Titanium alloy pipe JCO forming heating method, device and system

Abstract

The invention relates to a titanium alloy pipe JCO forming heating method, device and system.The titanium alloy pipe forming heating method comprises the steps that in the titanium alloy pipe forming process, an image of a titanium alloy plate is obtained in real time through a DIC visual image device, and the titanium alloy plate is used for forming a titanium alloy pipe; a current displacement field of the titanium alloy plate is determined based on the first image and the second image, the first image is a current image of the titanium alloy plate, and the second image is a historical image of the titanium alloy plate; determining the current strain and the current stress of the titanium alloy plate based on the current displacement field of the titanium alloy plate through a strain calculation formula and a stress calculation formula; determining an actual fracture risk area of the titanium alloy plate based on the current stress of the titanium alloy plate through a target judgment formula; and the actual fracture risk area of the titanium alloy plate is sent to a heating device, and the heating device is configured to heat the actual fracture risk area of the titanium alloy plate. The problem that in an existing titanium alloy pipe JCO forming heating method, a fracture risk area cannot be accurately heated is solved.

Description

Technical Field

[0001] The present application relates to the field of processing and manufacturing, and in particular to a titanium alloy tube JCO forming heating method, device and system. Background Art

[0002] The JCO forming process is an industrial straight seam welded pipe cold forming method. Titanium alloy materials have large deformation resistance and poor plasticity at room temperature, and are accompanied by springback distortion during the forming process. Usually, the fracture risk area of ​​the titanium alloy plate (the plate is curled to form a pipe) can be heated to reduce the deformation resistance of the corresponding area and improve its plasticity.

[0003] At present, JCO forming of titanium alloy tubes mainly relies on flame heating. Multiple workers hold torches and run back and forth to achieve mobile torch heating. This process requires workers to rely on experience to judge the fracture risk area of ​​the titanium alloy plate, which has the problem of low heating position accuracy and high labor intensity.

[0004] The current JCO forming heating method for titanium alloy tubes has the problem of being unable to accurately heat the fracture risk area, and no effective solution has been proposed yet. Summary of the invention

[0005] The present invention provides a titanium alloy tube JCO forming heating method, device and system to solve the problem that the current titanium alloy tube JCO forming heating method cannot accurately heat the fracture risk zone.

[0006] In a first aspect, the present invention provides a titanium alloy tube JCO forming heating method, which comprises:

[0007] Acquire an image of a titanium alloy plate in real time by a DIC visual imaging device, wherein the titanium alloy plate is used to form the titanium alloy tube;

[0008] Determine a current displacement field of the titanium alloy plate based on a first image and a second image, wherein the first image is a current image of the titanium alloy plate, and the second image is a historical image of the titanium alloy plate;

[0009] Determine the current strain and current stress of the titanium alloy plate based on the current displacement field of the titanium alloy plate by using a strain calculation formula and a stress calculation formula;

[0010] The strain calculation formula is:

[0011]

[0012] Among them, u(x,y) and v(x,y) are the displacement fields of the titanium alloy plate in the x direction and y direction respectively, ε xx and ε yyare the normal strains of the titanium alloy plate in the x and y directions, ε xy and ε yx is the tangential strain of the titanium alloy plate in the x and y directions;

[0013] The stress calculation formula is:

[0014]

[0015] Among them, E is the elastic modulus of the titanium alloy plate, s is the Poisson's ratio of the titanium alloy plate, σ xx and ε yy are the normal stresses of the titanium alloy plate in the x and y directions, σ xy is the shear stress of the titanium alloy plate in the x and y directions;

[0016] Determining the actual fracture risk area of ​​the titanium alloy plate based on the current stress of the titanium alloy plate by using a target judgment formula;

[0017] The target judgment formula is:

[0018]

[0019] Among them, σ b and σ s are tensile strength and yield strength respectively, and the set of positions that do not satisfy the target judgment formula constitutes the actual fracture risk area;

[0020] The actual fracture risk area of ​​the titanium alloy plate is sent to a heating device, and the heating device is configured to heat the actual fracture risk area of ​​the titanium alloy plate.

[0021] In a second aspect, the present invention provides a data processing device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute the titanium alloy tube JCO forming heating method described in the first aspect.

[0022] In a third aspect, the present invention provides a titanium alloy tube JCO forming system, comprising a DIC visual imaging device, a data processing device, a heating device and a forming die;

[0023] The DIC visual image device is used to obtain the image of the titanium alloy plate in real time during the titanium alloy tube forming;

[0024] The data processing device is the data processing device described in claim 8;

[0025] The heating device is used to heat the actual fracture risk area of ​​the titanium alloy plate;

[0026] The forming die is used to achieve deformation of the titanium alloy plate to achieve forming of the titanium alloy tube.

[0027] Compared with the related art, the titanium alloy tube JCO forming heating method provided by the present invention, in the titanium alloy tube forming, firstly, the image of the titanium alloy plate is obtained in real time through the DIC visual image device, and then the current displacement field of the titanium alloy plate can be obtained by matching the current image and the historical image of the titanium alloy plate, and then the current stress of the titanium alloy plate can be calculated according to the current displacement field, and the position area where the stress exceeds the threshold is the actual fracture risk area of ​​the titanium alloy plate, and finally it is sent to the heating device, and the heating device heats the actual fracture risk area. Therefore, the present invention provides a heating system based on numerical simulation results, which is monitored in real time by the DIC visual system and matched with an arc heating device with adjustable radius. Compared with manual judgment based on experience, the judgment accuracy and efficiency are improved, and the problem that the current titanium alloy tube JCO forming heating method cannot accurately heat the fracture risk area is solved.

