Friction stir welding weld thinning patching method, apparatus, and storage medium

Abstract

The application provides a friction stir welding weld thinning filling method, equipment and storage medium. The method comprises the following steps: calculating a first weld thinning theoretical value corresponding to a first stir head according to stir head parameters of the first stir head for friction stir welding of a workpiece to be welded and a machine setting down pressure amount of the first stir head; calculating a second weld thinning theoretical value corresponding to a second stir head according to stir head parameters of the second stir head without a stirring needle; adding the first weld thinning theoretical value and the second weld thinning theoretical value to obtain a total weld thinning theoretical value, determining the thickness of a target sheet according to the total weld thinning theoretical value, and setting the target sheet at a weld after the workpiece to be welded is subjected to friction stir welding by the first stir head, and filling the weld of the workpiece to be welded by friction stir welding of the target sheet by the second stir head. The application can better inhibit weld thinning and reduce the difficulty and cost of implementation.

Description

Technical Field

[0001] This invention relates to the field of friction stir welding technology, and in particular to a method, equipment, and storage medium for thinning and filling welds in friction stir welding. Background Technology

[0002] Aluminum alloys possess excellent properties such as being lightweight and flexible, having high strength, good corrosion resistance, good electrical conductivity, and easy recyclability. They are used in a wide range of industries, from construction and transportation to electronics, electrical engineering, machinery, petrochemicals, and aerospace. Welding technology plays a crucial role in aluminum alloys. Understanding the weldability characteristics of aluminum alloys, welding operation techniques, joint quality and performance, defect formation, and prevention measures is essential for developing correct welding processes, achieving good joint performance, and expanding the application range of aluminum alloys. Furthermore, welding technology is an indispensable part of the manufacturing process of aluminum alloy structural components; the quality of the weld directly affects the quality and safety of these components.

[0003] Friction stir welding (FSW) is a novel method for joining metallic materials. It was first invented and patented by the Welding Institute in the UK in 1991. This welding method primarily utilizes the frictional heat between a stirring pin and the workpiece to heat the workpiece to a plastic state. As the stirring head rotates and moves, the stirring pin and the workpiece behind it move towards the welding area. During this process, the stirring pin generates stirring friction within the workpiece, thereby achieving material joining. Compared to traditional fusion welding, friction stir welding offers many advantages, such as a safe and pollution-free welding process, high welding efficiency, low cost, good weld quality, and a wide range of weldable materials. It can effectively join aluminum alloys, producing high-strength joints. Furthermore, the dynamic plastic deformation during friction stir welding allows for the creation of dense weld joints, improving their strength and durability. Moreover, friction stir welding has minimal impact on the physicochemical properties, mechanical properties, and crystal structure of aluminum alloys, allowing for the joining of different types of aluminum alloys. Additionally, it enables automated production in aluminum alloy welding, improving production efficiency and reducing costs. However, during the welding process, the shoulder of the stirring head will press into the base material (i.e. the workpiece to be welded) to a depth of 0.1-0.3mm, which can easily lead to weld thinning and defects such as flash and burrs. After welding, secondary grinding and milling are often required, which not only increases the complexity of the process, but also leads to problems such as stress concentration, reduced joint performance and life.

[0004] Currently, weld thinning in friction stir welding can typically be prevented or suppressed by optimizing the stirring head design, controlling welding parameters, improving welding processes, or using shielding gases. For example, controlling the rotation speed, insertion depth, and shape parameters of the stirring head can reduce weld thinning; controlling welding temperature and time can also reduce thinning; segmented welding or changing the welding sequence can reduce thinning; and using shielding gases can reduce the contact between the material and gases such as oxygen and nitrogen, thereby reducing weld thinning. However, these methods generally require significant time and financial investment, thorough testing and verification, and may even necessitate redesigning the welding procedure and equipment to effectively suppress weld thinning, making them difficult and costly to implement. Summary of the Invention

[0005] This invention provides a method, equipment, and storage medium for thinning and filling weld seams in friction stir welding, thereby reducing the difficulty and cost of suppressing weld seam thinning and better suppressing weld seam thinning.

[0006] In a first aspect, embodiments of the present invention provide a method for thinning and filling weld seams in friction stir welding, comprising:

[0007] Based on the stirring head parameters of the first stirring head used for friction stir welding of the workpiece to be welded, and the machine setting of the first stirring head's downward pressure, the theoretical value of the first weld thinning corresponding to the first stirring head is calculated.

[0008] Based on the stirring head parameters of the second stirring head without stirring pin, calculate the theoretical value of the second weld thinning corresponding to the second stirring head;

[0009] The theoretical value of the first weld thinning and the theoretical value of the second weld thinning are added together to obtain the total theoretical value of weld thinning. The thickness of the target sheet is determined based on the total theoretical value of weld thinning. The target sheet is placed at the weld joint of the workpiece to be welded after friction stir welding using the first stirring head. The target sheet is then used to fill the weld joint of the workpiece to be welded by friction stir welding using the second stirring head. The target sheet is made of the same material as the workpiece to be welded.

