246 results about "Niobium alloy" patented technology

The invention discloses a method for preparing a copper-chromium-niobium alloy high-thermal-conductivity part based on green laser SLM, and relates to the technical field of copper-chromium-niobium alloys. Comprising the following steps that copper-chromium-niobium alloy powder is pretreated; the pretreated copper-chromium-niobium alloy powder is laid on a base plate, green laser is adopted for selective laser melting printing, at least two layers of printing parameters with different energy densities are set in a layered energy gradient control mode, layered printing is carried out, a pore structure with the porosity in continuous gradient distribution is formed, and a pre-machined part is obtained; wherein the wavelength of the green laser is 500 nm to 550 nm, and the spot diameter of the green laser is 15 [mu] m to 30 [mu] m; and the pre-machined part is subjected to heat treatment, and the high-heat-conduction part is obtained. The copper-chromium-niobium alloy part is prepared through the green laser SLM technology, the layered energy density gradient control technology is adopted, and the problems that in copper-based alloy additive manufacturing, the reflectivity is high, the structure is limited, and the performance is insufficient are systematically solved.

The invention relates to the technical field of joint prostheses, in particular to an ankle joint prosthesis implantation system based on zirconium-niobium alloy, which comprises a tibia prosthesis (10), a talus prosthesis (30) and a liner (20), the tibia prosthesis (10) and the talus prosthesis (30) are both made of zirconium-niobium alloy material and are integrally formed by 3D printing, the tibia prosthesis (10) comprises a tibia body (101), and the liner (20) is arranged on the tibia body (101). The first bone contact layer (100) is integrally formed on the tibia body (101), and the first bone contact layer (100) is of a porous structure of which the pore diameter is gradually reduced from outside to inside; the talus prosthesis (30) comprises a talus body (301) and a second bone contact layer (300) integrally formed on the talus body (301), and the second bone contact layer (300) is of a porous structure with the aperture gradually reduced from outside to inside.

The invention discloses a method for preparing copper-chromium-niobium series materials based on SLM, and relates to the technical field of copper-chromium-niobium alloys. Comprising the following steps that multiple kinds of copper-chromium-niobium alloy powder are pretreated, and pretreated copper-chromium-niobium series alloy powder is obtained; establishing a three-dimensional solid model of a to-be-formed sample, introducing the three-dimensional solid model into an SLM printer, setting printing parameters, respectively filling pretreated copper-chromium-niobium series alloy powder into a powder bin of the SLM printer, vacuumizing, introducing protective gas, and printing a first copper-chromium-niobium material layer by layer until the nth layer; the powder bin is replaced, and a second copper-chromium-niobium material is printed layer by layer on the n + 1 layer according to the printing parameters; the steps are repeated, printing of various copper-chromium-niobium materials is completed, and a formed sample is obtained; the contents of Cr and Nb in each copper-chromium-niobium material are different. By adjusting the content of Cr and Nb, various kinds of copper-chromium-niobium alloy powder can be provided in one-time construction operation, and additive manufacturing of functional gradient copper-chromium-niobium series materials is achieved.

The invention belongs to the field of metal materials, and particularly relates to a niobium alloy material which mainly comprises the following elements in percentage by weight: 4%-8.5% of tantalum, 4%-8.5% of tungsten, 1%-3% of molybdenum, 0.8%-2.5% of zirconium, 0-0.2% of carbon and the balance of niobium. The invention further relates to a method for preparing the niobium alloy material. The compactness of the niobium alloy material and the tensile property at the room temperature and the high temperature are obviously improved.

The invention relates to a vacuum diffusion bonding method for nickel-based superalloy and niobium alloy, and aims to solve the problems that the existing nickel-based superalloy and niobium alloy are difficult to bond and a brittle phase is easy to generate. The vacuum diffusion method comprises the steps that firstly, the surfaces of the nickel-based high-temperature alloy and the niobium alloy to be welded are polished and ultrasonically cleaned; preparing a Ti-Mo-Cr intermediate layer or a V-Cr intermediate layer, and placing the intermediate layer between the cleaned surfaces to be subjected to diffusion bonding of the nickel-based superalloy and the niobium alloy to obtain an accessory to be welded; thirdly, the to-be-welded part is placed in a high-temperature vacuum diffusion furnace to be vacuumized; and 4, applying working pressure, and controlling the bonding temperature to be 900-1300 DEG C for diffusion bonding. According to the present invention, the compound components of the joint can be changed through the intermediate layer, the generation of the brittle phase is limited, the bonding between atoms can be achieved, the reliable connection is formed, and the relatively high joint strength can be obtained.

