Machining method of hollow control surface part
By using forging and phased milling processes, the problems of low material utilization and low processing efficiency in the machining of hollow rudder surface parts have been solved, realizing a high-efficiency and low-loss machining method, and improving the mechanical strength and precision of the parts.
Patent Information
- Application Number
- CN202511333081.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2025-07-04
- Filing Date
- 2025-09-18
- Publication Date
- 2025-11-04
AI Technical Summary
In the existing technology, the processing of hollow rudder surface parts suffers from problems such as low material utilization, long processing cycle, high tool wear, and low equipment output.
The process employs forging and staged chemical milling, including forming with an electric screw press, die forming and heating forging, and staged chemical milling. Specific chemical milling solutions and protective adhesives are used, combined with ultraviolet laser curing and sandblasting to optimize the microstructure and shape of the forgings.
It improves material utilization, reduces processing stress and tool wear, enhances processing efficiency and mechanical strength of parts, ensures high precision and durability, and reduces scrap rate.
Smart Images
Figure CN120886012A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of parts processing technology, specifically to a method for processing hollow rudder surfaces. Background Technology
[0002] Hollow control surfaces are key control components for aerospace vehicles (such as airplanes, missiles, and drones), primarily used to adjust flight attitude and direction. Their core characteristics are lightweight, high strength, and high-precision aerodynamic shape. They are typically manufactured using special alloys (such as aluminum alloys and titanium alloys) or composite materials, and their internal rib support structure is formed through precision machining (such as chemical milling and 3D printing).
[0003] However, the control surface parts are machined from sheet metal using a milling process, which results in a material utilization rate of about 10%. This process is problematic due to the large amount of material removed, long milling cycle, high tool wear, and low output of the milling equipment. Summary of the Invention
[0004] To solve the above-mentioned technical problems, the present invention provides a method for processing hollow rudder surface parts.
[0005] The technical solution of this invention is: a method for processing hollow rudder surface parts, comprising the following steps:
[0006] S1, Rudder surface forging process
[0007] S1-1, Design drawing of the rudder surface forging;
[0008] S1-2. Design and process the mold according to the rudder surface forging drawing;
[0009] S1-3. Machining rudder surface forgings: The rudder surface forgings are obtained by following the process of blanking → heating and forging → deburring → solution heat treatment → aging heat treatment → inspection.
[0010] S2, rudder surface milling process
[0011] S2-1, Design and process marking tools for cutting protective adhesive;
[0012] S2-1. The rudder surface forging is processed according to the following steps: organic solvent cleaning → sandblasting → applying protective glue → drying → cutting with scribing tools → peeling off the glue → chemical milling → inspection, to obtain a hollow rib support structure. Then, skin is welded to both sides of the hollow rib support structure to obtain the hollow rudder surface part.
[0013] Furthermore, in S1-3, the forging equipment for processing the rudder surface forging is an electric screw press, the forging method is die forming, and the heating forging is heating at 1120-1140℃ for 30-40 minutes, and then naturally cooling to 850℃.
[0014] Note: Forgings produced using an electric screw press have high production efficiency. The forging method using a die ensures good consistency in part size and shape. Heating forging softens the plasticity of the forgings, which helps with the subsequent forming effect of the forgings.
[0015] Furthermore, the blank transfer speed during the processing of S1-3 is <10s;
[0016] Note: The above limitations are to reduce temperature loss in the parts and improve their plasticity.
[0017] Further, in S2-2, the chemical milling solution used in the chemical milling includes: 50-60 g / L hydrochloric acid, 110-120 g / L nitric acid, 400-500 g / L ferric chloride, and 300-400 mesh 20-30 g / L charcoal.
[0018] Note: The ribs are made of metal alloy or stainless steel. Hydrochloric acid + nitric acid rapidly dissolve the metal matrix. FeCl3 enhances the oxidation capacity. Charcoal powder adsorbs reaction products (such as Fe). 2+ To avoid uneven local corrosion caused by deposits.