[0010] In one possible implementation, calculating the theoretical value of the first weld thinning corresponding to the first stirring head based on the stirring head parameters of the first stirring head used for friction stir welding of the workpiece to be welded and the machine-set pressure of the first stirring head includes:

[0011] Based on the stirring head parameters of the first stirring head used for friction stir welding of the workpiece to be welded, calculate the theoretical downward pressure of the first stirring head after friction stir welding of the workpiece to be welded.

[0012] Based on the theoretical pressure and the machine's set pressure, calculate the theoretical value of the first weld thinning corresponding to the first stirring head.

[0013] In one possible implementation, calculating the theoretical downward pressure of the first stirring head after friction stir welding of the workpiece to be welded, based on the stirring head parameters of the first stirring head, includes:

[0014] Calculate the cone angle of the stirring needle of the first stirring head based on the tail radius, head radius, and length of the stirring needle.

[0015] Based on the shoulder radius and tilt angle of the first stirring head, as well as the tail radius and cone angle of the stirring pin, the theoretical downward pressure of the first stirring head after performing friction stir welding on the workpiece to be welded is calculated.

[0016] In one possible implementation, the cone angle of the stirring needle of the first stirring head is calculated based on the tail radius, tip radius, and length of the stirring needle, including:

[0017] according to Calculate the cone angle of the stirring needle of the first stirring head;

[0018] Wherein, β is the cone angle of the stirring needle, r is the radius of the tail of the stirring needle, r′ is the radius of the head of the stirring needle, and l is the length of the stirring needle.

[0019] In one possible implementation, the theoretical downward pressure of the first stirring head after friction stir welding of the workpiece is calculated based on the shoulder radius and tilt angle of the first stirring head, as well as the tail radius and cone angle of the stirring pin, including:

[0020] according to Calculate the theoretical downward pressure of the first stirring head after performing friction stir welding on the workpiece to be welded.

[0021] Wherein, T is the theoretical downward pressure, R is the shoulder radius, r is the tail radius of the stirring needle, α is the tilt angle of the stirring head, β is the cone angle of the stirring needle, and l is the length of the stirring needle.

[0022] In one possible implementation, the theoretical value of the first weld thinning corresponding to the first stirring head is calculated based on the theoretical downward pressure and the machine-set downward pressure, including:

[0023] Based on M1 = TH, calculate the theoretical value of the first weld thinning corresponding to the first stirring head;

[0024] Where M1 is the theoretical value of the first weld thinning, T is the theoretical pressure amount, and H is the machine-set pressure amount.

[0025] In one possible implementation, calculating the theoretical value of the second weld thinning corresponding to the second stirring head based on the stirring head parameters of the second stirring head without stirring pins includes:

[0026] according to Calculate the theoretical value of the second weld thinning corresponding to the second stirring head;

[0027] Where M2 is the theoretical value of the second weld thinning, R′ is the shoulder radius of the second stirring head, α′ is the stirring head tilt angle of the second stirring head, α′ is the same as the stirring head tilt angle of the first stirring head, and H′ is the machine-set pressure of the second stirring head.

[0028] In one possible implementation, the shoulder radius of the second stirring head is greater than or equal to the shoulder radius of the first stirring head.

[0029] In a second aspect, embodiments of the present invention provide a weld thinning and filling device for friction stir welding, comprising a memory and a processor. The memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to perform the steps of the method as described in the first aspect or any possible implementation thereof.

[0030] Thirdly, embodiments of the present invention provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method as described in the first aspect or any possible implementation thereof.

[0031] This invention provides a method, equipment, and storage medium for filling weld thinning in friction stir welding. The method calculates the theoretical value of weld thinning corresponding to the first stirring head based on the stirring head parameters of the first stirring head used in friction stir welding of the workpiece and the machine-set pressure of the first stirring head. It then calculates the theoretical value of weld thinning corresponding to the second stirring head based on the stirring head parameters of the second stirring head without stirring pins. The theoretical values ​​of the first and second weld thinning are added together to obtain the total theoretical value of weld thinning. This allows for accurate estimation of weld thinning after friction stir welding of the workpiece. The thickness of the target sheet is then determined based on the total theoretical value of weld thinning, and the target sheet is placed at the weld joint after friction stir welding of the workpiece using the first stirring head. Finally, the second stirring head is used to fill the weld joint of the workpiece using friction stir welding with the target sheet. This method effectively suppresses weld thinning and improves weld performance and integrity by increasing the amount of target sheet, without requiring redesign of the welding procedure and equipment, thus reducing implementation difficulty and cost. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart illustrating the implementation of the weld thinning and filling method for friction stir welding provided in this embodiment of the invention.

