117results about How to "Improve tissue uniformity" patented technology

The invention relates to a hot-rolled V-containing high-strength wire rod for a 1860MPa-grade bridge cable and a manufacturing method thereof.After a C-Si-Mn-Cr-V hypereutectoid component system is adopted for rolling and spinning to form a wire rod, online molten salt isothermal weak tempering treatment is conducted, the wire rod passes through front-section molten salt and is cooled at the cooling speed larger than or equal to 35 DEG C / s, the wire rod enters a sorbite phase region from an austenite state, and then the wire rod is cooled at the cooling speed larger than or equal to 35 DEG C / s; the preparation method comprises the following steps of: forming a structure taking sorbite as the main part, then promoting isothermal tempering and sorbite lamellar fusing of the structure through rear-section molten salt heating, and finally, slowly cooling through a roller way to prepare a microscopic structure which takes tempered sorbite as the main part and is a mixed structure consisting of ferrite and fused sorbite, so that the problems of network carbides and hard and brittle structures can be improved; and the structure uniformity and the strength and plasticity matching of the large-specification wire rod are improved, the tensile strength is 1340-1390 MPa, the percentage reduction of area is 38%-43%, and the steel wire rod can be used for manufacturing 1860 MPa bridge cables and meets the wire manufacturing and twisting requirements.

The invention belongs to the field of electrical electronics and advanced non-ferrous metal additive manufacturing, and particularly relates to a preparation method of a laser additive manufacturing copper alloy-tungsten copper composite electrical contact, which comprises the following steps of: preparing a nickel or nickel alloy coating on a copper alloy base material by adopting coaxial powder feeding laser cladding to serve as a middle layer, and then preparing a tungsten copper coating by laser cladding to obtain the copper alloy-tungsten copper composite electrical contact. The composite electrical contact is composed of a pure copper or copper alloy base material layer, a pure nickel or nickel alloy coating and a tungsten copper coating in sequence. The electrical contact obtained by the invention has relatively high electrical conductivity and thermal conductivity, and also has good arc ablation resistance; the copper alloy-tungsten copper electrical contact is prepared by adopting the laser cladding technology, so that the production cost can be effectively reduced, the production efficiency is improved, meanwhile, later maintenance and repair are facilitated, and the method is green and environment-friendly.

The invention is applicable to the technical field of titanium alloy pipe processing, and particularly relates to a preparation method of a high-plasticity TA15 titanium alloy pipe, which comprises the following steps: step S1, selecting sponge titanium, pure metal and intermediate alloy, preparing according to standard components of TA15 titanium alloy to obtain a prepared raw material, and smelting the prepared raw material for three times by adopting a vacuum consumable smelting furnace to obtain a high-plasticity TA15 titanium alloy pipe; and the TA15 titanium alloy cast ingot with the diameter being 600 mm is obtained. According to the method, the mechanical property and plasticity of the titanium alloy pipe are remarkably improved by accurately controlling the temperature and deformation of each machining step. And three-time upsetting and three-time drawing forging is carried out within the temperature range of T beta or above, coarse grains are effectively crushed, and grain structures are refined. And then, the metallographic structure of the wool rod is gradually optimized by accurately controlling the forging temperature and the deformation amount.

The invention discloses pipeline steel for carbon dioxide conveying and a production method thereof, and relates to the technical field of steel production, and the pipeline steel comprises the following chemical components in percentage by mass: 0.03%-0.07% of C, 0.10%-0.40% of Si, 1.00%-1.40% of Mn, less than or equal to 0.013% of P, less than or equal to 0.0020% of S, 0.030%-0.070% of Nb, less than or equal to 0.010% of V, 0.008%-0.030% of Ti, 0.20%-0.40% of Cr, 0.10%-0.30% of Ni, 0.05%-0.15% of Mo, less than or equal to 0.010% of Cu, 0.015%-0.055% of Al, less than or equal to 0.00050% of B, 0.0006%-0.0030% of Ca, less than or equal to According to the invention, a structure form taking bainite as a main component is realized, and the performance requirement of a product is met.

