A method and system for feeding a titanium alloy casting

Abstract

This invention provides a method and system for feeding titanium alloy castings via risers. The method includes the following steps: S1, numerical simulation to locate hot spots; S2, calculation of the hot spot modulus and optimization of the conical riser calculation model; S3, iterative optimization of the riser height H, end opening, and riser taper through simulation to eliminate isolated liquid phase regions; S4, adding an insulating shell layer in the riser area to enhance the feeding effect and promote sequential solidification. This invention achieves high-quality, high-efficiency, and low-cost manufacturing of aerospace-grade titanium alloy castings by integrating high-precision simulation hot spot location, titanium alloy conical riser configuration modeling, iterative simulation optimization, and local insulation strengthening.

Description

Technical Field

[0001] This invention relates to the field of precision casting technology for titanium alloys, and more specifically, to a method and system for feeding titanium alloy castings using risers. Background Technology

[0002] Titanium alloys are widely used in high-end equipment fields such as aerospace due to their high specific strength, excellent corrosion resistance, and high-temperature performance. However, their casting process faces severe challenges: the melting point is as high as 1660℃~1800℃, the melt viscosity is 10~20 times that of steel, and the liquid shrinkage rate is large (6.7%~10%), which makes it very easy to form isolated hot spots during solidification and induce defects such as shrinkage cavities and porosity. The defect rate of traditional castings reaches 20%~25%.

[0003] In existing technologies, hot spot identification mainly relies on manual experience or simplified hot spot modulus methods, lacking accurate modeling of the critical behavior of titanium alloys with high solids concentration and the temperature-flow field coupling effect. Prediction errors are >20%, and positioning deviations are large. Riser designs generally adopt uniform cross-section cylindrical structures, with a feeding efficiency of only 60%~75%, and are not adapted to the high shrinkage characteristics of titanium alloys, making it difficult to meet the requirements of sequential solidification. Although there are patent reports on recyclable risers, none have established a quantitative design model for conical risers based on the intrinsic parameters of titanium alloy materials. Furthermore, due to the lack of coordinated control of mold shell insulation, the riser liquid retention time is insufficient, further exacerbating feeding failure.

[0004] Chinese patent CN120429975A discloses a design method for a feeding riser structure. This method calculates the modulus of the feeding location in the casting based on computer numerical simulation or formulas, ensuring that the riser modulus is greater than the modulus of the feeding location. The diameter and height of the final solidified portion of the riser are calculated using the specific riser design formula of this invention, resulting in the riser structure shown in this invention. However, this method is suitable for aluminum-magnesium alloy gating systems and uses cylindrical risers; its effect on feeding titanium alloy castings remains unsatisfactory.

[0005] Therefore, a method and system for feeding risers in titanium alloy castings is needed to overcome the bottleneck of reliance on experience. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for feeding titanium alloy castings with risers. By integrating high-precision simulation hot spot positioning, titanium alloy conical riser configuration modeling, iterative simulation optimization and local heat preservation strengthening, it can achieve high-quality, high-efficiency and low-cost manufacturing of aerospace-grade titanium alloy castings.

[0007] To achieve the above objectives, this invention provides a method and system for feeding titanium alloy castings using risers. The technical solution of this invention is implemented as follows:

[0008] A method for feeding titanium alloy castings using risers includes the following steps:

[0009] S1, numerical simulation to locate the hot spot;

[0010] S2, optimization of the calculation model for hot spot modulus and conical riser;

[0011] S3, through simulation iteration, optimizes the riser height H, end opening and taper to eliminate isolated liquid phase regions;

[0012] S4. An insulating mold shell layer is added to the riser area to enhance the shrinkage compensation effect and promote sequential solidification.

[0013] Furthermore, in step S1, the location of the hot spot is determined by using the solid fraction as a critical criterion, tracking the last solidified area during the solidification process, and accurately determining the location of the hot spot.

[0014] Furthermore, TC4 titanium alloy uses a solid fraction of 0.7 as a critical threshold to identify independent, continuous liquid enrichment regions with a solid fraction <0.7 as thermal nodes.

[0015] Furthermore, the conical riser size model established in step S2 introduces the riser modulus M. r The riser modulus M r Let M be a function of the riser height H, end opening, and taper, and satisfy M. r ≥k·M c , of which M c denoted as the thermal modulus, and k as the shrinkage compensation coefficient.