[0034] Figure 2 This is a schematic diagram of a stirring head with a stirring head tilt angle inserted into a workpiece to be welded, provided in an embodiment of the present invention.

[0035] Figure 3 This is a schematic diagram of a stirring head with a stirring head tilt angle inserted into a workpiece to be welded, provided by another embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram illustrating the use of additive manufacturing materials to fill weld seams, as provided in an embodiment of the present invention.

[0037] Figure 5 This is a schematic diagram of the weld thinning and filling device for friction stir welding provided in an embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of the weld thinning and filling device for friction stir welding provided in an embodiment of the present invention. Detailed Implementation

[0039] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0041] See Figure 1 The diagram illustrates the implementation flowchart of the weld thinning and filling method for friction stir welding provided in this embodiment of the invention, which is described in detail below:

[0042] In step 101, the theoretical value of the first weld thinning corresponding to the first stirring head is calculated based on the stirring head parameters of the first stirring head for friction stir welding of the workpiece to be welded and the machine setting pressure of the first stirring head.

[0043] In this embodiment, a first stirring head with a stirring needle can be used to perform a first stage of friction stir welding on the workpiece to be welded. For example, a first stirring head with a conical stirring needle can be used to perform a first node friction stir welding on aluminum and aluminum alloy workpieces.

[0044] After performing the first stage of friction stir welding on the workpiece using the first stirring head, weld thinning occurs at the weld joint due to the downward pressure of the shoulder of the first stirring head. To suppress weld thinning without increasing the implementation difficulty, it is considered to fill the weld by adding material at the weld joint. Specifically, this can be achieved by adding sheet material. To reasonably add sheet material, the friction stir welding process of the first stirring head on the workpiece is analyzed. Based on the stirring head parameters and the machine setting of the downward pressure of the first stirring head, the theoretical value of the first weld thinning corresponding to the first stirring head is calculated. This allows for the determination of the thickness of the target sheet material to be added based on the theoretical value of the first weld thinning corresponding to the first stirring head.

[0045] Before performing the first stage of friction stir welding on the workpiece using the first stirring head, some pre-welding preparations can be carried out. For example, for aluminum alloy workpieces, the surface flatness of the aluminum alloy workpiece can be checked, and impurities such as oxide film and oil stains on the surface of the aluminum alloy workpiece can be removed. Then, the aluminum alloy workpiece is placed in a fixture or platform to ensure that the surface of the aluminum alloy workpiece is in close contact with the surface of the welding tool, and the aluminum alloy workpiece is fixed in place.

[0046] Based on this, the welding operation can be performed using the pre-set process parameters for friction stir welding to complete the first stage of friction stir welding.

[0047] For example, in the first stage of friction stir welding, the first stirring tool can be allowed to perform welding at a rotation speed S1, a welding speed v1 and a machine-set plunge depth H. The first stirring tool travels along the surface of the workpiece to be welded according to these process parameters, and finally completes the welding. Wherein, the rotation speed satisfies 0 < S1 ≤ 2000r / min, and the welding speed satisfies 0 < v1 ≤ 1000mm / min.

[0048] Wherein, the rotation speed S1 and the welding speed v1 can be determined according to the grade of the material of the workpiece to be welded and the machine model used in actual welding; the machine-set plunge depth H can be determined according to the length of the stirring pin of the first stirring tool selected in actual welding; and the length of the stirring pin of the first stirring tool can be determined according to the thickness and placement mode of the welded plate (i.e., the workpiece to be welded), which is not limited in this embodiment.

[0049] Optionally, in combination with Figure 2 , calculating the theoretical value of the first weld thinning corresponding to the first stirring tool according to the stirring tool parameters of the first stirring tool for performing friction stir welding on the workpiece to be welded and the machine-set plunge depth of the first stirring tool may comprise:

[0050] Calculating the theoretical plunge depth of the first stirring tool after friction stir welding on the workpiece to be welded according to the stirring tool parameters of the first stirring tool for performing friction stir welding on the workpiece to be welded.

[0051] Calculating the theoretical value of the first weld thinning corresponding to the first stirring tool according to the theoretical plunge depth and the machine-set plunge depth.

[0052] In this embodiment, considering the situation that the stirring tool for friction stir welding has a stirring tool tilt angle α (also referred to as tool tilt angle or spindle tilt angle), in combination with Figure 2 as shown, the theoretical value of weld thinning after friction stir welding is performed on the workpiece to be welded by using the stirring tool can be When the stirring tool has a tilt angle, with the plastic flow of the material, the plasticized material will flow from bottom to top along the shape of the stirring pin in the stirring tool, and the material will be wrapped under the shoulder of the stirring tool. Therefore, Figure 2 the vertical distance from point a to the straight line where the lowest end of the stirring pin, i.e., point f, is located, that is, T0, is used as the theoretical plunge depth after the stirring tool performs friction stir welding on the workpiece to be welded. And in combination with Figure 2 the geometric relationship therein, it can be calculated that and that is and since α is generally small, can be approximated as 1, can be approximated as 0, then This is approximately equal to hi, meaning bk is approximately equal to the machine-set pressure of the stirring head. Therefore, based on the theoretical pressure of the stirring head after friction stir welding of the workpiece and the machine-set pressure of the stirring head, the theoretical value of weld thinning corresponding to the stirring head can be approximately calculated.

