A low cost straightening process for titanium and titanium alloy blades

Abstract

The present application relates to the field of blade shaping, in particular to a low-cost shaping process method for titanium and titanium alloy blades, comprising the following steps: step one, scanning the incoming blade with a three-dimensional scanner to obtain the actual three-dimensional curve of the blade; step two, comparing the actual three-dimensional curve with the three-dimensional model of the blade; step three, marking the lack of value on the blade compared with the model; step four, drawing the deviation 0 line; step five, if the deviation 0 line is at the free end of the blade and is not a closed line, set the welding groove for shaping; step six, welding with welding wire; step seven, using a three-dimensional scanner to perform secondary scanning to obtain the corrected three-dimensional curve of the blade, comparing the corrected three-dimensional curve with the three-dimensional model of the blade, if they coincide, performing step eight, if they do not coincide, returning to step three; step eight, performing ray detection to exclude welding defects; step nine, heat treatment. The present application solves the problems that the blade type value cannot be measured and the shaping cannot be positioned, and corresponding shaping methods are adopted according to different situations.

Description

Technical Field

[0001] This invention relates to the field of blade straightening, and particularly to a low-cost straightening process for titanium and titanium alloy blades. Background Technology

[0002] Titanium and titanium alloys, due to their excellent specific strength, high-temperature resistance, and corrosion resistance, have become ideal materials for blades operating under acid, alkali, and seawater conditions. However, during the casting process of titanium and titanium alloy blades, the complex shape and uneven wall thickness distribution inevitably generate residual stress and thermal stress, leading to blade warping and dimensional deviations. These deformation problems seriously affect the accuracy and performance of the blades, becoming a major technical challenge in the manufacturing process. The shaping process of titanium alloys faces two main challenges: material property sensitivity and datum positioning. Titanium alloys have low elastic modulus, high deformation resistance, and temperature sensitivity, making them prone to elastic recovery and stress concentration during shaping, potentially leading to shaping cracks. Furthermore, the blade profile is often curved, making measurement and datum determination inconvenient, further increasing the complexity of the shaping process. Simultaneously, with the increasing market competition for titanium and titanium alloy cast blades, there is an urgent need to control the cost of the shaping process. Therefore, developing a low-cost shaping process is of great significance for the production and manufacturing of titanium and titanium alloy cast blades. Summary of the Invention

[0003] In view of this, the present invention aims to propose a low-cost shaping process for titanium and titanium alloy blades, in order to solve the problems of existing technologies that are difficult to effectively shape curved titanium and titanium alloy blades, and that the shaping accuracy is low, the time is long, and the cost is high.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] A low-cost forming process for titanium and titanium alloy blades includes the following steps:

[0006] Step 1: Use a 3D scanner to scan the incoming blades to obtain the actual 3D curve of the blades;

[0007] Step 2: Compare the actual 3D curve with the 3D model of the blade;

[0008] Step 3: Mark the missing values ​​of the model on the blades;

[0009] Step 4: Draw the deviation 0-position line;

[0010] Step 5: If the deviation 0-position line is at the free end of the blade and is not a closed line, a welding bevel is set for correction.

[0011] Step 6: Weld using welding wire;

[0012] Step 7: Use a 3D scanner to perform a secondary scan to obtain the corrected 3D curve of the blade. Compare the corrected 3D curve with the 3D model of the blade. If the two overlap, proceed to step 8. If they do not overlap, return to step 3.

[0013] Step 8: Radiographic testing to eliminate welding defects;

[0014] Step 9: Heat treatment to eliminate welding stress.

[0015] Furthermore, one end of the blade is a root and the other end is a tip. The root is mounted on a wheel or rotor, and the tip extends out and is not fixed. The root of the blade is the constrained end, and the tip is the free end.

[0016] Furthermore, in step five, if the deviation 0-position line is not at the free end of the blade, a welding repair method is used for correction.

[0017] Furthermore, in step five, a welding bevel is opened on the deviation 0 position line, with a bevel angle θ = 40°~60°, a bevel width B = 5i, and a bevel depth H = 2i, where i is the maximum defect value of the free end of the blade.

