363 results about "Cryogenic treatment" patented technology

The invention discloses super high-strength and high-toughness steel and a preparation method thereof. The super high-strength and high-toughness steel comprises the following components in percentage by mass: 0.18 to 0.35 percent of C, 0.05 to 0.12 percent of Si, 0.30 to 0.50 percent of Mn, less than or equal to 0.008 percent of P, less than or equal to 0.008 percent of S, 0.8 to 1.5 percent of Cr, 0.10 to 0.30 percent of Mo, 2.5 to 3.5 percent of Ni, 0.05 to 0.12 percent of V, 0.01 to 0.05 percent of RE and the balance of Fe. When the content of C is not higher than 0.25%, the alloy contains 0.0005-0.003% of B and the balance of Fe and other inevitable impurities; the preparation process comprises the steps of smelting, homogenization treatment and blank opening, intermediate annealing treatment, large-deformation warm rolling, subzero treatment and low-temperature tempering treatment. The medium-carbon martensite super-high-strength and high-toughness steel with a large enough metastable austenite phase region is obtained through component design, conventional equipment and a production process are utilized for tissue regulation and control, the size of a martensite block is refined to about 1 micron, and the comprehensive mechanical property of the medium-carbon martensite steel is remarkably improved. The material prepared by the invention has ultrahigh strength and high toughness, and is easy for industrial large-scale production and lower in cost.

The invention belongs to the technical field of wafer processing, and discloses a multi-section high-flatness wafer cutting method which comprises the following steps: S1, wafer pretreatment and stress buffer layer preparation; s2, performing layered rough cutting by using a diamond blade; s3, plasma fine cutting and interface repairing; s4, performing multi-layer cooling and surface polishing; and S5, surface quality closed-loop detection is carried out. According to the method, copper layer residues and resin carbonization defects are synchronously eliminated. Cryogenic treatment induces lattice reconstruction through ultrafast phase change and blocks a chain reaction of dislocation defects, so that the intrinsic mechanical strength of the material is recovered, and a chemical mechanical polishing system activates the self-repairing characteristic of the material while removing a sub-surface damaged layer through the synergistic effect of abrasive chemical activity and mechanical shearing force, so that an atomic-scale smooth interface is formed, and the self-repairing performance of the material is improved. A closed-loop detection system depends on multi-dimensional data fusion and ion beam fixed-point repair, accurate positioning and performance recovery of cross-scale defects are achieved, and the electrical integrity of a chip functional area is ensured.

The invention provides a multi-step aging treatment method for improving the toughness of an ultrahigh-strength steel ingot, and belongs to the technical field of steel heat treatment. The treatment method comprises the following steps: carrying out solution treatment on the ultrahigh-strength steel at the temperature above AC3, carrying out water cooling or oil cooling to the room temperature, then carrying out subzero treatment, taking out and recovering to the room temperature; the multi-step aging treatment comprises the first step of single-time or multi-time low-temperature aging at the temperature of 400-550 DEG C and the second step of high-temperature aging at the temperature of 550-650 DEG C, and the ultrahigh-strength steel ingot is obtained. According to the method, the content of reversed austenite is increased, especially film-shaped austenite with stable mechanics is increased, meanwhile, it is guaranteed that a precipitated phase is not obviously coarsened, and good obdurability matching is achieved.

The invention discloses a long-service-life composite heat treatment method for a harmonic reducer flexible gear made of an SNCM439 material, belongs to the technical field of long-service-life manufacturing of harmonic reducers, and solves the problem that the service life of the harmonic reducer flexible gear is short. According to the method, a flexible gear made of an SNCM439 material is subjected to a composite heat treatment method of secondary normalizing, quenching, deep cooling and tempering, and the specific process method is as follows: the primary normalizing temperature is 870-890 DEG C, the heat preservation time is 50-70 minutes, and air cooling is performed; the secondary normalizing temperature is 850-870 DEG C, the heat preservation time is 50-70 min, and air cooling is carried out; the quenching temperature is 830-850 DEG C, the heat preservation time is 50-70 min, and oil cooling is conducted; the subzero treatment temperature is-70 DEG C to-90 DEG C, and the heat preservation time is 110-120 min; the tempering temperature is 490-510 DEG C, and the heat preservation time is 120-140 minutes.

