliminated through heat treatment, and the mechanical performance of the forge piece is improved. The microstructure of the whole forge piece is more uniform, and the comprehensive performance of the material is improved.

The invention relates to the technical field of silicon carbide ceramics. The preparation method comprises the following steps: S1, weighing 70-90% by weight of silicon carbide, 5-15% by weight of an adhesive, 2-5% by weight of a recrystallization auxiliary agent, 0.5-1% by weight of a deoxidizing agent and 5-10% by weight of a filling agent, S2, carrying out ball milling treatment on the raw materials to obtain a mixture, S3, carrying out injection molding on the mixture to obtain a sheet-shaped material, and S4, carrying out heat treatment on the sheet-shaped material to obtain the silicon carbide ceramic. S4, carrying out pressing treatment on the flaky material to obtain a green body; and S5, carrying out heating, heat preservation and sintering treatment on the green body in an inert atmosphere to finally obtain the silicon carbide ceramic. By adding a proper amount of recrystallization aid and deoxidizer into the raw materials, growth of silicon carbide crystal grains can be effectively promoted, formation of pores and defects is avoided, and thus the mechanical property and the service life of the silicon carbide ceramic are improved. Various raw materials can be uniformly mixed together through ball milling treatment, the density of the green body is further improved in the pressing process, and the quality of the silicon carbide ceramic is guaranteed.

The invention discloses a red copper strip for an IGBT copper substrate and a processing method of the red copper strip, and belongs to the technical field of red copper processing. The red copper material is smelted, cast and processed into a cast ingot; heating is conducted in a stepping heating mode, the temperature range is 840-1000 DEG C, hot rolling and face milling are conducted, and a strip with the thickness being 15-20 mm is machined; rough rolling is conducted on the strip, and the strip is machined to be 3.8-4 mm in thickness through 8-pass rolling; annealing and cleaning; the cleaned strip is subjected to two-pass finish rolling, and a strip with the thickness ranging from 2.8 mm to 3.5 mm is formed; and cleaning to obtain the red copper strip for the IGBT copper substrate. The heat treatment, rough rolling and annealing processes in the red copper machining process are improved, the obtained red copper strip for the IGBT copper substrate is good in surface consistency, and the heat conduction performance is improved when the red copper strip is applied to an IGBT module.

The invention discloses an aluminum-scandium alloy and a preparation method and application thereof, and belongs to the technical field of rare earth alloy sputtering target materials, metal aluminum particles and metal scandium particles are used as raw materials, high vacuum is extracted, inert gas is introduced for multiple times of electric arc melting, aluminum-scandium alloy melt with uniform components is obtained, and after the aluminum-scandium alloy melt is cooled, the aluminum-scandium alloy is obtained. The method comprises the following steps: preparing an aluminum-scandium alloy ingot, carrying out induction heating on the aluminum-scandium alloy ingot prepared by electric arc melting to completely melt the alloy so as to obtain an alloy melt, guiding the alloy melt to be injected into a mold through an argon pressure difference, naturally cooling to form a primary alloy, and carrying out homogenizing annealing on the primary alloy under a vacuum condition to obtain the aluminum-scandium alloy. And eliminating the residual internal stress of the primary alloy to obtain the aluminum-scandium alloy. The aluminum-scandium alloy prepared through the method is low in oxygen content, high in density, fine in crystal grain, uniform in structure and good in machining performance.

The invention relates to a high-entropy oxide wave-absorbing ceramic powder material as well as a preparation method and application thereof, belongs to the technical field of electromagnetic wave absorbing materials, and solves the problems of poor high-temperature resistance and oxidation resistance and low absorption efficiency on low-frequency wave bands of an existing electromagnetic wave absorbing material. The high-entropy oxide ceramic material has a perovskite structure, the molecular structure is ABO3, A comprises La and Sr, and B is at least five elements of Cr, Ni, Mn, Fe, Co, Zr, Hf and Ti. According to the invention, the high-entropy oxide is combined with the perovskite structure, the electromagnetic function of the high-entropy oxide ceramic material is accurately regulated and controlled, and effective absorption of low-frequency electromagnetic waves is realized; the material has oxidation resistance and thermal stability under a high-temperature condition, and excellent electromagnetic function strength of the material at a high temperature is maintained. According to the high-entropy oxide ceramic powder material, the range of an electromagnetic wave absorbing material is widened, the environmental adaptability is improved, and higher requirements of development of a communication technology on the electromagnetic wave absorbing material are met.