[0019] Furthermore, the solution heat treatment temperature is 1030–1050℃, and the treatment time is 50–80 min; the aging heat treatment temperature is 490–510℃, and the treatment time is 225–255 min.
[0020] Explanation: Solution heat treatment parameters can reduce localized corrosion-sensitive areas caused by compositional inhomogeneity (such as increased lateral corrosion during chemical milling), lower the scrap rate, and provide a uniform supersaturated solid solution for subsequent aging, avoiding part scrap due to strength fluctuations. Aging heat treatment parameters can improve the overall strength consistency of forgings, preventing part failure under load due to localized weak areas (such as grain boundary depletion). It also reduces the risk of deformation during subsequent machining (such as chemical milling and cutting), minimizing dimensional deviations and scrap. By optimizing solution and aging parameters, the microstructure uniformity and performance consistency of rudder surface forgings can be significantly improved, thereby reducing machining scrap rate and material waste.
[0021] Furthermore, in S2-2, the organic solvent is alcohol;
[0022] Note: Organic solvents are used to remove oil and organic contaminants.
[0023] Further, in S2-2, the protective adhesive is a photosensitive protective adhesive with a thickness of 0.4 to 0.8 mm, and the coating method of the protective adhesive is ultraviolet laser curing, wherein the laser power is 10 to 20 W and the scanning speed is 500 to 1000 mm / s;
[0024] Note: Sandblasting is used to increase surface roughness and improve the adhesion of the protective adhesive to prevent it from falling off; UV laser curing can improve edge accuracy to ±0.02mm, reducing the risk of overcutting; it is suitable for complex curved surfaces of the rudder surface.
[0025] Furthermore, in S2-2, the milling method is a staged milling process;
[0026] The method for the staged milling process is as follows:
[0027] First stage: The rudder surface forging is first immersed in the first chemical milling fluid, and then the rudder surface forging is rotated around its own axis at a speed of 10-15 r / min, the temperature is 35-40℃, the immersion time is 10-15 min, and the chemical milling rate is 0.08-0.09 mm / min; the first chemical milling fluid includes a chemical milling solution and Na2MoO4 with a mass ratio of 1:0.8-1.2.
[0028] Second stage: The rudder surface forging is placed in NaCl electrolyte, a pulsed current is applied, and then the rudder surface forging is rotated around its own axis at a speed of 3-5 r / min, with a current density of 3-5 A / dm. 2 The temperature is 40–50℃, the duty cycle is 50–55%, the frequency is 0.8–1kHz, the chemical milling time is 20–25 min, and the chemical milling rate is 0.05–0.07 mm / min; the second chemical milling fluid includes NaCl, chemical milling solution, polyvinyl alcohol, and potassium thiocyanate in a mass ratio of 1:1:0.5–0.7:0.8–1.2.
[0029] Third stage: Finally, at room temperature, the rudder surface forging is placed in a passivation solution obtained by mixing a 5% nitric acid solution and a 1.5-2 g / L potassium dichromate aqueous solution and soaked for 3-5 minutes. Then, it is cleaned with deionized water at a frequency of 35-45 kHz, a power of 100-150 W / L, and a temperature of 30-40°C for 5-8 minutes. After dehydration with ethanol, it is dried with nitrogen.
[0030] Explanation: Limiting the pulse current reduces polarization layer buildup and stabilizes the corrosion rate; limiting the duty cycle balances corrosion and diffusion during the on / off cycle, preventing intergranular corrosion caused by overheating; polyvinyl alcohol increases electrolyte viscosity, forming a viscous barrier that restricts the lateral penetration of the chemical milling fluid; potassium thiocyanate and Fe... 3+ [Fe(SCN)] is formed. 2+ The complex accelerates the dissolution of Fe, increases the corrosion rate, selectively adsorbs at grain boundaries to inhibit intergranular corrosion, and low-speed rotation ensures a stable electrolyte flow field, avoiding uneven corrosion caused by turbulence, while also promoting bubble escape; the second stage achieves high-precision shape control and efficiently eliminates lateral corrosion; the third stage passivation treatment improves the durability of parts and meets the target requirements.