The invention discloses a method for refining grains of a titanium alloy. According to the method, an original low-oxygen-content titanium alloy plate is subjected to cryogenic pretreatment, the temperature of the core of the original low-oxygen-content titanium alloy plate is reduced to a certain temperature, then the cryogenic low-oxygen-content titanium alloy plate is fed into a rolling mill, the single-pass reduction rate is controlled, cryogenic rolling is completed, high refinement and uniform distribution of crystal grains are achieved, and the low-oxygen-content titanium alloy plate is obtained. And the rolled titanium alloy plate is subjected to subzero treatment again, and the titanium alloy plate of the complex twin crystal structure formed by intersection of {11-22} and {10-11} twin crystals is obtained. The method has the beneficial effects that under the synergistic effect of low oxygen and deep cooling, even under the extremely small deformation amount, the cross effect of various twin crystal systems can be efficiently activated, a high-density and complex twin crystal structure is formed, high refinement and uniform distribution of crystal grains are achieved, then the mechanical strength and low-temperature toughness of the material are remarkably improved, and the service life of the material is prolonged. And the application requirements in a severe low-temperature service environment are met.

The invention discloses an ejector pin anti-fatigue strengthening method based on multi-section variable-temperature treatment, and relates to the technical field of ejector pin anti-fatigue strengthening, and the ejector pin anti-fatigue strengthening method comprises the following steps: austenitizing high-temperature quenching: heating an ejector pin to an austenitizing temperature, and then carrying out zoned cooling on the ejector pin; medium-temperature tempering and thermal-state mechanical strengthening are conducted, specifically, the ejector pin is tempered at the medium-temperature tempering temperature, and thermal-state shot blasting or laser shock is conducted on the ejector pin in the heat preservation period or after heat preservation is completed; intermediate low-temperature plasma nitriding: carrying out plasma nitriding in a nitrogen-hydrogen gas environment; subzero treatment: placing the ejector pin in liquid nitrogen; and finally, low-temperature tempering and cold-state mechanical strengthening are conducted. Through multi-section temperature gradient treatment, phase change distribution control over different temperature sections is achieved, too high internal stress and brittleness generated by one-time quenching are avoided, sudden size change and hot cracks induced by phase change are prevented, a controllable surface-core hardness and toughness gradient is formed, the surface crack initiation tendency is reduced, and the surface quality is improved. And the consistency and controllability of anti-fatigue basic conditions are improved.

The invention relates to the field of superconducting wire forming methods, in particular to a Nb3Sn superconducting wire preparation method based on multi-core wire liquid nitrogen cold drawing, and the Nb3Sn superconducting wire preparation method based on multi-core wire liquid nitrogen cold drawing comprises the following steps: preparing ultrahigh-tin-content copper-tin alloy powder by adopting a gas atomization method; the oxygen-free copper pipe, the oxygen-free copper rod and the pure niobium rod are machined, and the oxygen-free copper pipe and an oxygen-free copper bolt plug are obtained; acid pickling, cleaning and drying are carried out; uniformly fixing the pure niobium rods in the oxygen-free copper pipe to form a combined blank; performing rotary swaging to a required size, and then continuously drawing to obtain a finished wire; carrying out pulse treatment, and then carrying out air cooling to room temperature; and finally obtaining the Nb3Sn superconducting wire. According to the method, the strength and plasticity of the oxygen-free copper pipe sheath are improved through a liquid nitrogen cold drawing method, the combined blank is subjected to subzero treatment in the rotary swaging and drawing process, the plasticity of the combined blank is improved, and the high-strength and high-plasticity Ni3Sn superconducting wire can be obtained.