The invention relates to the technical field of composite materials, and discloses a high-strength metal-ceramic composite material and a preparation method thereof, and the preparation method comprises the following steps: (a) mixing selected metal powder and ceramic powder according to a specific proportion to form a uniform mixture; (b) carrying out ultrasonic vibration assisted ball milling treatment on the mixture, wherein the ball milling time is 2-4 hours; (c) applying pressure to the mixture in an inert atmosphere, heating, and carrying out hot press molding for 2 hours; (d) adding a carbon nanotube subjected to surface treatment into the mixture as a nanoparticle reinforcement phase; through surface modification of the metal powder and addition of the carbon nanotubes, the interface bonding force between metal and ceramic is remarkably enhanced, the overall performance of the composite material is improved, ultrasonic vibration is adopted to assist ball milling treatment, the dispersity of the powder is improved, and the mixing uniformity is improved, so that the temperature required by sintering is reduced, and the service life of the composite material is prolonged. And deformation or decomposition of the ceramic phase at high temperature is avoided.

The invention discloses a preparation method of a titanium-aluminum intermetallic compound disc with uniform structure properties, relates to the technical field of preparation of titanium-aluminum intermetallic compounds, and provides a method for preparing the titanium-aluminum intermetallic compound disc by combining hot extrusion and vacuum isothermal forging technologies, so that high-quality forming of the titanium-aluminum intermetallic compound disc can be realized. The titanium-aluminum intermetallic compound disc prepared through the method is uniform and fine in microscopic structure and excellent in mechanical property, can meet the service working conditions of disc components for aerospace engines, and has important commercial value.

The application relates to the technical field of zirconium-niobium alloy material processing, in particular to a preparation method of a large-diameter zirconium-niobium alloy pipe for nuclear industry, which comprises the following steps: S1, mixing nuclear-grade sponge zirconium and niobium scraps, or mixing zirconium-niobium alloy, zirconium dioxide and iron; melting the mixture and preparing a zirconium-niobium alloy ingot; S2, sequentially performing large deformation forging in a beta single-phase zone and an alpha+beta two-phase zone; S3, drilling a central hole in the axial direction of a round-forging blank; quenching in the beta single-phase zone; S4, coating an anti-galling agent on the surface of the central hole and heating to prepare a pipe blank in the mode of cross piercing; S5, performing periodic forging and rolling on the pipe blank; S6, annealing the hot-rolled pipe twice; and straightening the hot-rolled pipe after the second-stage annealing. The zirconium-niobium alloy pipe has uniform microstructure, good mechanical properties and corrosion resistance, the production direction of the brittle hydride is nearly parallel to the circumferential direction of the pipe, and brittle damage of the pipe wall thickness caused by the crack propagation of the hydride is avoided.

The embodiment of the invention discloses a high-strength corrosion-resistant CuNi10Fe1Mn alloy copper pipe and a preparation method thereof, relates to the technical field of non-ferrous metal material manufacturing, and aims to solve the technical problem of poor production in the prior art. According to the high-strength corrosion-resistant CuNi10Fe1Mn alloy copper pipe, the content of Ni ranges from 9.0% to 11.0%, the content of Fe ranges from 1.0% to 2.0%, the content of Mn ranges from 0.5% to 1.0%, the sum of impurity elements does not exceed 0.2%, and the balance is Cu.

The present invention discloses a metal flux-cored welding wire for laser cladding and a preparation method and application thereof, belonging to the field of additive manufacturing technology. The metal flux-cored welding wire for laser cladding is mainly used for preparing a coating on the surface of a hydraulic support that is resistant to chloride ion corrosion and coal particle wear. The metal wire for laser cladding of the present invention is a flux-cored welding wire, which belongs to a martensitic rust steel type material. By adding alloy elements that improve strength and toughness, the material has good corrosion resistance while having high hardness and plastic toughness, so that it can be prepared into a metal wire by drawing, and the prepared cladding layer can meet the requirements of the hydraulic support for the service environment.

