Vortex cooling parameter regulation and control method for friction stir welding and control system of vortex cooling parameter regulation and control method

Abstract

The invention discloses an eddy current cooling parameter regulation and control method for friction stir welding and a control system of the eddy current cooling parameter regulation and control method, and relates to the technical field of welding temperature control. S2, calculating a cooling demand index; s3, vortex tube parameter adjustment; s4, adjusting the air injection direction and angle; s5, implementing multi-section temperature control; and S6, performing real-time feedback and adjustment. According to the vortex cooling parameter regulation and control method for friction stir welding and the control system of the vortex cooling parameter regulation and control method, the flow, pressure, temperature and spraying angle of cooling gas can be automatically regulated under the conditions of different materials and welding processes, and multi-section temperature control over a welding hot area, a stirring head and areas in front of and behind a welding seam is achieved; and the thermal field uniformity and the welding seam forming quality in the welding process are improved.

Description

Technical Field

[0001] This invention relates to the field of welding temperature control technology, specifically to a method and control system for adjusting eddy current cooling parameters in friction stir welding. Background Technology

[0002] Friction stir welding (FSW) is a typical solid-state joining technology widely used for joining alloys such as aluminum, copper, and titanium. During welding, a stirring head rotates at high speed on the workpiece surface, applying axial pressure and utilizing frictional heat and plastic deformation of the material to achieve the connection. However, due to concentrated heat input, the intense friction between the stirring head and the workpiece causes rapid temperature rise in the welding head and surrounding area. Without effective temperature control, this can easily lead to overheating of the weld metal, coarse microstructure, and abnormal expansion of the heat-affected zone, affecting weld quality and joint mechanical properties. Currently, some welding systems use air cooling or liquid cooling systems to cool the welding head, but these systems suffer from limitations such as reliance on a single cooling method, slow response, and inability to dynamically adjust according to changes in welding parameters, making them unsuitable for adapting to the thermal field control requirements of various materials and complex working conditions. Traditional air cooling methods cannot precisely control the direction, pressure, and flow rate of the air jet, resulting in insufficient or excessive cooling of the welding head, affecting the flow state and microstructure evolution in the stirring plastic zone, and increasing the probability of welding defects.

[0003] A vortex tube, a heat-splitting device based on the Ranque-Hilsch effect, can separate compressed gas into hot and cold end airflows without using electrical energy. It features a compact structure, fast temperature control response, and high energy efficiency. However, the vortex cooling principle has not yet been integrated with an adaptive control system driven by welding parameters, and a set of adjustable vortex cooling strategies and mathematical models for the heat input of friction stir welding is lacking. Summary of the Invention

[0004] The purpose of this invention is to provide a method for adjusting eddy current cooling parameters and a control system for friction stir welding, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: On the one hand, a method for controlling eddy current cooling parameters for friction stir welding is provided, including the following steps: S1. Welding Parameter Acquisition: Real-time acquisition of key parameters during the welding process, including welding speed, stirring head rotation speed, welding voltage, current, and current temperature; S2. Cooling demand index calculation: The cooling demand index is dynamically calculated based on the collected welding parameters. S3. Vortex tube parameter adjustment: Adjust the inlet air pressure, inlet flow rate, and hot end regulating valve opening of the vortex tube according to the cooling demand index. S4. Jet Direction and Angle Adjustment: The jet outlets at both ends of the vortex cooling pipe are designed with adjustable angles. The jet direction at the hot and cold ends is set to a variable angle relative to the workpiece surface within the range of 30°-60°. The jet angle is adjusted according to the welding speed. Welding heat input , plate thickness The combined process index of the three parameters is adjusted, as defined below: ; in, For the spray angle, For welding heat input, For welding speed, For plate thickness, For welding current, Where η is the welding voltage and η is the thermal efficiency; S5. Multi-stage temperature control implementation: The vortex cooling tube is equipped with multiple controllable jet channels facing the front, directly below and behind the welding head respectively. Different nozzles are opened independently according to the welding stage and temperature control area, supporting combined jet strategies to achieve integrated and efficient temperature control effect of simultaneous preheating and cooling of one tube. S6. Real-time feedback and adjustment: The system continuously monitors the welding process and cooling effect, and adjusts the vortex tube parameters and jet direction based on real-time feedback to ensure adaptive control of the welding thermal field.

