Dissimilar material stirring head welding system and welding method
Through the welding system that synergistically acts by alternating magnets and laser welding guns, the connection problem between ordinary carbon steel and high-temperature alloy steel is solved, and a low-cost and high-performance stirring head preparation is achieved.
Patent Information
- Application Number
- CN202510647593.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-20
- Publication Date
- 2025-08-05
AI Technical Summary
The prior art is difficult to achieve effective connection between ordinary carbon steel and high-temperature alloy steel, resulting in high preparation cost of stirring heads and poor joint performance.
A welding system that synergistically works by alternating magnets and laser welding torches is adopted to promote the combination of non-uniform nucleation and metallurgy through the coordination of alternating current and magnetic field, and combine with the negative defocus laser welding method to achieve effective connection between the two steels.
A good combination of ordinary carbon steel and high-temperature alloy steel is achieved, reducing the mixing head preparation cost and improving the joint performance.
Smart Images
Figure CN120421731A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a stirring head preparation technology, and in particular to a welding system and a welding method for stirring heads made of different materials. Background Art
[0002] The heat generated during the friction stir welding (FSW) process mainly comes from the friction heat between the stirring head and the workpiece material, so the stirring head needs to be made of high-temperature resistant and wear-resistant materials. Therefore, high-temperature resistant alloy steel is often used as the material for the stirring head in industry. However, high-temperature alloy steel is expensive, and in actual welding operations, the impact of friction heat is mainly concentrated in the stirring head. If ordinary carbon steel can be used as the clamping part and high-temperature alloy steel as the friction welding part, the cost of stirring head preparation will be greatly reduced, which has good development prospects. However, this requires a good metallurgical bond between ordinary carbon steel and high-temperature alloy steel.
[0003] Laser welding is a highly flexible and intelligent advanced welding technology that can achieve depth-to-width ratios of more than 10:1. It also features high welding speeds and minimal welding deformation, making it a commonly used technique for welding high-strength alloy steels. However, laser welding has extremely rapid heating and cooling rates, making it prone to welding defects such as pores and unfused sidewalls. Furthermore, the laser beam's active area is very small, which can easily lead to poor joint performance when welding high-strength steel and dissimilar metals. Some scholars have proposed external field-assisted control methods, such as electromagnetic stirring and ultrasonic vibration, aiming to improve joint performance by intervening in the solidification behavior of the molten pool through the introduction of dynamic energy fields. However, in the welding of columnar high-temperature alloy steels, not only a large penetration depth is required, but also good weld formation at the joint. A single auxiliary method makes it difficult to achieve a good bond between columnar high-strength steels. Summary of the Invention
[0004] Purpose of the invention: The purpose of the present invention is to provide a welding system and method for heterogeneous material stirring heads, which can achieve effective connection between ordinary carbon steel and high-temperature alloy steel, and thus prepare heterogeneous stirring heads.
[0005] Technical Solution: The present invention provides a dissimilar material stirring head welding system for welding carbon steel and high-temperature alloy steel, wherein the carbon steel and high-temperature alloy steel are assembled along the axial direction to form a workpiece to be welded; the system includes two conductive wires connected to the ends of the workpiece to be welded, a first alternating magnet and a second alternating magnet arranged circumferentially along the workpiece to be welded, a laser welding gun disposed above the first alternating magnet, a wire feeder for providing welding wire to the workpiece to be welded, a first control module connected to the A end of the first alternating magnet, and a second control module connected to the C end of the workpiece to be welded;
[0006] The first control module is used to control the current flowing through the first alternating magnet and the second alternating magnet coil, and the second control module is used to control the current flowing through the workpiece to be welded;
[0007] The first alternating magnet, the second alternating magnet, the wire, the first control module and the second control module are all connected to an alternating power supply.
[0008] Furthermore, the first alternating magnet and the second alternating magnet are perpendicular to each other, and both have a hollow core for the laser beam emitted by the laser welding gun to pass through. The laser beam passes through the hollow core of the first alternating magnet and reaches the workpiece to be welded.
[0009] Furthermore, the first control module is connected to the first alternating magnet A terminal via a first bidirectional thyristor.
[0010] Furthermore, the second control module is connected to the C end of the workpiece to be welded via a second bidirectional thyristor.