[0028] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a flow chart of a titanium alloy tube JCO forming heating method provided in an embodiment of the present invention;

[0030] Figure 2 is a structural diagram of a titanium alloy tube JCO forming heating system provided in an embodiment of the present invention;

[0031] Figure 3 is a structural diagram of a heating system module provided in an embodiment of the present invention;

[0032] Figure 4 is a structural diagram of a heating device provided in an embodiment of the present invention;

[0033] Figure 5 is a structural diagram of a heating assembly provided in an embodiment of the present invention;

[0034] Figure 6 is a structural diagram of a heating unit provided in an embodiment of the present invention;

[0035] Figure 7 It is the stress risk area of ​​the "J" stage in the JCO finite element simulation;

[0036] Figure 8 It is the stress risk area of ​​the "C" stage in the JCO finite element simulation;

[0037] Fig. 9It is the stress risk area of ​​the "O" stage in the JCO finite element simulation;

[0038] Fig.10 This is the stress diagram of the "C" model of the JCO finite element simulation under thermal load;

[0039] Fig.11 This is the stress diagram of the “O” model of the JCO finite element simulation under thermal load;

[0040] Fig.12 It is a schematic diagram of black and white speckle. DETAILED DESCRIPTION

[0041] In order to more clearly understand the purpose, technical solutions and advantages of the present application, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0042] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the general meaning understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the", "these" and the like in this application do not represent quantitative restrictions, and they can be singular or plural. The terms "include", "comprise", "have" and any variants thereof involved in this application are intended to cover non-exclusive inclusions; for example, a process, method and system, product or device comprising a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether directly or indirectly. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. Usually, the character " / " indicates that the objects associated with each other are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0043] The present invention provides a titanium alloy tube JCO forming heating method. Figure 1 : is a flow chart of the titanium alloy tube JCO forming heating method provided in an embodiment of the present invention, such as Figure 1 As shown, the process in titanium alloy tube forming includes:

[0044] Step S110, acquiring an image of a titanium alloy plate in real time through a DIC visual imaging device, where the titanium alloy plate is used to form a titanium alloy tube.

[0045] Specifically, the DIC visual image device usually includes at least a camera and its corresponding controller, and the camera is a CCD camera. During the titanium alloy tube forming process, the titanium alloy plate as the forming material is placed on the forming mold, and the camera is usually installed above the forming mold to continuously capture the image of the titanium alloy plate during the titanium alloy tube forming process. In some embodiments, the DIC visual image device may also include an illumination light source, which mainly improves the shooting brightness in the case of insufficient light, so that the image captured by the camera is more recognizable.

[0046] Step S120, determining the current displacement field of the titanium alloy plate based on the first image and the second image, the first image is the current image of the titanium alloy plate, and the second image is the historical image of the titanium alloy plate.

[0047] Specifically, the initial image of the titanium alloy plate refers to the image taken by the DIC visual image device before the current moment. Exemplarily, the DIC visual image device can take a photo of the titanium alloy plate once per second, and the second image can be the image of the titanium alloy plate in the previous second or the previous two seconds. Also, the titanium alloy tube is usually formed in stages. In one stage, the titanium alloy plate is pushed forward a certain distance, and then the mold pressure head is pressed down a certain distance to cause the titanium alloy plate to produce corresponding deformation. In the next stage, the titanium alloy plate is pushed forward a certain distance, and then the mold pressure head continues to press down a certain distance to cause the titanium alloy plate to produce corresponding deformation. At this time, the shooting cycle of the DIC visual image device can be set to the stage cycle, so that by comparing the two images before and after, the deformation of the titanium alloy plate in one stage can be determined. At this time, the first image is the image of the titanium alloy plate after the end of the most recent stage, and the second image is the image of the titanium alloy before the start of the most recent stage.

[0048] Among them, in one forming pass, the amount of the titanium alloy plate pushed in and pressed down can be calculated by the following formula.

[0049] 1. Calculate the diameter D of the titanium alloy tube.

[0050] Since the length L of the titanium alloy plate corresponds to the circumference length:

[0051] L=πD

[0052] so:

[0053]

[0054] 2. Calculate the bending radius R:

[0055]

[0056] 3. Calculate the bending angle θ for each forming process:

[0057]

[0058] 4. Calculate the amount of pressure each time Δh:

[0059]

[0060] 5. Calculate the feed amount A each time:

[0061]

[0062] W represents the length of the titanium alloy plate in the feed direction, and the two key parameters of the pressing amount and the feed amount are obtained by calculation.

[0063] At the same time, the current displacement field of the titanium alloy plate refers to the set of displacement changes generated by all position points in the most recent deformation of the titanium alloy plate. The current displacement field of the titanium alloy plate can be obtained by determining the corresponding pixel points in the first image and the second image through image matching technology and calculating the displacement between the corresponding pixel points in the same coordinate system.

[0064] In some embodiments, determining a current displacement field of the titanium alloy plate based on the first image and the second image includes:

[0065] The first image and the second image are matched by a cross-correlation function or a zero-mean normalized cross-correlation function, and a current displacement field of the titanium alloy plate is determined based on the matching result.

[0066] The cross-correlation function and the zero-mean normalized cross-correlation function are mainly used to achieve image matching, so as to determine the corresponding pixel points of each group and give the displacement between the corresponding pixel points of each group. In order to eliminate the influence of illumination changes, the zero-mean normalized cross-correlation function can be used.

[0067] Specifically, the cross-correlation function R(u,v) is:

[0068] R(u,v)=∑(x,y)[f(x,y)*g(x+u,y+v)

[0069] The zero-mean normalized cross-correlation function Rzncc(u, v) is:

[0070]

[0071] Among them, (x, y) represents the pixel coordinates, f represents the first image, g represents the second image, (u, v) represents the displacement, represents the average value of the first image, represents the average value of the second image.