[0053] Optionally, based on the stirring head parameters of the first stirring head used for friction stir welding of the workpiece, the theoretical downward pressure of the first stirring head after friction stir welding of the workpiece can be calculated, which may include:

[0054] Calculate the cone angle of the stirring needle of the first stirring head based on the tail radius, head radius, and length of the stirring needle.

[0055] Based on the shoulder radius and tilt angle of the first stirring head, as well as the tail radius and cone angle of the stirring pin, the theoretical downward pressure of the first stirring head after performing friction stir welding on the workpiece to be welded is calculated.

[0056] Optionally, the cone angle of the stirring pin of the first stirring head can be calculated based on the tail radius, head radius, and length of the stirring pin. This calculation may include:

[0057] according to Calculate the cone angle of the stirring needle of the first stirring head.

[0058] Where β is the cone angle of the stirring needle, r is the radius of the tail of the stirring needle, r′ is the radius of the head of the stirring needle, and l is the length of the stirring needle.

[0059] Optionally, based on the shoulder radius and tilt angle of the first stirring head, as well as the tail radius and cone angle of the stirring pin, the theoretical downward pressure of the first stirring head after friction stir welding of the workpiece to be welded can be calculated, which may include:

[0060] according to Calculate the theoretical downward pressure of the first stirring head after friction stirring welding of the workpiece.

[0061] Where T is the theoretical downward pressure, R is the shoulder radius, r is the tail radius of the stirring needle, α is the tilt angle of the stirring head, β is the cone angle of the stirring needle, and l is the length of the stirring needle.

[0062] To derive the relationship between the theoretical downward pressure of the stirring head after friction stir welding of the workpiece and the parameters of the stirring head, combined with Figure 2 First, we derive the relationship between the theoretical downward pressure and the stirring head parameters when the shoulder of the stirring head with the stirring head tilt angle is fully inserted into the workpiece to be welded:

[0063] Assume the stirring head is a stirring head with a conical stirring needle, the needle length is l, the needle tail radius is r, the needle head radius is r′, the shoulder diameter is D, the shoulder radius is R, the tilt angle is α, and the machine-set pressure is H. Then... Figure 2 middle, This is equal to the stirring needle length being l. The diameter of the shoulder of the stirring head is equal to D. The shoulder radius of the stirring head is equal to R. The radius of the stirring needle's tail is equal to r. It is equal to the radius of the stirring needle tip, r′.

[0064] Then according to Calculate the cone angle of the stirring needle.

[0065] The theoretical downward pressure when the shoulder of the stirring head with the tilt angle is fully inserted into the workpiece to be welded.

[0066]

[0067] in, From the above inference, we can conclude that:

[0068] so Therefore, the theoretical downward pressure when the shoulder of the stirring head with the stirring head tilt angle is fully inserted into the workpiece to be welded can be determined as follows:

[0069]

[0070] When selecting the shoulder diameter or shoulder radius of the stirring head, factors such as the thickness, strength, thermal conductivity, and melting point of the workpiece plate can be comprehensively considered. Similarly, when selecting the tail radius or head radius of the stirring pin, the shoulder diameter and the characteristics of the workpiece plate can be considered. This embodiment only determines the relationship between the theoretical downward pressure and the stirring head parameters; it does not limit the stirring head parameters such as the shoulder radius, tail radius, or head radius.

[0071] In order to achieve better vertical movement of the stirring head, while avoiding excessive material extrusion and forging extrusion, combined with Figure 3When the shoulder is tilted, the amount of shoulder insertion into the workpiece can be optimized by reducing it. For example, reducing the insertion by 25% ensures that 75% of the shoulder is in direct contact with the workpiece base material. Simultaneously, considering the pulling effect of the vertical movement of the material on the softened material below the stirring pin during friction stir welding, this pulling effect is sufficient to stir the entire material thickness when the stirring pin is positioned approximately 0.1 mm above the lower surface of the workpiece. It also compensates for the adhesion between the workpiece base material and the backing plate. Therefore, when selecting the stirring pin length, it should not penetrate the lower surface of the workpiece base material. Based on this, the relationship between the theoretical downward pressure of the stirring head and the stirring head parameters can be modified as follows:

[0072]

[0073] Therefore, the relationship between the theoretical downforce of the stirring head and the parameters of the stirring head can be determined as follows:

[0074]

[0075] That is, according to The theoretical downward pressure of the first stirring head after friction stir welding of the workpiece is calculated, and then the theoretical downward pressure of the first stirring head after friction stir welding of the workpiece is estimated more accurately.