[0018] Furthermore, the bevel width B ≤ 15mm and the bevel depth H ≤ 1 / 2d, where d is the thickness of the blade at the bevel location.

[0019] Furthermore, in step three, the missing value refers to the degree to which the actual three-dimensional curve or the corrected three-dimensional curve deviates from and is short of the model at the same location.

[0020] Furthermore, in step four, the deviation 0-position line refers to the line connecting the actual three-dimensional curve or the corrected three-dimensional curve to the position where it coincides with the three-dimensional model of the blade.

[0021] Furthermore, in step six, the welding current is 90~120A and the shielding gas flow rate is 8~25L / min.

[0022] Furthermore, after comparing the actual three-dimensional curve with the three-dimensional model of the blade, if the actual three-dimensional curve deviates from and exceeds the three-dimensional model, the excess portion is removed based on the amount of deviation.

[0023] Compared with existing technologies, the low-cost shaping process for titanium and titanium alloy blades described in this invention has the following advantages:

[0024] (1) It solves the problem of blade profile values ​​being unmeasurable and calibration location being unavailable. By using a 3D scanner and comparing it with a 3D model, the dimensional deviation values ​​of each region of the blade surface can be obtained quickly and accurately. Then, by using the method of determining the "0-position line", the calibration location can be accurately obtained. Compared with traditional measurement, the dimensional location is more accurate and the measurement time is shorter.

[0025] (2) This application solves the problem of cumbersome tooling manufacturing and poor shaping effect. The application adopts the "scanning + welding" cycle concept. According to the different degrees of deformation, the corresponding bevel width and depth are selected, which makes the operation simpler and can better ensure that the surface result meets the shape value. At the same time, with the help of radiographic testing and heat treatment, the residual stress of the blade is eliminated, and new defects are avoided, ensuring that the size and internal quality of the finished blade are 100% qualified.

[0026] (3) It solves the problems of long calibration time and high cost. This application adopts the process route of "scanning positioning + welding", which avoids the investment in calibration tooling and can achieve calibration qualification in 1 to 2 times. Compared with the traditional "tooling calibration + heat treatment calibration", the process time is reduced by 60% and the cost is reduced by 80%. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments. First, it should be noted that the data in the following experimental examples were obtained by the inventors through numerous experiments. Due to space limitations, only a portion of these data is shown in the specification, and those skilled in the art can understand and implement the present invention based on this data. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art can make various modifications or alterations to the invention, and these modifications or alterations also fall within the scope of protection of this application.

[0028] This invention discloses a low-cost shaping process for titanium and titanium alloy blades, used for shaping incoming blades made of titanium and titanium alloys, comprising the following steps:

[0029] Step 1: Use a 3D scanner to scan the incoming blades to obtain the actual 3D curve of the blades;

[0030] Step 2: Compare the actual 3D curve with the 3D model of the blade;

[0031] Step 3: Mark the missing values ​​of the model on the blades;

[0032] Step 4: Draw the deviation 0-position line;

[0033] Step 5: If the deviation 0-position line is at the free end of the blade and is not a closed line, a welding bevel is used for correction; if the deviation 0-position line is not at the free end of the blade, or if the deviation 0-position line is at the free end of the blade and is a closed line, welding repair is used for correction.

[0034] Step 6: Weld using welding wire;

[0035] Step 7: Use a 3D scanner to perform a secondary scan to obtain the corrected 3D curve of the blade. Compare the corrected 3D curve with the 3D model of the blade. If the two overlap, proceed to step 8. If they do not overlap, return to step 3.

[0036] Step 8: Radiographic testing to eliminate welding defects;

[0037] Step 9: Heat treatment to relieve welding stress.

[0038] It should be noted that blades typically exhibit two characteristics compared to the standard model: missing sections and excessive thickness. In the missing sections, the blade appears concave, and the deviation value compared to the standard model is negative. Since missing sections affect blade performance, it is crucial to focus on correcting the shape of blades in this condition. In the excessively thick sections, the deviation value compared to the standard model is positive. Because excessive thickness does not affect blade performance, blades in this condition do not require correction, or the excessively thick portion can be removed entirely.