The invention discloses a preparation method for improving the toughness of 17-4PH stainless steel manufactured by an additive in the technical field of heat treatment of metal materials. The preparation method comprises the following steps: forming a 17-4PH stainless steel component through an additive manufacturing process; the 17-4PH stainless steel component obtained through additive manufacturing is subjected to heat treatment, and the heat treatment process sequentially comprises direct aging treatment, subzero treatment and tempering treatment. According to the method, the 17-4PH stainless steel component is formed through the laser additive manufacturing process, then specific heat treatment is conducted on the 17-4PH stainless steel component, the strength and toughness of the component are optimized and improved, the method is simple in process, the problem of strength and toughness mismatch and the deformation and cracking risk caused by traditional high-temperature solid solution and aging heat treatment can be remarkably solved, and the method is suitable for industrial production. The strength and toughness of the laser additive manufactured 17-4PH stainless steel are greatly improved, and the service stability and safety of the laser additive manufactured 17-4PH stainless steel component are guaranteed.

The invention relates to an ultrahigh-strength and high-toughness steel member and a preparation method thereof. Comprising the following steps that (1) a cobalt-free maraging steel wire is adopted, and the wire is prepared from, by mass, 0%-0.02% of C, 0.5%-0.6% of Ti, 0.1%-0.2% of Al, 13.5%-14.5% of Ni, 2.5%-3.5% of Mo, 2.5%-3.5% of Cr, 0.5%-1.5% of Mn, 0%-0.02% of Si and the balance Fe; (2) process parameters and a material increasing path of electric arc material increasing are determined; (3) component material adding is conducted; (4) aging treatment is conducted, specifically, the component obtained in the step (3) is heated to 450-480 DEG C from the room temperature, heat preservation is conducted for 6 + / -0.5 h, and then the component is taken out and air-cooled to the room temperature; and (5) subzero treatment is conducted, specifically, the component subjected to air cooling to the room temperature in the step (4) is put into a subzero medium to be cooled to-130 DEG C or below, heat preservation is conducted for 6-12 h, then the component is taken out, and the ultrahigh-strength and high-toughness steel component is obtained. The component prepared by the preparation method disclosed by the invention finally has high strength and good toughness, and has a good application value.

The invention discloses special hot work die steel for large-scale integrated die casting and a preparation method of the special hot work die steel, and belongs to the technical field of hot work die steel. The steel comprises the following chemical components in percentage by mass: 0.28%-0.35% of C, 0.01%-0.025% of La, 0.01%-0.02% of Ce, 0.4%-0.45% of Mn, 0.1%-0.2% of Si, 4.5%-5.5% of Cr, 1.50%-2.00% of W, 2.2%-2.8% of Mo, 0.8%-1.2% of V, 1.0%-1.5% of Co, 0.1%-0.3% of Nb and the balance of Fe and impurities (S and P are less than or equal to 0.015%). The preparation method comprises the composite processes of vacuum induction melting and electroslag remelting purification, hydrogen firing high-temperature homogenization and three-upsetting and three-drawing multi-directional forging, spheroidizing annealing and subzero treatment, step quenching and double tempering, multi-element co-permeation, supersonic particle bombardment surface nanocrystallization and plasma boriding. The rare earth element La / Ce refined grain boundary is combined with multi-element alloy strengthening and surface nanocrystallization-boronizing synergistic treatment, so that the hardness, impact toughness and thermal fatigue life of the die steel are remarkably improved, and the die steel is suitable for high-temperature, high-pressure and high-wear working conditions of a large integrated die-casting die.

The invention discloses a preparation process of a high-strength corrosion-resistant stainless steel fastener. The preparation process comprises the steps of material modification, warm upsetting forming, stabilizing treatment, cryogenic strengthening, gradient aging, surface treatment, post-treatment and the like. According to the process, the alloy component proportion is optimized, a thermal mechanical treatment technology of warm upsetting forming, subzero treatment and gradient aging is combined, a nano-composite coating and micro-arc oxidation sealing process is innovatively introduced, and the process comprises vacuum melting and controlled rolling of customized high-nitrogen stainless steel wires, deformation-induced martensite regulation in warm upsetting forming, low-temperature hot rolling, high-temperature hot rolling, high-temperature hot rolling, high-temperature hot rolling, high-temperature hot rolling and high-temperature hot rolling. The tensile strength and the salt spray corrosion resistance of the fastener are remarkably improved through deep cooling-medium temperature aging synergistic strengthening, double-layer nano TiN / CrN composite coating deposition and micro-arc oxidation micropore sealing treatment, the problem that a traditional stainless steel fastener is insufficient in strength and low in stress corrosion sensitivity is solved through the technology, and the technology is particularly suitable for the extreme environments such as aerospace and ocean engineering.