[0016] Furthermore, the tapered riser size model established in step S2 introduces a taper compensation difference ΔM. c It is used to correct the change in effective heat dissipation area caused by the tilting of the riser sidewall and optimize the accuracy of riser modulus calculation.

[0017] The method for feeding titanium alloy castings using risers according to claim 5 is characterized in that, when the conical riser is a truncated cone, formula M is used. r =k·D1·H / 2(D1+H)+△M c Where D1 is the diameter of the large end opening of the conical riser.

[0018] Furthermore, k=2.3, H=(1.3~1.5)D1.

[0019] Furthermore, the taper compensation difference ΔM c The riser taper and the thermal conductivity of the material are obtained through empirical fitting or simulation calibration.

[0020] Furthermore, for every 1° increase in the riser taper, the riser modulus is corrected by -0.01 to -0.5.

[0021] Furthermore, according to formula M c =V / S is used to calculate the hot spot modulus, where V is the volume of the hot spot region and S is the heat dissipation surface area of ​​the hot spot region.

[0022] Furthermore, the simulation iterative design process in step S3 includes: setting multiple candidate riser structure parameter combination schemes, running multiple numerical simulations, evaluating whether each scheme forms an isolated liquid phase region, so as to select the optimal parameter combination to keep the feeding channel continuously connected until final solidification.

[0023] Furthermore, the insulation mold shell mentioned in step S4 is prepared using a silica sol-mullite system material and coated on the outer surface of the riser area to reduce the heat dissipation rate of the riser and prolong the feeding time.

[0024] Furthermore, the thickness of the insulation mold shell layer is 0.8mm~2mm.

[0025] A feeding system for titanium alloy castings, used to implement the above method, includes: a hot spot identification module, a riser parameter calculation module, a simulation optimization module, and an insulation structure configuration module. Each module is integrated into a unified design platform through a data interface.

[0026] Compared with existing technologies, the riser feeding method and system for titanium alloy castings described in this invention have the following advantages:

[0027] 1. Significantly improved high-precision hot spot identification capability. Based on temperature-flow field coupled simulation, combined with the TC4 titanium alloy critical solid fraction of 0.7 to determine independent hot spots, the hot spot positioning accuracy reaches 97%, which is a qualitative leap compared with the traditional empirical method or simplified modular method, fundamentally solving the core pain points of "inaccurate hot spot location and mismatched shrinkage".

[0028] 2. Conical riser design achieves intrinsic material compatibility. A quantitative model of a conical riser is designed for the high liquid shrinkage rate of titanium alloys. A taper compensation mechanism and shrinkage compensation coefficient are introduced to overcome the bottleneck of modulus mismatch of cylindrical risers, and the shrinkage compensation effect is significantly improved.

[0029] 3. Simulation-driven optimization significantly reduces the process development cycle. A closed-loop iterative process of "modeling → simulation → diagnosis → adjustment → re-verification" is constructed, and riser structural parameters (height H, large end opening diameter D1, taper) can be quickly and directionally optimized, which can compress the traditional trial-and-error design that takes about 35 days to less than 48 hours, greatly improving efficiency.

[0030] 4. Enhanced sequential solidification capability. Through the synergistic effect of conical riser geometry control and localized insulation mold shell, namely by applying silica sol-mullite slurry to the riser area to thicken the mold shell locally, the liquid holding time of the riser is significantly extended, effectively eliminating isolated liquid phase zones and achieving controllable sequential solidification of the entire casting.

[0031] 5. Casting quality and process yield both improved significantly. The measured shrinkage porosity of hot sections was reduced to below 1%, meeting the quality standards for aerospace-grade titanium alloy castings; at the same time, the process yield increased dramatically, from 60%~65% to 83%~87%.

[0032] 6. Significantly reduced overall manufacturing costs. The amount of riser material used per piece is reduced by 20% to 35%. Coupled with shorter design cycles, lower remelting and rework rates, and increased mold reuse rates, the overall cost of casting per piece is reduced by 15% to 28%, making it economically viable for large-scale applications. Attached Figure Description

[0033] Figure 1 This is a comparison image of the feeding effect of the conical riser in the casting as shown in Embodiment 1 of the present invention;

[0034] Figure 2 This is a simulation diagram showing the distribution of defects in the conical riser of the casting as described in Embodiment 1 of the present invention.