[0006] Furthermore, in step S2, the cooling demand index is calculated from the welding heat input and temperature deviation, and the calculation process is as follows: 1) The welding heat input is determined by the current, voltage, and speed. The calculation formula is as follows: ; in, For welding heat input, For welding current, For welding voltage, Where η is the welding speed, and η is the thermal efficiency (dimensionless, empirical value of 0.7-0.9). The formula shows that: as welding current and welding voltage increase, heat input increases; as welding speed increases, heat input decreases; and the greater the heat input, the higher the cooling requirement. 2) Formula for calculating temperature deviation (the difference between the current temperature and the set temperature): ;in, For temperature deviation, The current temperature. To set the temperature; From the formula, we can obtain: Current temperature Compared to the set temperature High, then If the value is greater than 0, cooling should be enhanced. Current temperature Compared to the set temperature Low, then If the value is less than 0, cooling should be reduced or preheating increased. 3) Input welding heat and temperature deviation These two quantities are unified into a dimensionless variable: In the formula, The standard reference heat input is obtained from experience or simulation. In the formula, The standard reference temperature deviation obtained from experience or simulation; 4) , Integrate into a single cooling coefficient: ; : Control intensity index; Large: High heat / high temperature, requiring stronger cooling; Small: Low heat / low temperature, requires weak cooling / more preheating.

[0007] Furthermore, in step S3, the inlet air pressure Entry traffic Hot end regulating valve opening The control situation is as follows: Controlling the compressed air intensity: the higher the air pressure, the more obvious the temperature difference between the hot and cold ends, and the stronger the cooling capacity. The greater the airflow, the stronger the heat exchange per unit time, and the faster the temperature response. Controlling the ratio of hot air to cold air is the key variable for regulating the temperature of the cold / hot end; reducing the opening, i.e., decreasing the flow to the hot end, makes the cold end colder.

[0008] Furthermore, the control of the inlet pressure: ;in, This is the inlet air pressure. , These represent the maximum and minimum inlet pressures, respectively. This refers to the cooling demand index; Larger diameter means higher pressure, colder cold end, and stronger cooling capacity; Smaller size results in lower pressure and weaker cooling capacity; ,when Weak cooling; when Strong cooling.

[0009] Furthermore, the control of the hot end opening degree: ;in, To regulate the opening of the hot-end regulating valve, , These represent the maximum and minimum values ​​of the hot-end opening, respectively. This refers to the cooling demand index; Larger volumes result in higher heat input, necessitating enhanced cooling to reduce heat input. Reduce → hot end becomes hotter, cold end becomes colder (enhanced cooling); If the temperature is low, the cooling requirement is low, and preheating should be increased. Increase → hot end becomes colder, cold end becomes warmer.

[0010] Furthermore, the relationship between the temperatures at both ends of the vortex tube (cold end temperature, hot end temperature) is as follows: ; ; in, This is the cold end temperature. This is the hot end temperature. This is the inlet air pressure. Adjust the opening degree of the hot-end regulating valve; cold end temperature : Follow Rise and fall, follow Rising and rising; Hot end temperature : Follow It rises and then falls.

[0011] Furthermore, in step S4, the nozzle angle is quickly adjusted via a spherical hinge mechanism and a scale locking device, which can be manually or automatically controlled by the system.

[0012] Furthermore, in step S4, the relationship between the spray angle and the welding heat input (used to control the angle) is as follows: For the hot-end injection angle (preheating): ; For the cold end spray angle (cooling): ; In the formula: , Default spray angle; Standard heat input reference value; , Angle adjustment coefficient; 5°-10°; From the formula, we can see that: High welding heat input necessitates wider preheating to expand the plastic zone, thereby increasing the welding efficiency. ; High welding heat input necessitates a wider cooling area after welding → increasing efficiency. .