[0072] Through any of the above cross-correlation functions, the matching between the first image and the second image can be achieved, that is, the corresponding pixels (x, y) of each group and the displacement (u, v) between the corresponding pixels (x, y) of each group can be determined. Then, the functions u(x, y) and v(x, y) of the displacement (u, v) with respect to the pixel (x, y), that is, the displacement field, can be obtained.

[0073] The displacement (u,v) may not be an integer and can be estimated by bilinear interpolation:

[0074] g(x+u,y+v)≈(1-α)(1-β)*g(x,y)+α*(1-β)*g(x+1,y)+(1-α)β*g(x,y+1)+α*β*g(x+1,y+1)

[0075] Where α and β are the fractional parts of u and v respectively.

[0076] In some embodiments, in order to better match the first image and the second image, the surface of the titanium alloy plate is black and the surface of the titanium alloy is coated with white speckles (such as Fig.12 As shown in the figure). Since the black and white colors are distinct, it is easier to match the corresponding pixels in the two images more accurately.

[0077] Step S130, determining the current strain and the current stress of the titanium alloy plate based on the current displacement field of the titanium alloy plate by using the strain calculation formula and the stress calculation formula.

[0078] The strain calculation formula is:

[0079]

[0080] Among them, u(x,y) and v(x,y) are the displacement fields of the titanium alloy plate in the x direction and y direction respectively, ε xx and ε yy are the normal strains of the titanium alloy plate in the x and y directions, ε xy and ε yx is the tangential strain of the titanium alloy plate in the x and y directions;

[0081] The stress calculation formula is:

[0082]

[0083] Among them, E is the elastic modulus of the titanium alloy plate, s is the Poisson's ratio of the titanium alloy plate, σ xx and ε yy are the normal stresses of the titanium alloy plate in the x and y directions, σ xy is the shear stress of the titanium alloy plate in the x and y directions.

[0084] Step S140, determining the actual fracture risk area of ​​the titanium alloy plate based on the current stress of the titanium alloy plate through a target judgment formula.

[0085] The target judgment formula is:

[0086]

[0087] Among them, σ b and σ s are tensile strength and yield strength respectively. The set of positions that do not meet the target judgment formula constitutes the actual fracture risk area.

[0088] Through the above two steps, the actual fracture risk area of ​​the titanium alloy plate during the deformation process can be determined. During the processing, the actual fracture risk area needs to be heated to reduce the normal stress and shear stress in the area, thereby reducing the fracture risk in the area and ensuring processing safety.

[0089] Step S150, sending the actual fracture risk area of ​​the titanium alloy plate to a heating device, and the heating device is configured to heat the actual fracture risk area of ​​the titanium alloy plate.

[0090] Specifically, the heating device includes at least a flame heater and a controller, and the controller is mainly used to control the position, heating temperature and heating time of the flame heater. After the actual fracture risk area is calculated, it can be sent to the controller in the heating device, and the controller controls the flame heater to move to the corresponding position to heat the actual fracture risk area.

[0091] In summary, the titanium alloy tube JCO forming heating method provided by the present invention, in the titanium alloy tube forming, firstly, the image of the titanium alloy plate is obtained in real time through the DIC visual image device, and then the current displacement field of the titanium alloy plate can be obtained by matching the current image and historical image of the titanium alloy plate, and then the current stress of the titanium alloy plate can be calculated according to the current displacement field, and the position area where the stress exceeds the threshold is the actual fracture risk area of ​​the titanium alloy plate, and finally it is sent to the heating device, and the heating device heats the actual fracture risk area. Therefore, the present invention provides a heating method based on data processing that can automatically calculate the actual fracture risk area of ​​the titanium alloy plate, which improves the judgment accuracy and efficiency compared to manual judgment based on experience, and solves the problem that the current titanium alloy tube JCO forming heating method cannot accurately heat the fracture risk area.

[0092] It should be noted that, for step S150, in addition to using a heating device to achieve mechanical automated heating, in some other embodiments, the actual fracture risk area of ​​the titanium alloy plate can also be displayed to the user, and the user can manually heat the titanium alloy plate according to the displayed actual fracture risk area.

[0093] In order to improve the data processing efficiency and processing efficiency in titanium alloy tube forming, the titanium alloy plate can be preheated first, so as to reduce the actual fracture risk area during the deformation process, thereby improving the efficiency of determining the actual fracture risk area and the heating efficiency.

[0094] Therefore, in some embodiments thereof, the titanium alloy tube JCO forming heating method includes, before the titanium alloy tube is formed:

[0095] Step S210, performing forming simulation on the titanium alloy plate to obtain a simulated fracture risk area, a simulated heating time, and a simulated heating temperature of the titanium alloy plate during the forming process.

[0096] Step S220, determining the preheating time and the preheating temperature according to the simulated heating time and the simulated heating temperature, and the titanium alloy plate is preheated using the preheating time and the preheating temperature before being used to form the titanium alloy tube.

