18 results about "Solidification microstructure" patented technology

This invention discloses a method for controlling the uniformity of gear steel microstructure, including hot metal desulfurization and vanadium extraction, semi-steel converter smelting, LF refining, RH refining, and continuous casting processes. The method controls the solidification process of the molten steel in the molten pool during continuous casting, ensuring solidification is completed within a 1 / 4 arc-shaped region of the slab, and implementing a specified cooling and solidification control process. This method effectively improves the macroscopic solute concentration uniformity in all directions of the cross-section of the gear steel continuous casting slab, improves the regional symmetry of the solidified microstructure, and promotes more uniform phase transformation and stress distribution in the gear microstructure during gear processing and subsequent heat treatment. The range of distance between the equiaxed crystal zone boundary and the slab surface is reduced from 30-40 mm to 10-15 mm. After rolling into a round bar, the range of distance between the equiaxed crystal trace zone boundary and the round bar surface is controlled to ≤5 mm, and the range of solute segregation (circumferential) at the same radial distance from the surface of the round bar is ≤0.02. The resulting gear steel grain size stabilizes from grade 6.0-7.0 to grade 7.0.

The invention discloses a nickel-based high-temperature alloy powder particle size and solidification structure optimization method, which comprises the following steps of: obtaining a corresponding relation between different particle sizes and cooling rates in a continuous atomization process window through a simulation step, carrying out microscopic structure characterization on powder with different particle size groups through an experiment, and obtaining experimental data of a solidification structure; and coupling results of the simulation step and the experiment step, establishing a quantitative mapping relation model among the particle size, the cooling rate and the solidification assembly, based on the quantitative mapping relation model, taking a target solidification structure as input, carrying out backstepping to obtain target particle size distribution and corresponding atomization process parameters, and adjusting the operation state of equipment in real time through a closed-loop control system. According to the method, through multi-physics field coupling simulation and real-time experimental verification, the quantitative mapping relation among the powder particle size, the cooling rate and the solidification structure is established, and accurate regulation and control of molten drop breaking, cooling and solidification paths in the gas atomization process are achieved.

The invention discloses a method and system for rapidly calculating morphology characteristic parameters of an alloy solidification structure, and relates to the technical field of metal material solidification structure characterization, and the method comprises the following steps: selecting an alloy with any component, obtaining solidification structure samples under different solidification conditions through a plurality of casting experiments, and calculating the morphology characteristic parameters of the alloy solidification structure; measuring the primary dendritic crystal arm spacing of each sample and at least two characteristic parameters representing the overall morphology; establishing a parameter relation graph based on measurement data, and further constructing a multivariate nonlinear fitting model of the primary dendritic crystal arm spacing and each morphological characteristic parameter; and measuring the primary dendritic crystal arm spacing of the target alloy, and substituting the primary dendritic crystal arm spacing into the model to calculate required morphology parameter values. The system comprises a data acquisition module, a model construction module and a parameter calculation module. According to the method, the problem of tedious parameter calculation is solved, the model applicability is wide, rapid evaluation is achieved, and casting process optimization and casting quality control are assisted.

The invention discloses a casting blank structure feature extraction method based on defect tracing, which comprises the following steps: 1) establishing a structure feature extraction and defect prediction system which comprises a steel grade structure case library, a steel grade classification model, a similarity calculation model group and a case library optimization module; 2) inputting component information of steel types, classifying the input steel types through a steel type classification model to determine the types of the input steel types, and finding out the steel types of the same type in a steel type organization case library; and (3) the similarity between the input steel grade and the steel grade of the same type in the steel grade organization case library is calculated through the similarity calculation model group, the most similar steel grade with the similarity larger than a set threshold value is obtained and found out, and the organization characteristics of the most similar steel grade are the input steel grade organization characteristics. According to the method, solidification structure feature extraction based on crack traceability becomes the premise and basis of a subsequent defect prediction model, and the accuracy is predicted through the defect prediction model.