The invention discloses a preparation method of a polyvinyl alcohol composite hydrogel coating, and belongs to the field of coating preparation. Polyvinyl alcohol, an organic silicon source and polydopamine are used as main raw materials, and the polyvinyl alcohol-silicon dioxide composite hydrogel coating is prepared on the surface of a substrate through a coating technology and cross-linking treatment. The preparation method comprises the following steps: fully hydrolyzing an organic silicon source to obtain uniform silicon dioxide sol; mixing the silicon dioxide sol with a polyvinyl alcohol solution to obtain polyvinyl alcohol-silicon dioxide composite sol; uniformly coating the composite sol on the surface of a substrate subjected to polydopamine modification treatment; and crosslinking the composite sol on the surface of the substrate to obtain the polyvinyl alcohol-silicon dioxide composite hydrogel coating. The obtained coating is smooth in surface, uniform in microstructure, simple in required equipment, convenient to operate, low in energy consumption and cost, environment-friendly and easy for industrial production. The coating can be used in the fields of biomedicine, crop planting, sewage treatment, cosmetics and the like.

The present application relates to core-pulling rivet titanium alloy wire processing technical field, specifically to a kind of preparation method of TB9 titanium alloy large disc round wire for core-pulling rivet.The method first obtains the TB9 titanium alloy ingot with a diameter of 500-700mm, then the TB9 titanium alloy ingot is forged into a bar blank with a diameter of 290-310mm at 1100-1200 ℃, then the TB9 titanium alloy bar blank is rough forged into a bar blank with a diameter of 130-150mm at 1000-1100 ℃, then the TB9 titanium alloy bar blank is precision forged into a bar blank with a diameter of 95-105mm at 850-950 ℃, then the TB9 titanium alloy bar blank is continuously rolled at 780-900 ℃, and then quenched after rolling, to obtain a large disc round wire blank with a diameter of 7.5-15mm, then room temperature drawing, then high-temperature solid solution, then room temperature drawing again, then peeling, polishing and coating treatment.At this time, the alloy cross-section structure is fine and uniform equiaxed structure, the longitudinal section structure is elongated fibrous structure, and after aging treatment, it meets the mechanical property requirements of AMS4957F for TB9 titanium alloy wire.

The invention belongs to the field of sodium-ion batteries, and particularly relates to a sodium-ion battery positive electrode material and a preparation method and application thereof. The preparation method comprises the following steps: S1, carrying out first mixing on a nickel source, a manganese source, a tellurium source and water to obtain a mixed solution, adding a precipitator and a chelating agent, and carrying out reaction, aging and first drying to obtain a precursor; and S2, carrying out second mixing on the precursor, a sodium source and a calcium source, carrying out second drying, compacting, and sintering to obtain the sodium ion battery positive electrode material, the tellurium element is introduced to regulate and control the particle morphology of a precursor microstructure and realize an in-layer Te-Ni-Ni-Te ordered upper layer structure, the ligand level structure is adjusted, and lattice oxygen loss is inhibited; the calcium element is added to maintain the cation content in the sodium layer and relieve O2-O2-rejection in the sodium extraction process, so that the prepared sodium ion battery positive electrode material can maintain a pure P2 type structure and has excellent capacity performance and cycle performance.

The invention provides a tape casting method high-transparency polysulfonamide film as well as a preparation method and application thereof. The light transmittance of the high-transparency polysulfonamide film obtained through the tape casting method is larger than or equal to 80% (400-800 nm), and the dimensional change rate at 250 DEG C is smaller than or equal to 1%. The preparation method comprises the following steps: S1, pretreatment of the polysulfonamide fibers: soaking and purifying the polysulfonamide fibers in acetone; then stirring and alkalizing in an alkaline solution; removing the alkaline solution and drying to obtain pretreated polysulfonamide fibers; s2, preparation of a membrane casting solution: dissolving the pretreated polysulfonamide fiber in a solvent to prepare a polymer solution; then adding a salt cosolvent and a polymeric dispersant to prepare a mixed solution, and stirring, filtering and carrying out vacuum defoaming to obtain a membrane casting solution; s3, film forming through a tape casting method, wherein the film casting solution is placed on a substrate, and a wet film is prepared through scraper tape casting; s4, coagulating bath phase inversion: transferring the wet film into a coagulating bath, and coagulating to form a preliminarily shaped film material; and S5, post-treatment: washing the preliminarily shaped membrane material with water, and carrying out gradient drying to obtain the high-transparency polysulfonamide membrane.