The invention relates to a method for improving the high-temperature creep resistance of a TiAl alloy containing a B2 phase, which is characterized in that the microstructure of the high-niobium TiAl alloy is cooperatively regulated and controlled through phase diagram calculation, directional solidification and a heat treatment process, so that the alloy obtains a directional columnar crystal structure and a fine and dispersed B2 phase, and the high-temperature creep resistance of the TiAl alloy is enhanced. The problem that a B2 phase in an existing novel TiAl alloy is not beneficial to high-temperature creep resistance is solved.

The invention discloses a heat treatment method for strengthening the high-temperature compression creep property of a high-niobium TiAl alloy by inducing carbide precipitation and regulating and controlling a second phase distribution configuration, and relates to the technical field of high-niobium TiAl alloys. The technical problem that an existing high-niobium TiAl alloy is insufficient in creep property is solved. The method comprises smelting to prepare an alloy ingot; determining the phase transition temperature of the as-cast alloy; and the alloy is subjected to solid solution and aging two-step heat treatment. The original structure of the prepared high-niobium TiAl alloy is a near-lamellar structure, no carbide is separated out, and a large-size strip-shaped Y2O3 second phase exists; after heat treatment, the structure morphology is basically kept unchanged and is still of a near-lamellar structure, but carbide is separated out at a lamellar interface, Y2O3 is changed into a fine ellipsoidal shape, and a part of B2 phase also has a spheroidizing phenomenon. The production process is simplified through the two-step heat treatment process, and the creep property is remarkably improved on the premise that the original structure is basically kept unchanged and the room-temperature plasticity of the alloy is not remarkably reduced. The method is used for improving the creep property of the high-niobium TiAl alloy.

The utility model relates to a niobium alloy surface treatment device which comprises a machine frame, and an intermittent feeding mechanism, a polishing mechanism and a material receiving mechanism are arranged on the machine frame. The polishing mechanism comprises a fixed support, and a first rotating roller is arranged at the upper end of the fixed support; a second rotating roller is arranged at the upper end of the linear sliding table, the linear sliding table can drive the second rotating roller to be close to or far away from the first rotating roller, when the second rotating roller is close to the first rotating roller, the blank can be placed between the second rotating roller and the first rotating roller and rotate, and when the second rotating roller is far away from the first rotating roller, the blank falls off between the second rotating roller and the first rotating roller, and discharging is completed; the polishing wheel set can be close to or far away from the first rotating roller and the second rotating roller; the material receiving mechanism is located below the first rotating roller and the second rotating roller and is arranged in an inclined mode relative to the machine frame. The first rotating roller is matched with the second rotating roller, automatic clamping and releasing of blanks are achieved through driving of the linear sliding table, and the problems that feeding and discharging are blocked and incoherent in a traditional polishing machine are solved.

The embodiment of the invention discloses a reverse prediction method and device for a niobium alloy laser welding process and a medium, and relates to the technical field of laser welding. The welding process performance demand information comprises any one or more of a high-temperature oxidation resistance index, a welding depth index, a welding width-depth ratio index, a heat affected zone width index, a tensile strength index and a shear strength index; and according to the welding process performance demand information, welding process parameters corresponding to niobium alloy laser welding are determined by adopting a pre-constructed laser welding process parameter reverse prediction model, and the laser welding process parameter reverse prediction model is a back propagation neural network model based on grey wolf optimization and differential evolution algorithm optimization. According to the method, a large number of repeated tests and cost waste caused by a traditional trial and error method are avoided, and the problem that performance and parameter matching is difficult in the niobium alloy laser welding process is solved.