[0035] Explanation of reference numerals in the attached figures:

[0036] none. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are only some, not all, of the embodiments of this invention. The specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0038] This invention provides a method and system for riser feeding in titanium alloy castings. Through "numerical simulation for precise location of hot spots, optimization of the conical riser calculation model, simulation iterative optimization, and riser insulation mold design," it overcomes the limitations of traditional empirical design and achieves precise control of the temperature field and feeding path during solidification. This method can significantly improve riser feeding efficiency, and the key indicators of titanium alloy castings can meet the standards for aerospace titanium alloy castings. The specific steps are as follows:

[0039] S1, numerical simulation to locate hot spots. A high-precision digital model of the solidification process is constructed to achieve accurate spatial identification of hot spots.

[0040] S11, Model building and mesh generation.

[0041] A 3D model of the casting is created using 3D modeling software such as UG; the investment casting mold shell is automatically generated using ProCAST. Preferably, the mesh size of the casting is ≤ 1 / 5 of the average wall thickness, and the mesh size of complex or thin-walled areas of precision parts is refined to 0.5mm; the mesh size of the mold shell is 6~10mm. This ensures the computational resolution of critical areas (thermal initiation zones), improves the coupling accuracy of the temperature field and flow field, and avoids missed or offset thermal points due to mesh coarsening.

[0042] S12, parameter input.

[0043] The initial conditions were as follows: the titanium alloy casting material was TC4 (Ti-6Al-4V), and the mold shell material was a refractory material mainly composed of SiO2-Al2O3. Both the casting and mold shell materials were selected from the corresponding materials in the ProCAST material database. The preheating temperature of the mold shell before pouring was 50℃~100℃, the pouring temperature of the casting was 1750℃±50℃, and the actual production pouring time was 3s~6s.

[0044] The boundary conditions are as follows: ambient temperature, based on the casting workshop environment, is set to 25℃~40℃; emissivity η = 0.82; ambient temperature of the outer surface of the mold shell is 60℃~80℃; and the heat transfer coefficient at the interface between the mold shell and the external environment is 75 W / (m²). 2 The heat transfer coefficient at the interface between the casting and the mold shell is 600 W / (m²). 2 ·K).

[0045] It reproduces the real melting and casting conditions, eliminates the simulation deviation caused by idealized boundaries, makes the solidification path consistent with reality, and provides a physically reliable basis for hot spot determination.

[0046] S13, Simulation analysis and positioning.

[0047] Temperature-flow field coupling calculations are performed to extract solids fraction distribution cloud maps. Hot spots are located using solids fraction as a critical criterion, tracking the last solidified region during solidification to accurately determine the hot spot location. Preferably, a critical solids fraction of 0.7 for TC4 titanium alloy is used as the threshold to identify independent, continuous liquid enrichment regions with a solids fraction <0.7 as hot spots.

[0048] Breaking through the limitations of empirical methods, it achieves three-dimensional quantitative characterization of hot spots in terms of "location-size-shape", with high prediction accuracy, supporting the subsequent "targeted deployment" of risers.

[0049] S2, optimization of the calculation model for hot spot modulus and conical riser. This aims to establish a riser design standard specific to titanium alloys and solve the problem of modulus mismatch under high shrinkage rates.

[0050] S21, Calculation of thermal modulus.

[0051] Based on the independent thermal node entity located in step S13, its volume V and surface area S data are extracted in 3D modeling software such as UG, and the thermal node modulus M is calculated. c M c =V / S. The heat dissipation capacity of the quantified hot spot is used as the benchmark parameter for the riser feeding capacity design, avoiding underestimation or overestimation of the modulus caused by empirical estimation methods.

[0052] S22, Construction and parameter assignment of the modular model of the conical riser.

[0053] Design riser module M r Satisfy M r ≥k·M c Among them, the riser modulus M r M is a function of riser height H, end opening, and riser taper. c Where M is the thermal modulus, and k is the shrinkage compensation coefficient. According to formula M... c =V / S, where V is the volume of the hot spot region and S is the heat dissipation surface area of ​​the hot spot region.