This invention discloses a hot pressing method for forming amorphous soft magnetic powder, wherein the amorphous powder is granulated and heat-treated under a protective atmosphere to a specific temperature. T x -150℃ to T x -50℃ and hold for 5–90 minutes; then transfer the powder to a mold, and... T g to T x High-density molded bodies are obtained by hot pressing for 30–180 seconds at a gauge pressure of 100–600 MPa within a temperature range. After sintering, high-density amorphous soft magnetic powder cores can be obtained. This method significantly reduces the gauge pressure, increases the relative density, improves the magnetic permeability, and reduces iron loss. Furthermore, the process is highly adaptable, can be easily modified from conventional powder metallurgy equipment, and offers high controllability, making it suitable for the industrial-scale preparation of high-performance amorphous soft magnetic materials.

The invention discloses a low-sensitivity soybean yogurt prepared by enzymolysis and synergistic bacterial fermentation and a preparation method thereof, belongs to the technical field of bean food processing, and provides a method for preparing low-sensitivity soybean yogurt by enzymolysis and synergistic bacterial fermentation, comprising: soaking soybeans in a sodium carbonate solution, then washing, preheating in a boiling water bath, mixing with water and grinding, ripening treatment, filtering, and obtaining cooked soybean milk; mixing with a flavor protease enzyme solution, enzymolysis, ice water bath to room temperature, and obtaining soybean milk enzymolysis solution; mixing with a glucose solution to obtain a fermentation substrate, inoculating plant lactobacillus, fermenting, and obtaining a fermentation product; post-ripening, and obtaining low-sensitivity soybean yogurt. The invention adopts flavor protease enzymolysis and synergistic bacterial fermentation to prepare soybean yogurt, and the obtained soybean yogurt has a reduced gel size, a delicate microstructure, a weakened syneresis shrinkage effect, and a significantly reduced allergenicity, and a scientific processing technology, a simple method, and easy operation.

The invention relates to a silicon carbide-based membrane, a synthesis method and a purification device for domestic sewage, and relates to the technical field of sewage treatment.The silicon carbide-based membrane is prepared from silicon carbide (SiC), borosilicate glass frit, a pore-forming agent and an adhesive, the particle size of the silicon carbide is 0.5-35 microns, the weight fraction of the borosilicate glass frit is 10-25 wt% of the weight of the SiC, and the weight fraction of the pore-forming agent is 10-25 wt% of the weight of the adhesive. The pore-forming agent is at least one of graphite powder, polymethyl methacrylate and polyvinyl chloride and accounts for 1-10wt% of the weight of SiC, the adhesive is at least one of polyvinyl alcohol and polyethylene glycol and accounts for 5-10wt% of the weight of SiC, the mass fraction of Al2O3 in the borosilicate glass material is 1-7%, and the mass fraction of Al2O3 in the borosilicate glass material is 1-7%. The bending strength and the acid-base tolerance of the silicon carbide-based membrane in the purification device can be improved, and meanwhile, the silicon carbide-based membrane also has relatively high purification performance on oily sewage.

The application discloses a gelatin-bacteriocin amino acid-dialdehyde starch composite film and a preparation method and application thereof. The preparation method of the composite film comprises the following steps: adding a crosslinking agent into a gelatin solution, adding N-hydroxysuccinimide into the gelatin solution after activation for a set time, then adding bacteriocin amino acid into the gelatin solution, coupling for a set time under weak acid condition and in the dark, and obtaining Gel-MAAs; dissolving the Gel-MAAs in water to obtain a composite solution; dissolving dialdehyde starch in water, gelatinizing, adjusting to weak alkalinity, and obtaining a dialdehyde starch solution; adding the dialdehyde starch solution into the composite solution, mixing uniformly, reacting at 35-45 DEG C for 1-3 h, adding glycerol with a mass fraction of 1-5%, ultrasonic degassing, pouring the film solution into a mold, and drying, and thus the composite film is obtained. The composite film has excellent mechanical properties, physicochemical properties, ultraviolet resistance, good biocompatibility, and great potential in the field of active composite films.

This invention relates to the field of electronic packaging substrates, and particularly to an alumina ceramic substrate material, its preparation method, and its application. The alumina ceramic substrate comprises 90-99 wt% alumina and 1-10 wt% sintering aids. The sintering aids have the following composition: xB₂O₃·zSiO₂·yBi₂O₃, where 15≦x≦25, 50≦y≦70, 15≦z≦25, and x+y+z=100, where x:y:z is the mass ratio. The density of the alumina ceramic substrate is ≥3.8 g / cm³. 3 The alumina ceramic substrate of this invention has the following characteristics: surface roughness ≤ 0.35 μm, breakdown strength ≥ 35 kV / mm, bending angle ≥ 350 MPa, and thermal conductivity ≥ 25 W / m·K. It also features high density, uniform microstructure, good surface flatness, high mechanical strength, high breakdown strength, low dielectric loss, and high thermal conductivity.