[0097] In the present embodiment, firstly, the strain and stress distribution of different specifications of titanium alloy plates at different stages under different heating conditions (heating time and heating temperature) is obtained in advance by simulation software, so as to determine the simulated fracture risk area. For example, for a titanium alloy plate of a certain specification, the strain and stress distribution of each stage when it is not heated can be simulated first. If there is a simulated fracture risk area, the strain and stress distribution of the titanium alloy plate at each stage under different heating conditions can be further simulated, so as to determine the simulated heating conditions (simulated heating time and simulated heating temperature) that basically eliminate the simulated fracture risk area or minimize the simulated fracture risk area. It should be noted that the simulated heating condition can be a simulated heating temperature and simulated heating time for uniformly heating the titanium alloy plate, or it can be a simulated heating temperature and simulated heating time for a local simulated fracture risk area. After obtaining the simulated heating temperature and simulated heating time, the preheating temperature and preheating time can be determined accordingly. Among them, the simulated heating temperature and simulated heating time can be directly determined as the preheating temperature and preheating time, respectively. Considering the errors in the simulation, the simulated heating temperature and the simulated heating time may be higher than the actual heating temperature and heating time required for the titanium alloy plate. In order to ensure the success rate of processing, the preheating temperature can be set to half of the simulated heating temperature while the simulated heating time is used in the preheating time. Since heating is an effective means to reduce the stress of the plate, the actual fracture risk area of ​​the titanium alloy plate during the deformation process can be effectively reduced by preheating, so that the execution efficiency of steps S110-S150 in the titanium alloy tube forming process is greatly improved, which not only improves the forming speed of the titanium alloy tube but also reduces the calculation amount of the processor used to execute steps S110-S150.

[0098] In summary, the titanium alloy tube JCO forming and heating method provided by the present invention is executed by a processor. Among them, steps S110-S150 are used to calculate the actual fracture risk area of ​​the titanium alloy plate in real time during the titanium alloy tube forming (deformation of the titanium alloy plate), which has the advantages of higher efficiency and accuracy compared to manually relying on experience to judge the actual fracture risk area of ​​the titanium alloy plate. Steps S210 and S220 are used to simulate the titanium alloy plate before the titanium alloy tube is formed (the titanium alloy plate is not deformed) and determine the corresponding preheating time and preheating temperature. The actual fracture risk area of ​​the titanium alloy plate during deformation can be effectively reduced by preheating, thereby improving the execution efficiency of steps S110-S150.

[0099] The present invention also provides a data processing device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the titanium alloy tube JCO forming heating method provided by the present invention.

[0100] Reference Figure 2 The present invention also provides a titanium alloy tube JCO forming system, including a DIC visual image device (DIC visual image module), a data processing device (processor and numerical simulation module), a heating device and a forming die (heating system module).

[0101] The DIC visual imaging device is used to obtain the image of the titanium alloy plate in real time during the forming of the titanium alloy tube; the data processing device is the data processing device provided by the present invention; the heating device is used to heat the actual fracture risk area of ​​the titanium alloy plate; and the forming mold is used to realize the deformation of the titanium alloy plate to realize the forming of the titanium alloy tube.

[0102] The DIC visual image device usually includes at least a camera and its corresponding controller, and the camera can be a CCD camera. During the titanium alloy tube forming process, the titanium alloy plate as the forming material is placed on the forming mold, and the camera is usually installed above the forming mold to continuously capture the image of the titanium alloy plate during the titanium alloy tube forming process. In some embodiments, the DIC visual image device may also include an illumination light source, which mainly improves the shooting brightness in the case of insufficient light, so that the image captured by the camera is brighter and clearer.

[0103] In some of the embodiments, the heating device includes a base, a mechanical arm and a heating assembly; one end of the mechanical arm is rotatably mounted on the base; the heating assembly includes an arc plate and a plurality of heating units, the arc plate is rotatably mounted on the end of the mechanical arm away from the base with the arc opening facing the side away from the mechanical arm, each heating unit includes a nozzle, and a coaxially arranged rectangular column and a cylinder, the nozzle is fixedly mounted on the side wall of the cylinder and used to spray flames, the rectangular column and the tooth column are respectively fixedly mounted on both ends of the cylinder; a plurality of rectangular grooves matching the rectangular column are evenly spaced on the arc plate, and the output shaft of the cylinder passes through the rectangular column and is fixedly connected to the bottom wall of the rectangular groove in its own axial direction. Specifically, the output shaft end of the cylinder can be connected to the bottom wall of the rectangular groove by a bearing.

[0104] In the above embodiment, guide rails can be installed on the ground on both sides of the forming mold, and the base of the heating device can be slidably installed on the guide rails to achieve the adjustment of the heating position. The mechanical arm can adopt a multi-degree-of-freedom mechanical arm with joint torsion and telescopic functions, so as to improve the freedom of movement of the heating component and make the adjustment of the heating position more flexible and comprehensive. For the heating component, it is more critical to use an arc plate as the mounting substrate of the nozzle. When all nozzles are uniformly facing the inner side of the arc plate, the curved titanium alloy plate on the inner side of the arc plate can be effectively heated. The flames ejected from multiple nozzles will converge at one point. If the flame convergence point is at the center position of the titanium alloy plate fracture risk zone (the fracture risk zone is curved), the spacing between each nozzle and the titanium alloy plate is relatively uniform, so uniform heating of the fracture risk zone can be achieved. Adjusting the angle of each nozzle can adjust the flame convergence radius, so as to adapt to fracture risk zones with different curvatures.

[0105] During installation, since the output shaft of the cylinder is fixedly connected to the bottom wall of the rectangular groove, the rectangular column on the cylinder housing can be embedded in the rectangular groove by contracting the cylinder output shaft, thereby fixing the angle of the cylinder housing and the nozzle. When the nozzle angle needs to be adjusted, the cylinder output shaft is extended so that the rectangular column is pushed out of the rectangular column in the opposite direction. At this time, the cylinder housing and the nozzle can be rotated to adjust the nozzle angle. After adjusting to the appropriate angle, the cylinder output shaft is contracted again so that the rectangular column is embedded in the rectangular groove to lock the nozzle angle. It should be noted that the cross-section of the rectangular column is a regular polygon, such as a regular hexagon, a regular octagon, etc. The minimum angle that the nozzle can be adjusted each time is related to the cross-section of the rectangular column, which is equal to the center angle corresponding to each side of the corresponding regular polygon.

