Low-heat-input arc welding device and control method

Abstract

The invention relates to the technical field of welding processes, in particular to a low-heat-input arc welding control method, which comprises the following steps of: acquiring welding parameters of an arc welding gun in a welding process, analyzing and processing, and carrying out auxiliary adjustment on droplet transition frequency according to obtained welding state data so as to assist smooth transition of droplets. Therefore, the welding current or voltage is reduced, on the premise that the original or better welding effect is kept, the welding heat input amount of the workpiece is reduced, welding deformation of the workpiece is reduced, or the problem that the performance is reduced due to the fact that the structure of the workpiece is changed due to too high heat input is solved, stable welding of low-heat-input arc welding is achieved, and the welding quality is improved. And the welding quality of welded workpieces is ensured. Meanwhile, a plurality of modes for assisting molten drop transition are provided, namely, the molten drops are cut off through pulse laser; or the molten drops are cut off through mechanical vibration; or the molten drops are cut off through mechanical vibration and a heat source; and smooth transition of molten drops is realized. The invention further provides a welding device adopting the low-heat-input arc welding control method.

Description

Technical Field

[0001] The present invention relates to the technical field of welding processes, and particularly to a low heat input arc welding control method and a welding device. Background Art

[0002] Gas metal arc welding refers to a welding method that uses the arc generated between the welding wire and the workpiece as the heat source to melt the metal. During the welding process, the arc melts the welding wire to form molten droplets that enter the molten pool formed by the base metal for welding. The welding area is protected by inert gas or active gas, which can effectively prevent the harmful effects of the surrounding ambient air. The droplet transfer in gas metal arc welding is mainly divided into three forms: short-circuit transfer, globular transfer, and spray transfer. Among them, (1) The voltage of short-circuit transfer is low, the arc is short, and the molten droplet contacts the molten pool to form a short-circuit liquid bridge before growing into a molten droplet. Under the action of the surface tension and electromagnetic constriction force in the direction of the molten pool, the molten droplet metal transfers into the molten pool; when the molten droplet enters the molten pool to form a short circuit, the current is large, resulting in a large heat input to the welded workpiece. (2) Globular transfer usually adopts fine droplet transfer, i.e., fine particle transfer. Fine droplet transfer requires a large current, corresponding large electromagnetic constriction force, reduced surface tension of the molten droplet, and refined molten droplets. These all promote the droplet transfer and increase the droplet transfer frequency, but it requires a large heat input. (3) Spray transfer is the most representative and widely used form of spray transfer. The frequency of this transfer can reach up to 500 molten droplets per second; the conditions for obtaining spray transfer are to use pure argon or argon-rich gas protection, high voltage, and the welding current must be greater than the critical value, so it also requires a large heat input.

[0003] Therefore, the above three common forms of droplet transfer all require large current or high voltage to promote the molten droplet to enter the molten pool, resulting in excessive heat input to the weld seam. At the same time, there are also welding quality problems such as large deformation of the welded workpiece, transformation of the raw material structure, and reduction of material properties. Based on the above problems, it is of great significance to study a low heat input arc welding control method to achieve smooth droplet transfer. Summary of the Invention

[0004] The purpose of the present invention is to provide a low heat input arc welding control method and a welding device, which solve the problem of how to reduce the heat input to the weld seam while ensuring the same welding effect of arc welding, thereby reducing the welding deformation of the workpiece or preventing the workpiece structure from changing due to excessive heat input, and further reducing the performance.

[0005] To solve the above technical problems, the technical solution provided by the present invention is: providing a low heat input arc welding control method, including the following steps: Step 1: Start the arc welding assembly, and the arc welding torch starts the arcing operation; Step 2: Collect the arc of the arc welding torch and the welding parameters of the molten pool during the welding process; Step 3: Perform data processing based on the obtained welding parameters of the arc and the molten pool to obtain welding state data; Step 4: According to the welding state data, assist in adjusting the droplet transfer frequency to achieve stable welding under low heat input.

[0006] Based on the above technical solution, the judgment method for assisting in adjusting the droplet transfer frequency in Step 4 includes: According to the welding state data, judge whether the data conforms to the historical data. If it conforms, correspondingly adjust the corresponding droplet transfer frequency.