The invention discloses a heat treatment process for improving the obdurability of die steel, and belongs to the technical field of metal heat treatment. The invention relates to a heat treatment process for improving the toughness of die steel, which adopts a die steel material with a specific component proportion, and the die steel material comprises carbon, chromium, molybdenum, vanadium, tungsten, nickel, niobium, niobium carbide and trace boron element. By sequentially implementing austenitizing, quenching, deformation heat treatment, multi-stage subzero treatment, pulsed magnetic field assisted tempering, gradient surface hardening and nano-precipitation regulation treatment, the hardness and toughness of the die steel are remarkably improved. Particularly, through the synergistic effect of multiple advanced heat treatment means, the martensite structure is effectively refined, carbide precipitation is strengthened, the surface hardness and the core toughness are improved, the comprehensive performance of toughness and toughness is achieved, and the method is suitable for the field of high-performance injection molds and hot-working molds.

The invention relates to the technical field of metal heat treatment, in particular to a silicon alloy steel bearing ring high-temperature salt bath quenching process for a high-temperature load environment, which comprises the following steps: S1, carrying out surface sand blasting treatment on a silicon alloy steel bearing ring; s2, stepped heating-heat preservation-cooling treatment is carried out, and the uniformly austenitized ferrule is obtained; s3, the uniformly austenitized ferrule is immersed in a composite salt bath; s4, staged cooling treatment of an air cooling stage and an oil cooling stage is conducted in sequence; s5, the martensite matrix ferrule is subjected to subzero treatment and staged heating; and S6, multi-stage tempering treatment with different temperature gradients is conducted, and the final high-temperature bearing ring is obtained. Through the combined process of stepped austenitizing, composite salt bath ultrasonic quenching, graded cooling, deep cooling and multi-stage tempering, homogenization and stabilization of the structure of the bearing ring are achieved, and the dimensional stability and the tempering resistance of the bearing ring in the high-temperature load environment are improved.

The utility model relates to a nitrogen filling inerting and exhaust liquid nitrogen subzero treatment system of an external floating roof tank, which comprises the external floating roof tank (1), an external floating roof (2), a primary seal (3), a sealed space (4), a secondary seal (5), a pressure transmitter (6), a frequency conversion fan (7), a sampling pump (8), a gas sensor, a subzero condenser (11), a liquid nitrogen tank (12), a nitrogen injection valve (15) and a nitrogen buffer tank (16). The sealed space (4) is connected with the cryogenic condenser (11) through the pressure transmitter (6) and the frequency conversion fan (7), the sampling pump (8) is connected with the sealed space (4) and the cryogenic condenser (11), the gas sensor is arranged between the sampling pump (8) and the cryogenic condenser (11), and the cryogenic condenser (11) is connected with the liquid nitrogen tank (12) and the nitrogen buffer tank (16). The problems of nitrogen source of active safe nitrogen charging and oil gas recycling and up-to-standard emission of exhausted gas during nitrogen charging are solved.

