316 results about "Cryogenic treatment" patented technology

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 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 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 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 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 invention relates to the field of boron steel materials, and particularly discloses a heat treatment method of high-strength boron steel. According to the high-strength boron steel, the process of annealing, quenching and subzero treatment is adopted, the metallographic structure in the boron steel is optimized, the strength, plasticity and impact resistance of the boron steel are remarkably improved, and meanwhile the service life of the boron steel is further prolonged. The boron steel material with high strength, high plasticity and excellent impact resistance is effectively prepared by utilizing the heat treatment method of the boron steel, and the hydraulic shear blade prepared by utilizing the boron steel material effectively solves the problems of poor hardness, plasticity and impact resistance of a blade of a hydraulic shear in the prior art.

The application discloses a process method for improving the hardness of 5A06 aluminum magnesium alloy, and comprises the following steps: step 1, cutting processing is performed on the 5A06 aluminum alloy rod to form a plurality of cylindrical short samples; step 2, the sample is subjected to deformation treatment: the sample is compressed once, and the deformation amount is 16%-32%; step 3, the sample subjected to the deformation treatment is directly immersed in liquid nitrogen for cryogenic treatment, is placed in air to be warmed to room temperature, and the hardness of the sample is measured. The application solves the problems that it is difficult to improve the hardness of the aluminum magnesium alloy and difficult to prolong the service life at present, the cryogenic treatment time has a significant influence on the structure of the 5A06 aluminum alloy, the number of Al3Mg2 phases in the structure is obviously increased with the prolonging of the cryogenic treatment time, the hardness of the alloy can be further improved by adopting the process of deformation superposition and cryogenic treatment, so that the wear resistance is improved, and the service life of the alloy is prolonged.

The invention relates to the technical field of metal material surface chemical heat treatment, in particular to W-containing ultrahigh-strength steel, a preparation method thereof and a surface carbon-nitrogen composite strengthening process. The preparation method comprises the following steps of smelting preparation of steel, forging cogging forming, annealing heat treatment after forging of a bar, carburization, subzero treatment and surface pressurization nitriding. The ultrahigh strength steel comprises the following chemical components: 0.27-0.34 wt.% of C; 0.4 to 1.4 wt.% of Cr; 9 to 10 wt.% of Ni; 6 to 8 wt.% of Co; 1.5 to 2.5 wt.% of Mo; 1.1 to 1.6 wt.% of W; and the balance of Fe and impurity elements. The highest hardness of the carbonitriding layer of the W-containing ultrahigh-strength steel is not lower than 900 HV, the tensile strength of the steel is not lower than 2000 MPa, the yield strength is not lower than 1700 MPa, the impact absorption capacity is not lower than 60 J, and the service condition requirements of gears for aero-engines are met.

This invention provides a high-strength, high-toughness martensitic precipitation hardening stainless steel fastener and its preparation method, belonging to the field of metallurgical technology. The fastener is made of X5CrNiCuMo15-06 steel, and its chemical composition, by mass percentage, includes: C: ≤0.05%, Cr: 14-16%, Ni: 6.0-7.0%, Cu: 1.25-1.75%, Mo: 0.5-1.0%, Mn: ≤1.0%, Si: ≤1.0%, P: ≤0.008%, S: ≤0.005%, V: ≥8%C, with the balance being Fe and unavoidable impurities. This invention utilizes an ultra-low C+V microalloying composition design, a dual high-purity smelting process of vacuum induction and protective atmosphere electroslag remelting, combined with an integrated heat treatment system of solution treatment, deep cryogenic treatment, and aging treatment. This allows the material to maintain high strength while achieving excellent room temperature and ultra-low temperature toughness. The fasteners prepared can meet the high load-bearing and long-term service requirements of high-end equipment.

The invention relates to heat treatment of steel, in particular to a rod type steel part and a heat treatment method thereof, and the heat treatment method comprises the following steps: sequentially carrying out stress relief heat treatment, preheating, vacuum quenching, tempering treatment and aging treatment on the rod type steel part; in the step of vacuum quenching, a gradient temperature rising mode is adopted for heating to the quenching temperature; the tempering treatment comprises first-time tempering treatment, subzero treatment, second-time tempering treatment, subzero treatment and third-time tempering treatment, after the second-time tempering treatment, the hardness of the rod type steel part is measured, and the temperature and the heat preservation time of the third-time tempering treatment are determined according to the measured hardness. The deformation problem of the heat treatment of the rod type steel part can be obviously improved.