[0011] Furthermore, the center line of the first alternating magnet is coaxial with the center line of the laser welding gun, and there is an angle between the laser beam emitted by the laser welding gun and the center line.
[0012] Furthermore, the center lines of the first alternating magnet and the second alternating magnet are on a plane, and the plane coincides with the plane of the weld gap of the workpiece to be welded.
[0013] Furthermore, the heat input to the welding area is increased by increasing the current flowing through the first alternating magnet and the second alternating magnet coil, or increasing the current flowing through the workpiece to be welded, or selecting a higher alternating power supply frequency; otherwise, the heat input to the welding area is reduced.
[0014] Furthermore, the welding penetration is increased by increasing the current flowing through the first alternating magnet and the second alternating magnet coil, or increasing the current flowing through the workpiece to be welded; otherwise, the welding penetration is reduced.
[0015] Furthermore, when the current flows from the c end to the d end of the workpiece to be welded, the coil branch current flows into the A end of the first alternating magnet and flows out from the B end of the second alternating magnet; conversely, when the current flows from the d end to the c end of the workpiece to be welded, the direction of the coil branch current flows into the B end of the second alternating magnet and flows out from the A end of the first alternating magnet.
[0016] Based on the same inventive concept, the present invention provides a method for welding a dissimilar material stirring head, which is applied to the above-mentioned dissimilar material stirring head welding system, and comprises:
[0017] Clamping stage: The carbon steel and high-temperature alloy steel remain fixed in position during the welding process and can rotate along the central axis. The laser welding gun and the first alternating magnet are adjusted so that the laser beam emitted by the laser welding gun passes through the first alternating magnet.
[0018] Welding stage: start the alternating power supply, set the laser defocus of the laser welding gun to negative defocus, and set the angle between the laser beam and the center line of the first alternating magnet; start welding, the wire feeder feeds the welding wire at a constant speed, and during the welding process, the workpiece to be welded keeps rotating clockwise along its own central axis. The current flowing through the first alternating magnet and the second alternating magnet coil is controlled by the first control module, and the current flowing through the workpiece to be welded or the frequency of the alternating power supply is adjusted by the second control module according to the experimental results.
[0019] Processing stage: After welding is completed, the high-temperature alloy steel is processed into the required stirring head shape.
[0020] Beneficial effects: Compared with the prior art, the significant technical effects of the present invention are as follows: (1) After the two ends of the workpiece to be welded are connected to the alternating power supply, when the alternating current generated by the alternating power supply flows through the workpiece to be welded, an induced magnetic field is generated between the changing current and the flowing molten pool (the magnetic field is generally weak in intensity, but has the effect of promoting non-uniform nucleation). The electromagnetic stirring effect is generated under the joint action of the current and the magnetic field, which promotes non-uniform nucleation and further promotes grain refinement; (2) When a part of the ordinary carbon steel protrusion is connected to the high-temperature alloy steel and the alternating current is connected, the resistance heat generated not only has a preheating effect, It can also make the two base materials produce preliminary metallurgical bonding at the raised part, reducing the pressure of clamping; (3) by using laser negative defocus welding, the power density inside the material is higher than that on the surface, which can easily form a stronger melting effect and transfer energy to a deeper part of the material; (4) the first alternating magnet and the second alternating magnet work together to generate an external auxiliary magnetic field, which is an adjustable magnetic field. The direction of the external auxiliary magnetic field changes according to the direction of the current. The magnetic field is generated by the coil and is easy to install. The device is simple to operate and has strong practicality. In addition, it is low-cost, easy to implement and easy to assemble, which is convenient for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 This is a schematic diagram of the overall structure of the heterogeneous material stirring head welding system of the present invention;
[0022] Figure 2 It is the main view of the workpiece to be welded;
[0023] Figure 3 for Figure 2 A transverse cross-sectional view of
[0024] Figure 4 is a front view of the first alternating magnet;
[0025] Figure 5 for Figure 4 A transverse cross-sectional view of
[0026] Figure 6 This is a control principle diagram of the heterogeneous material stirring head welding system of the present invention;
[0027] Figure 7 Schematic diagram of magnetic field distribution after forward current is passed.
