19results about How to "Short holding time" patented technology

The invention discloses a cold rolling process of an aluminum-based silicon carbide coil material. The cold rolling process comprises the following steps: carrying out surface treatment and coiling on a hot-rolled coil material; after the protective film is removed online, cold rolling-annealing I circulation is conducted, the single-pass rolling reduction of cold rolling is 5%-10%, the unit tension is 10%-30% of the yield strength of the material, the speed is smaller than or equal to 15 m / min, heat preservation is conducted for 1-2 h at the temperature of 430-480 DEG C in annealing I, and the heating and cooling rate is smaller than or equal to 10 DEG C / min; then edge cutting is carried out to remove edge cracks; the heating and cooling rate of the annealing II is smaller than or equal to 8 DEG C / min, and the heat preservation time is shorter than that of the annealing I; performing surface treatment after annealing II; and finally, finished product cold rolling is conducted, the single-pass rolling reduction is 5%-8%, and the speed is 5-10 m / min. By means of optimized multi-pass small rolling reduction rolling, staged temperature control annealing and tension control, the technical problem that the aluminum-based silicon carbide composite material is prone to cracking and strip breakage in the continuous cold rolling process is solved.

A high-alloy steel electroslag ingot and its homogenization method are provided, comprising the following steps: S1, electroslag ingot pretreatment: removing surface oxide scale and crack defects, and grinding to a surface roughness Ra≤6.3μm; S2, staged heating: heating to 800-900℃ at a rate ≤100℃ / h and holding for 2-6h; heating to 1000-1100℃ at a rate ≤100℃ / h and holding for 2-6h; heating to 1200-1300℃ at a rate ≤150℃ / h and holding for 10h. -20h; S3, Stepped cooling: Turn off the heating device and cool with the furnace to 800-1000℃, hold for 2-6h; cool to 500-650℃ at a rate of ≤50℃ / h, hold for 2-6h; open the furnace door and introduce cooling air at a speed of 0.5-3m / s to cool to room temperature, obtaining homogenized high-alloy steel electroslag ingots; S4, Post-homogenization testing: the relative standard deviation of each alloying element is ≤5%; the average grain size is ≤10μm; the Brinell hardness fluctuation range is ≤15HBW. This invention eliminates component segregation, refines grain structure, optimizes process parameters, is highly efficient and energy-saving, easy to promote, and has strong practicality.

The application belongs to the technical field of steel and iron, and particularly relates to a cold-rolled low-alloy steel strip and a preparation method thereof. The cold-rolled low-alloy steel strip contains the following chemical components in percentage by weight: C: 0.06%-0.09%, Si: 0.10%-0.30%, Mn: 1.20%-1.50%, S: <=0.010%, P: <=0.020%, Nb: 0.004-0.010%, Alt: 0.020%-0.050%, and the rest is iron and inevitable impurities. The preparation method comprises the following steps: hot-rolling raw material, pickling, cold-rolling, cover annealing, flattening, inspection, and warehousing. The cold-rolled low-alloy steel strip obtained by the application has a yield strength of >=305 MPa, a tensile strength of >=440 MPa, and an elongation of >=29%.

This invention discloses a rapid, high-strength microwave bonding method for ceramics and cemented carbide, belonging to the field of ceramic material bonding technology. The method includes the following steps: preparing a metal solder; grinding, polishing, and cleaning the bonding surfaces of the ceramic and cemented carbide respectively; loading the prepared metal solder into a mold and pressing it under uniaxial pressure to obtain a metal solder sheet; placing the ceramic, metal solder sheet, and cemented carbide in a stacked structure in a microwave sintering furnace for microwave sintering to achieve the bonding of the ceramic and cemented carbide. Compared with traditional brazing and diffusion welding, this ceramic-cemented carbide microwave bonding method increases the heating / cooling rate by 6-10 times, improves the single-furnace bonding efficiency by 5-9 times, allows for mass production, and yields ceramic-cemented carbide bonding interfaces with high strength. This invention significantly improves production efficiency, reduces energy consumption, and has widespread application value.