The invention discloses a method for achieving titanium-aluminum alloy additive manufacturing through an electron beam spot melting process. The method comprises the steps that firstly, after a three-dimensional CAD model of a target product is established, layering slicing is conducted; 2, preheating and heat preservation of the substrate; 3, spreading powder and preheating a powder bed; 4, additive manufacturing process parameters are set, powder melting and solidification are carried out point by point, and a single-layer solid sheet layer is obtained; 5, carrying out secondary preheating treatment on the powder bed and descending the forming platform; and 6, repeating the process to obtain the titanium-aluminum alloy. A discrete point melting technology is adopted to replace a traditional line scanning continuous melting technology, point melting and solidification are carried out on a target area in a powder bed one by one, the size of a molten pool is reduced, the cooling speed of the molten pool is increased, the heat affected zone range of the edge of the molten pool is reduced, the influence time of the heat affected zone is shortened, and the uneven structure caused by aluminum element volatilization and phase change is avoided; and meanwhile, single-process printing of the titanium-aluminum alloy complex part is achieved, the difficulty and cost of the additive manufacturing process are reduced, and the method is suitable for the field of titanium-aluminum alloy additive manufacturing.

The invention discloses a large-size low-grain-size 4N5 oxygen-free copper plate and a preparation method thereof, and the preparation method comprises the steps of first-fire forging, second-fire forging, third-fire forging and heat treatment to obtain the 4N5 oxygen-free copper plate. Through multiple times of upsetting and drawing in the forging process, crystal grains in metal are repeatedly crushed and recrystallized, the crystal grains are refined, then the heat treatment process is combined, the crystal grain size of the oxygen-free copper plate is further refined, large-size crystal grains are reduced, the structure uniformity of the oxygen-free copper plate is better, and the mechanical property of the oxygen-free copper plate is higher. After the low-grain-size 4N5 oxygen-free copper plate prepared through the method is precisely machined, due to the fact that the grain size of the low-grain-size 4N5 oxygen-free copper plate is small, grain growth is not obvious, residual stress is released in the heat treatment process, and then the problem that grains of a large-specification 4N5 oxygen-free copper plate grow abnormally in the high-temperature environment is solved.

The invention belongs to the technical field of composite material casting, and particularly relates to an aluminum-based composite material casting and a casting method and device thereof. Molding equipment in the casting device of the aluminum matrix composite casting comprises a mold and a sand core arranged in a mold cavity of the mold, the sand core divides the mold cavity into a first cavity and a second cavity, and at least one pouring gate communicating with the first cavity and the second cavity is arranged on the sand core; the pouring gate is configured to be used for cooling the aluminum-based composite material melt into semi-solid slurry; the smelting equipment is communicated with the first cavity through a liquid rising pipe, and the pressure regulation and control system is used for regulating and controlling the internal pressure of the forming equipment and the smelting equipment, so that an aluminum-based composite material melt in the smelting equipment is injected into the first cavity through the liquid rising pipe and passes through the pouring gate to form semi-solid slurry, and the semi-solid slurry is rapidly filled into the second cavity. By means of the casting device, casting of the aluminum-based composite material casting which is full in mold filling, high in compactness, fine in working face structure and uniform in reinforced phase distribution is achieved.

The invention relates to the technical field of aluminum alloy deformation machining, and discloses a reciprocating upsetting-extruding device and method for aluminum lithium alloy grain refinement, the reciprocating upsetting-extruding device comprises a die body, the die body is placed on a hydraulic machine, the die body comprises an upper die and a lower die, and the upper die is installed at the top end of the lower die through a bolt; an upsetting-extruding cavity is formed in the die body, an upper ejector rod, a lower ejector rod and a sample are arranged in the upsetting-extruding cavity, and the sample is located between the upper ejector rod and the lower ejector rod and is upset-extruded repeatedly through the upper ejector rod and the lower ejector rod. According to the method, grain refinement of the aluminum alloy bar is achieved, and the structure uniformity and obdurability of the aluminum alloy are effectively improved.

The invention relates to the technical field of metallurgy, in particular to a heat treatment process for improving the HIC resistance of a Q345R (HIC) steel plate, which comprises the following steps of: heating the steel plate to 30-50 DEG C above AC3, keeping in-furnace time for more than or equal to 30 minutes, and then cooling in two stages: in the first stage, quickly cooling, namely cooling to Ar1 temperature at the speed of 25-30 DEG C / s; in the second stage, the cooling speed is reduced, and cooling is conducted to the Bs temperature at the speed of 2-5 DEG C / s; and then air-cooling to room temperature. The phase change degree of the steel plate is controlled by adopting a two-stage cooling mode, so that the final structure of the steel plate is changed, the purposes of reducing the banded structure and improving the acid resistance of the Q345R (HIC) steel plate are achieved, and good social and economic benefits are achieved.

