Narrow gap welding device and method with preheating function

Abstract

The invention provides a narrow gap welding device with a preheating function and a welding method.The welding device comprises a wire feeding device, a welding gun, a high-frequency induction heating power source, a high-frequency heating coil, a thermocouple, a stirring needle and a controller, and the high-frequency heating coil is located on the front portion below the welding gun and fixed to the welding gun through an adjustable support; the heating coil is electrically connected with the high-frequency induction heating power supply; the thermocouples are arranged on the two sides of a weld joint in an array mode and used for detecting the temperature of the weld joint of a workpiece to be welded. The controller obtains temperature distribution of workpieces to be welded on the two sides of the weld joint in real time and controls the output power of the high-frequency induction heating power source and / or adjusts the adjustable support to regulate and control the distance between the high-frequency heating coil and the workpieces to be welded so as to regulate and control the preheating temperature of the workpieces to be welded. The high-frequency induction heating device is combined to the welding gun, efficient and accurate preheating is achieved, and the welding efficiency and the welding quality are improved; and the welding device disclosed by the invention is high in applicability.

Description

Technical Field

[0001] The present invention relates to the field of welding technology, and in particular to a narrow gap welding device and method with a preheating function. Background Art

[0002] Currently, narrow gap GMAW is an efficient method for welding thick plates. It uses an electrode and shielding gas to generate an arc to melt and join metal materials together. Narrow gap GMAW requires precise welding parameter control, proper selection of welding electrodes and shielding gas, as well as preheating and post-weld treatment techniques. Since narrow gap welding can reduce the amount of heat input during welding, it can reduce the deformation and stress of the welded joint and improve the stability and reliability of the welded joint. Narrow gap welding can reduce the amount of filler material required during welding, thereby saving material costs.

[0003] However, due to the small gap of the narrow gap groove and the fast heat transfer speed of the thick plate, excessive temperature can easily lead to high stress and cause deformation of the workpiece. At the same time, under low heat input, the arc cannot directly heat the side wall, which is prone to defects such as unfused side walls, seriously threatening the service safety of large thick plate components. In order to solve the problems of large stress, large temperature gradient and insufficient side wall fusion in the narrow gap GMAW process, many efficient welding methods have emerged, such as rotating arc technology, magnetic field stirring welding pool and other welding methods. However, the above technical solutions have the following disadvantages: the simple arc rotation has high requirements for the welding gun, the welding process is difficult to control, and the magnetic field stirring molten pool is slightly insufficient in energy. At the same time, it cannot solve the problems of excessive stress in the workpiece and large temperature gradient, resulting in defects in the weldment. Summary of the invention

[0004] In view of this, the present invention proposes a narrow gap welding device and method with a preheating function, aiming to solve the defects of the above-mentioned prior art.

[0005] In one aspect, the present invention provides a narrow gap welding device with a preheating function, characterized in that it includes a wire feeding device, a welding gun, a high-frequency induction heating power supply, a high-frequency heating coil, a thermocouple, a controller, and a stirring needle;

[0006] The welding gun is arranged above the U-shaped groove of the workpiece to be welded, the wire feeding device is located at the upper end of the welding gun, and the high-frequency heating coil is located at the front part below the welding gun, fixed to the welding gun through an adjustable bracket, and electrically connected to the high-frequency heating coil;

[0007] The stirring needle is arranged on one side below the welding gun and is synchronized with the welding gun;

[0008] A plurality of the thermocouples are arranged in an array on both sides of the weld to detect the temperature of the weld of the workpiece to be welded;

[0009] The controller is respectively connected to the thermocouple, the high-frequency induction heating power supply and the driving mechanism of the adjustable bracket, and is used to obtain the temperature distribution of the workpieces to be welded on both sides of the weld in real time, and control the output power of the high-frequency induction heating power supply and / or adjust the adjustable bracket to adjust the distance between the high-frequency heating coil and the workpiece to be welded, so as to realize the regulation of the preheating temperature of the workpiece to be welded.

[0010] Furthermore, the high-frequency heating coil is hinged on a connecting ear fixed to the welding gun through a connecting rod and an articulated shaft, a nut block capable of rotating relative to the connecting rod is provided on the connecting rod, a first screw rod is fixedly connected to the output shaft of the first motor fixed on the welding gun, and the first screw rod is threadedly connected to the nut block; the first motor is connected to a controller, and the operation of the first motor is controlled by the controller.