The invention belongs to the technical field of aluminum alloy casting, and particularly relates to a preparation device and method for an aluminum alloy sample with two ends cooled. According to the technical scheme, the preparation device of the aluminum alloy sample with the two ends cooled comprises a cavity, a cavity cover, a sprue plug, a shrinkage compensation plate, a cooling plate and a spraying system, a cavity is formed in the cavity, and the two ends of the cavity are open; the cavity cover is placed on the cavity body and used for covering the mold cavity, the cavity cover is provided with a pouring hole, and the pouring plug is used for blocking the pouring hole; the two shrinkage compensation plates are arranged at the two ends of the cavity respectively, a cooling plate is arranged on the outer side of each shrinkage compensation plate, and two nozzles of the spraying system face the two cooling plates respectively. According to the preparation device and method for the aluminum alloy sample with the two ends cooled, the small-size aluminum alloy solidification structure sample can be prepared, and the structure and segregation characteristics of a large aluminum alloy ingot with the approximate cooling direction from outside to inside are obtained.

This invention discloses a method and apparatus for applying a composite force field in vacuum arc melting, belonging to the field of high-end alloy special melting technology. The application method includes the following steps: during vacuum arc melting, dynamically adjusting the type and / or intensity of the physical force field applied to the melting area according to different stages of the melting process; applying a first force field combination during the arc initiation and molten pool formation period; applying a second force field combination different from the first force field combination during the stable melting period; and applying a third force field combination different from the second force field combination during the hot capping period. Through the programmed synergistic effect of this composite force field in the arc initiation, melting, and capping stages, the solidification structure of the ingot is significantly improved, segregation is reduced, and density and purity are increased, thereby ensuring the performance and reliability of the alloy under ultra-supercritical extreme environments.

This invention relates to a high-homogeneity bearing steel GCr15 continuous casting billet and its preparation method, belonging to the technical field of bearing steel continuous casting billet preparation. To address the problems of compositional segregation, uneven microstructure, and internal defects in high-end bearing steel continuous casting billets, this invention provides a high-homogeneity bearing steel GCr15 continuous casting billet and its preparation method, including the coordinated control of raw material preparation, converter smelting, refining, and continuous casting. This invention strictly controls the chemical composition of bearing steel from the source, eliminates the risk of raw material segregation at its root, precisely connects the refining-continuous casting temperature, coordinates the time nodes of each process, ensures constant pouring temperature and billet pulling speed, avoids time and temperature discrepancies, effectively improves the solidification structure, and reduces segregation and porosity. By constructing a full-process homogenization control system, the center segregation index of the continuous casting billet is ≤1.05, the center porosity level is ≤1, and the shrinkage cavity level is ≤0.5, significantly improving the uniformity and consistency of the product and meeting the requirements of high-end bearing steel.

The invention provides an aggressive agent for non-destructive testing of an oriented silicon steel solidification structure, a preparation method and a non-destructive testing method. The preparation method comprises the following steps: S1, adding stannous chloride, anhydrous ferric trichloride, anhydrous copper chloride, anhydrous magnesium chloride and sodium dodecyl benzene sulfonate into deionized water, and stirring for dissolving; and S2, sequentially adding absolute ethyl alcohol and hydrochloric acid into the ionized water, and continuously stirring to obtain the aggressive agent. The aggressive agent is developed for oriented silicon steel for a high-voltage transformer, the aggressive agent is expected to be used for carrying out nondestructive characterization on the solidification structure of an oriented silicon steel casting blank, statistical analysis of the microstructure of the casting blank is facilitated, and a technical basis is provided for optimizing a field continuous casting process and regulating and controlling the solidification structure of the casting blank.

This invention discloses a multi-throughput permanent magnet stirring device and method. The device includes a sleeve, a permanent magnet, a permanent magnet rotation mechanism, an A tray, a B tray, a trolley, an annular track, an A telescopic rod, a B telescopic rod, and a control system. The sleeve is nested and assembled with the permanent magnet. The annular track is supported inside the sleeve by the B telescopic rod. The A tray is supported inside the sleeve by the A telescopic rod. The B tray is mounted on the trolley via the tray rotation mechanism. The trolley is slidably assembled with the annular track. Using the permanent magnet stirring device of this application, multiple melts can be stirred simultaneously, enabling diversified and multi-level permanent magnet stirring experiments. It has a simple structure, is easy to operate and maintain, and can be widely used in the field of permanent magnet stirring of metallurgical melts. It can also be used in experimental research, satisfying the needs of diversified laboratory research on the effects of permanent magnet stirring on melt solidification, microstructure, and properties, laying the foundation for future industrial applications.