[0031] Furthermore, the nitrogen drying method involves using nitrogen gas with a purity ≥99.99% at a pressure of 0.2–0.4 MPa, a flow rate of 10–20 L / min, and a temperature of 40–50 °C to remove droplets from the rib surface using a wide-angle nozzle for 2–4 minutes, followed by removing dead corners from the rib surface using a spot-jet nozzle for 4–6 minutes.
[0032] Note: Wide-angle nozzles quickly remove over 90% of liquid droplets from the rib surface, preventing liquid film residue from causing localized corrosion (such as uneven passivation film after chemical milling). Spot nozzles precisely handle dead corners such as rib gaps and weld seams; the surface cleanliness is high after drying, reducing rework or scrap due to contamination.
[0033] Furthermore, the sandblasting method is as follows: the sandblasting abrasive used is 20# / 46# white corundum, the sandblasting pressure is 0.2-0.3MPa, and the spraying distance is 20-30cm;
[0034] Note: The above parameters can improve the surface roughness of the parts and enhance the adhesion of the protective adhesive, preventing it from falling off during chemical milling.
[0035] The beneficial effects of this invention are:
[0036] (1) This invention uses forging to process rudder surface parts. The low-magnification streamlines of the forging are consistent with the shape of the part, and the forging structure is more compact with finer grains. The parts produced by this process have better mechanical strength. The metal in the cavity is removed by chemical milling, resulting in low processing stress and no deformation of the parts. The machining method is used, only the installation position is processed, the amount of machining is small, and the tool wear is low. At the same time, the forging process can effectively save raw materials compared with the direct processing of sheet metal, and the processing of forgings is more efficient and time-saving.
[0037] (2) The phased milling process of this invention can utilize Na2MoO4 to inhibit corrosion in the first stage, reduce intergranular corrosion and avoid local strength weakening; achieve high-precision shape control in the second stage and efficiently eliminate side corrosion; passivation treatment in the third stage improves the durability of parts and meets the target requirements; and the uniformity of dynamic rotational corrosion in the first stage is improved, with side corrosion width ≤0.1mm; the penetration of electrolyte is reduced by pulse current + PVA viscosity control in the second stage, and the material allowance is reduced; the ultrasonic cleaning and nitrogen blowing in the third stage accurately removes residues and reduces rework rate. Attached Figure Description
[0038] Figure 1 The hollow rib support structure obtained in this application;
[0039] Figure 2 This is a schematic diagram of the line drawing tool in this application. Detailed Implementation
[0040] The present invention will now be described in more detail with reference to specific embodiments, so as to better demonstrate the advantages of the present invention.
[0041] Example 1: A method for machining a hollow rudder surface part, comprising the following steps:
[0042] S1, Rudder surface forging process
[0043] S1-1, Design drawing of the rudder surface forging;
[0044] S1-2. Design and process the mold according to the rudder surface forging drawing;
[0045] S1-3, Machining the Rudder Face Forging: The rudder face forging is obtained by the following process: blanking → heating and forging at 1130℃ for 35 minutes, then naturally cooling to 850℃ → trimming the burrs → solution heat treatment at 1040℃ for 65 minutes → aging heat treatment at 500℃ for 240 minutes → inspection. The forging equipment for machining the rudder face forging is an electric screw press, and the forging method is die forming. The blank transfer speed during the machining process of S1-3 is 8 seconds.
[0046] S2, rudder surface milling process
[0047] S2-1, Design and process marking tools for cutting protective adhesive;
[0048] S2-2. The rudder surface forging is processed according to the following steps: alcohol cleaning → sandblasting → applying protective glue → drying → cutting with scribing tools → peeling off the glue → chemical milling → inspection, to obtain a hollow rib support structure. Then, skin is welded to both sides of the hollow rib support structure to obtain the hollow rudder surface part. In this embodiment, the protective glue used is commercially available solvent-based protective glue SX-150.