The invention provides a high-strength niobium alloy processing method, which relates to the technical field of alloy processing, and comprises the following steps: step 1, ingot casting preparation: niobium, tungsten, tantalum, molybdenum, zirconium and carbon are subjected to powder mixing and ingot casting to obtain a first alloy product; step 2, extrusion processing: heating the first alloy product by adopting a medium-frequency induction furnace, and carrying out extrusion treatment by adopting an extrusion ingot supply device to obtain a second alloy product; step 3, forging: performing intermediate annealing treatment on the extruded second alloy product twice by adopting a first annealing process in the forging process to obtain a third alloy product; wherein free forging treatment is carried out on the alloy product between the two times of intermediate annealing treatment; and (4) finished product processing: carrying out finished product annealing treatment on the third alloy product by adopting a second annealing process to obtain the final high-strength niobium alloy. Wherein in the second annealing process, the temperature is increased to 1200-1450 DEG C at the speed of 18-20 DEG C / min, and heat preservation is conducted for 60-120 min. According to the scheme, the strength of the niobium alloy can be improved.

The invention provides a niobium alloy longitudinal seam tailor-welding method which at least comprises the following steps that a male die is manufactured, a copper pipe provided with a vent hole is arranged in a groove in the outer surface of the male die, and the vent hole faces the interior of the groove; the scalloped segments to be welded are fixed to the outer surface of the male die, the adjacent scalloped segments are close to each other to form a welding seam, and the welding seam is arranged at the opening of the groove; a wide pressing plate is applied to the position, close to the weld joint, of the outer surface of the scalloped segment and fixed, so that the inner surface of the scalloped segment is tightly attached to the outer surface of the male die, and the weld joint gap meets the spot welding requirement; after ventilation is conducted in the groove through the copper pipe for a certain time, spot welding is conducted along the weld joint; after spot welding is completed, the wide pressing plates on the two sides of the welding seam are replaced with narrow pressing plates and fixed; welding equipment is used for welding the welding seams, and the adjacent scalloped segments are welded and fixed; and after welding is finished, the narrow pressing plate is removed, and the welded scalloped segment is taken down.

The invention provides a composite current collector and a preparation method thereof, an electrode plate and a secondary battery. The composite current collector comprises a base film; the transition layer is arranged on the surface of at least one side of the base film; the transition layer is made of any one or a combination of at least two of metal niobium, metal tantalum, niobium alloy, tantalum alloy, niobium-based compound or tantalum-based compound; and the conductive layer is arranged on the surface of one side, relatively far away from the base film, of the transition layer. The transition layer with good compactness, stability and corrosion resistance is arranged between the base film and the conducting layer, on one hand, the binding power between the base film and the conducting layer can be improved, formation of holes in the conducting layer is reduced, and corrosion of electrolyte and a high-temperature environment are resisted; therefore, the charge-discharge cycle performance of the battery based on the composite current collector is improved; on the other hand, due to the arrangement of the transition layer, a closed loop formed by conduction of the positive and negative current collectors and thermal runaway of the battery caused by the closed loop are avoided, and the safety performance of the battery is improved.

The invention discloses a high-titanium nickel niobium-based alloy and a preparation method thereof, the method comprises the following steps: step 1, niobium alloy powder is prepared and subjected to vacuum drying, the atom proportion of Nb powder in the niobium alloy powder is 60%-75%, the atom proportion of Ti powder in the niobium alloy powder is 15%-25%, the atom proportion of Ni powder in the niobium alloy powder is 6%-12.5%, and the balance is refractory metal element powder; 2, the niobium alloy powder is made into a high-titanium-nickel-niobium-based alloy blank through laser additive manufacturing equipment; and 3, the high-titanium-nickel-niobium-based alloy blank is put into a high-temperature furnace with the high vacuum degree, after the air pressure in the furnace reaches 1 * 10 <-3 > Pa to 5 * 10 <-3 > Pa through a mechanical pump and a diffusion pump, the temperature is increased to 1000-1200 DEG C from the room temperature at the temperature increasing rate of 10 DEG C / min, annealing is conducted for 1-10 h, and after furnace cooling is conducted, the high-titanium-nickel-niobium-based alloy is obtained and has the high melting point and the excellent mechanical property.