[0013] Furthermore, in step S5, hot-end airflow is used to preheat the front of the weld to improve the plasticity of the base metal and increase the fluidity of the metal in the starting section; cold-end airflow is used to cool the rear of the weld to reduce the temperature of the overheated zone after welding and control the weld structure and residual stress.

[0014] On the other hand, an eddy current cooling parameter control system for friction stir welding is provided, which is applied to the above-mentioned eddy current cooling parameter control method for friction stir welding, including an eddy current tube and a cooling control mechanism based on welding parameter sensing and feedback. The vortex tube, as the core temperature control unit, is based on the principle of gas vortex hot and cold separation. It divides the compressed gas into two parts: a high-temperature airflow and a low-temperature airflow. Specifically, the hot-end airflow is guided to the area in front of the weld to preheat the base material or the metal in the arc segment, thereby improving the plastic deformation capacity. At the same time, the cold-end airflow is sprayed to the rear of the weld or the heat-affected zone to achieve rapid cooling and suppress microstructure coarsening and residual stress accumulation. The cooling control mechanism based on welding parameter sensing and feedback is used to collect key parameters such as welding speed, stirring head rotation speed, welding voltage and current, current temperature and material type in real time, and dynamically calculate the cooling demand index based on the collected parameters to adjust the flow rate, pressure, temperature and spray angle of the cooling gas.

[0015] This invention provides a method and control system for regulating eddy current cooling parameters in friction stir welding, which has the following advantages: it can automatically adjust the flow rate, pressure, temperature and spray angle of cooling gas under different material and welding process conditions, realize multi-segment temperature control of the welding hot zone, stirring head and the area before and after the weld, and improve the uniformity of the thermal field and the quality of weld formation during the welding process. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the steps of an eddy current cooling parameter control method for friction stir welding according to the present invention. Figure 2This is a schematic diagram of the actual operation of an eddy current cooling parameter control method and its control system for friction stir welding according to the present invention – an eddy current tube. Detailed Implementation

[0017] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0018] like Figures 1-2 As shown, a method for controlling eddy current cooling parameters for friction stir welding includes the following steps: S1. Welding Parameter Acquisition: Real-time acquisition of key parameters during the welding process, including welding speed, stirring head rotation speed, welding voltage, current, and current temperature. These parameters are the basis for subsequent calculation of the cooling demand index.

[0019] S2. Cooling Demand Index Calculation: Based on the collected welding parameters, the cooling demand index is dynamically calculated. This cooling demand index is derived from the welding heat input and temperature deviation. The calculation process is as follows: 1) The welding heat input is determined by the current, voltage, and speed. The calculation formula is as follows: ; in, For welding heat input, For welding current, For welding voltage, Where η is the welding speed, and η is the thermal efficiency (dimensionless, empirical value of 0.7-0.9). The formula shows that as welding current and welding voltage increase, heat input increases; as welding speed increases, heat input decreases; and the greater the heat input, the higher the cooling requirement.

[0020] 2) Formula for calculating temperature deviation (the difference between the current temperature and the set temperature): ;in, For temperature deviation, The current temperature. To set the temperature; From the formula, we can obtain: Current temperature Compared to the set temperature High, then If the value is greater than 0, cooling should be enhanced. Current temperature Compared to the set temperature Low, then If the value is less than 0, cooling should be reduced or preheating should be increased.

[0021] 3) Input welding heat and temperature deviation These two quantities are unified into a dimensionless variable: In the formula, The standard reference heat input is obtained from experience or simulation. In the formula, The standard reference temperature deviation is obtained from experience or simulation.

[0022] 4) , Integrate into a single cooling coefficient: ; : Control intensity index; Large: High heat / high temperature, requiring stronger cooling; Small: Low heat / low temperature, requires weak cooling / more preheating.