The invention discloses a high-wear-resistance hard alloy CVD (Chemical Vapor Deposition) coated cutting tool and a preparation method thereof, WC-Co (4-8) Ti (1-5) Ta (1-5) Nb (0.2-2) Cr (0.2-2) Fe (0.2-2) Al (0.2-2) is used as a blade substrate, TiN, TiCN, Al2O3 and a surface TiN coating are deposited firstly, and then the coated blade is subjected to subzero treatment and tempering treatment. According to the method, through subzero treatment between the base body and the coating, the compressive stress is introduced into the coating or an interface by utilizing the difference of the extremely low temperature shrinkage rates of the coating and the base body, the tensile stress caused by the compressive stress neutralization deposition is utilized, and the uniform distribution of nanoscale carbide precipitates is promoted by utilizing a proper tempering process; and the cold brittleness phenomenon caused by subzero treatment and the generated high residual compressive stress are avoided, and the abrasion resistance and the anti-stripping capacity of the base body are further improved. According to the method, the driving effect of residual tensile stress in the CVD coating on crack initiation is reduced, the crack density is greatly reduced, the mechanical property of a hard alloy matrix and the stress state of the coating are synergistically improved, and the mechanical property of the cutter is enhanced.

The invention relates to the technical field of ultrahigh-strength and high-toughness steel thermal deformation and thermal treatment production, and particularly discloses a fastener, a W-containing high-cobalt-nickel secondary hardening steel small-specification bar and a preparation method. An intermediate blank bar is heated to a solid solution temperature interval to be subjected to heat preservation solid solution treatment; continuously rolling the intermediate blank bar subjected to solid solution treatment to obtain a small-specification bar primary product; after online sizing blanking is conducted on the small-specification bar primary product, quenching treatment is conducted, and the small-specification bar primary product is cooled to the room temperature; the small-specification bar primary product cooled to the room temperature is subjected to subzero treatment and then is air-cooled to the room temperature, the subzero treatment temperature is smaller than or equal to-73 DEG C, and a subzero bar is obtained; after secondary hardening and tempering treatment is conducted on the deeply-cooled bar, the bar is air-cooled to the room temperature; the diameter of the W-containing high-cobalt-nickel secondary hardening steel small-specification bar ranges from 20 mm to 35 mm. The performance of the material is improved, the production process can be optimized, and the production efficiency is improved.

The invention discloses a heat treatment process for spring processing and production, and belongs to the technical field of metal material heat treatment, the heat treatment process for spring processing and production comprises the following steps: detecting element content through laser-induced breakdown spectroscopy, and dynamically adapting parameters such as quenching temperature by using a reinforcement learning algorithm; calculating the critical concentration of titanium carbide based on JMatPro, monitoring the component gradient of a cladding layer in real time, and adjusting the laser power, the powder feeding rate and the cladding path; acquiring temperature field and stress field data by using a sensor, and adjusting the magnetic field intensity, the pre-deformation amount and the flow velocity of a cooling medium; a metallographic image is analyzed through a convolutional neural network, subzero treatment is intelligently triggered, and tempering parameters are optimized; and according to the surface roughness, parameters are reversely corrected, and self-optimization is carried out through the block chain. Intelligent and accurate regulation and control of the whole process of component detection, process control and quality detection are achieved, the mechanical property and production efficiency of the spring are improved, and the method has the advantages of dynamic adaptation, real-time monitoring, multi-field coupling control, data closed-loop optimization and the like.

The invention discloses a multifunctional tumor targeted low-temperature treatment nano platform and application thereof, and belongs to the technical field of nano biological medicines. According to the multifunctional tumor targeted low-temperature treatment nano platform, the two-dimensional Ti3C2 nano material serves as a carrier, indocyanine green is loaded to serve as a photosensitizer, polydopamine is modified on the surface to improve the stability, and gambogic acid is loaded to serve as an anti-tumor drug and a heat shock protein inhibitor; and a nucleic acid aptamer capable of recognizing specific protein on the cell surface is coupled in a covalent binding manner. The multifunctional tumor targeted low-temperature treatment nano platform is small in particle size, high in dispersion degree and good in biocompatibility, and shows excellent photo-thermal conversion capacity, photodynamic treatment effect and chemotherapy effect in tumor targeted treatment. The apoptosis of tumor cells can be effectively induced under a relatively low temperature condition, and the damage of high temperature to surrounding healthy tissues is remarkably reduced. The tumor focus specific recognition capability is also realized, the high enrichment at the tumor part can be realized, and the treatment effect is enhanced.