[0106] Furthermore, the arc plate can be rotatably mounted on the end of the robot arm away from the base through an extension structure. For example, the arc plate has some extension structures, and the extension structure is fixedly connected to the end of the robot arm away from the base through bearings. And, in order to better realize the rotation of the nozzle angle, a gear column can be coaxially fixedly arranged at the end of the cylinder housing away from the rectangular column, and the gear column is meshed with a gear, and the gear can be rotatably mounted on the end of a fixed rod. The relative posture between the fixed rods corresponding to each cylinder housing and the arc plate is fixed, for example, the same bearing and the extension structure of the arc plate can be installed together at the end of the robot arm away from the base. At this time, the arc plate and the fixed rod form a whole, and can be synchronously rotated around the end of the rear robot arm through the bearing, so as to adjust the angle of the heating component as a whole. When adjusting the nozzle angle, it can be achieved by rotating the gear to drive the gear column to rotate.

[0107] It should be noted that the rotation of the gear can be achieved by some micro motors, such as micro motors that can be installed on a fixed rod or an arc plate. The rotation between the heating component and the robot arm can also be achieved by micro motors.

[0108] For the heating component, assume that n flame nozzles are evenly distributed on a curved plate with a central angle of θ and a radius of R. It has several important parameters, such as the radius R and the central angle θ of the curved plate. The initial angle of the flame nozzle defaults to point to the center of the curved plate, and the nozzle angle Γ=n*α, (α is the angle between the nozzles, n=0, 1, 2, 3···), and the nozzle position is γ=(R, θi), (i=0, 1, 2, 3, 4···),.

[0109] 1. The angle between each nozzle is:

[0110] (n is an odd number, generally n≥3)

[0111] 2. The position of each nozzle can be expressed in polar coordinates as (R,θi), where:

[0112] θ i =i*α(i=0,1,2,3,4···)

[0113] 3. Calculation of the radius r of the flame convergence point:

[0114]

[0115] 4. When a single square flame nozzle rotates a fixed angle β i , calculation of the radius r' of the flame convergence point:

[0116] Assume that the angle between the original flame direction and the new direction is β i, the new flame convergence point P is located on the extension line of the original center O, the distance between the new convergence point P and the original center O is d, r' is the distance from the new flame convergence point P to the nozzle, using the relationship of the right triangle:

[0117]

[0118] It should be added that the angle α between any flame nozzles satisfies 0°<α<90°, otherwise the flame is not in a converging state.

[0119] In order to simply and effectively reflect the effect of the present invention, the convergence point of the flames sprayed from the multiple flame nozzles in this embodiment is the center of the arc plate, that is, r=R.

[0120] The titanium alloy tube JCO forming heating system provided by the present invention is specifically described below through some specific embodiments.

[0121] Reference Figures 2 to 6 In some embodiments, a movable radius-adjustable arc heating system suitable for JCO forming of titanium alloy plates is provided, including a numerical simulation module, a DIC visual image module and a heating system module.

[0122] The numerical simulation module includes a computer and numerical finite element simulation software matched with the computer. The numerical finite element simulation software inputs the mold size and material of the JCO forming equipment, the size and mechanical property parameters of the titanium plate to be formed, and obtains the JCO forming deformation data of titanium tubes with different wall thicknesses and diameters, and obtains the maximum strain and stress area during the JCO forming process of the titanium plate, that is, the cracking risk area of ​​the titanium plate JCO forming. Apply temperature load to the cracking risk area, simulate the JCO forming heating process, and transmit the obtained strain distribution data of the JCO forming process of titanium alloy welded pipes of different specifications to the processor terminal.

[0123] The DIC visual image module includes a CCD camera 007, an illumination light source, a black and white speckle spraying device, and a processor.

[0124] The heating system module includes a heating system and a controller. The heating system includes a guide rail 000, a plate 001, a support roller 002, a forward push plate 003, a pressure head 004, a heating unit 005, a retracting push plate 006, a mold 008 and a motor 009. The heating system is installed on the guide rails installed on the ground, and the guide rails are installed on both sides of the mold. The mold is connected to the ground by mechanical riveting. Support rollers are installed on the mold, and a chain transmission device is also installed. The chain transmission device is connected to a servo motor, and the servo motor is installed on both sides of the mold; the forward push plate and the support rollers are distributed on different guide rails and are distributed on the same side of the mold in a spaced manner. The movement of the forward push plate and the support rollers is controlled by the servo motor; the retracting push plate is installed on the other side of the mold installed on the guide rail; the heating is installed between the guide rail and the mold, and a longitudinal guide rail is installed at one end of the transverse guide rails on both sides close to the mold, and the heating unit is moved by the longitudinal guide rail; the pressure head is installed on the upper part of the hydraulic support with columns, and the extension and retraction of the hydraulic support is controlled by the servo motor to realize the downward pressure of the pressure head; the CCD camera is installed on both sides of the pressure head and connected to the processor of the DIC visual image module. The heating unit 005 is an arc-shaped heating device with an adjustable radius mounted on the robot arm. The radius of the arc can be adjusted according to the size of the risk area of ​​cracking during the JCO molding process. It includes a robot arm base 010, a robot arm joint 011, an arc-shaped heating unit 012 (heating component) and an independent heating unit 013 (heating unit). The robot arm base 010 is the fixed part of the robot arm 014, providing stable support; the robot arms 014 are connected by robot arm joints 011, allowing them to move within a certain range. These joints are driven by servo motors to achieve precise control. The robot arm 014 can rotate around the axis of the base, and this movement is achieved through rotating joints; the sections of the robot arm 014 can be relatively telescopic to adjust the distance between the heating unit and the workpiece. The arc-shaped heating unit 012 is installed at the end of the robot arm 014 and can move with the robot arm 014. Each independent heating unit 013 can adjust its angle individually. The transmission mechanism of the independent heating unit 013 is that each independent heating unit 013 has an independent driving system, including a hydraulic cylinder and a gear transmission device; the arc heating unit 012 is a semicircular heating device with adjustable radius, including an independent heating unit 013, a rotating joint 015, a connecting rod 016, a transmission gear 017, an arc-shaped air pipeline 018, a nozzle 020 and a hydraulic cylinder 021. The rotating joint 015 is the fulcrum of the entire device and the connection point between the mechanical arm 014 and the arc heating unit 012. The rotation movement of the mechanical arm is realized through the joint. The rotating joint 015 is driven by a motor or a hydraulic system and can rotate flexibly within a certain range; the connecting rod 016 connects the rotating joint 015 and multiple transmission gears 017. The connecting rod system transmits the driving force through the rotation movement of the mechanical arm to ensure the synchronous movement of the transmission gears. Each independent heating unit 013 is equipped with a transmission gear 017.Each independent heating unit 013 is equipped with a nozzle 020 and a coaxially arranged cylinder 021, a rectangular column 022 and a tooth column 023. The nozzle 020 generates a high-temperature flame by burning gas to heat the titanium alloy plate. The rectangular column 022 and the tooth column 023 are respectively fixedly arranged at the connecting section of the cylinder 021. The upper tooth column 023 of the rectangular column 022 is meshed with the transmission gear 017. The arc plate is provided with a multi-angle rectangular groove composed of a plurality of rectangular grooves that match the rectangular column 022.