[0011] Furthermore, there are two high-frequency heating coils, which are arranged side by side; there are also two connecting ears, which are respectively fixed to the two end portions of the welding gun; the two ends of the articulated shaft have reverse threads, and the connecting rods of the two high-frequency heating coils are respectively threadedly connected to the two reverse threads of the articulated shaft, and the two ends of the articulated shaft pass through the two connecting ears respectively, one end of which is fixedly connected to the second motor fixed on the welding gun; the second motor is connected to the controller, and the operation of the second motor is controlled by the controller.

[0012] Furthermore, the thermocouple arrays on both sides of the weld are arranged in three rows, with the spacings from the weld being 3 mm, 5 mm, and 7 mm, respectively, for monitoring the temperatures at 3 mm, 5 mm, and 7 mm from the weld, respectively.

[0013] Furthermore, the power of the high-frequency induction heating power supply can be infinitely adjusted between 15 and 85 kW.

[0014] Furthermore, the distance between the high-frequency heating coil and the lower end of the welding gun is 3 to 5 cm, and the distance between the high-frequency heating coil and the two side walls of the U-shaped groove is 1 to 3 mm.

[0015] Furthermore, the stirring needle is made of tungsten or ceramic, the inclination angle of the stirring needle relative to the welding wire is 15-90 degrees, and the horizontal distance between the end of the stirring needle and the end of the welding wire is 10 mm.

[0016] On the other hand, the present invention also proposes a welding method based on the narrow gap welding device with preheating function, characterized in that it includes the following steps:

[0017] Step 1: Fix the workpiece to be welded on the welding fixture, and connect the high-frequency induction heating power supply, high-frequency heating coil, thermocouple, temperature recorder, stirring needle and stirring needle power supply;

[0018] Step 2: Set welding processing parameters, start high-frequency induction heating power supply, stirring needle power supply, thermocouple and temperature recorder, and introduce protective gas;

[0019] Step 3: The controller collects and obtains the temperature distribution of the workpieces to be welded on both sides of the weld in real time, and controls the output power of the high-frequency induction heating power supply and / or the distance between the high-frequency heating coil and the weld groove based on the output power of the high-frequency induction heating power supply, the heating efficiency of the high-frequency heating coil, and the heat transfer efficiency of the air and the workpiece, so that the temperature of the workpiece to be welded meets the set preheating temperature.

[0020] Furthermore, the distance between the end of the welding wire and the U-shaped groove surface of the workpiece to be welded is 5 to 8 mm.

[0021] Furthermore, the welding current of the welding machine power supply is 50-400A, the gas flow in the welding gun is 5-30L / min, the welding speed is 140-400mm / min, the rotation speed of the stirring needle is 0-3000rps, and the high-frequency induction heating power is 15-85KW.

[0022] Compared with the prior art, the beneficial effect of the present invention is that the high-frequency induction heating device is combined with the welding gun in the present invention, and the real-time high-power preheating of the base material is realized through high-frequency induction heating, which can greatly save the preheating time cost. The preheating and weldment processing are almost synchronous, which effectively avoids the energy consumption problem of cooling the base material after preheating, and can reduce the temperature gradient during welding, reduce the post-weld stress, and improve the quality of the weld. At the same time, the present invention optimizes the adjustable connection structure between the high-frequency induction heating coil and the welding gun, combines the thermocouple and the controller, realizes the effective and precise control of the preheating parameters and preheating effect of the workpiece to be welded, and also improves the adaptability of the welding device to welding workpieces of different materials and sizes, and has strong versatility.

[0023] At the same time, the present invention effectively combines the mechanical stirring needle system to stir the welding molten pool while realizing high-frequency induction heating, promoting the flow of the molten pool to form a vortex, which is beneficial to accelerate heat exchange, so that the arc heat of the molten pool is effectively transmitted to the side wall, making the temperature distribution more uniform, and increasing the penetration depth of the narrow gap side wall. Under the sufficient stirring action of the welding molten pool, the gas in the molten metal overflows, the appearance of pores is reduced, and the beneficial elements are evenly distributed in the molten pool.