The invention relates to the technical field of bearing manufacturing, and provides a high-strength and high-toughness double-peak tempering heat treatment method for aero-engine high-nitrogen bearing steel, which comprises the following steps: a steel ingot of the high-nitrogen bearing steel is subjected to cold rolling after being forged and annealed, the rolling speed is less than 10m / min, and the rolling deformation is 30-40%; after a rolled workpiece is austenitized, the workpiece is sequentially subjected to first-time deep cooling (-196 DEG C to-80 DEG C), pre-strengthening tempering (160-180 DEG C), second-time deep cooling (-196 DEG C to-80 DEG C) and final strengthening tempering (450-500 DEG C), and the high-strength and high-toughness aero-engine high-nitrogen bearing steel is obtained. According to the high-strength, high-toughness and high-corrosion-resistance forming and manufacturing method, the high-strength, high-toughness and high-corrosion-resistance requirements of a bearing under the extreme working condition of an aero-engine are met, the tempering technology of'double-peak tempering 'formed by cold rolling forming in advance, pre-strengthening tempering and final strengthening tempering is organically combined, a double-strength structure of solution strengthening and precipitation strengthening is obtained, and the high-strength, high-toughness and high-corrosion-resistance forming and manufacturing method is achieved.

The present invention belongs to the technical field of composite material preparation, and particularly relates to a high-performance conch shell bionic structure aluminum-based composite armor and a forming method thereof. The forming process is as follows: first, mix powders, then stack and compact the powders to form a fixed combination, solutionize the laminated material of the combination and immediately perform hot rolling, and then perform aging treatment. Deep cryogenic treatment can be carried out after aging; at least one layer in the intermediate layer of the laminated material before rolling is composed of powders, and the high-strength layer is located between metal plates. The high-strength layer is composed of ceramic particles and metal particles evenly mixed. The present invention first attempts to introduce powders between two metal plates. By virtue of the high activity of the powders, solutionizing is carried out first and then rolling, which can improve the diffusion of the powders and achieve better bonding. The strong and tough alternating stacking of the conch shell structure causes cracks to deflect when passing between layers, and will bypass the particles when passing through the particles in the high-strength layer to achieve deflection. This form of multiple reciprocating deflection of cracks can improve the energy absorption rate, thereby improving the impact resistance, and also greatly improving the strength and toughness of the aluminum-based composite armor.

The invention belongs to the technical field of aerospace part machining, and particularly relates to a forming process of a titanium alloy cylindrical spiral spring for an aerospace craft, and the forming process specifically comprises the following steps: S1, carrying out flaw detection on a titanium alloy raw material; s2, a titanium alloy raw material is machined into a cylindrical spiral spring; s3, vacuum aging heat treatment is conducted on the cylindrical spiral spring, the heat treatment parameters are 545 + / -5 DEG C, heat preservation is conducted for 5.5 h to 6.5 h, and vacuum cooling is conducted in a cold chamber; s4, the formed cylindrical spiral spring is subjected to liquid nitrogen subzero treatment; s5, the cylindrical spiral spring subjected to subzero treatment is subjected to strong pressure treatment; and S6, shot blasting treatment is conducted on the cylindrical spiral spring subjected to strong pressing treatment. Compared with a traditional carbon steel spring, the weight of the titanium alloy cylindrical spiral spring manufactured through the process is reduced by about 50% on the premise that the same mechanical property is kept, and the effective loading capacity of a spacecraft is remarkably improved.

The invention discloses high-toughness low-carbon bainite steel and a preparation method and application thereof, and belongs to the technical field of metal heat treatment, and the high-toughness low-carbon bainite steel comprises the following chemical components: 0.2-0.3% of C, 1.50-1.70% of Si, 0.3-0.6% of Al, 0.1-0.3% of Mo, 1.80-2.1% of Mn, 0.75-0.95% of Cr, 0.01-0.03% of Ni and inevitable impurities. The preparation method comprises the following steps that steel is subjected to heat preservation heat treatment and then sequentially subjected to two-stage isothermal quenching heat treatment, two times of subzero treatment and tempering treatment, and the high-toughness low-carbon bainite steel is obtained. According to the preparation method disclosed by the invention, the low-carbon bainite steel is ensured to have good comprehensive mechanical properties on the basis of a preparation process combined with structure regulation and optimization. And in addition, a complex process is avoided, the production efficiency is improved, and rapid and large-batch production of the low-carbon bainite steel is facilitated.