[0049] The chemical milling solution used in chemical milling includes: 55 g / L hydrochloric acid, 115 g / L nitric acid, 450 g / L ferric chloride, and 25 g / L charcoal of 300-400 mesh.
[0050] The sandblasting method is as follows: the abrasive used is 20# white corundum, the sandblasting pressure is 0.25MPa, and the spraying distance is 25cm.
[0051] Example 2: Unlike Example 1, the rudder surface forging is processed as follows: blanking → heating and forging at 1120℃ for 30 minutes, then naturally cooling to 850℃ → trimming the burrs → solution heat treatment at 1030℃ for 50 minutes → aging heat treatment at 490℃ for 225 minutes → inspection.
[0052] Example 3: Unlike Example 1, the rudder surface forging is processed as follows: blanking → heating and forging at 1140℃ for 40 minutes, then naturally cooling to 850℃ → trimming the burrs → solution heat treatment at 1050℃ for 80 minutes → aging heat treatment at 510℃ for 255 minutes → inspection.
[0053] Example 4: Unlike Example 1, the chemical milling solution used in the chemical milling process includes: 50 g / L hydrochloric acid, 110 g / L nitric acid, 400 g / L ferric chloride, and 20 g / L charcoal of 300-400 mesh.
[0054] Example 5: Unlike Example 1, the chemical milling solution used in the chemical milling process includes: 60 g / L hydrochloric acid, 120 g / L nitric acid, 500 g / L ferric chloride, and 30 g / L charcoal of 300-400 mesh.
[0055] Example 6: Unlike Example 1, the sandblasting method is as follows: the sandblasting abrasive used is 20# white corundum, the sandblasting pressure is 0.2MPa, and the spraying distance is 20cm.
[0056] Example 7: Unlike Example 1, the sandblasting method is as follows: the sandblasting abrasive used is 46# white corundum, the sandblasting pressure is 0.3MPa, and the spraying distance is 30cm.
[0057] Example 8: Unlike Example 1, the protective adhesive is a photosensitive protective adhesive with a thickness of 0.6 mm. The coating method of the protective adhesive is ultraviolet laser curing, wherein the laser power is 15W and the scanning speed is 750mm / s; the photosensitive protective adhesive used in this example is SU-8.
[0058] Example 9: Unlike Example 8, the protective adhesive thickness is 0.4 mm, the UV laser curing power is 10W, and the scanning speed is 500 mm / s.
[0059] Example 10: Unlike Example 8, the protective adhesive thickness is 0.8 mm, the UV laser curing power is 20 W, and the scanning speed is 1000 mm / s.
[0060] Example 11: Unlike Example 8, in S2-2, the chemical milling method is a staged chemical milling process;
[0061] The method of phased milling is as follows:
[0062] First stage: The rudder surface forging is first immersed in the first chemical milling fluid, and then the rudder surface forging is rotated around its own axis at a speed of 13 r / min, the temperature is 38℃, the immersion time is 13 min, and the chemical milling rate is 0.085 mm / min; the first chemical milling fluid includes a chemical milling solution and Na2MoO4 with a mass ratio of 1:1.
[0063] Second stage: The rudder surface forging is placed in the second chemical milling fluid, a pulsed current is applied, and then the rudder surface forging is rotated around its own axis at a speed of 4 r / min, with a current density of 4 A / dm. 2 The temperature was 45℃, the duty cycle was 53%, the frequency was 0.9kHz, the chemical milling time was 23min, and the chemical milling rate was 0.06mm / min; the second chemical milling fluid included NaCl, chemical milling solution, polyvinyl alcohol, and potassium thiocyanate in a mass ratio of 1:1:0.6:1.