[0076] Optionally, the theoretical value of the first weld thinning corresponding to the first stirring head can be calculated based on the theoretical downward pressure and the machine-set downward pressure. This may include:

[0077] Based on M1 = TH, calculate the theoretical value of the first weld thinning corresponding to the first stirring head.

[0078] Where M1 is the theoretical value of the first weld thinning, T is the theoretical pressing amount, and H is the machine-set pressing amount.

[0079] In this embodiment, the relationship between the theoretical underpressure of the stirring head and the parameters of the stirring head is determined as follows: In this case, consider The machine setting pressure is approximately equal to that of the stirring head. Therefore, based on M1=TH, the theoretical value of the first weld thinning corresponding to the first stirring head is calculated, and the theoretical value of weld thinning after friction stirring welding of the workpiece to be welded using the first stirring head is estimated more accurately.

[0080] In step 102, the theoretical value of the second weld thinning corresponding to the second stirring head is calculated based on the stirring head parameters of the second stirring head without stirring pin.

[0081] In this embodiment, to more accurately estimate the theoretical value of weld thinning, after performing a first stage of friction stir welding on the workpiece to be welded using a first stirring head, a sheet is added to the weld area after the first stirring head friction stir welding, and a second stirring head without stirring pins is used to perform friction stir welding on the added sheet to fill the weld thinning amount after the first stirring head friction stir welding on the workpiece to be welded. Considering that the weld is filled by using a second stirring head without stirring pins to perform friction stir welding on the added sheet, and that friction stir welding with a second stirring head without stirring pins also introduces weld thinning, a method similar to step 101 is used to calculate the second theoretical value of weld thinning corresponding to the second stirring head based on the stirring head parameters of the second stirring head without stirring pins. The total theoretical value of weld thinning is estimated based on the first and second theoretical values ​​of weld thinning corresponding to the first and second stirring heads. Then, the thickness of the sheet filling the weld area of ​​the workpiece to be welded is determined based on the total theoretical value of weld thinning, thereby better suppressing weld thinning based on the sheet of appropriate thickness.

[0082] Optionally, based on the stirring head parameters of the second stirring head without stirring pins, the theoretical value of the second weld thinning corresponding to the second stirring head can be calculated, which may include:

[0083] according to Calculate the theoretical value of the second weld thinning corresponding to the second stirring head.

[0084] Where M2 is the theoretical value of the second weld thinning, R′ is the shoulder radius of the second stirring head, α′ is the stirring head tilt angle of the second stirring head, α′ is the same as the stirring head tilt angle of the first stirring head, and H′ is the machine-set downward pressure of the second stirring head.

[0085] In order to achieve the effect of filling the weld seam using the second stirring head, the shoulder radius of the second stirring head can be greater than or equal to the shoulder radius of the first stirring head.

[0086] In step 103, the theoretical value of the first weld thinning and the theoretical value of the second weld thinning are added together to obtain the total theoretical value of weld thinning. The thickness of the target sheet is determined based on the total theoretical value of weld thinning. The target sheet is then placed at the weld seam of the workpiece to be welded after friction stir welding using the first stirring head. The target sheet is then used to fill the weld seam of the workpiece to be welded by friction stir welding using the second stirring head.

[0087] The target sheet is made of the same material as the workpiece to be welded.

[0088] In this embodiment, after performing the first stage of friction stir welding on the workpiece to be welded using the first stirring head, the surface of the plate after the first stage of friction stir welding can be cleaned to avoid affecting the stability of the clamping. Then, a sheet material that is substantially consistent with the weld seam after the first stage of friction stir welding is selected or processed as the target sheet material and placed at the weld seam of the workpiece to be welded.

[0089] The thickness of the target sheet is determined by the theoretical value of total weld thinning calculated according to the above steps. To facilitate obtaining the target sheet, the thickness of the target sheet can be selected between the theoretical value of the first weld thinning and the theoretical value of the total weld thinning.

[0090] Among them, the length L2 of the target sheet can be greater than the weld length L1, and the width W2 of the target sheet can be slightly greater than the weld width W1, but must be less than or equal to the shoulder diameter D′ of the second stirring head, that is, W1≤W2≤D′.

[0091] After selecting the target sheet, place it at the weld seam of the workpiece to be welded and clamp it with a fixture. Pay attention to the position and angle of the target sheet to ensure smooth welding during friction stir welding using the second stirring head. When fixing the target sheet with the fixture, be careful not to apply excessive force to avoid deforming it. Keep the additive manufacturing material (i.e., the target sheet) in a fixed position and use the second stirring head to weld on the surface of the additive manufacturing material, such as... Figure 4 As shown, this continues until welding is complete. The second stirring head without a stirring pin can be a stirring head with a smooth, flat shoulder.