[0054] When the conical riser is frustoconical, the preferred method is to use formula M. r =k·D1·H / 2(D1+H)+△M c Where, k is the shrinkage compensation coefficient of titanium alloy, k=2.3; H is the riser height, H=(1.3~1.5)D1; D1 is the opening diameter of the large end of the conical riser; ΔM c This is for taper compensation difference.

[0055] The tapered riser size model introduces a taper compensation difference ΔM. c This is used to correct for changes in effective heat dissipation area caused by riser sidewall inclination, and to optimize the accuracy of riser modulus calculation. The taper compensation difference ΔM... c The riser taper θ and the material's thermal conductivity are obtained through empirical fitting or simulation calibration and integrated into the automatic riser size calculation module. Preferably, the riser modulus is corrected by -0.01 to -0.5 for every 1° increase in riser taper θ. More preferably, the riser modulus is corrected by -0.03 for every 1° increase in riser taper θ.

[0056] By employing a tapered riser and introducing a titanium alloy-specific shrinkage compensation coefficient and a taper correction term, the riser module M is improved. r ≥2.3M c This design overcomes the problems of large modulus deviation and insufficient feeding caused by the uniform cross-section of cylindrical risers. The conical structure, combined with an insulating mold shell, extends the liquid retention time of the riser, promotes sequential solidification, avoids isolated liquid phases in hot spots, and improves feeding efficiency and sequential solidification. At the same time, the conical riser reduces the amount of material removed and the cost, increases feeding efficiency by 83%~87%, and reduces the material cost of a single riser to 65%~80% of the original, significantly reducing metal waste.

[0057] S3 uses simulation and iterative optimization to design the riser's height, end opening, and taper to eliminate isolated liquid phase regions. Closed-loop verification of riser effectiveness enables dynamic control of the feeding path.

[0058] S31, Initial riser implantation and solidification simulation.

[0059] Integrate the conical riser designed in S22 into the model formed in S1, rerun the solidification simulation, and output the distribution of isolated liquid phase regions. This visually exposes the feeding blind zone and determines whether the riser covers all hot spots and whether there is an interruption in the feeding channel.

[0060] S32, Defect-driven dynamic parameter optimization.

[0061] If shrinkage cavities appear in the riser, increase the riser height H or the diameter D1 of the large end opening of the conical riser to increase the feeding head and liquid volume; if the riser solidifies before the hot spot, increase the taper or enlarge the small end opening of the conical riser to delay heat dissipation at the top and enhance the central liquid flow.

[0062] S33 sets up multiple candidate riser structure parameter combinations, runs multiple ProCAST simulations, evaluates whether isolated liquid phase regions are formed under each scheme, and selects the optimal parameter combination to keep the feeding channel continuously connected until final solidification. This forms a rapid closed loop of "simulation diagnosis - parameter adjustment - re-simulation" to ensure that the final scheme completely eliminates isolated liquid phase regions and achieves sequential solidification of the entire casting.

[0063] S4, riser insulation shell design. The riser insulation thickness is increased, and the liquid retention time of the riser is extended to achieve enhanced local thermal management and extend the effective feeding window time of the riser.

[0064] S41, Thermal insulation slurry preparation and coating process.

[0065] The refractory materials and preparation process used in investment casting molds are adopted. The coating slurry is prepared using a silica sol-mullite system and applied to the outer surface of the riser area to reduce the riser's heat dissipation rate and extend its effective feeding time. Specifically, 30% SiO2 silica sol and 200-mesh mullite powder are mixed at a powder-to-liquid ratio of 2.0~2.2:1 to prepare the slurry. An additional 1~2 layers of slurry are added only to the riser area, and 16-30 mesh mullite sand is sprinkled on top. Afterwards, it is dried at a constant temperature and humidity for 12h~24h.

[0066] The thickness of the insulation mold shell layer is controlled within the range of 0.8mm to 2mm to reduce the heat conduction rate in this area, extend the liquid holding time of the riser by more than 30%, and allow the feeding to continue until the final solidification of the hot spot.

[0067] S42, gradient mold shell structure design.