[0039] Specifically, in steps one and seven, a 3D scanner with a measurement accuracy of no less than 0.1 mm is used. Since obtaining the actual 3D curve of the incoming blade by scanning it with a 3D scanner is existing technology, it will not be described in detail here.

[0040] For a blade, one end is the root and the other end is the tip. The root is mounted on a disk or rotor, and the tip extends out and is not fixed. Therefore, the root of the blade is the constrained end, and the tip is the free end.

[0041] In step three, the missing value refers to the degree to which the actual three-dimensional curve or the corrected three-dimensional curve deviates from and is short of the model at the same location.

[0042] In step four, the deviation 0-position line refers to the line connecting the actual three-dimensional curve or the corrected three-dimensional curve to the position where it coincides with the three-dimensional model of the blade. That is, the deviation 0-position line is obtained by connecting the points where the missing value is 0.

[0043] Specifically, in this invention, the deviation 0-position line is a closed line, meaning that connecting all points with a deficiency value of 0 results in a continuous loop, and the curve used for this connection also lies on the deviation 0-position line. Conversely, if the deviation 0-position line is not a closed line, then it is not a closed line.

[0044] This invention uses the deviation 0-position line to divide the missing area and the super-thick area on the blade surface. The deviation 0-position line serves as the boundary between the missing area and the super-thick area. At the same time, it combines a 3D scanner to generate a color deviation map or deviation value data with positive and negative signs, which can visualize and clearly distinguish the boundary of the missing area, thereby enabling precise shaping.

[0045] The present invention provides a low-cost shaping process for titanium and titanium alloy blades, which can obtain multiple deviation zero-position lines. These deviation zero-position lines can be distinguished at different positions on the curved surface of the incoming blade, thereby facilitating the adoption of different methods for reasonable shaping.

[0046] In step five, a welding bevel is made on the deviation 0-position line, with a bevel angle θ = 40°~60°, a bevel width B = 5i, and a bevel depth H = 2i, where i is the maximum defect value at the free end of the blade. The shape of the welding bevel can be V-shaped, U-shaped, etc.

[0047] In the case where the deviation 0-position line is at the free end of the blade and is not a closed line, it indicates that there is still a small area at the free end of the blade that needs to be corrected. Considering that the free end of the blade lacks support and has weak rigidity, making it a deformation-sensitive area, a welding bevel is used to achieve the correction purpose by utilizing the shrinkage deformation of the weld. At the same time, the welding bevel enables the welding behavior to be realized in the form of internal filling connection, thereby better controlling the welding stress and preventing warping of the free end.

[0048] The welding bevel is set on the deviation 0-position line, and the shrinkage area is pre-positioned to accurately supplement the missing area. The weld metal and the base material near the bevel expand when heated during welding and shrink dramatically when cooled. The constraint force generated during shrinkage causes tensile stress to be generated inside the weld after cooling. Since the blade and the model have a missing value, that is, the blade is shorter than the model, in the area with the missing value, the incoming blade is concave compared to the three-dimensional model of the blade. The tensile stress generated can pull the concave area towards the center of the weld, making it bulge and thus compensating for the missing amount.

[0049] The bevel width B and bevel depth H are further determined based on the maximum defect value i at the free end of the blade, and are combined with the bevel angle θ to accurately correct the deformation. If the bevel width B and bevel depth H are too large, it will cause overcorrection and may introduce welding quality defects; if the values ​​are too small, the deformation will be too small to achieve the desired correction.

[0050] In addition to meeting the requirements of bevel angle θ = 40°~60°, bevel width B = 5i, and bevel depth H = 2i, the bevel dimensions also need to meet the following conditions: bevel width B ≤ 15mm, bevel depth H ≤ 1 / 2d, where d is the blade thickness at the bevel location. By limiting the bevel width B to ≤ 15mm and the bevel depth H to ≤ 1 / 2d, the bevel size is prevented from being too large, which could affect the performance of the blade's free end.