[0092] After filling the weld, post-weld treatment can be performed. This involves allowing the welded area to cool naturally after friction stir welding; do not use coolants such as water or ice, as this can affect weld quality and material properties. If the welded surface is uneven or has defects such as protrusions, it can be machined to smooth it out.

[0093] This embodiment fills the weld seam through additive manufacturing. On the one hand, during friction stir welding, defects such as porosity and cracks may appear in the weld seam due to material flow and agitation. Additive manufacturing can fill these defects to a certain extent, improving the quality and integrity of the weld seam. On the other hand, by adding extra material to the friction stir weld seam, the cross-sectional area of ​​the weld seam can be increased, improving its strength and stability. Simultaneously, these additive materials can also promote metallurgical bonding between materials, thereby improving the mechanical properties of the weld seam. Furthermore, the aesthetics and sealing performance of the friction stir weld seam can affect the overall quality and performance of the structure. Additive manufacturing can improve the aesthetics and sealing performance of the weld seam to a certain extent, enhancing the overall quality and performance of the structure. Moreover, the flow and agitation of materials during friction stir welding can lead to low production efficiency. Additive manufacturing can shorten the production cycle, increase production efficiency, and reduce production costs to a certain extent. Additionally, traditional fusion welding methods require large amounts of welding materials and shielding gases, while also generating large amounts of waste slag and harmful gaseous pollutants. In contrast, additive manufacturing does not require the use of these welding materials and shielding gases, nor does it generate these pollutants, thus having a smaller impact on the environment.

[0094] To further illustrate the calculation process of the theoretical thinning values ​​of the first and second weld seams, and the process of determining the thickness of the target sheet based on the total theoretical thinning value of the weld seams, the following examples are provided:

[0095] Taking 2mm aluminum alloy lap welding as an example:

[0096] Based on the 2mm thickness of the aluminum alloy workpiece to be welded, the shoulder radius of the first stirring head is selected to be 5mm, the length of the conical stirring needle of the first stirring head is 2.5mm, and the radius of the needle tail and the radius of the needle head are 2.5mm and 1.5mm respectively. The tilt angle of the stirring head is 2°, and the machine is set to a downward pressure of 2.5mm. The aluminum alloy workpiece to be welded and the first stirring head are fixed in the corresponding positions on the welding machine. The first stirring head is moved above the workpiece to be welded to determine the welding position.

[0097] The first stage of friction stir welding was carried out with the stirring head rotating at 1100 r / min, the welding speed at 100 mm / min, and the machine set to a downward pressure of 2.5 mm. The dwell time in the keyhole after welding was 4 s.

[0098] To determine the theoretical value of weld thinning corresponding to the first stirring head, first substitute the values ​​of the stirring pin tail radius, stirring pin head radius, and stirring pin length into the formula to obtain the stirring pin cone angle:

[0099]

[0100] Then, substituting the values ​​of the shoulder radius, the tail radius of the stirring pin, the tilt angle of the stirring head, the cone angle of the stirring pin, and the length of the stirring pin into the formula, we obtain the theoretical downward pressure of the first stirring head after performing friction stir welding on the workpiece to be welded:

[0101]

[0102] The theoretical value for the thinning of the first weld corresponding to the first stirring head is: M1 = 2.64 - 2.5 = 0.14 mm.

[0103] The weld seam was clamped onto the surface of the first-stage friction stir welding weld. A flat, needle-free stirring head with a shoulder diameter of 10mm was used at a rotation speed of 800 r / min, a welding speed of 60 mm / min, a stirring head tilt angle of 2°, and a machine-set downward pressure of 0.2 mm. The theoretical thinning value of the second weld seam corresponding to the second stirring head is then:

[0104] The theoretical value for total weld thinning is 0.202mm. Considering that the aluminum alloy sheet thickness is not 0.202mm, a target sheet with a thickness of 0.2mm is selected for welding. The aesthetics of the weld after additive manufacturing are improved, and the surface quality of the joint is also improved.

[0105] This invention calculates the theoretical value of weld thinning corresponding to the first stirring head based on the stirring head parameters of the first stirring head used for friction stir welding of the workpiece to be welded, as well as the machine-set pressure of the first stirring head. It then calculates the theoretical value of weld thinning corresponding to the second stirring head based on the stirring head parameters of the second stirring head without stirring pins. The theoretical values ​​of the first and second weld thinning are added together to obtain the total theoretical value of weld thinning. This allows for an accurate estimation of weld thinning after friction stir welding of the workpiece to be welded. The thickness of the target sheet is then determined based on the total theoretical value of weld thinning. The target sheet is placed at the weld joint after friction stir welding of the workpiece to be welded using the first stirring head. The second stirring head then performs friction stir welding on the target sheet to fill the weld joint of the workpiece to be welded. This method not only better suppresses weld thinning by increasing the target sheet, improving weld performance and integrity, but also eliminates the need to redesign the welding procedure and equipment, reducing implementation difficulty and cost.