The invention discloses a preparation method of a niobium and niobium alloy capillary tube, which comprises the following steps of: 1, filling high-purity argon into an inner hole of a seamless tube, and sealing two ends by argon arc welding; 2, performing surface oxidation on the pipe by adopting an electromagnetic induction constant-temperature oxidation device to obtain a pipe to be cold-drawn; 3, cold drawing to obtain a capillary tube; and 4, cleaning the outer surface of the capillary tube, cutting off the sealing head, carrying out finished product heat treatment, and straightening to obtain a finished tube. According to the method, the inner hole of the pipe is filled with argon, the two ends of the pipe are welded and sealed, an existing surface oxidation technology is changed, only the outer surface of the drawn pipe is oxidized, and the inner hole can be prevented from being oxidized during surface oxidation; meanwhile, the trouble brought to later cleaning due to the fact that oil stains pollute the inner hole in the cold drawing process can be avoided; the electromagnetic induction constant-temperature oxidation device is adopted, the thickness of an oxidation layer is very uniform, the yield can reach 100% in the later cold drawing process, and the yield is increased.

The invention discloses a preparation method of a Ni3Sn superconducting wire based on 3D printing. The preparation method comprises the following steps: depositing a reticular niobium film on the surface of a tin-titanium alloy rod through 3D printing to obtain a tin-titanium-niobium alloy rod; drilling a hole in the center of the tin-titanium-niobium alloy rod, and inserting a tin-silver alloy rod to obtain the tin-titanium-niobium-silver alloy rod; the tin-titanium-niobium-silver alloy bar is put into the Ni3Sn-copper-niobium composite tube, and then an internal tin method Ni3Sn sub-component is obtained; sequentially putting the internal tin method Ni3Sn subcomponents into the tantalum tube and the oxygen-free copper tube to obtain an internal tin method Ni3Sn blank; and stretching the inner tin method Ni3Sn blank to obtain the Ni3Sn superconducting wire. Due to the existence of the silver element, uniform diffusion of the tin element in the heat treatment process is facilitated, the netted niobium film is deposited on the surface of the tin-titanium alloy rod through 3D printing, the precision and quality of the niobium film are guaranteed, more high-quality Ni3Sn crystal grains can be generated in the heat treatment process of the wire, and the performance of the Ni3Sn wire prepared through the internal tin method is improved.

The present invention relates to a high-temperature environmental barrier coating for niobium alloy and a preparation method thereof. The coating system sequentially comprises a Nb-Si bonding layer, a Mo-Si-Al-O anti-oxidation layer and a Yb-Si-Al-O environmental barrier outer layer on the surface of the niobium alloy. The coating preparation comprises: preparing a surface roughened Nb-Si coating by halide reaction embedding infiltration, and preparing a Mo-Si-Al-O anti-oxidation coating and a Yb-Si-Al-O environmental barrier coating by supersonic atmospheric plasma spraying. Yb 2 SiO 5 、MoSi 2 As well as the good thermophysical compatibility of niobium alloys, Yb 2 SiO 5 High toughness of doped components and Yb 2 SiO 5 Excellent water vapor corrosion resistance gives the coating better bonding strength and adaptability to high-temperature water vapor environments, improves the damage tolerance of the coating, and enhances the high-temperature water-oxygen corrosion protection effect of niobium alloy at 1500°C.

The invention discloses a copper-chromium-niobium alloy, a preparation method and a vacuum arc extinguish chamber, and the preparation method comprises the following steps: heating and melting a chromium block and a niobium block to prepare a Cr2Nb intermediate alloy; the Cr2Nb intermediate alloy and a copper bar are smelted, so that Cu4Cr2Nb alloy liquid is obtained; the Cu4Cr2Nb alloy liquid is subjected to atomization powder preparation, so that Cu4Cr2Nb alloy powder is obtained; the Cu4Cr2Nb alloy powder is subjected to cold isostatic pressing, so that a Cu4Cr2Nb alloy bar material is obtained; the Cu4Cr2Nb alloy bar is subjected to hot isostatic pressing, so that a Cu4Cr2Nb alloy ingot is obtained; the Cu4Cr2Nb alloy ingot is subjected to hot extrusion, so that a Cu4Cr2Nb alloy ingot blank is obtained; and the Cu4Cr2Nb alloy ingot blank is machined, so that the copper-chromium-niobium alloy is obtained. Various properties of the copper-chromium-niobium alloy can be improved.