[0064] The third stage: Finally, the rudder surface forging is placed in a passivation solution obtained by mixing a 5% nitric acid solution and a 1.8 g / L potassium dichromate aqueous solution at 27°C for 4 min, then cleaned with deionized water at a frequency of 40 kHz, a power of 125 W / L, and 35°C for 7 min, and then dried with nitrogen after being dehydrated with ethanol.
[0065] The nitrogen drying method involves using a wide-angle nozzle to remove droplets from the rib surface for 3 minutes at a purity of 99.99% under conditions of 0.3 MPa, a flow rate of 15 L / min, and a temperature of 45 °C, followed by removing dead corners from the rib surface for 5 minutes using a spot-jet nozzle.
[0066] Example 12: Unlike Example 11, in the first stage: the rudder surface forging is first immersed in the first chemical milling fluid, and then the rudder surface forging is rotated around its own axis at a speed of 10 r / min, the temperature is 35℃, the immersion time is 10 min, and the chemical milling rate is 0.08 mm / min.
[0067] Example 13: Unlike Example 11, in the first stage: the rudder surface forging is first immersed in the first chemical milling fluid, and then the rudder surface forging is rotated around its own axis at a speed of 15 r / min, the temperature is 40℃, the immersion time is 15 min, and the chemical milling rate is 0.09 mm / min.
[0068] Example 14: Unlike Example 11, the first chemical milling fluid includes a chemical milling solution and Na2MoO4 in a mass ratio of 1:0.8.
[0069] Example 15: Unlike Example 11, the first chemical milling fluid includes a chemical milling solution and Na2MoO4 in a mass ratio of 1:1.2.
[0070] Example 16: Unlike Example 11, in the second stage: the rudder surface forging is placed in the second chemical milling fluid, a pulsed current is applied, and then the rudder surface forging is rotated around its own axis at a speed of 3 r / min, with a current density of 3 A / dm. 2 Temperature 40℃, duty cycle 50%, frequency 0.8kHz, milling time 20min, milling speed 0.05mm / min.
[0071] Example 17: Unlike Example 11, in the second stage: the rudder surface forging is placed in the second chemical milling fluid, a pulsed current is applied, and then the rudder surface forging is rotated around its own axis at a speed of 5 r / min with a current density of 5 A / dm. 2 Temperature 50℃, duty cycle 55%, frequency 1kHz, milling time 25min, milling speed 0.07mm / min.
[0072] Example 18: Unlike Example 11, the second chemical milling fluid includes NaCl, chemical milling solution, polyvinyl alcohol, and potassium thiocyanate in a mass ratio of 1:1:0.5:0.8.
[0073] Example 19: Unlike Example 11, the second chemical milling fluid includes NaCl, chemical milling solution, polyvinyl alcohol, and potassium thiocyanate in a mass ratio of 1:1:0.7:1.2.
[0074] Example 20: Unlike Example 11, the rudder surface forging was finally placed in a passivation solution obtained by mixing a 5% nitric acid solution and a 1.5 g / L potassium dichromate aqueous solution at 25°C for 3 min, then cleaned with deionized water at a frequency of 35 kHz, a power of 100 W / L, and 30°C for 5 min, dehydrated with ethanol, and then dried with nitrogen.
[0075] Example 21: Unlike Example 11, the rudder surface forging was finally placed in a passivation solution obtained by mixing a 5% nitric acid solution and a 2g / L potassium dichromate aqueous solution at 30°C for 5 minutes. It was then cleaned with deionized water at a frequency of 45kHz, a power of 150W / L, and 40°C for 8 minutes. After dehydration with ethanol, it was dried with nitrogen.
[0076] Example 22: Unlike Example 11, the nitrogen drying method involves using a wide-angle nozzle to remove droplets from the rib surface for 2 minutes at a pressure of 0.2 MPa, a flow rate of 10 L / min, and a temperature of 40 °C, with 99.99% pure nitrogen gas. Then, the dead corners of the rib surface are removed using a spot-jet nozzle for 4 minutes.