The invention discloses a method for optimizing residual stress distribution of a high-speed steel punch based on a spheroidizing annealing process, and belongs to the technical field of metal material heat treatment. The method for optimizing the residual stress distribution of the high-speed steel punch based on the spheroidizing annealing process comprises a circulating spheroidizing annealing process, a quenching process, a subzero treatment process and a multi-stage tempering process, and aims at achieving the following purposes that punch machining residual stress is remarkably released, especially compressive stress concentration of geometric mutation areas (such as the root and the head), and the crack initiation risk is reduced; the microstructure uniformity is optimized, and the comprehensive mechanical property of the material is improved through carbide refining and dispersion distribution; the stress evolution rule under the synergistic effect of multiple processes is quantified, and accurate guidance is provided for process optimization.

The invention provides an aluminum-based powder metallurgy automobile skylight guide rail sample piece preparation process and device, and the preparation process specifically comprises the following steps: preparing aluminum-based alloy powder, and uniformly mixing the aluminum-based alloy powder; carrying out ball milling and mixing treatment; gradient pre-pressing treatment; sintering treatment is carried out, and ultrasonic waves are added; carrying out hot isostatic pressing molding and simultaneously carrying out electric pulse treatment; carrying out solution treatment; aging treatment; and performing subzero treatment and ultrasonic treatment. The aluminum-based alloy powder comprises the following components in percentage by mass: 4.9%-5.9% of Cu, 6.8%-8.2% of Zn, 1%-5% of Si, 0.2%-0.8% of Mn, 0.6%-1.2% of Mg, 0.2%-0.9% of Zr, 0.3%-1.0% of Fe and the balance of Al; the ratio of the Ni powder to the carbon fibers to the aluminum-based alloy powder is 0.02-0.05, and the ratio of the Ni powder to the carbon fibers is (2-4): (0.6-1.2). According to the preparation process of the aluminum-based powder metallurgy automobile sunroof guide rail sample piece, the powder metallurgy automobile sunroof guide rail sample piece can have the technical effects of high strength and high precision, and meanwhile, the surface quality is guaranteed by improving the material design.

The invention discloses a method for rapidly optimizing components and heat treatment of super martensitic stainless steel, and relates to the technical field of material research methods.The method comprises the steps that firstly, a wide component FCC phase region of a stainless steel system is determined according to a phase diagram calculation result, end component components are determined, and then two end components are obtained through smelting and linear cutting in sequence; and fixing the two end components together, annealing and carrying out subzero treatment to obtain a super martensitic stainless steel diffusion couple, and finally carrying out component gradient analysis and hardness and Young modulus test on the diffusion couple to obtain the corresponding relationship among the components, hardness and Young modulus of the stainless steel under different heat treatments. Therefore, the composition of the high-hardness super martensite and corresponding heat treatment parameters are determined. A large amount of approximately continuous phase composition-component-heat treatment-hardness-Young modulus corresponding experimental data information can be obtained in a short time, and the high-performance martensitic stainless steel and heat treatment parameters thereof can be quickly optimized.

The invention discloses a preparation method of a copper alloy crystallizer, and belongs to the technical field of copper alloy forming machining. According to the method, a copper alloy raw material serves as a basis, a cast ingot is prepared through burdening and vacuum melting casting in sequence, hot forging reaming operation is conducted on the cast ingot to form an alloy pipe blank, then the alloy pipe blank is machined into an intermediate pipe fitting through a spinning procedure, finally, aging treatment and subzero treatment are conducted on the intermediate pipe fitting in a combined mode, and the copper alloy crystallizer is finally prepared. According to the preparation method, the uniformity of alloy components is guaranteed through vacuum melting, precise plastic processing of the crystallizer is achieved by means of hot forging reaming and spinning forming, the alloy structure performance is optimized in cooperation with aging-cryogenic composite heat treatment, and the prepared crystallizer has excellent mechanical performance and service stability and is suitable for industrial large-scale production.