[0028] Figure 8 Schematic diagram of magnetic field distribution after reverse current is applied. DETAILED DESCRIPTION
[0029] The technical solution of the present invention is described in detail below in conjunction with specific implementation methods and the accompanying drawings.
[0030] Example 1
[0031] like Figure 1 As shown, the dissimilar material stirring head welding system of the present invention is used to weld ordinary carbon steel 4 and high-temperature alloy steel 5. The ordinary carbon steel 4 and high-temperature alloy steel 5 are assembled along the axial direction to form the workpiece to be welded. The welding system of the present invention includes a wire feeder 1, a welding wire 2, a laser welding gun 3, a conductor 6, a first alternating magnet 7, a second alternating magnet 8, a laser beam 9, a worktable 10, a first control module 11, a first bidirectional thyristor 12, a second bidirectional thyristor 13, a second control module 14, and an alternating power supply 15. The workpiece to be welded is placed on the worktable 10, and two conductors 6 are connected to the ends of the workpiece to be welded. During welding, the workpiece to be welded rotates clockwise along the central axis. The first alternating magnet 7 and the second alternating magnet 8 are arranged circumferentially around the workpiece to be welded. At the same time during welding, the magnetic poles generated by the first alternating magnet 7 and the second alternating magnet 8 have opposite directions. The laser welding gun 3 is positioned above the first alternating magnet 7, and a laser welding method with negative defocus is used. In this embodiment, the first alternating magnet 7 and the second alternating magnet 8 are perpendicular to each other, that is, the angle between the first alternating magnet 7 and the second alternating magnet 8 is 90 degrees. Figure 4 and Figure 5 As shown, both the first alternating magnet 7 and the second alternating magnet 8 have a hollow core 17 through which the laser beam 9 emitted by the laser welding gun 3 passes. The laser beam 9 passes through the hollow core 17 of the first alternating magnet 7 and reaches the workpiece to be welded. The centerline of the first alternating magnet 7 is coaxial with the centerline of the laser welding gun 3, and there is an angle between the laser beam 9 emitted by the laser welding gun 3 and the centerline. The centerlines of the first alternating magnet 7 and the second alternating magnet 8 are aligned in a plane that coincides with the plane of the weld gap 16 of the workpiece to be welded.
[0032] The first control module 11 is connected to the A terminal of the first alternating magnet 7 via a first bidirectional thyristor 12, and the second control module 14 is connected to the C terminal of the workpiece to be welded via a second bidirectional thyristor 13. The first control module 11 is used to control the current flowing through the coils of the first alternating magnet 7 and the second alternating magnet 8, while the second control module 14 is used to control the current flowing through the workpiece to be welded. The direction of the coil current is controlled by the first bidirectional thyristor 12, while the direction of the current flowing through the workpiece to be welded is controlled by the second bidirectional thyristor 13. The first alternating magnet 7, the second alternating magnet 8, the conductor 6, the first control module 11, and the second control module 14 are all connected to an alternating power supply 15.
[0033] like Figure 6 As shown, the coil terminal a of the first alternating magnet 7 is electrically connected to the coil terminal b of the second alternating magnet 8. During the laser wire welding process of ordinary carbon steel 4 and high-temperature alloy steel 5 with alternating current flowing at both ends, an alternating magnetic field is introduced. The current direction in the coil branches of the first alternating magnet 7 and the second alternating magnet 8 is specific. That is, when the current flows from the end c to the end d of the workpiece to be welded (positive current is passed), the coil branch current flows into the end A of the first alternating magnet 7 and flows out of the end B of the second alternating magnet 8, as shown in FIG. Figure 7 On the contrary, when the current flows from the end d to the end c of the workpiece to be welded (reverse current), the direction of the coil branch current flows into the B end of the second alternating magnet 8 and flows out from the A end of the first alternating magnet 7, as shown. Figure 8 As shown. The first alternating magnet 7 and the second alternating magnet 8 use the same alternating power supply as the conductor on the parent material. A current control module and a bidirectional thyristor are used to control the intensity of the alternating current. The interaction between the current and the magnetic field improves joint performance. When the magnetic field and current interact, the workpiece rotates clockwise. The synergistic effect of the alternating magnetic field and alternating current, combined with laser wire welding, enables the effective connection of the two steels, resulting in the production of a heterogeneous stirring head and significantly reducing the cost of preparing the stirring head.