The present invention relates to the field of material science and metal processing technology, and discloses a high-strength and toughening heat treatment process for thick-walled forgings for pressure vessels, comprising the following steps: S1, selecting a low-alloy steel material containing a specific proportion of vanadium, molybdenum, manganese, silicon and nickel; S2, gradually preheating the forging in a furnace to 450°C to 500°C, and continuously heating for 2 hours; S3, heating the forging to 870°C to 920°C, and adjusting the holding time according to the thickness of the forging to ensure that the heat is fully penetrated; S4, carburizing treatment is performed at 680°C to 720°C for 8 to 12 hours; S5, using oil for rapid cooling, and then air cooling to room temperature. The present invention significantly improves the hardness and toughness of the forging, while enhancing its corrosion resistance and fatigue life, and optimizing the microstructure of the material, so that the forging is suitable for the field of pressure vessel manufacturing with high requirements.

The invention discloses a low-temperature sintered and low-loss manganese zinc ferrite material and a preparation method thereof, and the preparation method comprises the following steps: (1) uniformly mixing Fe2O3, Mn2O3 and ZnO powder, and carrying out mechanical ball milling in water; pre-sintering at the temperature of 850-950 DEG C to obtain a ferrite pre-sintered material; (2) adding a sintering aid containing V2O5 and Al2O3 into the ferrite pre-sintered material to obtain a mixture, and then performing plasma-assisted ball milling to obtain refined powder; preparing a green body sample; and (3) carrying out low-temperature sintering on the green body sample in a nitrogen atmosphere at the sintering temperature of 1050-1250 DEG C for 2-5 hours, and then cooling to obtain the manganese-zinc ferrite material. According to the invention, the densified sintering of the ceramic material is realized at a relatively low temperature (-1200 DEG C) by adding the specific sintering aid and combining with plasma-assisted ball milling, and the power loss value in a relatively wide range is lower than 300kW / m < 3 >.

The application belongs to the technical field of refractory materials for blast furnace ironmaking, and particularly relates to a thermal shock cracking resistant taphole clay material and a preparation method thereof. The taphole clay material comprises aggregates, matrix powder and a binder system; the binder system is composed of polysilazane, isocyanate curing agent and B4C micropowder. By introducing polysilazane as the main binder, the application realizes high ceramic yield and low volume shrinkage by using the characteristics of polysilazane being converted into Si-B-C-N ceramic at high temperature. Meanwhile, B4C micropowder is oxidized to generate B2O3 at high temperature, which fills pores, promotes sintering and protects carbon phase, so as to realize volume shrinkage compensation and high temperature strength improvement. The taphole clay material has low shrinkage rate, high cold compressive strength, high high-temperature bending strength and excellent thermal shock cracking resistance, and solves the technical problems of poor volume stability and insufficient high-temperature strength of traditional taphole clay caused by binder carbonization shrinkage.

The invention relates to the field of piezoelectric ceramic materials, and in particular to a method for preparing a potassium sodium niobate-based lead-free piezoelectric ceramic. A two-step molten salt method is adopted to synthesize a KNN prefabricated powder, the KNN prefabricated powder, a BNT prefabricated powder and a LS prefabricated powder are mixed and ball-milled and dried, a binder is added to granulate, sieve and press to obtain a green body, the green body is heated to 500-600 DEG C in a first stage, kept warm for debinding for 1-5 hours, and then heated to 1000-1150 DEG C in a second stage, kept warm for sintering for 1-5 hours. The potassium sodium niobate-based lead-free piezoelectric ceramic prepared by the invention has excellent piezoelectric properties and can meet the application requirements of small components, precision instrument control and other equipment.

The present invention relates to a fluidized solidified slag and a preparation method of the fluidized solidified slag, wherein the components of the fluidized solidified slag include, by weight, 100 parts of construction slag, 3-5 parts of calcium carbide slag powder, 4-10 parts of mineral powder, 2-8 parts of fly ash, 2-3 parts of sodium silicate powder, 6-7 parts of rice husk ash, and 36-42 parts of water. The present invention screens the proportion of the fluidized solidified slag composition and uses a special preparation process for preparation. The prepared fluidized solidified slag has high fluidity, moderate viscosity, and low water seepage rate, which meets the requirements of pumping and even self-leveling; it has high wet density, excellent mechanical properties and water stability: short setting time, and improved construction efficiency. At the same time, it solves the problems of narrow foundation trench and pipeline laying faced by soil backfill.