[0007] Based on the above technical solution, the method for assisting in adjusting the droplet transfer frequency includes: Use pulsed laser to cut off the droplets; or use mechanical vibration to cut off the droplets; or use mechanical vibration and heat source to cut off the droplets; to achieve smooth transfer of the droplets.

[0008] Based on the above technical solution, the pulsed laser power is 100 - 500W, the pulsed laser pulse width is in nanoseconds, and the pulsed laser frequency is 30 - 300Hz; the mechanical vibration frequency is 20 - 300Hz.

[0009] This application also provides a welding device, which adopts the above low heat input arc welding control method, including an arc welding torch, an image acquisition module, a data processing module, a droplet control module, and a droplet adjustment module. The arc welding torch is arranged above the welding workpiece for starting the arc welding. The image acquisition module is used to collect the welding parameters of the arc and the molten pool. The data processing module is used to perform data processing on the welding parameters. The droplet control module is used to judge and control the start and stop of the droplet adjustment module. The droplet adjustment module is used to cut off the droplets and adjust the droplet transfer frequency.

[0010] Based on the above technical solution, the droplet adjustment module includes a laser gun head. The arc welding torch is located on one side of the laser gun head, and the laser gun head is correspondingly arranged above the welding wire of the arc welding torch.

[0011] Based on the above technical solution, the output of the laser gun head is pulsed laser.

[0012] Based on the above technical solution, the droplet adjustment module includes a vibration generator and a horn. The vibration generator is arranged at the top of the arc welding torch through a fixture, and the horn is arranged between the vibration generator and the fixture.

[0013] Based on the above technical solution, the droplet adjustment module includes a vibration generator, a horn, and a TIG welding torch. The vibration generator is arranged at the top of the TIG welding torch through a fixture. The horn is arranged between the vibration generator and the fixture. The arc welding torch is arranged on one side of the TIG welding torch, and the TIG welding torch is correspondingly arranged above the welding wire of the arc welding torch.

[0014] Based on the above technical solution, the droplet adjustment module further includes a height adjustment component arranged on the fixture for adjusting the height of the welding torch.

[0015] The beneficial effects produced by the technical solution provided by the present invention are as follows: The present invention provides a low heat input arc welding control method, which collects the welding parameters of the arc welding torch during the welding process, analyzes and processes them, and assists in adjusting the droplet transfer frequency according to the obtained welding state data to assist the smooth transfer of droplets, thereby reducing the welding current or voltage. On the premise of maintaining the original or better welding effect, the heat input of the workpiece during welding is reduced, so as to reduce the welding deformation of the workpiece or prevent the problem that the workpiece structure changes due to excessive heat input and then the performance decreases, realizing stable welding of low heat input arc welding and ensuring the welding quality of the welded workpiece.

[0016] At the same time, a variety of different ways to assist droplet transfer are also proposed, that is, using pulsed laser to cut off the droplet; or using mechanical vibration to cut off the droplet; or using mechanical vibration and heat source to cut off the droplet; to achieve the smooth transfer of droplets, reduce the heat input of the welded workpiece, reduce the risk of welding workpiece deformation, and ensure the welding quality of the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of the principle structure of the welding device of the present invention; Figure 2 is a schematic diagram of the structure of the welding device in Embodiment 1 of the present invention; Figure 3 is a schematic diagram of the structure of the welding device in Embodiment 2 of the present invention; Figure 4 is a schematic diagram of the structure of the welding device in Embodiment 3 of the present invention; DETAILED DESCRIPTION OF THE INVENTION The present invention will be further described below with reference to the drawings and embodiments: In the present invention, unless otherwise clearly specified and defined, terms such as "installation", "connection", "linkage", "fixation" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral one; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0018] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "left", "right", "front", "rear", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0019] Embodiment 1 As Figures 1 to 4 shown, a low heat input arc welding control method includes the following steps: Step 1: Start the arc welding assembly, and the arc welding torch starts arc striking. Step 2: Collect the arc of the arc welding torch and the welding parameters of the molten pool during the welding process. Step 3: Perform data processing based on the obtained welding parameters of the arc and the molten pool to obtain welding state data. Step 4: According to the welding state data, assist in adjusting the droplet transfer frequency to achieve stable welding under low heat input.