[0023] S3. Vortex Tube Parameter Adjustment: Adjust the inlet air pressure of the vortex tube according to the cooling demand index. Entry traffic Hot end regulating valve opening .

[0024] Controlling the compressed air intensity: the higher the air pressure, the more obvious the temperature difference between the hot and cold ends, and the stronger the cooling capacity. The greater the airflow, the stronger the heat exchange per unit time, and the faster the temperature response. Controlling the ratio of hot air to cold air is the key variable for regulating the temperature of the cold / hot end; reducing the opening, i.e., decreasing the flow to the hot end, makes the cold end colder.

[0025] In this embodiment, the inlet pressure is controlled: ;in, This is the inlet air pressure. , These represent the maximum and minimum inlet pressures, respectively. This represents the cooling demand index.

[0026] Larger diameter means higher pressure, colder cold end, and stronger cooling capacity.

[0027] Smaller pressure results in lower cooling capacity.

[0028] ,when Weak cooling; when Strong cooling.

[0029] In this embodiment, the hot end opening degree is controlled: ;in, To regulate the opening of the hot-end regulating valve, , These represent the maximum and minimum values ​​of the hot-end opening, respectively. This represents the cooling demand index.

[0030] Larger volumes result in higher heat input, necessitating enhanced cooling to reduce heat input. Reduce → hot end becomes hotter, cold end becomes colder (enhanced cooling).

[0031] If the temperature is low, the cooling requirement is low, and preheating should be increased. Increase → hot end becomes colder, cold end becomes warmer.

[0032] In this embodiment, the temperature relationship between the two ends of the vortex tube (cold end temperature, hot end temperature) is as follows: ; ; in, This is the cold end temperature. This is the hot end temperature. This is the inlet air pressure. This refers to the opening degree of the hot-end regulating valve.

[0033] cold end temperature : Follow Rise and fall, follow It rises and rises.

[0034] Hot end temperature : Follow It rises and then falls.

[0035] S4. Jet Direction and Angle Adjustment: The jet outlets at both ends of the vortex cooling pipe are designed with adjustable angles. The jet direction at the hot and cold ends is set to a variable angle relative to the workpiece surface within the range of 30°-60°. In this step, the nozzle angle is quickly adjusted via a spherical hinge mechanism and a scale locking device, which can be manually or automatically controlled by the system. The jet angle setting will be based on the welding speed. Welding heat input , plate thickness The combined process index of the three parameters is adjusted, as defined below: ; in, For the spray angle, For welding heat input, For welding speed, For plate thickness, For welding current, η is the welding voltage, and η is the thermal efficiency.

[0036] In this embodiment, the relationship between the spray angle and the welding heat input (used to control the angle) is as follows: For the hot-end injection angle (preheating): ; For the cold end spray angle (cooling): ; In the formula: , Default spray angle (30°); Standard thermal input reference value (determined by experience / simulation); , Angle adjustment coefficient (empirical setting or automatic adjustment, 0.6-1.2); : 5°-10°.

[0037] From the formula, we can see that: High welding heat input necessitates wider preheating to expand the plastic zone, thereby increasing the welding efficiency. ; High welding heat input necessitates a wider cooling area after welding → increasing efficiency. .

[0038] S5. Multi-stage temperature control implementation: The eddy current cooling pipe is equipped with multiple directional controllable air jet channels, facing the front, directly below, and rear of the welding head respectively. Different nozzles open independently according to the welding stage and temperature control zone, supporting combined air jet strategies to achieve integrated and efficient temperature control for simultaneous preheating and cooling of a single pipe. In this step, hot-end airflow is used for preheating in front of the weld to improve the plasticity of the base metal and increase the fluidity of the weld entry section; cold-end airflow is used for cooling behind the weld to reduce the temperature of the overheated zone after welding and control the weld microstructure and residual stress.