[0051] When the deviation 0-position line is not located at the free end of the blade, welding repair is used for correction regardless of whether it is a closed line. The presence of a deviation 0-position line indicates a deficiency in the area near the deviation 0-position line, thus requiring correction. The deviation 0-position line not being at the free end of the blade means a deficiency exists at the blade's constraint end. Since the blade constraint end is connected to the wheel or rotor, the wheel or rotor provides a certain restraint effect. The blade constraint end itself, the wheel, or the rotor all possess a certain rigidity. Direct welding repair in this area effectively suppresses and disperses the heat and shrinkage stress generated during welding, resulting in controllable post-weld deformation and reducing the likelihood of overall warping. Furthermore, direct welding repair offers flexibility, allowing for supplementation at the required correction location based on the deficiency value, making it highly suitable for curved and concave structures like blades.

[0052] For cases where the deviation 0-position line is located at the free end of the blade and is a closed line, a welding repair method is used for reshaping. Since the deviation 0-position line is a closed line, it indicates the existence of a continuous missing area in the vicinity of the deviation 0-position line. This makes it difficult to uniformly bevele the continuous area, resulting in high operational difficulty. Furthermore, welding after setting the welding bevel in the continuous area will cause the weld shrinkage to generate uniform radial tensile force, leading to wrinkling and deformation of the free end of the blade, which is detrimental to reshaping. Using a welding repair method for reshaping allows for relatively flexible segmented or non-segmented welding within the continuous area, reducing operational difficulty and avoiding the introduction of tensile forces that would cause additional deformation.

[0053] As a specific example of the present invention, in step six, a suitable welding wire is selected according to the welding wire selection standard for welding. The welding current is 90~120A, and the shielding gas flow rate is 8~25L / min.

[0054] As a preferred example of the present invention, in step two, after comparing the actual three-dimensional curve and the three-dimensional model of the blade, if the actual three-dimensional curve deviates from and exceeds the three-dimensional model, the excess part is removed according to the amount of excess.

[0055] This invention provides a low-cost forming process for titanium and titanium alloy blades. Through three-dimensional scanning, determining the deformation zone using the zero-position line, and employing various forming techniques, it solves the problem of difficult correction after deformation of cast titanium and titanium alloy blades. The formed blade surface profile has a high conformity rate, short production time, and low forming cost, effectively meeting production needs. Testing shows that for titanium and titanium alloy blades with a length >1000mm and a width >300mm, the formed blade profile achieves 100% compliance with technical requirements. Forming time is reduced by 5-10 days. Aside from normal labor and material losses, no scrap is generated, tooling costs are not increased, and costs are reduced by 80%, significantly improving production efficiency and lowering overall costs.

[0056] The present invention has the following advantages:

[0057] (1) It solves the problem of the inability to measure blade profile values ​​and locate the calibration position. Since the profile of titanium alloy blades is often curved, conventional measurement methods cannot determine its size. By using a 3D scanner and comparing it with a 3D model, the dimensional deviation values ​​of each area of ​​the blade's curved surface can be obtained quickly and accurately. Then, by using the method of determining the "0-position line", the calibration position can be accurately obtained. Compared with traditional measurement, the size positioning is more accurate and the measurement time is shorter.

[0058] (2) This invention solves the problems of cumbersome tooling fabrication and poor calibration results. The traditional method of "tooling + multiple hot calibration" requires the fabrication of calibration tooling. Due to the rebound characteristics of titanium and titanium alloys, the calibration process often requires 3 to 5 times or even more to barely achieve the required calibration, which consumes a lot of time and cost. This application adopts the "scanning + welding" cycle concept. According to the different degrees of deformation, the corresponding bevel width and depth are selected, making the operation simpler and ensuring that the surface result meets the shape value. At the same time, by using radiographic testing and heat treatment, residual stress in the blades is eliminated, avoiding the introduction of new defects and ensuring that the dimensions and internal quality of the finished blades are 100% qualified.

[0059] (3) It solves the problems of long calibration time and high cost. This application adopts the process route of "scanning positioning + welding", which avoids the investment in calibration tooling and can achieve calibration qualification in 1 to 2 times. Compared with the traditional "tooling calibration + heat treatment calibration", the process time is reduced by 60% and the cost is reduced by 80%. Example 1

[0060] Incoming blades: Titanium alloy blades used in aircraft generators.