[0077] Example 23: Unlike Example 11, the nitrogen drying method involves using a wide-angle nozzle to remove droplets from the rib surface for 4 minutes at a pressure of 0.4 MPa, a flow rate of 20 L / min, and a temperature of 50 °C, with 99.99% pure nitrogen gas. Then, the dead corners of the rib surface are removed using a spot-jet nozzle for 6 minutes.
[0078] Experimental Example: The hollow rib support structures of the hollow rudder surface parts obtained in Examples 1-23 and Control Groups 1-4 were tested for tensile strength (MPa), material utilization rate (material utilization rate = initial forging blank weight / finished part net weight × 100%), and maximum side erosion width. The results are as follows:
[0079] 1. Investigate the effect of the composition of the chemical milling solution on the performance of the hollow rib support structure.
[0080] Control group 1: Unlike Example 1, the chemical milling solution did not contain charcoal.
[0081] Table 1. Performance effects of Examples 1-7 and Control Group 1 on the hollow ribbed support structure.
[0082] Group Tensile strength (MPa) Material utilization rate % Maximum lateral erosion width (mm) Example 1 480 87 0.08 Example 2 475 84 0.1 Example 3 477 82 0.09 Example 4 479 86 0.11 Example 5 480 85 0.1 Example 6 477 84 0.09 Example 7 474 85 0.09 Control group 1 380 70 0.3
[0083] Conclusion: A comparison of Examples 1-7 and Control Group 1 shows that excessively large or small parameters within the scope of this application have a relatively small impact on the performance of the hollow rib support structure. However, if the chemical milling solution does not contain charcoal, it will have a more significant adverse effect on the performance of the hollow rib support structure. This is because charcoal particles can adsorb Fe generated during the chemical milling process. 2+ Al 3+ The presence of metal ions in the slurry helps prevent them from depositing on the surface of parts and forming localized corrosion pits. It also reduces suspended particles in the slurry, preventing uneven corrosion due to concentration gradients. Conversely, the absence of charcoal particles can exacerbate localized pitting corrosion and increase the risk of grain boundary corrosion, thereby reducing tensile strength. Charcoal adsorbs Fe... 2+ Subsequently, the oxidizing power of FeCl3 remained stable, with the chemical milling rate fluctuating by ≤±5%; and the uniform corrosion environment controlled the lateral corrosion width to ≤0.1mm; while in control group 1, Fe... 2+ Accumulation leads to decreased activity of the chemical milling fluid, requiring frequent parameter adjustments or fluid replacement. This increases the scrap rate and significantly reduces material utilization. Furthermore, the absence of charcoal will cause Fe... 2+ Local enrichment leads to "tunnel corrosion," and the lateral corrosion width fluctuates more. Therefore, Example 1 is the optimal solution.
[0084] 2. Investigate the effect of protective adhesive coating methods on the performance of hollow rib support structures.
[0085] Table 2. Performance impact of Examples 1, 8-10 on the hollow ribbed support structure.
[0086] Group Tensile strength (MPa) Material utilization rate % Maximum lateral erosion width (mm) Example 1 480 87 0.08 Example 8 508 90 0.04 Example 9 500 89 0.05 Example 10 502 90 0.05
[0087] Conclusion: Comparison of Examples 1 and 8-10 shows that applying the protective adhesive using UV laser curing can further optimize the performance of the cavity rib support structure. This is mainly because using UV laser to directly cure the photosensitive protective adhesive on the surface of the part results in a sharp, burr-free surface (uniform side etching), improving edge accuracy to ±0.02mm, reducing the risk of overcutting, reducing stress concentration, and significantly improving tensile strength. The side etching width of UV laser curing is ≤0.05mm, while that of manual adhesive application is 0.08mm, and material utilization is also improved. Considering all factors, Example 8 is selected as the further optimization solution.
[0088] 3. Investigate the impact of chemical milling on the performance of hollow ribbed support structures.