[0039] S6. Real-time feedback and adjustment: The system continuously monitors the welding process and cooling effect, and adjusts the vortex tube parameters and jet direction according to real-time feedback to ensure adaptive control of the welding heat field. This real-time feedback mechanism enables the system to adapt to different material types, plate thicknesses, welding speeds and welding torch posture conditions, thereby improving the stability and intelligence level of the welding process.

[0040] An eddy current cooling parameter control system for friction stir welding, applied to the aforementioned eddy current cooling parameter regulation method for friction stir welding, includes an eddy current tube and a cooling control mechanism based on welding parameter sensing and feedback.

[0041] Eddy current tube: As the core temperature control unit, it is based on the principle of gas vortex hot and cold separation, dividing the compressed gas into two parts: a high-temperature airflow and a low-temperature airflow. Specifically, the eddy current tube guides the hot-end airflow to the area in front of the weld to preheat the base material or the metal at the start of the arc, thereby improving the plastic deformation capacity; at the same time, it sprays the cold-end airflow to the rear of the weld or the heat-affected zone to achieve rapid cooling and suppress microstructure coarsening and residual stress accumulation.

[0042] A cooling control mechanism based on welding parameter sensing and feedback is used to collect key parameters such as welding speed, stirring head rotation speed, welding voltage and current, current temperature and material type in real time, and dynamically calculate the cooling demand index based on the collected parameters to adjust the flow rate, pressure, temperature and spray angle of the cooling gas.

[0043] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A method for controlling eddy current cooling parameters in friction stir welding, characterized in that, Includes the following steps: S1. Welding Parameter Acquisition: Real-time acquisition of key parameters during the welding process, including welding speed, stirring head rotation speed, welding voltage, current, and current temperature; S2. Cooling demand index calculation: The cooling demand index is dynamically calculated based on the collected welding parameters. S3. Vortex tube parameter adjustment: Adjust the inlet air pressure, inlet flow rate, and hot end regulating valve opening of the vortex tube according to the cooling demand index. S4. Jet direction and angle adjustment: The jet outlets at both ends of the vortex cooling pipe are designed with adjustable angles. The jet direction of the hot end and the cold end relative to the workpiece surface are set to a variable angle within the range of 30°-60°. The spray angle depends on the welding speed. Welding heat input , plate thickness The combined process index of the three parameters is adjusted, as defined below: ； in, For the spray angle, For welding heat input, For welding speed, For plate thickness, For welding current, Where η is the welding voltage and η is the thermal efficiency; S5. Multi-stage temperature control implementation: The eddy current cooling pipe is equipped with multiple controllable air jet channels, which are directed towards the front, directly below and behind the welding head respectively, and different nozzles are opened independently according to the welding stage and temperature control area. S6. Real-time feedback and adjustment: The system continuously monitors the welding process and cooling effect, and adjusts the vortex tube parameters and jet direction based on real-time feedback.

2. The method for controlling eddy current cooling parameters for friction stir welding according to claim 1, characterized in that, In step S2, the cooling demand index is calculated from the welding heat input and temperature deviation, and the calculation process is as follows: 1) The welding heat input is determined by the current, voltage, and speed. The calculation formula is as follows: ； in, For welding heat input, For welding current, For welding voltage, Where η is the welding speed, and η is the thermal efficiency; The formula shows that: as welding current and welding voltage increase, heat input increases; as welding speed increases, heat input decreases; and the greater the heat input, the higher the cooling requirement. 2) Formula for calculating temperature deviation: ;in, For temperature deviation, The current temperature. To set the temperature; From the formula, we can obtain: Current temperature Compared to the set temperature High, then If the value is greater than 0, cooling should be enhanced. Current temperature Compared to the set temperature Low, then If the value is less than 0, cooling should be reduced or preheating increased. 3) Input welding heat and temperature deviation These two quantities are unified into a dimensionless variable: In the formula, The standard reference heat input is obtained from experience or simulation. In the formula, The standard reference temperature deviation obtained from experience or simulation; 4) , Integrate into a single cooling coefficient: ; : Control intensity index; Large: High heat / high temperature, requiring stronger cooling; Small: Low heat / low temperature, requires weak cooling / more preheating.