[0034] like Figure 2 and Figure 3 As shown, a raised portion of ordinary carbon steel 4 is spliced with high-temperature alloy steel 5. The resistance heat generated after the alternating current is connected not only has a preheating effect, but also can produce a preliminary metallurgical bond between the two base materials, reducing the pressure of clamping.
[0035] In this example, two base materials (ordinary carbon steel 4 and high-temperature alloy steel 5) are tightly spliced together to ensure there is no gap between them. The two materials are held in a fixed position while simultaneously rotating clockwise along their axis. A suitable welding wire 2 is selected based on the physical and chemical parameters of the two base steels. Low-power-density laser welding is employed, with negative defocusing. Wire feeder 1 delivers the wire at a constant speed.
[0036] The current control module can be a commonly used AC digital display bidirectional thyristor controller on the market, and the bidirectional thyristor can be a voltage-regulated bidirectional thyristor MTC55A. The winding method of the coils of the two alternating magnets is not fixed, and the generated magnetic fields must be opposite ends. The frequency of the AC power supply is adjustable within a range of [50Hz to 2000Hz]. During the welding process, the operator adjusts the current according to the weld formation. Specifically, the current regulation method in the coil is as follows: Figure 6 As shown, when the heat input is insufficient, the heat input to the welding area is increased by increasing the current flowing through the coils of the first alternating magnet 7 and the second alternating magnet 8, or increasing the current flowing through the workpiece to be welded, or selecting a higher frequency of the alternating power supply 15; when the heat input is excessive, the current flowing through the coils of the first alternating magnet 7 and the second alternating magnet 8, or reducing the current flowing through the welding workpiece, or reducing the frequency of the alternating current, thereby reducing the heat input to the welding area. The current adjustment method flowing through the workpiece: when there is an incomplete weld defect, increase the current flowing through the workpiece, or select a lower frequency of the alternating current; when the center of the weld is overburned, reduce the current flowing through the workpiece, or increase the frequency of the alternating current of the power supply. The first alternating magnet 7, the second alternating magnet 8 and the current flowing through the workpiece to be welded are all generated by the alternating power supply 15.
[0037] like Figure 6 As shown, the welding penetration is increased by increasing the current flowing through the coils of the first alternating magnet 7 and the second alternating magnet 8, or increasing the current flowing through the workpiece to be welded; the welding penetration can be reduced by reducing the current flowing through the coils of the first alternating magnet 7 and the second alternating magnet 8, or reducing the current flowing through the workpiece to be welded.
[0038] Example 2
[0039] A method for welding a dissimilar material stirring head according to the present invention is applied to the dissimilar material stirring head welding system described in Example 1, and the method comprises the following steps:
[0040] S1. Clamping Stage: During the welding process, the ordinary carbon steel 4 and the high-temperature alloy steel 5 remain fixed on the workbench 10 and can rotate along its central axis. The laser welding gun 3 and the first alternating magnet 7 are adjusted so that the laser beam 9 emitted by the laser welding gun 3 passes through the first alternating magnet 7.
[0041] When clamping, the workpiece to be welded is given power to rotate clockwise.
[0042] S2, welding stage: start the alternating power supply 15, set the laser defocus of the laser welding gun 3 to negative defocus, and set the angle between the laser beam 9 and the center line of the first alternating magnet 7 to 5°; start welding, the wire feeder 1 feeds the welding wire at a constant speed, and during the welding process, the workpiece to be welded keeps rotating clockwise along its own central axis. The operator controls the current flowing through the coils of the first alternating magnet 7 and the second alternating magnet 8 through the first control module 11, and adjusts the current flowing through the workpiece to be welded or changes the frequency of the alternating power supply 15 through the second control module 14 according to the experimental results.
[0043] The purpose of setting the clockwise rotation is to allow the magnetic field to better act on the molten pool and improve the joint formation.
[0044] S3, processing stage: After welding is completed, the high-temperature alloy steel 5 is processed into the required stirring head shape.