The invention belongs to the technical field of aviation annular forge piece forming, and particularly discloses a Haynes 242 forge piece with a uniform structure and a forming method of the Haynes 242 forge piece, and the forming method comprises the following steps of blanking, upsetting and punching, trestle chambering and end face flattening, rolling and heat treatment. In the upsetting punching process, the blanked blank is heated to the first forging temperature of 1020-1060 DEG C; in the mandrel supporter chambering flat end face, the blank is heated to the second forging temperature of 1020-1060 DEG C, and the forging deformation is 10%-15%; rolling comprises prefabrication and finish rolling, in the pre-rolling process, heating is conducted till the third forging temperature ranges from 1020 DEG C to 1060 DEG C, rolling is conducted through at least one heating number, and the rolling deformation of each heating number is controlled to range from 10% to 20%; and the blank is heated to the fourth forging temperature in a step heating mode in the final rolling process, the fourth forging temperature ranges from 1030 DEG C to 1050 DEG C, the forging deformation ranges from 10% to 15%, the appearance shape of the obtained Haynes242 forged piece meets the part machining size requirement, cracks are few in the production process, and the uniform structure and mechanical performance meeting the standard requirement are obtained.

The invention belongs to the field of molding and connection of plastics, and provides a fiber reinforced composite material ultrasonic welding method and a variable flexibility energy conducting rib, which comprises the following steps of: adopting a thermoplastic hollow grid as the variable flexibility energy conducting rib for ultrasonic welding; the density of openings of the thermoplastic hollow grids is changed in a gradient manner from a central area to an edge area; the flexibility-variable energy-conducting rib is fixed above a to-be-welded area of the to-be-welded thermoplastic composite lower workpiece and abuts against the welding face of the to-be-welded thermoplastic composite upper workpiece; and carrying out ultrasonic welding on the thermoplastic composite material to be welded. Uniformity of heat production, melt flow and temperature distribution of a welding interface in the ultrasonic welding process is achieved, and the forming efficiency, quality and connection strength of a welding head are remarkably improved. The problems that in the thermoplastic composite material ultrasonic welding process, heat is generated on the welding face, and temperature distribution is uneven, so that a welding head is locally overheated and decomposed or is not welded are solved.

The invention provides a friction stir welding seam structure regulation and control device and method, and belongs to the technical field of welding equipment.The friction stir welding seam structure regulation and control device comprises a main shaft, a workbench and a regulation and control system, and a stirring head is fixed to the bottom end of the main shaft and located over the workbench; the regulation and control system comprises a laser vibration meter, an infrared thermometer, an ultrasonic vibration excitation body and a flow controller, the laser vibration meter and the infrared thermometer are fixed to the two sides of the main shaft through a main shaft support, the ultrasonic vibration excitation body is vertically installed between the main shaft support and the workbench, one end of the flow controller is connected with the water cooling machine, and the other end of the flow controller is connected with the water cooling machine. And the other end is connected with a liquid inlet of the cooling cavity in the main shaft bracket. The temperature and amplitude frequency of the welding seam can be dynamically collected and analyzed in real time, and parameters are adjusted and optimized in real time through computer-aided calculation processing, so that the uniformity of the welding seam structure is adjusted and controlled, and it is guaranteed that the strength of the welding seam reaches the standard.

The invention provides a TC32 titanium alloy large-specification forged plate and a preparation method thereof. The preparation method comprises the following steps that S1, a TC32 titanium alloy cast ingot is subjected to repeated upsetting and drawing treatment at the temperature of 1000-1200 DEG C, and a cogged forging stock is obtained; s2, the cogged forging stock is sequentially subjected to first heating number upsetting and drawing treatment and second heating number upsetting and drawing treatment below a phase transformation point, a flat square is obtained through the first heating number upsetting and drawing treatment, the second heating number upsetting and drawing treatment is conducted according to the sequence of flat square upsetting, axial upsetting, axial drawing and flat square pressing, and a first flat blank is obtained; s3, the first flat blank is subjected to one-heating-number upsetting and drawing treatment above the phase transformation point, an obtained forging blank is subjected to recrystallization annealing treatment, and a second flat blank is obtained; and S4, the second flat blank is subjected to broadening and drawing-out treatment below the phase transformation point, machining is conducted, and the TC32 titanium alloy large-specification forged plate is obtained. By means of the method, accurate control over homogenization forging deformation of the large-specification plate blank is achieved, and the production period is shortened.