[0089] Control group 2: Unlike Example 11, the first stage lacks the step of rotating the rudder surface forging around its own axis.
[0090] Control group 3: Unlike Example 11, Na2MoO4 in the first chemical milling fluid was replaced with PEG-400.
[0091] Control group 4: Unlike Example 11, the second chemical milling fluid lacked potassium thiocyanate.
[0092] Table 3. Performance impact of Examples 8 and 11-23 on the hollow ribbed support structure.
[0093]
[0094]
[0095] Conclusion: A comparison of Examples 8 and Examples 11-23 shows that staged chemical milling significantly improves the performance of the hollow rib support structure. This is mainly because staged chemical milling effectively ensures efficiency and improves the milling effect, with Example 11 showing the best results. However, a comparison of Examples 11-13 and Control Group 2 reveals that in Control Group 2, during static immersion, the chemical milling fluid, due to gravity stratification and concentration gradients, results in more contact with fresh milling fluid at the surface, leading to faster corrosion at the top and accumulation of reaction products at the bottom, inhibiting corrosion and resulting in slower corrosion at the bottom. Simultaneously, non-uniform corrosion creates stress concentration points at the rib roots and corners, significantly weakening tensile strength. Furthermore, during static immersion, more allowance is needed to compensate for non-uniform corrosion, thus significantly reducing material utilization. Additionally, during static immersion, Fe... 2+ Al 3+ When metal ions are deposited on the surface of a part, a "masking effect" is formed, which leads to: the deposits hindering the contact of the chemical milling fluid and exacerbating lateral diffusion, thus increasing the maximum lateral erosion width;
[0096] A comparison of Examples 11, 14-15, and Control Group 3 shows that replacing Na2MoO4 with PEG-400 in Control Group 3 causes a decrease in the performance of the cavity rib support structure. This indicates that Na2MoO4 is more suitable for strongly acidic environments than PEG-400, with advantages including: forming a molybdate passivation film, suppressing lateral corrosion (lateral corrosion width ≤ 0.1 mm), and... 3+ Synergistically promotes uniform corrosion and avoids pitting corrosion (PEG-400 is easily decomposed in acidic environments); PEG-400 decomposes rapidly in strong acids and cannot effectively inhibit Al. 3+ / Fe 2+ Along-grain boundary corrosion weakens the grain boundaries, significantly reducing tensile strength. Simultaneously, PEG-400 cannot suppress transverse corrosion, requiring additional allowance and significantly reducing material utilization. Na2MoO4 exhibits uniform lateral corrosion, making it suitable for precision rib structures. PEG-400 exhibits large fluctuations in lateral corrosion, necessitating subsequent machining correction.
[0097] A comparison of Examples 11, 18-19, and Control Group 4 shows that the lack of potassium thiocyanate in Control Group 4 leads to a decrease in the performance of the hollow rib support structure. Potassium thiocyanate (KSCN) complexes Fe... 3+ Suppressing lateral erosion and stabilizing the corrosion rate are important components for ensuring high-precision milling of hollow rudder surface parts. Removing KSCN will lead to a decrease in tensile strength due to grain boundary weakening and local overcutting; the increased lateral erosion and scrap rate will reduce material utilization and increase the maximum lateral erosion width. Therefore, considering all factors, Example 18 is selected as a further optimization scheme.
Claims
1. A method for machining a hollow rudder surface part, characterized in that, Includes the following steps: S1, Rudder surface forging process S1-1, Design drawing of the rudder surface forging; S1-2. Design and process the mold according to the rudder surface forging drawing; S1-3. Machining rudder surface forgings: The rudder surface forgings are obtained by following the process of blanking → heating and forging → deburring → solution heat treatment → aging heat treatment → inspection. S2, rudder surface milling process S2-1, Design and process marking tools for cutting protective adhesive; S2-2. The rudder surface forging is processed according to the following steps: organic solvent cleaning → sandblasting → applying protective glue → drying → cutting with scribing tools → peeling off the glue → chemical milling → inspection, to obtain a hollow rib support structure. Then, skin is welded to both sides of the hollow rib support structure to obtain the hollow rudder surface part.