[0125] The arc-shaped gas pipeline 018 is designed to be arc-shaped to match the movement of the heating unit. The argon protection gas 019 ejected from the arc-shaped gas pipeline 018 is used to protect the flame spray nozzle during the heating process.

[0126] The heating steps corresponding to the system include:

[0127] S1, through the numerical simulation module, obtains in advance the stress and strain distribution of titanium alloy plates of different specifications at different stages during the JCO forming process, transmits the data to the processor terminal, and determines the theoretical reference values ​​of preheating temperature and preheating time based on the simulation data.

[0128] S2, the preheated sheet to be formed is transferred to the designated position, and the sheet to be formed is pushed forward according to the preset feed amount by the support roller and the forward push plate. After reaching the designated position of the first pass, the pressure head is started and the pressing and forming is performed according to the preset pressing amount.

[0129] S3, during the implementation of step S2, the DIC visual image module collects the deformation data of the workpiece in each pass, transmits it to the processor for processing, obtains the risk area of ​​the workpiece forming, and feeds the data back to the processor. The processor transmits the work instruction to the controller to realize precise control of the heating system module.

[0130] S4, after receiving the instruction from the controller, the heating unit in the heating system heats the area to be heated.

[0131] S5, after the forming is completed, the titanium alloy welded pipe is transferred to the designated position through the chain transmission device on the mold.

[0132] In the above scheme, the coordination between various modules is particularly important. In order to make the system operate more efficiently, each module must have an independent controller and processor to quickly calculate the data and transmit it to the next process.

[0133] In order to improve the response speed, the numerical simulation module needs to convert the JCO forming data of titanium alloy welded pipes of different specifications and the simulation results of the strain change and distribution of titanium alloy plates during the forming process into program files that can be called by the next process in advance.

[0134] In step S1, the data obtained include heating position, heating temperature, heating time and other data information.

[0135] In step S2, when the feed amount accuracy of the support roller and the forward push plate is insufficient, a limit block can be added or the feed amount can be marked on the sheet to be formed in advance.

[0136] In step S3, the image information acquisition accuracy in the DIC visual image module depends on the accuracy of the CCD camera, and the accuracy depends on the resolution and the number of effective pixels, that is, the resolution of the camera itself and the distribution of black and white speckles.

[0137] In step S4, the components of the heating unit are made of high temperature resistant materials as much as possible to extend the service life.

[0138] In step S4, when the heating unit is heating, argon gas with a flow rate of 15-25 L / min is passed through to protect the surface of the titanium alloy plate from oxidation.

[0139] In step S4, when the heating area is heated, the number of rows of flame nozzles or the number of heating units can be appropriately increased according to the length of the titanium alloy welded pipe, and it is generally required to install a set of heating units within 1-3m. Preferably, an independent control system is used between each heating unit, and the heating units do not execute exactly the same heating instructions.

[0140] Specifically, in S6, after the welding of the welded pipe is completed, the diameter error of the welded pipe shall not exceed 1% of the diameter of the welded pipe, the difference in the outer circumference at both ends of the pipe mouth is less than 3mm, and the curvature is less than 1mm / M.

[0141] In a specific embodiment, a TC4 welded pipe commonly used in ships was selected for the experiment. The size of the TC4 titanium alloy plate is 6000mm×1500mm×3mm (length×width×plate thickness), and the density is 4.43g / cm 3 , melting point: 1604-1660℃, elastic modulus: 110Gpa, Poisson's ratio: 0.34, tensile strength: ≥895Mpa, yield strength: ≥830Mpa, elongation: 10-15%. After inputting the parameters of the sheet into the numerical simulation module, the stress risk areas of the sheet in the three forming processes of J, C, and O were obtained, such as Figure 7 , 8 , 9. In the figure, blue represents lower stress and red represents higher stress.

[0142] In order to simulate the effect of thermal load on stress distribution during the forming process, a uniform thermal load of 400 °C was applied to the model for 30 min, and the stress distribution model during the forming process of the titanium alloy sheet was obtained, as shown in Fig.10 , 11The numerical simulation module transmits the location information of the risk area to the processor, and the processor transmits the information to the heating system.