The invention belongs to the technical field of non-ferrous metal material processing, and particularly discloses a Ti575G titanium alloy bar and a preparation method and application thereof.The preparation method comprises the technological route of cogging forging, intermediate forging and forming forging, firstly, a large deformation technology above a phase transformation point is adopted, the thermal diffusivity of atoms under the high-temperature condition is fully utilized, and the thermal diffusivity of the atoms under the high-temperature condition is utilized; according to the method, the component and structure uniformity of a blank is greatly improved, then a repeated upsetting and drawing deformation mode is applied in a two-phase region, and meanwhile, the deformation uniformity of all positions of a bar is effectively improved by strictly controlling the temperature, the heat preservation time, upsetting and drawing deformation parameters and the like of each stage. The Ti575G bar prepared by the preparation method disclosed by the invention is uniform in component and structure, has matched strong plasticity and impact toughness characteristics, can completely meet strict requirements of wings, fuselage frames, undercarriages and weapon barrels of airplanes on the alloy bar, and is very suitable for industrial large-scale production.

The invention discloses a 900MPa-grade ultra-fine grain steel material, which contains Fe and inevitable impurities, and further contains the following chemical elements in percentage by mass: 0.20 to 0.28 percent of C, 0.15 to 0.35 percent of Si, 0.90 to 1.40 percent of Mn, 0.80 to 1.30 percent of Cr, 0.30 to 0.65 percent of Mo, 0.86 to 1.25 percent of Ni, 0.01 to 0.08 percent of Nb, 0.015 to 0.05 percent of Al and the balance of Fe and inevitable impurities. In addition, the mass percentage content of each chemical element meets the following conditions: (Mn + Ni) / C is more than or equal to 6 and less than or equal to 12; and 4 < = (Cr + Mo) / C < = 8. Correspondingly, the invention further provides a manufacturing method of the 900 MPa grade ultra-fine grain steel. The yield ratio of the steel is controllable, high strength is guaranteed, and meanwhile good low-temperature toughness and ductility are achieved.

The invention discloses a 5200MPa-grade steel wire, a hot-rolled wire rod and a production method of the wire rod. The wire rod comprises the following chemical components in percentage by mass: 0.95-0.98% of C, 0.45-0.65% of Si, 0.20-0.40% of Mn, 0.20-0.40% of Cr, 0.05-0.30% of Ni and the balance of Fe and inevitable impurities, and the content of impurity elements is controlled as follows: less than or equal to 0.002% of Al, less than or equal to 0.0008% of Ti, less than or equal to 0.005% of S, less than or equal to 0.008% of P, less than or equal to 0.0010% of O and less than or equal to 0.0020% of N. The steel wire rod can be used as a base material for producing a steel wire with the diameter being 0.03-0.045 mm and the tensile strength being larger than or equal to 5200 MPa, and in the process of further drawing the steel wire rod to prepare the steel wire, the mileage without breaking the wire can be larger than or equal to 300 km.

The invention relates to a high-plasticity GH4141 alloy cold-drawn bar with a uniform structure and a preparation method of the high-plasticity GH4141 alloy cold-drawn bar, belongs to the field of high-temperature alloy materials, and solves at least one of the problems that in the prior art, a GH4141 bar is poor in grain size uniformity, and a fastener is poor in performance stability, low in forming qualification rate and the like due to insufficient plasticity. The preparation method of the high-plasticity GH4141 alloy cold-drawn bar with the uniform structure comprises the steps that a hot-rolled GH4141 alloy bar blank is subjected to solution treatment, and then first-time cold drawing, first-time intermediate annealing treatment, second-time cold drawing, second-time intermediate annealing treatment, finished product cold drawing and finished product annealing treatment are sequentially carried out. According to the method, the plasticity is remarkably improved while the strength of the GH4141 alloy cold-drawn bar is guaranteed, and the upsetting qualification rate of a fastener and the product performance consistency are effectively improved.