[0024] At the same time, based on traditional narrow gap welding, the present invention improves the adverse effects of excessive temperature gradient and uneven molten pool distribution on the weld during welding by combining high-frequency induction heating and a mechanical stirring needle device, and at the same time, well combines high-frequency induction heating and the stirring needle with the welding gun. This device can be used in all scenarios used in traditional narrow gap welding, thereby improving the efficiency and quality of welding production, and has broad industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of an embodiment of a narrow gap welding device with a preheating function according to the present invention;

[0026] Figure 2 It is a structural schematic diagram of a high-frequency induction heating power supply and a high-frequency heating coil in the narrow gap welding device with preheating function of the present invention;

[0027] Figure 3 It is a side schematic diagram of the connection structure between the high-frequency heating coil and the welding gun of the narrow gap welding device with preheating function according to the present invention;

[0028] Figure 4 It is a front schematic diagram of the connection structure between the high-frequency heating coil and the welding gun of the narrow gap welding device with preheating function according to the present invention.

[0029] In the figure: 1-welding machine power supply, 2-wire feeding device, 3-welding wire. 4-welding gun, 5-high-frequency induction heating power supply. 6-arc, 7-high-frequency heating coil, 8-molten pool, 9-thermocouple, 10-workpiece, 11-stirring needle, 12-controller, 13-stirring needle power supply, 14-first motor, 15-first screw, 16-nut block, 17-connecting rod, 18-connecting ear, 19-articulated shaft, 20-second motor. DETAILED DESCRIPTION

[0030] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0031] like Figure 1 As shown, the narrow gap welding device with preheating function described in this embodiment includes a wire feeding device 2, a welding gun 4, a high-frequency induction heating power supply 5, a high-frequency heating coil 7, a thermocouple 9, a stirring needle 11, and a controller 12. The welding gun 4 is arranged above the U-shaped groove of the workpiece to be welded, the wire feeding device 2 is located at the upper end of the welding gun 4, the high-frequency heating coil 7 is located at the front part below the welding gun 4, is fixed to the welding gun 4 through an adjustable bracket, and is electrically connected to the high-frequency induction heating power supply 5, as shown in FIG. Figure 2 The stirring needle 11 is arranged on one side below the welding gun 4 and is synchronized with the welding gun 4 .

[0032] The plurality of thermocouples are arranged in an array on both sides of the weld to detect the temperature of the weld of the workpiece to be welded. Specifically, the thermocouple arrays on both sides of the weld are three rows, and the spacing from the weld is 3mm, 5mm, and 7mm, respectively, for monitoring the temperature at 3mm, 5mm, and 7mm from the weld, respectively.

[0033] The controller 12 is respectively connected to the thermocouple 9, the high-frequency induction heating power supply 5 and the driving mechanism of the adjustable bracket, and is used to obtain the temperature distribution of the workpieces to be welded on both sides of the weld in real time, and control the output power of the high-frequency induction heating power supply 5 and / or adjust the adjustable bracket to adjust the distance between the high-frequency heating coil 7 and the workpiece to be welded, so as to realize the regulation of the preheating temperature of the workpiece to be welded.

[0034] The welding gun 4 is placed above the U-shaped groove of the workpiece 10 to be welded, and the welding wire 3 in the wire feeding device 2 is fed into the U-shaped groove through the welding gun 4. The positive pole of the welding machine power supply 1 is connected to the welding wire 3 in the welding gun 4, and the negative pole is connected to the workpiece 10 to be welded. When working, the high-frequency induction heating coil 7 is placed inside the groove of the workpiece 10 to be welded for heating, and the end of the stirring needle 11 is extended into the molten pool 8 in the groove of the workpiece 10 to be welded for stirring.

[0035] In the present invention, by combining a high-frequency induction heating device with a welding gun, real-time high-power preheating of the base material is achieved through high-frequency induction heating, which can greatly save the preheating time cost. At the same time, the preheating and weldment processing are almost carried out simultaneously, which effectively avoids the energy consumption problem of cooling the base material after preheating, and can reduce the temperature gradient during welding, reduce post-weld stress, and improve the weld quality.

[0036] Specifically, the adjustable bracket between the high-frequency heating coil 7 and the welding gun 4 is as follows: Figure 3 As shown, the height of the high-frequency heating coil 7 and the distance between it and the welding gun 4 are adjustable. The welding gun 11 is welded with a connecting ear 18 for connecting the high-frequency heating coil 7. The high-frequency heating coil 7 is hinged on the connecting ear 18 through a connecting rod 17 and a hinge shaft 19. The connecting rod 17 is provided with a nut block 16 that can rotate relative to it, and the nut block 16 is threadedly connected to the first screw rod 15. The first motor 14 is fixed on the welding gun 11 as a driving power source and is connected to the controller. The first screw rod 15 is fixedly connected to the output shaft of the first motor 14, and the operation of the first motor 14 is controlled by the controller to drive the first screw rod 15 to rotate, thereby driving the nut block 16 to move on the first screw rod 15, realizing the rotation of the connecting rod 17 around the hinge shaft 19, so that the height of the high-frequency heating coil 7 and the distance between it and the welding gun 4 are adjustable.