Claims
1. A heterogeneous material stirring head welding system, characterized by: Used for welding carbon steel (4) and high-temperature alloy steel (5), wherein the carbon steel (4) and high-temperature alloy steel (5) are assembled along the axial direction to form a workpiece to be welded; the system comprises two wires (6) connected to the two ends of the workpiece to be welded, a first alternating magnet (7) and a second alternating magnet (8) arranged along the circumference of the workpiece to be welded, a laser welding gun (3) arranged above the first alternating magnet (7), a wire feeder (1) for providing welding wire (2) to the workpiece to be welded, a first control module (11) connected to the A end of the first alternating magnet (7), and a second control module (14) connected to the C end of the workpiece to be welded; The first control module (11) is used to control the current flowing through the coils of the first alternating magnet (7) and the second alternating magnet (8), and the second control module (14) is used to control the current flowing through the workpiece to be welded; The first alternating magnet (7), the second alternating magnet (8), the wire (6), the first control module (11) and the second control module (14) are all connected to an alternating power supply (15).
2. The heterogeneous material stirring head welding system according to claim 1 is characterized in that: The first alternating magnet (7) and the second alternating magnet (8) are perpendicular to each other, and both the first alternating magnet (7) and the second alternating magnet (8) have a hollow iron core (17) for a laser beam (9) emitted by a laser welding gun (3) to pass through. The laser beam (9) passes through the hollow iron core (17) of the first alternating magnet (7) and reaches a workpiece to be welded.
3. The heterogeneous material stirring head welding system according to claim 1 is characterized in that: The first control module (11) is connected to the A end of the first alternating magnet (7) via a first bidirectional thyristor (12).
4. The heterogeneous material stirring head welding system according to claim 1 is characterized in that: The second control module (14) is connected to the C end of the workpiece to be welded via a second bidirectional thyristor (13).
5. The heterogeneous material stirring head welding system according to claim 1 is characterized in that: The center line of the first alternating magnet (7) is coaxial with the center line of the laser welding gun (3), and an angle exists between the laser beam (9) emitted by the laser welding gun (3) and the center line.
6. The heterogeneous material stirring head welding system according to claim 1, characterized in that: The center lines of the first alternating magnet (7) and the second alternating magnet (8) are on a plane, and the plane coincides with the plane of the weld gap of the workpiece to be welded.
7. The heterogeneous material stirring head welding system according to claim 1, characterized in that: The heat input to the welding area is increased by increasing the current flowing through the coils of the first alternating magnet (7) and the second alternating magnet (8), or increasing the current flowing through the workpiece to be welded, or selecting a higher frequency of the alternating power supply (15); conversely, the heat input to the welding area is reduced.
8. The heterogeneous material stirring head welding system according to claim 1, characterized in that: By increasing the current flowing through the coils of the first alternating magnet (7) and the second alternating magnet (8), or increasing the current flowing through the workpiece to be welded, the welding penetration is increased; otherwise, the welding penetration is reduced.
9. The heterogeneous material stirring head welding system according to claim 1, characterized in that: When the current flows from the C end to the D end of the workpiece to be welded, the coil branch current flows into the A end of the first alternating magnet (7) and flows out from the B end of the second alternating magnet (8); conversely, when the current flows from the D end to the C end of the workpiece to be welded, the direction of the coil branch current flows into the B end of the second alternating magnet (8) and flows out from the A end of the first alternating magnet (7).
10. A method for welding a stirring head of different materials, characterized in that: The method is applied to the dissimilar material stirring head welding system according to claim 1, and the method comprises: Clamping stage: the carbon steel (4) and the high-temperature alloy steel (5) are kept in a fixed position during the welding process and can rotate along the central axis, and the laser welding gun (3) and the first alternating magnet (7) are adjusted so that the laser beam (9) emitted by the laser welding gun (3) passes through the first alternating magnet (7); Welding stage: starting the alternating power supply (15), setting the laser defocus of the laser welding gun (3) to negative defocus, and setting the angle between the laser beam (9) and the center line of the first alternating magnet (7); starting welding, the wire feeder (1) feeds the welding wire at a constant speed, and during the welding process, the workpiece to be welded keeps rotating clockwise along its own center axis. The current flowing through the coils of the first alternating magnet (7) and the second alternating magnet (8) is controlled by the first control module (11), and the current flowing through the workpiece to be welded or the frequency of the alternating power supply (15) is adjusted according to the experimental results by the second control module (14). Processing stage: After welding is completed, the high temperature alloy steel (5) is processed into the required stirring head shape.