The chemical component of the carbide-based eutectic medium-entropy alloy is CrFeNi (NbC) x, x is larger than or equal to 0.1 and smaller than or equal to 0.3, the carbide-based eutectic medium-entropy alloy is prepared through a vacuum arc melting method, and after vacuum arc melting, the solidification phase of the carbide-based eutectic medium-entropy alloy is FCC, MC carbide and M7C3 carbide; and when x is equal to 0.1, the solidification structure of the alloy is primary FCC + reticular eutectic FCC / MC + superfine eutectic FCC / M7C3. When x is equal to 0.2-0.3, the solidification structure of the alloy is primary MC + primary FCC + reticular eutectic FCC / MC + superfine eutectic FCC / M7C3; the Vickers hardness of the alloy ranges from 235.6 HV to 287.0 HV, the yield strength of the alloy ranges from 439 MPa to 534 MPa, and the compressive strength (Rpc30) of the alloy under the specified strain (30%) ranges from 1482 MPa to 1607 MPa.

This invention discloses a method for synergistic control of residual stress and microstructure in a pulsed current-assisted metal additive manufacturing process, belonging to the field of metal material additive manufacturing technology. The method includes the following steps: S1, setting the process parameters for metal additive manufacturing and planning the area and timing for synchronously applying pulsed current; S2, during the layer-by-layer deposition process of the component, when a high-energy laser beam, electron beam, or electric arc acts on the deposition area to form a molten pool, a pulsed power supply is triggered by a synchronous control unit to apply a pulsed current with preset parameters to the molten pool and the heat-affected zone; S3, through the synergistic effect of the electroplasticity and Joule heating of the pulsed current, thermal stress relaxation, grain refinement, and microstructure homogenization are simultaneously achieved during the manufacturing process. This invention, by employing the above method and precisely controlling the electrical pulse parameters, simultaneously achieves stress relaxation and solidification microstructure optimization during the manufacturing process, significantly improving the dimensional stability, fatigue life, and mechanical properties of the formed component.

The invention discloses a method for preventing silicon cracking of a high-silicon aluminum ingot, which belongs to the technical field of alloy preparation, and can effectively avoid adverse effects of components on a solidification structure by accurately controlling the components of the material, obtain a stable and uniform alloy structure, and fundamentally reduce the risk of silicon cracking caused by component segregation. Besides, most macroscopic inclusions and hydrogen in the melt can be effectively removed through first refining treatment and a specific refining agent A, micron-sized inclusions are further removed, the hot brittleness of the alloy is remarkably reduced, factors inducing silicon cracks are effectively reduced in combination with a second refining treatment process, deterioration is successful in combination with addition of a specific refining agent, and the quality of the alloy is improved. And the morphology of the eutectic silicon is changed from a thick plate sheet shape to a fine fiber shape or a particle shape, so that the harm caused by taking a thick silicon phase as a crack source is fundamentally eliminated, the continuity of an aluminum matrix is enhanced, and the purpose of preventing silicon cracks is achieved.

A method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current control, comprising: selecting high-grade silicon steel alloy raw materials and adding rare earth elements; smelting molten steel in an electric arc furnace and monitoring the composition using an online analysis instrument; in the continuous casting process, using an adjustable pulse power supply to optimize the current frequency, amplitude and application time; using a machine learning model to predict defects and automatically adjust the process parameters; slowly discharging the furnace, using an intelligent cooling system to control the cooling speed, reduce thermal stress and reduce the risk of surface defects; then uniform heat treatment is carried out, using layered heating technology to ensure uniform internal structure; then heat the casting blank to hot rolling temperature, and then cold roll the hot rolled plate using gapless rolling technology, and then use nano coating technology for surface treatment. The present application significantly improves the corrosion resistance, wear resistance and oxidation resistance of the cold rolled plate through the nano coating technology, prolonging the service life.