[0106] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0107] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0108] Figure 5A schematic diagram of the weld thinning and filling device for friction stir welding provided in an embodiment of the present invention is shown. For ease of explanation, only the parts related to the embodiment of the present invention are shown, and are described in detail below:

[0109] like Figure 5 As shown, the weld thinning and filling device for friction stir welding includes: a first processing module 51, a second processing module 52 and a third processing module 53.

[0110] The first processing module 51 is used to calculate the theoretical value of the first weld thinning corresponding to the first stirring head based on the stirring head parameters of the first stirring head for friction stir welding of the workpiece to be welded and the machine setting pressure of the first stirring head.

[0111] The second processing module 52 is used to calculate the theoretical value of the second weld thinning corresponding to the second stirring head based on the stirring head parameters of the second stirring head without stirring pin.

[0112] The third processing module 53 is used to add the theoretical value of the first weld thinning and the theoretical value of the second weld thinning to obtain the total theoretical value of weld thinning, so as to determine the thickness of the target sheet based on the total theoretical value of weld thinning, and to place the target sheet at the weld after friction stir welding of the workpiece to be welded using the first stirring head, and to fill the weld of the workpiece to be welded by friction stir welding of the target sheet using the second stirring head; wherein, the target sheet is made of the same material as the workpiece to be welded.

[0113] This invention calculates the theoretical value of weld thinning corresponding to the first stirring head based on the stirring head parameters of the first stirring head used for friction stir welding of the workpiece to be welded, as well as the machine-set pressure of the first stirring head. It then calculates the theoretical value of weld thinning corresponding to the second stirring head based on the stirring head parameters of the second stirring head without stirring pins. The theoretical values ​​of the first and second weld thinning are added together to obtain the total theoretical value of weld thinning. This allows for an accurate estimation of weld thinning after friction stir welding of the workpiece to be welded. The thickness of the target sheet is then determined based on the total theoretical value of weld thinning. The target sheet is placed at the weld joint after friction stir welding of the workpiece to be welded using the first stirring head. The second stirring head then performs friction stir welding on the target sheet to fill the weld joint of the workpiece to be welded. This method not only better suppresses weld thinning by increasing the target sheet, improving weld performance and integrity, but also eliminates the need to redesign the welding procedure and equipment, reducing implementation difficulty and cost.

[0114] In one possible implementation, the first processing module 51 can be used to calculate the theoretical downward pressure of the first stirring head after performing friction stir welding on the workpiece to be welded, based on the stirring head parameters of the first stirring head for performing friction stir welding on the workpiece to be welded.

[0115] Based on the theoretical pressure and the machine's set pressure, calculate the theoretical value of the first weld thinning corresponding to the first stirring head.

[0116] In one possible implementation, the first processing module 51 can be used to calculate the cone angle of the stirring needle of the first stirring head based on the tail radius, head radius and length of the stirring needle of the first stirring head.

[0117] Based on the shoulder radius and tilt angle of the first stirring head, as well as the tail radius and cone angle of the stirring pin, the theoretical downward pressure of the first stirring head after performing friction stir welding on the workpiece to be welded is calculated.

[0118] In one possible implementation, the first processing module 51 can be used to... Calculate the cone angle of the stirring needle of the first stirring head;

[0119] Wherein, β is the cone angle of the stirring needle, r is the radius of the tail of the stirring needle, r′ is the radius of the head of the stirring needle, and l is the length of the stirring needle.

[0120] In one possible implementation, the first processing module 51 can be used to... Calculate the theoretical downward pressure of the first stirring head after performing friction stir welding on the workpiece to be welded.

[0121] Wherein, T is the theoretical downward pressure, R is the shoulder radius, r is the tail radius of the stirring needle, α is the tilt angle of the stirring head, β is the cone angle of the stirring needle, and l is the length of the stirring needle.

[0122] In one possible implementation, the first processing module 51 can be used to calculate the theoretical value of the first weld thinning corresponding to the first stirring head based on M1 = TH.

[0123] Where M1 is the theoretical value of the first weld thinning, T is the theoretical pressure amount, and H is the machine-set pressure amount.

[0124] In one possible implementation, the second processing module 52 can be used to... Calculate the theoretical value of the second weld thinning corresponding to the second stirring head;

[0125] Where M2 is the theoretical value of the second weld thinning, R′ is the shoulder radius of the second stirring head, α′ is the stirring head tilt angle of the second stirring head, α′ is the same as the stirring head tilt angle of the first stirring head, and H′ is the machine-set pressure of the second stirring head.

[0126] In one possible implementation, the shoulder radius of the second stirring head is greater than or equal to the shoulder radius of the first stirring head.