The invention relates to the technical field of stainless steel materials, and particularly discloses 304 stainless steel for a flow-limiting downward-opening type checkgate and a machining process thereof.The machining process comprises the steps that firstly, the surface of the 304 stainless steel is pretreated through aluminum oxide particles, the roughness of the surface of the stainless steel is increased, and then an aluminum-cobalt-chromium-iron-nickel high-entropy alloy layer is formed on the surface of the stainless steel through magnetron sputtering; aluminum is distributed in an alloy layer in a gradient mode by adopting a mode of improving the power of an aluminum target to form a gradient layer, and then subzero treatment, pulse circulation treatment, hole sealing by a hole sealing agent and annealing treatment are carried out, so that the 304 stainless steel for the flow-limiting open-type checkgate with good hardness, erosion resistance and corrosion resistance is obtained, the service life of the checkgate is prolonged, and the service life of the checkgate is prolonged. And the maintenance cost during weir gate replacement is reduced.

The application relates to the technical field of alloy steel, in particular to a rare earth-containing high-strength corrosion-resistant cutter alloy steel and a preparation method thereof. Fe is used as a matrix, and the alloy steel contains C, Si, Mn, Cr, Mo, V, Nb, N, composite rare earth and TiB2, the contents of P and S are controlled in an extremely low range; the composite rare earth is a mixture of La and Ce, the content and form of inevitable impurities are strictly controlled, there is no coarse Al2O3 inclusion, and the non-metallic inclusions are spherical or spheroidal and small in size; the preparation method comprises raw material pretreatment, electric arc furnace smelting, AOD refining, electroslag remelting, homogenization annealing and hot forging, hot rolling, cold rolling and cryogenic treatment, tempering and post-treatment. The alloy component and the preparation process are optimized, the organization is refined, the inclusion form is improved, the matrix density and dislocation density are improved, the mechanical properties, corrosion resistance and wear resistance of the alloy are far superior to those of the prior art, and the balance between strength, toughness and corrosion resistance is achieved.

The invention belongs to the field of material processing and manufacturing, and particularly relates to a preparation method and application of a surface-strengthened anti-corrosion steel mold. One purpose of the invention is to provide a material for a surface-strengthened anti-corrosion steel mold. The material comprises the following chemical components in percentage by weight: 75 to 80 percent of Fe, 11 to 13 percent of Cr, 0.5 to 2.5 percent of Ni, 1 to 5 percent of Mo, 2 to 5 percent of Co, 0.3 to 0.6 percent of Cu, 0.1 to 0.2 percent of C, 0 to 2 percent of W, 0.3 to 0.6 percent of Cu, 0.1 to 0.2 percent of C, 0 to 0.3 percent of V, 0 to 0.1 percent of Nb and 0 to 0.005 percent of La. The invention provides the preparation method of the steel mold for compression molding of the PBX raw material, which is simple and convenient to operate and can be industrially applied. Through combination of alloy matrix design, high-temperature and high-pressure nitriding and subzero treatment, collaborative optimization of corrosion resistance and mechanical properties of the steel die is achieved, and it is guaranteed that the surface of the steel die has long service life and high stability in the complex forming environment where the surface makes contact with PBX raw materials.

The invention belongs to the technical field of aluminum alloy material processing, and discloses a cryogenic treatment process of a 7xxx series high-strength aluminum alloy pipe, the process sequentially comprises three core steps of solution treatment, cryogenic treatment and aging treatment, and the 7xxx series high-strength aluminum alloy pipe is obtained by accurately controlling key parameters of each step. The technical problems that in a traditional T6 heat treatment process, a 7xxx series aluminum alloy pipe is uneven in precipitated phase distribution, grain refinement is insufficient, the strength and plasticity are difficult to consider, and internal stress is large are solved. After being treated by the process, the tensile strength of the pipe is improved to 705MPa, the yield strength is improved to 678MPa, the ductility is improved to 11.8%, the size of a precipitated phase in a microstructure is smaller, distribution is more uniform, the internal stress is remarkably reduced, the size stability is greatly improved, industrial batch production can be realized, and the requirements of the fields of aerospace, rail transit and the like on the high-performance aluminum alloy pipe are met.