The invention relates to the technical field of alloys, in particular to a high-strength and high-toughness molybdenum-niobium alloy target material and a preparation method and application thereof, and the alloy target material comprises the following components in parts by weight: 12.23%-24.55% of niobium, 2.87%-6.54% of chromium, 3.45%-6.58% of titanium, 4.12%-7.52% of silicon, 5.32%-12.14% of zirconium, 14.12%-22.45% of aluminum hydroxide doped carbon nanotubes and the balance of molybdenum. The molybdenum-niobium alloy target material provided by the invention has excellent mechanical properties, and the electrical properties of the molybdenum-niobium alloy target material are improved greatly.

The utility model belongs to the technical field of cold forging, and particularly relates to an easy-to-form niobium alloy cold forging die which comprises a cold forging shell and a lower die, the lower die is installed in the cold forging shell, a cold forging device is installed at the top of the cold forging shell, and the cold forging device comprises a cold forging unit, a discharging unit and a fixing unit. The cold forging unit is installed on the top of the cold forging shell, the discharging unit is installed in the cold forging shell, and the fixing unit is installed on the front face of the cold forging shell. According to the niobium alloy cold forging die easy to form, the cold forging unit is installed, so that a material is placed in the lower die, the turnover shell is turned over around the turnover shaft by turning over the turnover shell, the cold forging shell and the turnover shell are further fixed through the fixing unit, and therefore a first telescopic part is started, so that the material is placed in the lower die; and the first telescopic part drives the upper die to move downwards, so that cold forging is started through the upper die and the lower die.

The invention discloses a method and a device for simulating the mechanical property of a zirconium-tin-niobium alloy under an irradiation condition, and mainly aims to solve the problems of lack of microstructure simulation of the irradiated zirconium-tin-niobium alloy and high cost, long period and low safety coefficient of mechanical property inspection of the irradiated zirconium-tin-niobium alloy. Comprising the following steps: establishing a microstructure model of the zirconium-tin-niobium alloy by adopting a phase field method, and introducing a rate theoretical model of irradiation defect evolution into the model to obtain a microstructure evolution model of the zirconium-tin-niobium alloy under the irradiation condition; the defect concentration under the irradiation condition is determined based on the model; the zirconium element concentration and the niobium element concentration under the irradiation condition are obtained, and the nonlinear elastic energy density of the zirconium-tin-niobium alloy is determined based on the obtained concentration values; determining a total free energy density function of the zirconium-tin-niobium alloy based on the nonlinear elastic energy density, the defect concentration, the zirconium element concentration and the niobium element concentration of the zirconium-tin-niobium alloy under the irradiation condition; and performing derivation processing on the total free energy density function to obtain a target stress tensor component.

A coating system includes a diffusion coating on a refractory metal or refractory metal alloy. The coating can be applied to a component such as a rocket engine component that includes a substrate including the refractory metal and is useful to protect the substrate from high temperature oxidation. The diffusion coating process employs an activator that includes a compound of the metal to be diffused into the surface of the substrate and is a vapor phase process in which the vapor includes metal from the activator and additional from the metal source being activated. Aluminum trifluoride can be used to activate an aluminum metal source to form an aluminide coating on a refractory metal-based alloy, such as a niobium alloy.

The invention discloses an electron beam welding method for a molybdenum alloy / niobium alloy dissimilar material with a preset middle layer. The electron beam welding method aims at solving the problem that solid crack defects exist in existing electron beam welding for the molybdenum alloy / niobium alloy dissimilar material. The electron beam welding method comprises the steps that firstly, the to-be-welded faces of the to-be-welded molybdenum alloy part, the to-be-welded niobium alloy part and the to-be-welded Re middle layer are mechanically polished and cleaned after being polished; secondly, the Re middle layer is placed between the to-be-welded faces of the clean molybdenum alloy part and the niobium alloy part to form a welding assembly; thirdly, welding parameters are set; and fourthly, electron beam welding is conducted. According to the method, the Re intermediate layer is adopted to carry out electron beam welding on the molybdenum alloy / niobium alloy, the characteristic that Re can improve the toughness of the molybdenum alloy is utilized, the metal brittleness of a weld joint is reduced, the crack tendency of a joint is greatly reduced, and a crack-free and high-strength molybdenum alloy / niobium alloy dissimilar material electron beam welding joint is obtained.