[0037] like Figure 4As shown, the number of high-frequency heating coils 7 can also be set to two, and the two are arranged side by side. There are also two connecting ears 18, which are respectively fixed to the two end portions of the welding gun 11. The two ends of the articulated shaft 19 have reverse threads, and the connecting rods 17 of the two high-frequency heating coils 7 are respectively threadedly connected to the two reverse threads of the articulated shaft 19, and the two ends of the articulated shaft 19 pass through the two connecting ears 18 respectively, one end of which is fixedly connected to the second motor 20 fixed on the welding gun 4; the second motor 20 is connected to the controller, and the operation of the second motor 20 is controlled by the controller. Driven by the second motor 20, the articulated shaft 19 rotates. Since the threads at the two ends of the articulated shaft 19 are reversed, the connecting rods 17 at the two ends will move towards each other, and the two will approach or move away from each other, thereby achieving an adjustable spacing between the high-frequency heating coil 7 and the side wall of the weld.

[0038] Of course, for the embodiment with only one high-frequency heating coil 7, the structure of the second motor 20 and the lead screw can also be used to achieve position adjustment of the high-frequency induction coil in the weld groove.

[0039] Specifically, the high-frequency induction heating coil 7 is placed 2 to 4 cm in front of the welding gun 4 and about 1 to 3 cm away from both sides of the groove of the workpiece 10 to be welded. The power of the high-frequency induction heating power supply 5 can be adjusted between 15 and 85 KW, which can efficiently preheat the workpiece before welding.

[0040] Specifically, the inclination angle of the stirring needle 11 relative to the welding wire 3 is 15 to 90 degrees, the horizontal distance between the end of the stirring needle 11 and the end of the welding wire 3 is 10 mm, and the distance from the end of the welding wire 3 to the groove surface of the workpiece 10 to be welded is 5 to 8 mm. The material of the stirring needle 11 can be selected from high temperature resistant materials such as tungsten or ceramics. The rotation speed of the stirring needle 11 is 0 to 3000 rpm. The welding current of the welding machine power supply 1 is 50 to 400 A, and the gas flow rate in the welding gun 4 is 5 to 30 L / min.

[0041] The welding method of the narrow gap welding device with preheating function according to the present invention comprises the following steps:

[0042] Step 1: Fix the workpiece to be welded on the welding fixture, and connect the high-frequency induction heating power supply, high-frequency heating coil, thermocouple, temperature recorder, stirring needle and stirring needle power supply;

[0043] Step 2: Set welding processing parameters: welding current 50-400A, welding speed: 140-400mm / min, gas flow rate in welding gun 5-30L / min, stirring needle speed 0-3000rps, high-frequency induction heating power 15-85KW, stirring needle and welding wire form an angle of 15-90°, and the horizontal distance between the end of stirring needle and the end of welding wire is 10mm; start the high-frequency induction heating power supply, stirring needle power supply, thermocouple and temperature recorder, and introduce protective gas;

[0044] Step 3: The controller collects and obtains the temperature distribution of the workpieces to be welded on both sides of the weld in real time, and controls the output power of the high-frequency induction heating power supply and / or the distance between the high-frequency heating coil and the weld groove based on the output power of the high-frequency induction heating power supply, the heating efficiency of the high-frequency heating coil, and the heat transfer efficiency of the air and the workpiece, so that the temperature of the workpiece to be welded meets the set preheating temperature.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A narrow gap welding device with preheating function, characterized in that: It comprises a wire feeding device (2), a welding gun (4), a high-frequency induction heating power supply (5), a high-frequency heating coil (7), a thermocouple (9), a stirring needle (11), and a controller (12); The welding gun (4) is arranged above the U-shaped groove of the workpiece to be welded, the wire feeding device (2) is located at the upper end of the welding gun (4), the high-frequency heating coil (7) is located at the front part below the welding gun (4), is fixed to the welding gun (4) through an adjustable bracket, and is electrically connected to the high-frequency induction heating power supply (5); The stirring needle (11) is arranged on one side below the welding gun (4) and is synchronized with the welding gun (4); A plurality of the thermocouples (9) are arranged in an array on both sides of the weld to detect the temperature of the weld of the workpiece to be welded; The controller (12) is respectively connected to the thermocouple (9), the high-frequency induction heating power supply (5) and the driving mechanism of the adjustable bracket, and is used to obtain the temperature distribution of the workpieces to be welded on both sides of the weld in real time, and to control the output power of the high-frequency induction heating power supply (5) and / or adjust the adjustable bracket to adjust the distance between the high-frequency heating coil (7) and the workpiece to be welded, so as to achieve the control of the preheating temperature of the workpiece to be welded.