[0068] By utilizing the natural flow characteristics of the grout, the thickness of the mold shell is distributed with "thicker at the top of the riser and gradually thinner at the bottom." This creates a heat gradient from bottom to top, forcing the solidification front to migrate upwards, further solidifying the sequential solidification path, and preventing shrinkage porosity caused by reverse solidification.

[0069] The riser designed using this method can completely transfer shrinkage defects to the interior of the riser. X-ray inspection shows that there are no visible shrinkage cavities or shrinkage defects in the casting body, and the process yield reaches 83%~87%.

[0070] The present invention also provides a feeding system for titanium alloy castings to implement the above-mentioned method, comprising: a hot spot identification module, a riser parameter calculation module, a simulation optimization module, and an insulation structure configuration module, wherein each module is integrated into a unified design platform through a data interface.

[0071] The hot spot identification module takes the casting model and process parameters as input and outputs the hot spot coordinates, volume, surface area, and module M. c The riser parameter calculation module is based on M c Based on the properties of titanium alloys, the initial dimensions of the trapezoidal riser are automatically calculated; the simulation optimization module calls ProCAST to perform solidification simulation on the preliminary design riser, providing feedback to correct the dimensions / taper until there is no isolated liquid phase in the hot spot region; the insulation structure configuration module designs the riser insulation mold shell, outputting the number of thickened layers and material ratios. All modules are integrated through a unified design platform to form a closed-loop workflow.

[0072] Example 1

[0073] This embodiment uses an aerospace-grade TC4 (Ti-6Al-4V) titanium alloy channel casting as an example, and employs the "simulation-driven-conical riser-insulating mold shell" collaborative feeding method proposed in this invention. The casting includes flange transition fillets and a multi-channel confluence structure. The specific implementation steps are as follows:

[0074] S1, numerical simulation to locate the hot spot.

[0075] S11, Model building and mesh generation.

[0076] A complete 3D model of the casting was created using UG software; ProCAST automatically generated the investment casting mold shell. The casting mesh was controlled differently for different regions: the mesh size in the junction area of ​​the flange fillet and flow channel (a candidate area for critical hot spots) was refined to 0.5mm; the mesh size in other areas was set to ≤1 / 5 of the wall thickness, i.e., ≤5.6mm; the mold shell mesh was uniformly set to 8mm. This ensured sub-millimeter-level computational resolution in areas prone to hot spots, eliminated geometric discretization errors, and provided the necessary prerequisite for fine analysis of the solid fraction field.

[0077] S12, parameter input.

[0078] The material parameters were referenced from ProCAST's built-in TC4 alloy database (density 7.8 g / cm³, liquidus 1660℃, solidus 1620℃, latent heat 320 J / g) and the SiO₂-Al₂O₃ base mold shell database. The mold shell preheating temperature was set to 80℃, the pouring temperature to 1780℃, and the pouring time to 5 seconds; the ambient temperature was 30℃, the emissivity ε=0.82, and the heat transfer coefficient of the outer surface of the mold shell was 75 W / (m²). 2 The heat transfer coefficient at the interface between the casting and the mold shell is 600 W / (m²). 2 •K). To realistically reproduce the thermal boundary conditions of investment casting, the deviation between the simulated solidification path and the measured cooling curve is less than 3%, ensuring the physical reliability of the thermal boundary criterion.

[0079] S13, Simulation analysis and positioning.

[0080] Temperature-flow field coupled simulation was used to extract the solids fraction distribution cloud map during the mid-solidation stage (t=42s). Based on the TC4 critical solids fraction threshold of 0.7, two independent hot spots were identified: ① the center area of ​​the flange transition fillet; ② the triangular area where the main channel and branch channel intersect. Both regions have a solids fraction <0.7 and are completely surrounded by the surrounding solidified areas, forming typical isolated liquid phase regions. The high-incidence location of defects was accurately located, confirming that the traditional gating system loses its feeding capacity in this area due to the pre-solidification of the surrounding area, providing a prerequisite for the "targeted placement" of risers.

[0081] The following explanation uses the hot spot at the flange transition fillet as an example; hot spots at other locations are treated similarly.

[0082] S2, optimization of the calculation model for hot spot modulus and conical riser.

[0083] S21, Calculation of thermal modulus.