The invention discloses an aluminum-titanium-boron-carbon-niobium-rare earth intermediate alloy refiner and a preparation method and application thereof, and relates to the technical field of refiners, the refiner comprises the following components in percentage by mass: 4.5-5.5% of titanium, 0.8-1.2% of boron, 0.1-0.3% of carbon, 0.1-1.5% of niobium, 0.2-0.5% of rare earth and the balance of aluminum. The preparation method comprises the following steps: ball-milling and mixing a titanium source, a carbon source and aluminum powder, and hydraulically pressing into a precast block; heating an aluminum ingot until the aluminum ingot is completely molten, and then pressing the mixed powder precast blocks into an aluminum melt in batches to obtain a mixed melt; and sequentially adding an aluminum-boron alloy, an aluminum-niobium alloy and rare earth into the melt for melting, then adding carbon hexachloride for deslagging and refining, and then pouring into a mold for cooling. According to the refining agent, the grain structure of the aluminum-silicon alloy can be remarkably improved, the recession resistance and poison resistance of the high-silicon-content aluminum-silicon alloy are effectively improved through introduction of niobium and rare earth, and an effective refining effect on the aluminum-silicon alloy can be achieved.

This invention discloses a method for preparing a uniform microstructure on the surface of a containerless solidified niobium alloy for a space station, relating to the field of containerless materials science experimental technology. The method first screens for highly supercooled samples suitable for preparing a uniform microstructure using this method in containerless space station experiments; calculates or experimentally determines the primary phase dendrite growth rate, the cooling rate coefficient of radiative heat dissipation during the cooling stage, and the primary phase nucleation rate; and conducts containerless space station experiments to allow the niobium alloy to undergo deep supercooling and rapid solidification within a determined suitable supercooling range, thus obtaining a solidified alloy sample with a uniform surface microstructure. This invention actively controls the distribution of dendrites and eutectic phases, resulting in a surface microstructure with uniformly distributed dendrites and interdendritic eutectic phases.

The invention relates to the technical field of coating preparation, in particular to a niobium alloy surface thermal spraying coating, a preparation method and application, according to the method, a silicide coating is prepared on the niobium alloy surface, halide reaction embedding siliconizing treatment is conducted, and the niobium alloy surface thermal spraying coating is obtained; the silicide coating is prepared on the surface of the niobium alloy through the thermal spraying technology, the rough surface can be formed, anchoring sites are provided for follow-up halide reaction embedding siliconizing treatment, in the follow-up halide reaction embedding siliconizing treatment process, silicon is diffused to a base body to react to form a siliconizing diffusion layer, and metallurgical bonding of a coating-base body interface is achieved. In addition, a continuous transition area is formed between the siliconizing diffusion layer and the silicide coating, stress concentration caused by component mutation is reduced, the risk of interface cracking is effectively reduced, the service life of the coating is prolonged, and the problems that in the prior art, the interface bonding force between a thermal spraying MoSi2-based silicide coating and a base body is poor, and the service life is short are solved.

The invention relates to a preparation method of a molybdenum-niobium thermocouple wire, according to the method, dispersion strengthening and toughening are adopted, the problem of uniformity of molybdenum-niobium alloy components is solved through a method of combining high-energy ball milling, vacuum gradient sintering and electron beam melting, and the prepared molybdenum-niobium alloy thermocouple wire is high in thermoelectric stability and precision through drawing and surface treatment. The high-temperature-resistant strength and the neutron irradiation-resistant performance are good.