3. The method for controlling eddy current cooling parameters for friction stir welding according to claim 1, characterized in that, In step S3, the inlet air pressure Entry traffic Hot end regulating valve opening The control situation is as follows: Controlling the compressed air intensity: the higher the air pressure, the more obvious the temperature difference between the hot and cold ends, and the stronger the cooling capacity. The greater the airflow, the stronger the heat exchange per unit time, and the faster the temperature response. Controlling the ratio of hot air to cold air is the key variable for regulating the temperature of the cold / hot end; reducing the opening, i.e., decreasing the flow to the hot end, makes the cold end colder.

4. The method for controlling eddy current cooling parameters for friction stir welding according to claim 3, characterized in that, The controlled inlet pressure: ;in, This is the inlet air pressure. , These represent the maximum and minimum inlet pressures, respectively. This refers to the cooling demand index; Larger diameter means higher pressure, colder cold end, and stronger cooling capacity; Smaller size results in lower pressure and weaker cooling capacity; ,when Weak cooling; when Strong cooling.

5. The method for controlling eddy current cooling parameters for friction stir welding according to claim 4, characterized in that, The control of the hot end opening: ;in, To regulate the opening of the hot-end regulating valve, , These represent the maximum and minimum values ​​of the hot-end opening, respectively. This refers to the cooling demand index; Larger volumes result in higher heat input, necessitating enhanced cooling to reduce heat input. Decrease → Hot end becomes hotter, cold end becomes colder; If the temperature is low, the cooling requirement is low, and preheating should be increased. Increase → hot end becomes cold, cold end becomes warm.

6. The method for controlling eddy current cooling parameters for friction stir welding according to claim 5, characterized in that, The temperature relationship between the two ends of the vortex tube is as follows: ； ； in, This is the cold end temperature. This refers to the hot end temperature. This is the inlet air pressure. Adjust the opening degree of the hot-end regulating valve; cold end temperature : Follow Rise and fall, follow Rising and rising; Hot end temperature : Follow It rises and then falls.

7. The method for controlling eddy current cooling parameters for friction stir welding according to claim 1, characterized in that, In step S4, the nozzle angle is quickly adjusted through a spherical hinge mechanism and a scale locking device, which can be manually or automatically controlled by the system.

8. The method for controlling eddy current cooling parameters for friction stir welding according to claim 1, characterized in that, In step S4, the relationship between the spray angle and the welding heat input is as follows: Regarding the hot-end injection angle: ; For the cold end injection angle: ; In the formula: , Default spray angle; Standard heat input reference value; , Angle adjustment coefficient; ：5°-10°； From the formula, we can see that: High welding heat input necessitates wider preheating to expand the plastic zone, thereby increasing the welding efficiency. ; High welding heat input necessitates a wider cooling area after welding → increasing efficiency. .

9. The method for controlling eddy current cooling parameters for friction stir welding according to claim 1, characterized in that, In step S5, the weld seam is preheated by hot airflow in front of it and cooled by cold airflow behind it.

10. An eddy current cooling parameter control system for friction stir welding, applied to the eddy current cooling parameter adjustment method for friction stir welding as described in any one of claims 1-9, comprising an eddy current tube and a cooling control mechanism based on welding parameter sensing and feedback, characterized in that: The vortex tube, as the core temperature control unit, is based on the principle of gas vortex hot and cold separation. It divides the compressed gas into two parts: a high-temperature airflow and a low-temperature airflow. Specifically, the hot-end airflow is guided to the area in front of the weld to preheat the base material or the metal in the arc segment; at the same time, the cold-end airflow is sprayed to the rear of the weld or the heat-affected zone to achieve rapid cooling. The cooling control mechanism based on welding parameter sensing and feedback is used to collect key parameters in the welding process in real time and dynamically calculate the cooling demand index based on the collected parameters in order to adjust the flow rate, pressure, temperature and spray angle of the cooling gas.

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