[0084] Based on the flange fillet thermal joint entity identified by S13, its closed volume V = 163.66 cm³ was measured in UG. 3 Surface area S = 149.2 cm² 2 Substituting into the formula, we get the thermal modulus M. c =1.09cm. This transforms the abstract thermal node into a calculable geometric-thermal parameter, avoiding modulus deviations caused by empirical estimations and laying the foundation for quantitative riser design.

[0085] S22, Solving the modular model and inverting the dimensions of a conical riser.

[0086] The titanium alloy shrinkage compensation coefficient k is set to 2.3, and the target riser modulus M is set to 2.3M. c =2.507cm. The riser taper θ = 10°, then the taper compensation difference ΔM c =-0.03*10=-0.3; constraint height ratio H=1.3D1; substituting into the conical riser module formula:

[0087] M r =2.3·D1·H / 2(D1+H)-0.3

[0088] Solving for D1 and H, we get D1 = 4.3 cm and H = 5.6 cm.

[0089] S3, closed-loop verification and compensation.

[0090] S31, Initial riser implantation and solidification simulation.

[0091] The conical riser (D1=4.3cm, H=5.6cm, θ=10°) obtained in S22 was placed directly above the flange fillet hot spot and integrated into the S1 model. The solidification simulation was then rerun. Figure 2 As shown, it is clearly visible that a continuous liquid bridge is formed between the riser and the hot spot, and the original isolated liquid phase region (purple-red highlighted area) has shrunk significantly.

[0092] S32, Defect-driven parameter fine-tuning and final version confirmation.

[0093] Simulation results showed that a weak residual isolated liquid phase existed at the bottom of the riser, with a volume <0.8 cm³, indicating a slightly insufficient feeding head. Based on this, a fine-tuning was performed: keeping D1 = 4.3 cm constant, H was increased from 5.6 cm to 6.0 cm (an increase of 7.1%), and the simulation was repeated. The results of the second simulation showed that the isolated liquid phase region completely disappeared, and the final solid fraction evolution in the hot spot region was smooth, with no local depressions.

[0094] By precisely controlling a single variable, the ability to compensate for shrinkage is significantly enhanced with minimal structural increment, thus verifying the feasibility of the "diagnosis-adjustment-verification" closed loop of this method.

[0095] S4 enhances the timeliness of shrinkage compensation.

[0096] S41, Preparation of thermal insulation mold shell.

[0097] In the conical riser area confirmed by S32, two additional layers of grout were applied: the grout was prepared by mixing 30% SiO2 silica sol and 200-mesh mullite powder at a powder-to-liquid ratio of 2.1:1; after each layer of grout was applied, 16-30 mesh mullite sand was sprinkled on top; and the mixture was dried at a constant temperature (25℃±2℃) and constant humidity (60%RH±5%RH) for 18 hours. The measured thickness of the riser top mold shell increased from the original 8.5mm to 10.2mm (an increase of 1.7mm).

[0098] The riser liquid holding time is extended by 42 seconds, which is 37% higher than that without insulation, ensuring that there is still a sufficient supply of liquid metal during the final solidification stage of the hot spot, and the feeding window coverage reaches 100%.

[0099] S42, gradient shell structure is formed.

[0100] The natural flow of the grout creates a mold shell thickness distribution that is "thickest at the top (+1.7mm), gradually thinner on the sidewalls (+0.8mm), and basically unchanged at the root," forming a thermal gradient from top to bottom. This guides the solidification front to advance steadily from bottom to top, completely suppressing "necking and flow interruption" caused by premature solidification at the riser root, and ensuring unobstructed flow throughout the feeding channel.

[0101] Comparison of implementation results:

[0102] After implementing the entire process from S1 to S4, the actual production data of the TC4 channel casting is shown in the table below, which fully verifies the engineering superiority of this method.

[0103] Table 1 Comparison of Indicator Effects

[0104] index Traditional technology This patented technology Improvement effect Riser design cycle 3-5 days 4~8 hours Shortened by 95%, supporting rapid response to development needs Process yield 60%~65% 83%~87% Increase by ≥23 percentage points porosity in hot spot region 20%~25% ≤1% Reaching aviation standards Single riser material cost 100% 65%~80% Reduction of 20%~35%, significant material savings with annual production of tens of thousands of pieces.