[0143] Determine the tensile strength σ of the material b =895MPa, minimum yield strength σ s =830MPa, and the minimum normal stress and tangential stress are calculated according to the risk zone determination criteria:

[0144]

[0145] Calculated:

[0146]

[0147] The critical conditions in the above formula are input into the DIC visual image module as the basis for determining the risk area.

[0148] Start the JCO molding process:

[0149] Calculate the amount of pressure each time and the amount of sheet material fed each time. The calculation process is as follows:

[0150] 1. Calculate the diameter D of the pipe:

[0151] Since the plate width L corresponds to the circumference length:

[0152] L=πD

[0153] so,

[0154]

[0155] 2. Calculate the bending radius R:

[0156]

[0157] 3. Calculate the bending angle θ for each forming process:

[0158]

[0159] 4. Calculate the amount of pressure each time Δh:

[0160]

[0161] cos13.845=0.9724

[0162] Substituting into the formula:

[0163] △h=238.85*(1-0.9724)

[0164] △h=238.85×0.0276=6.6mm

[0165] Therefore, the amount of pressure per pass is 6.6 mm.

[0166] 5. Calculate the feed amount each time:

[0167]

[0168] After the process parameters are determined, the plate is transported to the support slide rail with rollers, the sled is started, the feed amount per pass is 122mm, and the pressure head is pressed down by 6.6mm. After the forming starts, the DIC visual image module collects the deformation data of the titanium alloy plate after each pass, and uniformly heats the cracking risk area obtained by the numerical simulation module and the deformation risk area collected by the DIC image, with a heating temperature of 400℃ and a heating time of 30min.

[0169] In order to compare the influence of the present invention on the stress distribution during the forming of titanium alloy welded pipe, the prepared titanium alloy welded pipe was heated using the following three process schemes:

[0170] Solution 1: Use a manual handheld flame spray gun to heat the titanium alloy plate in the risk areas of the three stages of JCO.

[0171] Solution 2: The mobile radius-adjustable arc heating system of the present invention is used to heat only the risk areas of the three stages of JCO.

[0172] Solution 3: The movable radius-adjustable arc heating system of the present invention is used to heat each pass in the entire JCO process.

[0173] The titanium alloy welded pipes obtained by the three schemes were subjected to tensile tests, and the tensile strength, yield strength and elongation of the three titanium alloy welded pipes were obtained as shown in Table 1.

[0174] Table 1 Comparison of three process solutions

[0175]

[0176] It can be seen from Table 1 that the tensile strength σ of the titanium alloy welded pipes prepared by the three schemes b >895MPa, yield strength σ s>830MPa, which meets the mechanical property requirements of the welded pipe. The reason why the tensile strength of the titanium alloy welded pipe in Scheme 1 is low is that this process may lead to uneven heating and produce large residual stress. Although local heating can reduce the stress concentration in the risk area to a certain extent, the overall uniformity is poor; the tensile strength of the titanium alloy welded pipe in Scheme 2 is improved. This is because this scheme is more accurate than Scheme 1, and can heat the risk area evenly, reducing stress concentration and unevenness. However, since only the risk area is heated, it may have a certain impact on the overall uniformity; the tensile strength of the titanium alloy welded pipe in Scheme 3 is the highest among the three schemes. This is because this method can ensure that the stress after each pass can be released, thereby ensuring the overall uniformity and reducing the impact of residual stress. It is the best of the three schemes.

[0177] The samples of the three schemes were subjected to electrochemical corrosion experiments respectively, and the corrosion solution was 3.5% NaCl solution. The corrosion resistance parameters of different samples were obtained, as shown in Table 2. The smaller the corrosion rate D in the table, the better the corrosion resistance of the titanium alloy welded pipe. It can be seen from Table 2 that the titanium alloy welded pipe obtained by scheme 3 has the best corrosion resistance, followed by scheme 2, and scheme 1 is the worst. This is because the titanium alloy plate is heated by a manual handheld flame spray gun, and the heating uniformity is poor, which may cause more microscopic defects and residual stresses on the surface of the material. These defects and stress concentration areas will become the starting point of corrosion, increase the corrosion current density of the material, and make the corrosion rate higher. In addition, the lower corrosion potential indicates that the corrosion resistance of the material in a corrosive environment is poor; scheme 2 uses a more precise heating system to heat only the risk area, and the heating uniformity and control ability are significantly improved. Due to the improvement of heating uniformity, the microscopic defects and residual stress on the surface of the material are reduced, resulting in a decrease in corrosion current density and a slowdown in corrosion rate. At the same time, a higher corrosion potential indicates that the corrosion resistance of the material has been improved. Option 3 is to heat each pass after completion of the entire process, ensuring uniform heating and stress release of the material, and minimizing surface micro defects and residual stress. This treatment method is optimal, reducing the corrosion starting point, reducing the corrosion current density, and further slowing down the corrosion rate. The higher corrosion potential also indicates that the corrosion resistance of the material in a corrosive environment is significantly improved.

[0178] Table 2 Corrosion resistance parameters of samples in different groups

[0179]

[0180] By comparing the mechanical properties and corrosion resistance of the titanium alloy welded pipes obtained by the three process schemes, it is found that the mobile radius adjustable arc heating system of the present invention has a significant effect on improving the mechanical properties and corrosion resistance of the titanium alloy welded pipe. Although the mechanical properties and corrosion resistance of the titanium alloy welded pipe obtained by Scheme 3 are better than those of Scheme 2, heating each pass in Scheme 3 increases the production cycle. After comprehensive consideration, the process scheme in Scheme 2 is the best scheme for improving the performance of titanium alloy welded pipes prepared by TC4 titanium alloy sheets through the JCO forming process and improving the economic benefits of TC4 titanium alloy welded pipes.