2. The method for processing a hollow rudder surface part as described in claim 1, characterized in that, In S1-3, the forging equipment for machining the rudder surface forging is an electric screw press. The forging method is die forming. The heating forging is carried out at 1120-1140℃ for 30-40 minutes, and then naturally cooled to 850℃.
3. The method for processing a hollow rudder surface part as described in claim 1, characterized in that, During the processing of S1-3, the blank transfer speed is <10s.
4. The method for processing a hollow rudder surface part as described in claim 1, characterized in that, In S2-2, the chemical milling solution used in the chemical milling includes: 50-60 g / L hydrochloric acid, 110-120 g / L nitric acid, 400-500 g / L ferric chloride, and 300-400 mesh 20-30 g / L charcoal.
5. The method for machining a hollow rudder surface part as described in claim 1, characterized in that, The solution heat treatment temperature is 1030–1050℃ and the treatment time is 50–80 min; the aging heat treatment temperature is 490–510℃ and the treatment time is 225–255 min.
6. The method for machining a hollow rudder surface part as described in claim 1, characterized in that, In S2-2, the organic solvent is alcohol.
7. The method for machining a hollow rudder surface part as described in claim 1, characterized in that, In S2-2, the protective adhesive is a photosensitive protective adhesive with a thickness of 0.4 to 0.8 mm. The coating method of the protective adhesive is ultraviolet laser curing, wherein the laser power is 10 to 20 W and the scanning speed is 500 to 1000 mm / s.
8. The method for processing a hollow rudder surface part as described in claim 4, characterized in that, In S2-2, the milling method is a staged milling process; The method for the staged milling process is as follows: First stage: The rudder surface forging is first immersed in the first chemical milling fluid, and then the rudder surface forging is rotated around its own axis at a speed of 10-15 r / min, the temperature is 35-40℃, the immersion time is 10-15 min, and the chemical milling rate is 0.08-0.09 mm / min; the first chemical milling fluid includes a chemical milling solution and Na2MoO4 with a mass ratio of 1:0.8-1.
2. Second stage: The rudder surface forging is placed in NaCl electrolyte, a pulsed current is applied, and then the rudder surface forging is rotated around its own axis at a speed of 3-5 r / min, with a current density of 3-5 A / dm. 2 The temperature is 40–50℃, the duty cycle is 50–55%, the frequency is 0.8–1kHz, the chemical milling time is 20–25 min, and the chemical milling rate is 0.05–0.07 mm / min; the second chemical milling fluid includes NaCl, chemical milling solution, polyvinyl alcohol, and potassium thiocyanate in a mass ratio of 1:1:0.5–0.7:0.8–1.
2. Third stage: Finally, at room temperature, the rudder surface forging is placed in a passivation solution obtained by mixing a 5% nitric acid solution and a 1.5-2 g / L potassium dichromate aqueous solution and soaked for 3-5 minutes. Then, it is cleaned with deionized water at a frequency of 35-45 kHz, a power of 100-150 W / L, and a temperature of 30-40°C for 5-8 minutes. After dehydration with ethanol, it is dried with nitrogen.
9. A method for machining a hollow rudder surface part as described in claim 8, characterized in that, The method of nitrogen drying is to use nitrogen with a purity ≥99.99% to remove droplets from the rib surface using a wide-angle nozzle for 2-4 minutes under the conditions of 0.2-0.4 MPa, flow rate of 10-20 L / min and temperature of 40-50℃, and then use a spot spray nozzle to remove dead corners on the rib surface for 4-6 minutes.
10. A method for machining a hollow rudder surface part as described in claim 1, characterized in that, In S2-2, the sandblasting method is as follows: the sandblasting abrasive used is 20# / 46# white corundum, the sandblasting pressure is 0.2-0.3MPa, and the spraying distance is 20-30cm.