The application provides a process for semi-continuous casting of copper-magnesium alloy, which is smelted by argon protection and combined with multi-element synergistic alloying, and metal elements and intermediate alloy are added in stages to improve the uniformity of composition. A vertical pulse magnetic field is introduced to cooperate with the directional solidification technology, combined with a double-layer protection of composite covering agent and boron nitride, which significantly reduces the impurity content and refines the grain structure. The multi-directional rolling process cooperates with the cyclic heat treatment method to effectively eliminate residual stress and promote the uniform distribution of precipitated phase. Through the staged aging stabilization treatment, the morphology of the precipitated phase is adjusted to realize the synergistic improvement of strength and corrosion resistance. Compared with the traditional process, the alloy obtained by the process has the advantages of dense solidification structure, excellent comprehensive performance, high yield, etc., and has important application value in the fields of aerospace and rail transportation.

The application belongs to the field of metal material casting, and discloses a method for improving the hot crack resistance of heat treatment-free aluminum alloy and high hot crack resistance heat treatment-free aluminum alloy. The method comprises the following steps: melting heat treatment-free aluminum alloy to obtain a melt; adding Zr, and optionally Sc and / or Er, to the melt, stirring, degassing, cooling and standing to obtain an alloy melt; carrying out high-temperature melt ultrasonic treatment on the alloy melt to obtain a high-temperature melt, pouring into a mold and carrying out casting to obtain high hot crack resistance heat treatment-free aluminum alloy. The application can effectively control the microstructure and hot crack resistance of the aluminum alloy, and obtain high-quality heat treatment-free aluminum alloy castings with refined solidification structure and eliminated casting hot cracks.

The application relates to a preparation method of a directional solidification TiAl-based alloy with stable mechanical properties, comprising the following steps: ingredient preparation: using single elements and intermediate alloy raw materials to configure a molten material with an atomic percentage component of Ti-(40-50)Al-(1-10)M; fine-grain element addition: B, Y and C elements; master alloy ingot preparation: ultrasonic vibration assisted electromagnetic cold crucible suspension smelting preparation is carried out; directional solidification preparation: a material rod is cut from the master alloy ingot, ultrasonic vibration assisted electromagnetic cold crucible directional solidification preparation is carried out, and the preparation is always accompanied by ultrasonic vibration assistance; and preparation completion: the product is taken out after cooling to complete the preparation. The preparation method can simultaneously ensure that the TiAl-based alloy is pollution-free, high-flux, organization directional, and B, Y and C fine-grain element compounds are dispersedly distributed without agglomeration, can realize obtaining stable fine-grain directional solidification organization, and thus the stability of the mechanical properties of the alloy is improved.

The application discloses a kind of electric arc additive-pool solidification microstructure evolution multi-field coupling simulation method, solve the problem that present stage additive phase field simulation ignores various physical phenomena in the solidification process of deposited metal and makes the low precision of solidification microstructure prediction.The method proposes the substrate material grain structure generation method, progressive arc process simulation method, equiaxed crystal heterogeneous nucleation method, dendritic solid phase movement speed calculation method and the coupling simulation method of electric arc additive-pool solidification temperature field, flow field, solute field and phase field.The simulation method proposed in the application is used to simulate the solidification process of certain aluminum-copper alloy electric arc additive-pool, and the results show that the method can accurately reproduce the phenomena of dendritic remelting, pool expansion, synnthetic crystallization, polycrystalline growth, pool flow, solute convection and diffusion, heterogeneous nucleation, columnar crystal-equiaxed crystal transformation and equiaxed crystal solid phase movement in the electric arc additive manufacturing process.

The application discloses a high-Zn-content 7-series aluminum alloy ingot and a preparation method thereof. The 7-series aluminum alloy ingot comprises the following components in percentage by mass: Zn 8.5-11.5%, Mg 1.5-2.5%, Cu 0.5-1.5%, Zr 0.1-0.4%, Cr 0.1-0.4%, Ti 0.1-0.3%, rare earth elements 0.1-0.5%, the rare earth elements being Y and / or Er, and the rest being Al and inevitable impurities. The impurity content is less than 0.1%. The application realizes the preparation of a large-size 7-series aluminum alloy round ingot by reasonably regulating the element ratio in the 7-series aluminum alloy, adopting the synergistic treatment of multiple trace elements, combining the flexible permanent magnetic stirring process, the tundish transition and the split-flow casting technology, so that the 7-series aluminum alloy round ingot has uniform solidification structure and good comprehensive performance.