The application discloses a kind of vacuum brazing methods of conical honeycomb inner ring assembly, S1: make the conical honeycomb ring of interference fit with the inner surface of support piece, the length interference amount of honeycomb ring is 1-3mm;S2: polishing cleaning;S3: filling adhesive tape brazing material;S4: honeycomb positioning and spot welding;S5: honeycomb brazing;The application does not need to clamp positioning tool, and the clearance between honeycomb ring and support piece during assembly and brazing process is guaranteed by process combination, and the brazing rate of more than 95% of the conical honeycomb inner ring assembly can be obtained by once brazing;Excess honeycomb is used, and the honeycomb interference amount is evenly distributed on the support piece by the center alternating spot welding fixing mode, to form pressure stress on the support piece;Vacuum brazing is carried out by short-time holding and slow cooling process combination, and the synchronous shrinkage of honeycomb and support piece during cooling process is guaranteed by slow cooling process, to reduce the possibility that honeycomb is forced to separate from support piece;At the same time, the holding time is appropriately shortened, so that the time of brazing material above liquidus temperature is reduced, and the corrosion of brazing material to honeycomb is avoided.

The invention provides a micro-channel heat exchange device based on high-entropy alloy connection and a preparation method and application of the micro-channel heat exchange device. According to the micro-channel heat exchange device, the connection quality of the joints of all layers of the micro-channel heat exchange device is improved, the tensile strength, the corrosion resistance and the hydrogen embrittlement resistance are improved, and the compactness, the corrosion resistance and the hydrogen embrittlement resistance of the fluid contact surface in the micro-channel heat exchange device are improved; the strength, the corrosion resistance and the hydrogen embrittlement resistance of the micro-channel heat exchange device are integrally improved, so that the micro-channel heat exchange device based on high-entropy alloy connection is suitable for places with high requirements for the space utilization rate and the reliability such as a hydrogen refueling station, and is particularly applied as a micro-channel heat exchanger of a hydrogen cooling system of the hydrogen refueling station.

This invention discloses a type of steel for hydropower engineering and its preparation method. The steel comprises the following chemical components: C, Mn, Si, Alt, Nb, V, Ti, Cr, Ni, Mo, Cu, and B. Its yield strength is ≥950 MPa, tensile strength is ≥1000 MPa, and it exhibits excellent load-bearing capacity, meeting the structural material requirements for high-stress conditions in large-scale hydropower projects. Its impact value at -40℃ is ≥200 J, and its aging impact value at -40℃ is ≥200 J, demonstrating excellent low-temperature toughness and aging stability. It exhibits outstanding resistance to low-temperature brittle fracture and long-term service embrittlement, providing strong service safety and durability. It is suitable for critical load-bearing structures in hydropower projects operating in cold, high-stress, and long-term service conditions.

The present application relates to the technical field of limestone lithium extraction, and particularly relates to a method for extracting lithium by transforming granulation into lithium clinker stacking and leaching, and the method comprises a water adding and grinding process.The present application has the beneficial effects of reducing grinding time, saving leaching time and reducing energy consumption.

The present application provides a preparation method and application of a crystalline silicon solar cell having a shallow junction diffusion emitter. The preparation method comprises a diffusion process and a chain oxidation process, the diffusion process comprises low temperature diffusion and high temperature propulsion, and the chain oxidation process comprises high-temperature chain oxidation. According to the present application, firstly, a low-doped diffusion shallow junction having a depth of 0.15 um is prepared by means of optimization of the diffusion process, and doping with a certain dose concentration is formed on the surface of a diffusion layer by using photon thermal activation radiation energy of high-temperature chain oxidation, so as to solve the mismatch problem of alloy ohmic contact subsequently formed with silver paste, and finally, the photoelectric conversion efficiency is improved to a high degree.

The application belongs to the technical field of inorganic nonmetallic materials, and relates to a high-thermal-conductivity spark plasma sintering silicon carbide ceramic material and a preparation method thereof. The application discloses a high-thermal-conductivity spark plasma sintering silicon carbide ceramic material, and raw materials of the high-thermal-conductivity spark plasma sintering silicon carbide ceramic material, according to mass percentage, include 85-98 wt.% of submicron silicon carbide powder, 0.01-2 wt.% of micron silicon carbide powder, 1-10 wt.% of rare earth oxide, 0.5-3 wt.% of magnesium oxide, 0.01-2 wt.% of carbon and 0.5-2 wt.% of dispersant. The application further discloses a preparation method of the high-thermal-conductivity spark plasma sintering silicon carbide ceramic material. The application adds magnesium oxide as a second sintering aid on the basis of a raw material system taking submicron silicon carbide powder as raw material and rare earth oxide as a sintering aid, significantly reduces the eutectic point and viscosity of a liquid phase, can effectively promote the mass transfer efficiency in the sintering process, improves the densification and grain growth efficiency, and thus improves the thermal conductivity of the SiC ceramic.