The invention discloses a dissimilar material integrated manned lunar rover wheel hub and a forging-material adding-re-forging integral forming method thereof, and relates to manned lunar rover wheel hubs and forming methods thereof. The invention aims to solve the problem that the wheel-shaped component made of the dissimilar aluminum alloy material is difficult to integrally form. An integrated manned lunar rover wheel hub made of dissimilar materials is formed by connecting a rim and a spoke, the rim is composed of a rim body, an outer ring assembling ring and strip-shaped reinforcing ribs, and the spoke is composed of a plurality of Y-shaped sheet-shaped thin plates, an axle assembling flange and a transition area. The method comprises the steps of 1, blank making; 2, forging and forming a rim and a transition area; 3, finishing an additive interface; 4, adding materials; 5, homogenizing heat treatment; sixthly, integral forging forming is conducted; 7, aging strengthening treatment; and 8, machining and forming the wheel part. The method is used for the dissimilar material integrated manned lunar rover wheel hub and forging-material adding-re-forging integral forming of the dissimilar material integrated manned lunar rover wheel hub.

The invention relates to the technical field of backing bearing outer rings, in particular to a forging heat treatment process of a low-carbon bearing steel backing bearing outer ring, which at least comprises the following steps: S1, smelting raw materials of the low-carbon bearing steel backing bearing outer ring, pouring, controlling the pouring temperature at 1570-1590 DEG C, and cooling to 500-600 DEG C to form a blank; s2, the blank is subjected to jaw pressing, chamfering and water gap end cutting and then subjected to initial forging deformation; s3, finish forging deformation is conducted at the finish forging temperature of 1030-1080 DEG C, and a forged piece is obtained; and S4, performing post-forging heat treatment on the forge piece. The low-carbon bearing steel backing bearing outer ring is prepared by adopting a specific forging process and a heat treatment process after forging, the low-carbon bearing steel backing bearing outer ring has excellent obdurability, wear resistance and heat crack resistance, the problems that an original outer ring cracks due to penetration, is short in service life, often peels off and the like are solved, the production efficiency is improved, the production cost is reduced, and the low-carbon bearing steel backing bearing outer ring has a good application prospect.

The present invention relates to a high temperature wear resistant dry brake friction plate material and a preparation method thereof, belonging to the technical field of alloy friction materials. The material strengthens the iron-copper alloy matrix by precisely controlling the addition amount of Mo and Y2O3; adds a high entropy alloy strengthening phase (Al‑Cr‑Fe‑Ni‑Ti) to the iron-copper alloy to improve the wear resistance; adopts a composite lubricating phase (CaF2+BaF2+Ag), and adjusts its ratio so that CaF2‑BaF2 weakens the two-body wear effect and Ag weakens the three-body wear effect, thereby achieving the improvement of lubrication performance under high temperature and room temperature conditions; adds a high entropy alloy strengthening phase (Al‑Cr‑Fe‑Ni‑Ti) and a composite lubricating phase (CaF2+BaF2+Ag) at the same time, and adjusts its ratio so that (CaF2+BaF2+Ag) weakens the adhesive wear effect and (CaF2+BaF2+Ag) weakens the abrasive wear effect, thereby reducing the friction coefficient and wear rate.

This invention relates to the field of gray cast iron material preparation technology, and particularly to a method for preparing multi-alloy synergistically strengthened gray cast iron, comprising: adding steel raw materials to a smelting apparatus and heating to form molten iron; adding a chromium alloy to the molten iron, heating and holding at that temperature to form a basic mixture; determining the degree of furnace lining peeling based on the vibration frequency of the smelting apparatus, and determining the overheating risk level of the basic mixture based on the degree of furnace lining peeling; determining a target heating temperature based on the overheating risk level; determining the eddy current risk level based on the actual rotation speed; adjusting the stirring intensity during the smelting process based on the eddy current risk level; detecting the mixing ratio of the basic mixture and adjusting the amount of steel raw materials or the chromium alloy added to form a target solution; and simultaneously adding manganese nitride, alloyed tin, and ferrous sulfide to the target solution in a specified ratio to form multi-alloy synergistically strengthened gray cast iron. This invention improves the strength, toughness, fluidity, and resistance to solidification defects of gray cast iron.