The application belongs to the technical field of mechanical property strengthening of metal materials, and particularly relates to a composite strengthening method for improving the strength and plasticity of metal alloys. The method comprises the following steps: (1) performing surface pretreatment on a metal alloy sample; (2) performing ion implantation processing on the pretreated metal alloy sample; (3) coating a layer of nanoparticles on the surface of the metal alloy sample after ion implantation processing; (4) performing cryogenic treatment on the metal alloy sample with the surface coated with the nanoparticles; (5) performing electric pulse treatment on the metal alloy sample after the cryogenic treatment; and (6) performing cryogenic holding treatment on the metal alloy sample after the electric pulse treatment. The application can effectively improve the strength and plasticity of the metal alloy.

The invention discloses a cryogenic heat treatment method for reducing elastic hysteresis of 40CrNiMo alloy, which comprises the following steps of: (1) quenching the 40CrNiMo alloy at the quenching temperature of 850 DEG C, preserving heat for 1 hour, and cooling to room temperature by adopting a 10% PAG solution; (2) the quenched 40CrNiMo alloy is subjected to tempering treatment, the tempering temperature ranges from 400 DEG C to 600 DEG C, heat preservation is conducted for 3 h, and after heat preservation is completed, air cooling is conducted to the room temperature; and (3) the tempered 40CrNiMo alloy is subjected to subzero treatment, the subzero temperature ranges from-180 DEG C to-196 DEG C, the heat preservation time ranges from 12 h to 24 h, and then the temperature is naturally increased to the room temperature. According to the method, conventional quenching and tempering processes are combined with subzero treatment, so that the elastic lag of the 40CrNiMo alloy steel is effectively reduced.

The invention discloses a titanium alloy precision ring part cutting process which comprises the following steps: 1, carrying out solution treatment on a titanium alloy blank at the treatment temperature of 925-955 DEG C for 1-1.5 hours, and then carrying out air cooling; secondly, after solution treatment, the blank is subjected to subzero treatment, the subzero temperature ranges from-196 DEG C, the subzero time ranges from 12 hours to 14 hours, and then air cooling is conducted; thirdly, the optimized cutting parameters are adopted for cutting the blank; fourthly, after cutting machining is completed, the part is subjected to annealing treatment, the heat preservation time is 3 hours, and then air cooling is conducted; and fifthly, after annealing treatment, the part is subjected to subzero treatment again, the subzero treatment time is 12 hours, and then air cooling is conducted. By optimizing cutting parameters and a subsequent treatment process, the cutting residual stress of the titanium alloy precision ring part is reduced, so that the dimensional stability of the part is improved, and meanwhile, the service life of the part is prolonged.

The present invention provides a method and device for ultra-low temperature plastic connection of aluminum alloy thin-walled conical tubes and thin plates, belonging to the technical field of light alloy tube-sheet connection. Aiming at the difficulty of efficient connection of aluminum alloy thin-walled conical tubes and thin plates, the conical tube and the prefabricated thin plate are clamped and positioned with a half-type pressure ring; by virtue of the ultra-low temperature deformation enhancement and plasticization characteristics of aluminum alloy, an ultra-low temperature medium is filled in the insulation tank, and the conical tube and the thin plate are cryogenically treated at the same time; the root of the conical tube is expanded in an ultra-low temperature environment by using an expanding punch, and the tube material is squeezed out of the center hole of the thin plate; the remaining material is pressed into the annular groove near the center hole on the lower surface of the thin plate by a rotating extrusion plate, so as to realize efficient connection of the aluminum alloy thin-walled conical tube and the thin plate. The present invention combines the expansion process of thin-walled conical tubes with the plastic connection process of conical tubes, and has the advantages of high efficiency and speed, green and environmental protection, high process integration, and good plastic joint quality.