This invention discloses a plasma arc welding method for titanium / steel with pre-filled powder, belonging to the field of arc welding. The invention involves a bevel on the steel plate side of the weld joint, where a multi-element alloy powder is pre-filled. This multi-element alloy powder is a copper-titanium-iron-nickel-niobium alloy powder, with the following mass percentages: Cu: 35-45 wt%, Ti: 15-20 wt%, Fe: 15-20 wt%, Ni: 15-20 wt%, Nb: 3-5 wt%, to optimize the metallurgical properties of the titanium-steel interface. The upper part of the bevel is tightly fitted with the titanium, leaving a gap at the bottom for the multi-element alloy powder. During welding, the pre-filled multi-element alloy powder forms an alloy transition layer with the titanium-steel interface. After the welding wire melts, it fills the weld joint, forming the weld area together with the pre-filled powder. This method maintains the stability of the multi-element alloy powder and prevents it from being dispersed by the gas flow. This method overcomes the shortcomings of filler materials in traditional welding, avoids the high cost of laser coaxial powder feeding, and significantly reduces powder loss and particle size limitations in arc powder feeding.

The invention provides a method for preparing a high-purity niobium ingot by utilizing multistage refining and the high-purity niobium ingot, and the method comprises the following steps: (1) taking aluminum particles, niobium pentoxide, a heat generating agent and a slag former as raw materials, preparing an aluminum-niobium alloy ingot by adopting an exothermic method outside a furnace, and then carrying out surface treatment and crushing treatment to obtain aluminum-niobium alloy particles; (2) the aluminum-niobium alloy particles are subjected to horizontal electron beam smelting, and a smelted niobium plate is obtained; (3) stacking a plurality of smelting niobium plates, and then sequentially performing vacuum diffusion welding and vacuum arc smelting to obtain a primary niobium ingot; and (4) the primary niobium ingot is placed in a double-gun electron beam smelting furnace to be smelted, and the high-purity niobium ingot is obtained. The stable production of the high-RRR value high-purity niobium is realized by adopting a multi-stage refining process coupling system of an aluminothermy method, horizontal electron beam melting, diffusion welding, electric arc melting and double-gun electron beam melting, and the technical problems of high energy consumption, high cost, low production efficiency and the like in the traditional process are effectively solved.

The application relates to a connecting structure applied to a high-temperature and high-pressure heat exchanger, which comprises a tube sheet flange and a tube sheet flat cover, the tube sheet flange and the tube sheet flat cover are connected through a plurality of fixing members, a sealing film gasket is arranged between the tube sheet flange and the tube sheet flat cover, one side of the sealing film gasket is attached to the tube sheet flat cover, the other side of the sealing film gasket is outwardly provided with a boss, a sealing surface is formed between the boss and the tube sheet flange, a sawtooth groove is arranged on the sealing surface of the boss, the sawtooth groove is filled with graphite, and a low-carbon nickel-chromium-molybdenum-niobium alloy build-up welding layer is built up and welded on the sealing surface of the tube sheet flange, so that the sealing performance of the connecting structure is greatly improved, and medium leakage is avoided.

The invention belongs to the field of metal material surface engineering, and provides a high-strength wear-resistant shell alloy material and a preparation method thereof. According to the invention, a synergistic process route of alloy component optimization design, surface mechanical rolling and gas nitriding composite strengthening is adopted, and a double-layer gradient structure of a gradient nanocrystalline strengthening area and a nitriding diffusion area is constructed on a carbon-manganese-silicon-chromium-molybdenum-nickel-vanadium-niobium alloy matrix; gradient matching of surface layer superhardness and core part toughness with the surface Vickers hardness being 850-1100 HV0.1 and the core part Vickers hardness being 350-550 HV1 is achieved, the thickness of a gradient nanocrystalline strengthening area is 50-300 microns, the thickness of a nitriding diffusion area is 0.30-0.60 mm, the room-temperature tensile strength is 1100-1600 MPa, the percentage elongation after fracture is 8-20%, and the hardness of the surface layer superhardness and the core part toughness is not larger than 100%. The cross-domain coupling contradictions that extremely high hardness and overall toughness of the surface of a shell type wear-resistant material are difficult to consider at the same time and the residual stress gradient and the dimensional stability are difficult to control are solved, and the method has wide application value in manufacturing of wear-resistant parts such as shells, shells and protective covers under the high-strength wear working condition.