This invention belongs to the field of alloy preparation technology, and specifically relates to a TB5 titanium alloy wire and its cold drawing preparation method. Firstly, the forging and rolling of the TB5 titanium alloy involves selecting a large deformation amount and a low processing temperature, effectively ensuring that the coarse microstructure is broken down to a certain extent, improving the internal structure and increasing plasticity. Then, the surface oxide scale of the TB5 titanium alloy wire is removed to avoid introducing oxygen, hydrogen, nitrogen, and carbon elements. Next, online solution treatment is used to regulate the microstructure, improving the cold working performance and microstructure uniformity of the wire. Finally, roll drawing is performed to cold work the wire to reduce its diameter, effectively avoiding problems such as film adhesion and surface scratches, extending the service life of the drawing die. Simultaneously, the TB5 titanium alloy wire exhibits good grain size and microstructure uniformity, meeting the requirements for use. The final TB5 titanium alloy wire is delivered directly in a bright state and can be used for subsequent processing.

The invention belongs to the technical field of copper alloy materials, and particularly relates to a titanium bronze alloy material and a preparation method thereof. The invention provides a preparation method of a titanium bronze alloy material. The titanium bronze alloy material comprises the following components in percentage by mass: 1.5 to 5 percent of Ti, 0.06 to 0.5 percent of Fe and the balance of Cu. The preparation raw materials of the titanium bronze alloy material are subjected to vacuum casting, an obtained titanium bronze alloy ingot is subjected to hot rolling treatment, cold rolling treatment and aging treatment, and the titanium bronze alloy material is obtained. The titanium bronze alloy material obtained by the preparation method provided by the invention has high strength and conductivity, meanwhile, the processing procedure of the titanium bronze alloy material is shortened, the preparation efficiency of the titanium bronze alloy material is improved, and the practical application requirements of the fields of electronic elastic elements, connectors and the like on ultrahigh-strength conductive copper alloy strips can be effectively met.

This invention relates to a steel for automobile engine pistons and its manufacturing method. The chemical composition of the steel, by weight percentage, is: C: 0.41–0.47%, Si: 0.15–0.35%, Mn: 0.70–1.00%, Cr: 1.10–1.40%, P: ≤0.020%, S: 0.015–0.035%, Mo: 0.17–0.27%, Al: 0.010–0.030%, N: 0.0040–0.0060%, with the balance being Fe and unavoidable impurities. The microstructure consists of ferrite and pearlite, with uniform distribution of ferrite and pearlite structures. The geometric center distance between each ferrite and pearlite structure is 15–30 μm. The hot-rolled hardness of the steel is ≤230 HBW, and the banded structure in the steel is ≤1.5 grade. The product features a narrow range of carbon deviation in cross-section, shallow decarburized layer and microcrack depth on the steel surface, low hot-rolled hardness, good banded structure, and high tensile strength after quenching and tempering.

The invention belongs to the technical field of forge piece manufacturing, and particularly relates to an evaluation method for a strip-shaped grain structure in a GH4169 alloy disc forge piece. According to the technical scheme, the method comprises the following steps that 1, a GH4169 alloy disc forging strip-shaped grain structure detection method is formulated; the method comprises the following steps: 1.1, carrying out strip-shaped grain structure detection on a high-power sample of the forge piece, wherein the strip-shaped grain structure is in a strip shape with different color shades under a 25-time microscope after the sample is corroded; 1.2, original state grain size / original state microscopic structure detection; 1.3, a heat treatment state strip-shaped grain structure / microscopic structure detection method; 2, formulating evaluation requirements of strip-shaped grain structures of the GH4169 alloy disc forgings; 2.1, evaluation requirements of the original state strip-shaped grain size / microscopic structure are met; and 2.2, evaluation requirements of strip-shaped grain size / microscopic structure in a heat treatment state are met. According to the method, the acceptance technical indexes of the GH4169 alloy disc forgings can be perfected, the structure uniformity of the forgings is improved, the metallurgical quality control requirements of the forgings are optimized, and the comprehensive mechanical property level of the forgings is guaranteed.

The application aims to provide a device and a process method for preparing fine-grain magnesium alloy through multi-petal staggered torsion composite extrusion, and belongs to the technical field of plastic processing of metal materials.The device comprises a die holder, and a lower concave die is arranged on the inner side of the die holder.The lower concave die is a fixed deformation concave die with a necked channel at the lower side, the top end of the necked channel is provided with an upper convex die, the outer side wall of the upper convex die is provided with a wedge-shaped block, and the wedge-shaped block is embedded in a wedge-shaped guide groove in the inner side wall of the lower concave die.The upper convex die is a funnel-shaped deformation die, which comprises eight fan-shaped convex die petals that are sequentially wedged, and the inner side wall of the fan-shaped convex die petal is a fan blade curved surface.The initial state of the fan-shaped convex die petal is high-low interval arrangement.Through the use of the application, the magnesium alloy blank can be subjected to continuous, uniform and significantly accumulated strain severe plastic deformation in a single extrusion process, the grain structure is significantly refined and the texture is weakened, the tensile strength, yield strength and elongation of the magnesium alloy at room temperature are greatly improved, and the preparation cost is reduced.