This invention relates to the field of magnesium alloy smelting technology, and in particular to a smelting process and apparatus for a semi-solid non-dendritic slurry of rare earth AS-based magnesium alloy. Using AS magnesium alloy as the base material and a Ce-La-Nd ternary rare earth mixture as the rare earth modifier, the process involves vacuum melting, electromagnetic stirring, and stepped cooling to obtain an ingot. A three-dimensional curve is plotted based on the JMAK equation to determine the critical temperature. Using a rheological casting apparatus, through internal cooling gradient, stirring-assisted slurry preparation, and ultrasonic-assisted isothermal treatment, combined with three-level quality judgment and defect closed-loop adjustment, a slurry with controllable liquid phase content, fine and rounded grains, and uniform rare earth distribution is prepared. The process exhibits high repeatability and meets the requirements of high-end semi-solid forming.

The application discloses a rolling method of isotropic TA22 titanium alloy sheet, which comprises the following steps: one, first fire rolling by stage heating; two, cutting and quenching; three, second fire rolling; four, cutting; five, third fire rolling; six, cutting and external cladding with a ladle cover; seven, cladding and stacking rolling; eight, finished product heat treatment, to obtain the TA22 titanium alloy sheet. The preparation method adopts the process of one fire rolling + quenching + two fire rolling + cladding and stacking rolling + finished product heat treatment, and combines with the control of rolling direction changing and the temperature and pass deformation rate in each rolling process, so that the plate is fully and uniformly deformed; the heat treatment mode of furnace cooling + air cooling is adopted, so that the plate is fully recrystallized, the plate deformation caused by direct cooling after heat treatment of the plate is avoided, the TA22 titanium alloy sheet with fine and uniform structure, high size uniformity and high isotropy is obtained, and the TA22 titanium alloy sheet is suitable for fields of ships, machinery, chemical industry, petroleum and the like.

The invention relates to a semi-solid alloying method for preparing a metal alloy material. The method comprises the following steps: firstly, obtaining a solid-liquid coexistence temperature interval suitable for treatment based on a phase diagram and thermodynamics calculation; then selecting metal raw materials forming the target component, and assembling the metal raw materials into an original blank with a close contact interface; and in the semi-solid temperature interval, a heat-force coupling process is adopted, a solid-liquid coexisting semi-solid structure is formed through local liquefaction induced by diffusion / mass transfer, and macroscopic flow mixing and microstructure reconstruction of the material are enhanced under the shear deformation or stirring effect, so that uniform alloying and structure refinement of the target alloy material are achieved. Compared with the prior art, the method has the advantages that uniform alloying and structure refinement of the alloy material can be realized under the condition that the traditional multi-step series connection of smelting, casting, heat treatment, deformation processing and the like is not needed, the alloy material with uniform components, fine matrix structure and uniformly distributed second phase is obtained, the process flow is simplified, and the energy consumption is low.

This invention belongs to the field of alloy forming technology and discloses a 2GPa-grade hydrogen embrittlement-resistant hot-formed steel containing NbVTiMo composite precipitates, its preparation method, and its applications. Through the synergistic proportioning of Nb, V, Ti, and Mo quaternary microalloys, a NbVTiMo composite nano-precipitate with high thermal stability and good interfacial bonding is formed. Compared with traditional single / low-element microalloy precipitates, this composite precipitate can act as a highly efficient hydrogen trap, significantly improving the hydrogen atom capture ability, effectively inhibiting hydrogen enrichment at grain boundaries and defects, improving the hydrogen embrittlement resistance of hot-formed steel, and reducing the risk of hydrogen-induced cracking and delayed fracture. Simultaneously, extending the coiling holding time promotes the full nucleation and dispersed distribution of the precipitates; shortening the austenitizing holding time avoids excessive dissolution and coarsening of the precipitates, maintaining the nanoscale of the precipitates, and achieving a fine and dense distribution of the precipitates, thus balancing hydrogen embrittlement resistance with the strength and toughness of the steel.