This invention provides a method for preparing WC-Co cemented carbide based on electron beam selective melting, belonging to the field of cemented carbide additive manufacturing technology. The method includes: 1) mixing tungsten carbide powder and cobalt powder; 2) modeling the component to be printed; 3) setting substrate preheating parameters; 4) setting contour scanning parameters; 5) setting part scanning parameters; 6) setting the part scanning strategy; 7) loading the mixed powder into the hopper of an electron beam selective melting device, leveling the substrate, and evacuating the vacuum; 8) cyclically stacking the powder according to steps 2) to 6) to obtain the WC-Co cemented carbide. The microstructure of this cemented carbide shows that the average size of the WC grains is 50-60 μm, and the Co phase is uniformly distributed between the WC hard phases. Room temperature tribological tests show that the cemented carbide has a friction coefficient of 0.55–0.65 at room temperature, exhibiting excellent room temperature wear resistance, making it suitable for cutting tools, molds, mechanical parts, etc., where room temperature tribological performance is required.

The invention provides an isotropic tough aluminum alloy and a preparation method thereof. The aluminum alloy comprises, by weight, 3%-6% of Cu, 0.5%-2% of Ni, 0.1%-0.5% of Mn, 0.3%-1.5% of Zr, 0.1%-0.2% of Ti and the balance Al. The preparation method comprises the steps that firstly, spherical aluminum alloy powder is prepared according to optimized components, and the particle size D50 / (D100-D10) of the powder meets the range of 30%-65%; and then, by optimizing laser additive manufacturing and heat treatment process parameters, a fine and uniform equiaxed crystal structure and a dispersed precipitated phase are obtained, the isotropy of the alloy is improved, and the high-toughness aluminum alloy with the ductility larger than or equal to 20% is obtained.

The invention relates to a forming method of a ring piece with an L-shaped outer diameter. The forming method of the ring piece with the L-shaped outer diameter comprises the following steps that heating is conducted before forging, specifically, a blank is heated to the forging temperature, and heat preservation is conducted for a period of time; blank forging, wherein the blank is sequentially subjected to upsetting, drawing-out and re-upsetting; the height of the blank is H1; a blank punching step: punching the blank by a punch with the diameter of d1 to obtain a ring blank; the ring blank is heated to the ring rolling temperature, and heat preservation is conducted for a period of time; forming the inner diameter of the ring blank into a conical inclined surface by adopting the conical section of the core rod; and a rolling forming step: moving the core rod, and forming the inner diameter of the ring blank into a rectangular section by adopting the cylindrical section of the core rod. The conical section of the core rod is used for pre-grinding and extruding the inner diameter of the ring blank, so that the inner diameter of the ring blank forms a conical inclined surface, and more materials are accumulated at the position with smaller diameter of the inner diameter of the ring blank. And during subsequent rolling forming, the annular groove of the main roller can be rapidly filled with materials accumulated at the inner diameter position, so that mold filling of the extending part of the outer diameter L-shaped ring piece is normal.

This invention discloses a high-alloy high-performance rotary guide component and its manufacturing method, belonging to the field of stainless steel technology. It solves the problems of poor microstructure uniformity and inability to simultaneously achieve mechanical properties and stress corrosion resistance in existing rotary guide components. The manufacturing method includes: smelting molten steel; preparing ingots; forging the ingots into steel billets using a high-speed forging machine after they are tapped from the furnace; heating and holding the steel billets; forging the steel billets into intermediate billets using a radial forging machine; water cooling the intermediate billets; forging the water-cooled intermediate billets a second time using a radial forging machine, followed by air cooling to obtain finished steel billets; straightening, machining, and shot peening of the finished steel billets to obtain rotary guide components; the composition of the rotary guide components, by mass percentage, includes: 18.00% ≤ Cr < 28.00%, 3.00% ≤ Mo ≤ 6.00%, 14.00% ≤ Ni ≤ 20.00%, 3.00% ≤ Mn ≤ 8.00%, Si ≤ 0.4%, Nb ≤ 0.25%, P ≤ 0.025%, S ≤ 0.02%, C ≤ 0.03%, N ≥ 0.3%, with the balance being Fe and other unavoidable impurities. The rotary guide components of this invention have fine and uniform grains and excellent mechanical and corrosion resistance.