[0127] Figure 6 This is a schematic diagram of a weld thinning and filling device for friction stir welding provided in an embodiment of the present invention. Figure 6 As shown, the weld thinning and filling device 6 for friction stir welding in this embodiment includes: a processor 60, a memory 61, and a computer program 62 stored in the memory 61 and executable on the processor 60. When the processor 60 executes the computer program 62, it implements the steps in the various embodiments of the friction stir welding weld thinning and filling method described above, for example... Figure 1 Steps 101 to 103 are shown. Alternatively, when processor 60 executes computer program 62, it implements the functions of each module / unit in the above-described device embodiments, for example... Figure 5 The functions of modules / units 51 to 53 shown.

[0128] For example, computer program 62 can be divided into one or more modules / units, one or more of which are stored in memory 61 and executed by processor 60 to perform the present invention. One or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of computer program 62 in the friction stir welding weld thinning and filling device 6. For example, computer program 62 can be divided into... Figure 5 Modules / units 51 to 53 are shown.

[0129] The weld thinning and filling device 6 for friction stir welding can be a computing device such as a desktop computer, laptop, handheld computer, or cloud server. The weld thinning and filling device 6 for friction stir welding may include, but is not limited to, a processor 60 and a memory 61. Those skilled in the art will understand that... Figure 6 This is merely an example of the weld thinning and filling device 6 for friction stir welding, and does not constitute a limitation on the weld thinning and filling device 6 for friction stir welding. It may include more or fewer components than shown, or combine certain components, or different components. For example, the weld thinning and filling device for friction stir welding may also include input / output devices, network access devices, buses, etc.

[0130] The processor 60 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0131] The memory 61 can be an internal storage unit of the friction stir welding weld thinning and filling device 6, such as a hard disk or memory of the friction stir welding weld thinning and filling device 6. The memory 61 can also be an external storage device of the friction stir welding weld thinning and filling device 6, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the friction stir welding weld thinning and filling device 6. Furthermore, the memory 61 can include both internal storage units and external storage devices of the friction stir welding weld thinning and filling device 6. The memory 61 is used to store computer programs and other programs and data required by the terminal. The memory 61 can also be used to temporarily store data that has been output or will be output.

[0132] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0133] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0134] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0135] In the embodiments provided by this invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0136] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0137] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0138] If integrated modules / units are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the above embodiments of the friction stir welding weld thinning and filling methods. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0139] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for thinning and filling weld seams in friction stir welding, characterized in that, include: Based on the stirring head parameters of the first stirring head used for friction stir welding of the workpiece to be welded, and the machine setting of the first stirring head's downward pressure, the theoretical value of the first weld thinning corresponding to the first stirring head is calculated. according to Calculate the cone angle of the stirring needle of the first stirring head; in, The angle of the stirring needle cone of the first stirring head. Let be the radius of the stirring needle tail of the first stirring head. Let be the radius of the stirring needle of the first stirring head. The length of the stirring needle of the first stirring head; according to Calculate the theoretical downward pressure of the first stirring head after performing friction stir welding on the workpiece to be welded; in, This is the theoretical downward pressure of the first stirring head after performing friction stir welding on the workpiece. Let be the shoulder radius of the first stirring head. Let be the radius of the stirring needle tail of the first stirring head. The tilt angle of the first stirring head is [angle not specified]. The angle of the stirring needle cone of the first stirring head. The length of the stirring needle of the first stirring head; according to Calculate the theoretical value of the thinning of the first weld corresponding to the first stirring head; in, This is the theoretical value for the thinning of the first weld seam corresponding to the first stirring head. This is the theoretical downward pressure of the first stirring head after performing friction stir welding on the workpiece. Set the pressure for the machine with the first stirring head; Based on the stirring head parameters of the second stirring head without stirring pin, calculate the theoretical value of the second weld thinning corresponding to the second stirring head; according to Calculate the theoretical value of the second weld thinning corresponding to the second stirring head; in, This represents the theoretical value for the thinning of the second weld seam corresponding to the second stirring head. The radius of the shoulder of the second stirring head. The tilt angle of the second stirring head. The tilt angle of the stirring head is the same as that of the first stirring head. Set the pressure for the machine with the second stirring head; The theoretical value of the first weld thinning and the theoretical value of the second weld thinning are added together to obtain the total theoretical value of weld thinning. The thickness of the target sheet is determined based on the total theoretical value of weld thinning. The target sheet is placed at the weld joint of the workpiece to be welded after friction stir welding using the first stirring head. The target sheet is then used to fill the weld joint of the workpiece to be welded by friction stir welding using the second stirring head. The target sheet is made of the same material as the workpiece to be welded.

2. The method for thinning and filling weld seams in friction stir welding according to claim 1, characterized in that, The shoulder radius of the second stirring head is greater than or equal to the shoulder radius of the first stirring head.

3. A weld thinning and filling device for friction stir welding, characterized in that, It includes a memory and a processor, the memory being used to store computer programs, and the processor being used to call and run the computer programs stored in the memory to perform the method as described in claim 1 or 2.

4. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in claim 1 or 2 above.

Images