This invention discloses a seamless stainless steel tube for heat exchangers and its manufacturing process, relating to the field of metal materials technology. The tube wall consists of three metallurgically bonded gradient functional layers, from the inside out: an inner layer (30%-40% of the wall thickness) made of copper microalloyed austenitic stainless steel, wherein Cu elements are uniformly distributed in the austenitic matrix in the form of nano / submicron dispersed particles; a middle layer (20%-30% of the wall thickness) made of ultra-low carbon high nitrogen austenitic stainless steel; and an outer layer (30%-50% of the wall thickness) made of molybdenum-nitrogen composite reinforced austenitic stainless steel. This invention achieves improved thermal conductivity, a qualitative leap in corrosion resistance, reduced residual stress, energy-saving processes, and permanent protection of the inner surface through the synergistic effect of a three-layer gradient structure design, internal surface strengthening, and pulsed current heat treatment.

This invention relates to a high-density, high-strength, and ductile TaNbZr multiphase alloy and its preparation method, belonging to the field of alloy technology. The alloy consists of a Ta phase, a TaNb solid solution phase, and a NbZr solid solution phase. Through multiphase structure design, high density, high strength, and good ductility are synergistically optimized. The preparation method employs a powder metallurgy process of stepwise ball milling and pressure-driven rapid sintering. First, stepwise ball milling disperses excess Ta into different phases, reducing the modulus mismatch caused by Ta and avoiding the formation of brittle phases such as TaZr. Second, pressure-driven rapid sintering achieves good material density, and increasing the heating rate and shortening the holding time reduces elemental diffusion. Finally, a refractory high-entropy TaNbZr alloy with excellent mechanical properties is obtained.

This invention discloses a method for preparing highly spherical zirconia microspheres based on a controllable emulsion template method. Using a water-in-oil emulsion as a template, a composite emulsifier of Span-80 and Tween-80 is employed at a mass ratio of 2:1-4:1, a total concentration of 2-3%, and an oil-to-water volume ratio of 3:1-5:1. Uniform and stable emulsion droplets are formed under a stirring intensity of 800-1500 rpm. The emulsion is then cured at a constant temperature of 50-65℃ for 1-3 hours to allow the gel network to form slowly, preventing microsphere shrinkage and cracking. Finally, a three-stage stepped sintering process is used: increasing the temperature at 1-3℃ / min to 300-400℃ and holding for 1-2 hours; increasing the temperature at 2-5℃ / min to 700-800℃ and holding for 1-2 hours; and increasing the temperature at 3-8℃ / min to 1350-1400℃ and holding for 15-30 minutes to inhibit abnormal grain growth and achieve sufficient densification. Through the coordinated control of emulsification, curing and sintering, the prepared zirconia microspheres have excellent sphericity, particle size uniformity, density and mechanical properties, and the process parameters can be adjusted over a wide range, showing good prospects for industrial application.

The application discloses a kind of super-high-strength mining round-link chain steel and a preparation method thereof, and belongs to the technical field of round-link chain steel, solve the problem that the strength and toughness of round-link chain steel in prior art cannot be effectively improved simultaneously.The components of the super-high-strength mining round-link chain steel include, by mass percentage: C: 0.22% to 0.27%, Si: 0.10% to 0.17%, Mn: 0.48% to 0.62%, P: ≤0.015%, S: ≤0.005%, Cr: 0.41% to 0.66%, Ni: 0.88% to 1.23%, Mo: 0.87% to 1.13%, Cu: 0% to 0.60%, V: 0.18% to 0.36%, W: 0.21% to 0.45%, and the balance is Fe and unavoidable impurities.The super-high-strength mining round-link chain steel has high strength and good plasticity and toughness.

The present application relates to a kind of high-temperature-resistant polymer foam material and its preparation method, belong to polymer processing technical field.The present application is by BMI resin (bismaleimide resin) and polyaryletherketone resin are compounded, after foaming, heat treatment is carried out, BMI resin is completed solidification, crosslinking structure is formed, to form semi-interpenetrating network, so, compared with the mechanical properties and heat resistance of polyaryletherketone foam of thermoplasticity, material can be obviously improved, in addition, the cold-pressing foaming mode used in the present application has the characteristics of short heat preservation time, foaming efficiency is high, can effectively control the solidification degree of BMI resin in foaming process, avoid BMI resin excessive crosslinking, so that composite material has good foaming performance.