[0105] This embodiment fully presents the entire technology implementation path from hot spot digital identification, riser precise modeling, simulation closed-loop optimization to insulation time enhancement. The effects of each step are clear, the parameters are measurable, and the results are verifiable, demonstrating outstanding substantive features and significant progress.

[0106] It should be noted that all terms used in this invention to indicate direction and position, such as "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "inner", "outer", "top", "lower", "tail end", "head end", "center", etc., are only used to explain the relative positional relationship and connection between components in a specific state. They are only for the convenience of describing this invention and do not require that this invention must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0107] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for feeding titanium alloy castings using risers, characterized in that, Includes the following steps: S1, numerical simulation to locate the hot spot; S2, optimization of the calculation model for hot spot modulus and conical riser; S3, through simulation iteration, optimizes the riser height H, end opening and taper to eliminate isolated liquid phase regions; S4. An insulating mold shell layer is added to the riser area to enhance the shrinkage compensation effect and promote sequential solidification.

2. The method for feeding titanium alloy castings via risers according to claim 1, characterized in that, The hot spot location described in step S1 uses the solid fraction as a critical judgment condition, tracks the last solidified area during the solidification process, and accurately determines the hot spot location.

3. The method for feeding titanium alloy castings via risers according to claim 2, characterized in that, Using a solid fraction of 0.7 as the critical threshold, TC4 titanium alloy identifies independent, continuous liquid enrichment regions with a solid fraction <0.7 as thermal nodes.

4. The method for feeding titanium alloy castings via risers according to claim 1, characterized in that, The conical riser size model established in step S2 introduces the riser modulus M. r The riser modulus M r Let M be a function of the riser height H, end opening, and taper, and satisfy M. r ≥k·M c , of which M c denoted as the thermal modulus, and k as the shrinkage compensation coefficient.

5. The method for feeding titanium alloy castings via risers according to claim 4, characterized in that, In step S2, the tapered riser size model is used to introduce a tapered compensation difference ΔM. c It is used to correct the change in effective heat dissipation area caused by the tilting of the riser sidewall and optimize the accuracy of riser modulus calculation.

6. The method for feeding titanium alloy castings via risers according to claim 5, characterized in that, When the conical riser is frustum conical, formula M is used. r =k·D1·H / 2(D1+H)+△M c Where D1 is the diameter of the large end opening of the conical riser.

7. The method for feeding titanium alloy castings via risers according to claim 6, characterized in that, k=2.3, H=(1.3~1.5)D1.

8. The method for feeding titanium alloy castings via risers according to claim 5, characterized in that, The taper compensation difference ΔM c The riser taper and the thermal conductivity of the material are obtained through empirical fitting or simulation calibration.

9. The method for feeding titanium alloy castings via risers according to claim 8, characterized in that, For every 1° increase in the riser taper, the riser modulus is corrected by -0.01 to -0.

5.

10. The method for feeding titanium alloy castings via risers according to claim 4, characterized in that, According to formula M c =V / S is used to calculate the hot spot modulus, where V is the volume of the hot spot region and S is the heat dissipation surface area of ​​the hot spot region.

11. The method for feeding titanium alloy castings via risers according to claim 1, characterized in that, The simulation iterative design process in step S3 includes: setting multiple candidate riser structure parameter combination schemes, running multiple numerical simulations, evaluating whether each scheme forms an isolated liquid phase region, and selecting the optimal parameter combination to keep the feeding channel continuously connected until final solidification.

12. The method for feeding titanium alloy castings via risers according to claim 1, characterized in that, The insulation mold shell layer mentioned in step S4 is prepared using a silica sol-mullite system material and coated on the outer surface of the riser area to reduce the heat dissipation rate of the riser and prolong the feeding time.

13. The method for feeding titanium alloy castings via risers according to claim 12, characterized in that, The thickness of the insulation mold shell layer is 0.8mm~2mm.

14. A feeding system for titanium alloy castings, characterized in that, The system is used to implement the method as described in any one of claims 1 to 13, and includes: a hot spot identification module, a riser parameter calculation module, a simulation optimization module, and a thermal insulation structure configuration module, with each module integrated into a unified design platform through a data interface.

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