The invention relates to a wear-resistant and corrosion-resistant iron-nickel alloy material and a preparation method thereof, and belongs to the technical field of alloy material preparation, and the preparation method specifically comprises the following steps: firstly, using Mo, Si and Cr to reinforce an iron-nickel alloy matrix, mixing and smelting, and pouring into a cast ingot; then, the cast ingot is subjected to quenching, tempering and homogenizing heat treatment, and a primary blank is prepared; and then, the surface of the primary blank is roughened and pre-oxidized, the primary blank is coated with a nano TiN and WC enhanced NiCrBSi material, and finally the wear-resistant and corrosion-resistant iron-nickel alloy material is obtained. According to the prepared alloy, the hardness, the strength, the wear resistance and the corrosion resistance are remarkably improved, due to the solid solution and the compound formed by the reinforcing elements and the compact coating structure reinforced by the nano-particles, wear and corrosion are effectively resisted, and the service life is prolonged.

This invention discloses a method for preparing high-entropy ceramic matrix composites using a reactive infiltration process, belonging to the technical field of ceramic matrix composites. The steps are as follows: at least four single-component carbides are ball-milled and mixed with a carbon source, then dispersed in a dispersion liquid to obtain a slurry; continuous fibers are woven into a preform, and an interface layer and a matrix layer are deposited to obtain a semi-dense composite material; the slurry is introduced through vacuum or pressure impregnation; and a high-entropy carbide matrix is ​​generated in situ and densified by reactive infiltration after embedding with a transition metal and its alloy. This invention solves the problems of long process cycles, high porosity, high cost, and insufficient introduction of high-entropy ceramics in existing processes, achieving rapid densification and improving the material's high-temperature stability, oxidation resistance, and ablation resistance. It is suitable for the large-scale production of thermal protection materials for hypersonic vehicles.

The present application relates to a kind of high-precision cold-rolled screw with medium carbon steel hot rolled wire rod in metallurgical technology field, preparation method and application.The present application is aimed at solving the technical problems of low first processing qualified rate of cold-rolled screw caused by poor material organization uniformity and low purity.The chemical composition of the wire rod according to the present application is as follows: C 0.52-0.58%, Si 0.15-0.35%, Mn 0.70-0.90%, Cr 0.10-0.35%, Al 0.015-0.045%, Ti≤0.0025%, [O]≤0.0015%, [N]≤0.0060% and the like, with the balance being Fe.The preparation method of the present application obtains uniform organization with cross-section hardness range ≤20HV through the combined action of narrow component design, continuous casting end electromagnetic stirring, high temperature diffusion annealing and "fast first and slow later" controlled cooling process.The present application is mainly used for manufacturing high-precision ball screw, and the finished product precision reaches more than 5 levels, with first cold-rolled forming qualified rate ≥85%.

The invention relates to the technical field of precious metal metallurgy, and discloses a high-density iridium ingot sedimentation type smelting process which comprises the following steps: preparing a water-cooled copper crucible with a zirconium oxide inner wall coating; iridium powder and calcium oxide powder are mixed and put into a crucible; performing induction heating in a vacuum environment until the raw materials are molten; protective gas is inflated, periodic variable-pressure oscillation operation is applied under the condition that the temperature of the melt is kept, and slag crust on the surface of the melt is destroyed through pressure fluctuation and deep gas is promoted to be exhausted; after oscillation is stopped, the melt is left to stand, and a slag system floats upwards and is separated; and establishing a bottom-to-top temperature gradient to control directional solidification of the melt. According to the invention, oxide hard shells are destroyed through a variable-pressure oscillation mechanism, and efficient degassing and impurity removal are realized by cooperating with calcium oxide slagging; the zirconia coating effectively prevents the crucible material from being polluted; the directional solidification and hot isostatic pressing process eliminates internal shrinkage cavities and looseness. According to the process, the impurity content in the iridium ingot is remarkably reduced, and the purity and compactness of the material are improved.