[0061] Step 1: Use a 3D scanner to scan the incoming blades to obtain the actual 3D curve of the blades;

[0062] Step 2: Compare the actual 3D curve with the 3D model of the blade;

[0063] Step 3: Mark the missing values ​​on the blades, corresponding to the model values;

[0064] Step 4: Draw the deviation 0-position line;

[0065] Step 5: For the case where the deviation 0-position line is at the free end of the blade and is not a closed line, a welded V-shaped bevel is set at this deviation 0-position line for correction. The maximum defect value i at the free end of the blade in this area is 5.09mm, so the bevel width B is 15mm and the bevel depth H is 8mm (the blade thickness d at the position of the 0-position line is 16mm).

[0066] If the deviation 0-position line is not at the free end of the blade, or if the deviation 0-position line is at the free end of the blade and is a closed line, the shape is corrected by welding according to the marked defect value, and the defect is repaired as much as is missing.

[0067] Step 6: Use welding wire for welding. The welding current is 90A, and argon gas is introduced to prevent the welding part from being affected by air at high temperature. The flow rate of argon gas is 8L / min.

[0068] Step 7: Use a 3D scanner to perform a secondary scan to obtain the corrected 3D curve of the blade. Compare the corrected 3D curve with the 3D model of the blade; the two overlap.

[0069] Step 8: Radiographic testing to eliminate welding defects;

[0070] Step 9: Heat treatment to relieve welding stress.

[0071] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various alterations and modifications 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 low-cost forming process for titanium and titanium alloy blades, characterized in that, The steps for correcting missing blades include the following: Step 1: Use a 3D scanner to scan the incoming blades to obtain the actual 3D curve of the blades; Step 2: Compare the actual 3D curve with the 3D model of the blade; Step 3: Mark the missing values ​​on the blades, corresponding to the model values; Step 4: Draw the deviation 0-position line; Step 5: If the deviation 0-position line is at the free end of the blade and is not a closed line, a welding bevel is used for correction; if the deviation 0-position line is not at the free end of the blade, or if the deviation 0-position line is at the free end of the blade and is a closed line, welding repair is used for correction. Step 6: Weld using welding wire; Step 7: Use a 3D scanner to perform a secondary scan to obtain the corrected 3D curve of the blade. Compare the corrected 3D curve with the 3D model of the blade. If the two overlap, proceed to step 8. If they do not overlap, return to step 3. Step 8: Radiographic testing to eliminate welding defects; Step 9: Heat treatment to relieve welding stress.

2. The calibration process according to claim 1, characterized in that, One end of the blade is the root and the other end is the tip. The root is mounted on the wheel or rotor, and the tip extends out and is not fixed. The root of the blade is the constrained end, and the tip is the free end.

3. The calibration process according to claim 1, characterized in that, In step five, a welding bevel is made on the deviation 0 position line, with a bevel angle θ = 40°~60°, a bevel width B = 5i, and a bevel depth H = 2i, where i is the maximum defect value at the free end of the blade.

4. The straightening process method according to claim 3, characterized in that, The bevel width B ≤ 15mm, and the bevel depth H ≤ 1 / 2d, where d is the thickness of the blade at the bevel location.

5. The calibration process according to claim 1, characterized in that, In step three, the missing value refers to the degree to which the actual three-dimensional curve or the corrected three-dimensional curve deviates from and is short of the model at the same location.

6. The calibration process according to claim 1, characterized in that, In step four, the deviation 0-position line refers to the line connecting the actual three-dimensional curve or the corrected three-dimensional curve to the position where it coincides with the three-dimensional model of the blade.

7. The straightening process method according to claim 1, characterized in that, In step six, the welding current is 90~120A and the shielding gas flow rate is 8~25L / min.

8. The calibration process according to claim 1, characterized in that, After comparing the actual 3D curve with the 3D model of the blade, if the actual 3D curve deviates from and exceeds the 3D model, the excess part will be removed according to the amount of deviation.