[0181] It should be noted that the above modules can be functional modules or program modules, and can be implemented by software or hardware. For modules implemented by hardware, the above modules can be located in the same processor; or the above modules can be located in different processors in any combination.

[0182] It should be understood that the specific embodiments described herein are only used to explain the application, rather than to limit it. Based on the embodiments provided in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of this application.

[0183] Obviously, the drawings are only some examples or embodiments of the present application. For ordinary technicians in the field, the present application can also be applied to other similar situations based on these drawings without creative work. In addition, it is understandable that although the work done in this development process may be complicated and lengthy, for ordinary technicians in the field, certain changes in design, manufacturing or production based on the technical content disclosed in this application are only conventional technical means and should not be regarded as insufficient content disclosed in this application.

Claims

1. A titanium alloy tube JCO forming heating method, characterized in that: Titanium alloy tube forming includes: Acquire an image of a titanium alloy plate in real time by a DIC visual imaging device, wherein the titanium alloy plate is used to form the titanium alloy tube; Determine a current displacement field of the titanium alloy plate based on a first image and a second image, wherein the first image is a current image of the titanium alloy plate, and the second image is a historical image of the titanium alloy plate; Determine the current strain and current stress of the titanium alloy plate based on the current displacement field of the titanium alloy plate by using a strain calculation formula and a stress calculation formula; The strain calculation formula is: Among them, u(x,y) and v(x,y) are the displacement fields of the titanium alloy plate in the x direction and y direction respectively, ε xx and ε yy are the normal strains of the titanium alloy plate in the x and y directions, ε xy and ε yx is the tangential strain of the titanium alloy plate in the x and y directions; The stress calculation formula is: Among them, E is the elastic modulus of the titanium alloy plate, s is the Poisson's ratio of the titanium alloy plate, σ xx and σ yy are the normal stresses of the titanium alloy plate in the x and y directions, σ xy is the shear stress of the titanium alloy plate in the x and y directions; Determining the actual fracture risk area of ​​the titanium alloy plate based on the current stress of the titanium alloy plate by using a target judgment formula; The target judgment formula is: Among them, σ b and σ s are tensile strength and yield strength respectively, and the set of positions that do not satisfy the target judgment formula constitutes the actual fracture risk area; The actual fracture risk area of ​​the titanium alloy plate is sent to a heating device, and the heating device is configured to heat the actual fracture risk area of ​​the titanium alloy plate.

2. The titanium alloy tube JCO forming heating method according to claim 1, characterized in that: The determining the current displacement field of the titanium alloy plate based on the first image and the second image comprises: The first image and the second image are matched by a cross-correlation function or a zero-mean normalized cross-correlation function, and a current displacement field of the titanium alloy plate is determined based on the matching result.

3. The titanium alloy tube JCO forming heating method according to claim 2, characterized in that: The cross-correlation function R(u,v) is: R(u,v)=∑(x,y)[f(x,y)*g(x+u,y+v) The zero-mean normalized cross-correlation function Rzncc(u, v) is: Among them, (x, y) represents the pixel coordinates, f represents the first image, g represents the second image, (u, v) represents the displacement, represents the average value of the first image, represents the average value of the second image.

4. The titanium alloy tube JCO forming heating method according to claim 3, characterized in that: The displacement is estimated by bilinear interpolation: g(x+u,y+v) ≈(1-α)(1-β)*g(x,y)+α*(1-β)*g(x+1,y)+(1-α)β*g(x,y+1)+α*β*g(x+1,y+1) 5. The titanium alloy tube JCO forming heating method according to claim 2, characterized in that: The surface of the titanium alloy plate is black and the surface of the titanium alloy plate is coated with white speckles.

6. The titanium alloy tube JCO forming heating method according to claim 1, characterized in that: Before the titanium alloy tube is formed, it includes: Performing a forming simulation on the titanium alloy plate to obtain a simulated fracture risk area, a simulated heating time, and a simulated heating temperature of the titanium alloy plate during the forming process; The preheating time and preheating temperature are determined according to the simulated heating time and the simulated heating temperature, and the titanium alloy plate is preheated using the preheating time and preheating temperature before being used to form the titanium alloy tube.

7. The titanium alloy tube JCO forming heating method according to claim 6, characterized in that: The preheating time is the same as the simulated heating time, and the preheating temperature is half of the simulated heating temperature.

8. A data processing device, comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to run the computer program to execute the titanium alloy tube JCO forming heating method according to any one of claims 1 to 7.

9. A titanium alloy tube JCO forming system, characterized in that: It includes a DIC visual image device, a data processing device, a heating device and a molding die; The DIC visual image device is used to obtain the image of the titanium alloy plate in real time during the titanium alloy tube forming; The data processing device is the data processing device described in claim 8; The heating device is used to heat the actual fracture risk area of ​​the titanium alloy plate; The forming die is used to achieve deformation of the titanium alloy plate to achieve forming of the titanium alloy tube.

10. The titanium alloy tube JCO forming system according to claim 9, characterized in that: The heating device comprises a base, a mechanical arm and a heating assembly; One end of the mechanical arm is rotatably mounted on the base; The heating assembly includes an arc plate and a plurality of heating units, wherein the arc plate is rotatably mounted on an end of the mechanical arm away from the base and the arc opening faces a side away from the mechanical arm, and each heating unit includes a nozzle, and a coaxially arranged rectangular column, a cylinder and a tooth column, wherein the nozzle is fixedly mounted on a side wall of an outer shell of the cylinder, and the rectangular column and the tooth column are respectively fixedly mounted on both ends of the outer shell of the cylinder; The arc-shaped plate is provided with a plurality of rectangular grooves matching the rectangular column at equal intervals, and the output shaft of the cylinder passes through the rectangular column and is fixedly connected to the bottom wall of the rectangular groove.

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