2. The narrow gap welding device with preheating function according to claim 1, characterized in that: The high-frequency heating coil (7) is hinged to a connecting ear (18) fixed to a welding gun (11) through a connecting rod (17) and an articulated shaft (19); a nut block (16) capable of rotating relative to the connecting rod (17) is provided on the connecting rod (17); a first screw rod (15) is fixedly connected to the output shaft of a first motor (14) fixed to the welding gun (11); the first screw rod (15) is threadedly connected to the nut block (16); the first motor (14) is connected to a controller, and the operation of the first motor (14) is controlled by the controller.

3. The narrow gap welding device with preheating function according to claim 1, characterized in that: The number of the high-frequency heating coils (7) is two, and the two are arranged side by side; the number of the connecting ears (18) is also two, and they are respectively fixed to the two end portions of the welding gun (11); the two ends of the hinge shaft (19) have reverse threads, and the connecting rods (17) of the two high-frequency heating coils (7) are respectively threadedly connected to the two reverse threads of the hinge shaft (19), and the two ends of the hinge shaft (19) respectively pass through the two connecting ears (18), one end of which is fixedly connected to the second motor (20) fixed on the welding gun (4); the second motor (20) is connected to the controller, and the operation of the second motor (20) is controlled by the controller.

4. The narrow gap welding device with preheating function according to claim 1, characterized in that: Thermocouple (9) arrays located on both sides of the weld are in three rows, with spacings of 3 mm, 5 mm and 7 mm from the weld respectively, and are used to monitor the temperature at 3 mm, 5 mm and 7 mm from the weld respectively.

5. The narrow gap welding device with preheating function according to claim 1, characterized in that: The power of the high-frequency induction heating power supply (5) can be infinitely adjusted between 15 and 85 kW.

6. The narrow gap welding device with preheating function according to claim 1, characterized in that: The distance between the high-frequency heating coil (7) and the lower end of the welding gun (4) is 3 to 5 cm, and the distance between the high-frequency heating coil (7) and the two side walls of the U-shaped groove is 1 to 3 mm.

7. The narrow gap welding device with preheating function according to claim 1, characterized in that: The stirring needle (11) is made of tungsten or ceramic, the inclination angle of the stirring needle (11) relative to the welding wire is 15-90 degrees, and the horizontal distance between the end of the stirring needle and the end of the welding wire is 10 mm.

8. A welding method based on the narrow gap welding device with preheating function according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: Fix the workpiece to be welded on the welding fixture, and connect the high-frequency induction heating power supply, high-frequency heating coil, thermocouple, temperature recorder, stirring needle and stirring needle power supply; Step 2: Set welding processing parameters, start high-frequency induction heating power supply, stirring needle power supply, thermocouple and temperature recorder, and introduce protective gas; Step 3: The controller collects and obtains the temperature distribution of the workpieces to be welded on both sides of the weld in real time, and controls the output power of the high-frequency induction heating power supply and / or the distance between the high-frequency heating coil and the weld groove based on the output power of the high-frequency induction heating power supply, the heating efficiency of the high-frequency heating coil, and the heat transfer efficiency of the air and the workpiece, so that the temperature of the workpiece to be welded meets the set preheating temperature.

9. The welding method according to claim 8, characterized in that: The distance between the end of the welding wire and the U-shaped groove surface of the workpiece to be welded is 5 to 8 mm.

10. The welding method according to claim 8, characterized in that: The welding current of the welding machine power supply is 50-400A, the gas flow in the welding gun is 5-30L / min; the welding speed is 140-400mm / min, the rotation speed of the stirring needle is 0-3000rps, and the high-frequency induction heating power is 15-85KW.

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