[0020] The present invention provides a low heat input arc welding control method, which collects the welding parameters of the arc welding torch during the welding process, analyzes and processes them, and assists in adjusting the droplet transfer frequency according to the obtained welding state data to assist the smooth transfer of droplets, thereby reducing the welding current or voltage. On the premise of maintaining the original or better welding effect, the heat input of the workpiece during welding is reduced, so as to reduce the welding deformation of the workpiece or prevent the problem that the high heat input causes changes in the workpiece structure and then leads to performance degradation, and realize the stable welding of low heat input arc welding, ensuring the welding quality of the welded workpiece. The welding parameters include droplet transfer frequency parameters under the arc and welding states such as the size of the molten pool, the shape and size of the droplets, the presence or absence of spatter, and metal vapor parameters, which are collected by a high-speed camera for spatter, welding stability, etc. through high-frequency photography of the high-speed camera.

[0021] Preferably, a pulsed laser, mechanical vibration, or a combination of mechanical vibration and heat source is used to promote droplet transfer, assist in adjusting the droplet transfer frequency, and at the same time reduce the heat input. In the traditional welding method, assuming a 5-mm thick steel plate is welded, the welding current required is 350 A, and the droplet transfer frequency is about 200 Hz, that is, 200 droplets drip per second. The heat input calculation formula is E = UI / V, where U is the voltage, I is the welding current, and V is the welding speed; U, I, and the wire feeding speed are adjusted manually, and the welding speed is determined manually or by a machine. By adopting the technical solution of the present application, that is, on the basis of the original welding method, the droplet transfer frequency is assisted in adjustment. Since the pulsed laser, mechanical vibration, and TIG welding all act directly on the welding wire to promote droplet transfer, that is, by adjusting the parameters of the device such as the pulsed laser power, frequency, or the vibration frequency of the mechanical structure, etc., the droplet transfer frequency is still maintained at 200 Hz. At this time, the welding effect is the same as that at 350 A, and the original heat input E is reduced.

[0022] Based on the above technical solution, the method for judging the auxiliary adjustment of the droplet transfer frequency in step four includes: according to the welding state data, judging whether the data conforms to the historical data, and if it conforms, adjusting the corresponding droplet transfer frequency accordingly.

[0023] By storing historical data, that is, the corresponding relationship data between the welding state and the droplet transfer frequency, in the droplet control module, when receiving real-time welding state data, the required droplet transfer frequency can be adjusted correspondingly to achieve stable welding. At the same time, the input of voltage or current can be reduced to achieve smooth droplet transfer, and the welding heat input is smaller.

[0024] Based on the above technical solution, the method for auxiliary adjustment of the droplet transfer frequency includes: Using a pulsed laser to cut off the droplet; or using mechanical vibration to cut off the droplet; or using mechanical vibration and a heat source to cut off the droplet; to achieve smooth droplet transfer.

[0025] Based on the above technical solution, the pulsed laser power is 100 - 500 W, the pulsed laser pulse width is in nanoseconds, and the pulsed laser frequency is 30 - 300 Hz; the mechanical vibration frequency is 20 - 300 Hz.

[0026] In one preferred embodiment, the method of using a pulsed laser to cut off the droplet is adopted to adjust the droplet transfer frequency. More preferably, the parameters of the pulsed laser are set as above to achieve the matching of the pulsed laser and the arc, and then the welding of the workpiece is completed. In particular, the pulsed laser frequency directly affects the welding quality and efficiency; a high-frequency pulse means more energy outputs in the same time, which helps to improve the welding speed and maintain the continuity and consistency of the weld. For thin-walled materials or precision parts, using a higher frequency can reduce the heat-affected zone and avoid deformation or damage caused by overheating.

[0027] In another preferred embodiment, a mechanical vibration method is adopted to cut off the connection between the molten droplet and the welding wire, promoting the molten droplet transition and realizing the adjustment of the molten droplet transition frequency.

[0028] In still another preferred embodiment, a method of jointly cooperating mechanical vibration and a heat source is adopted to cut off the molten droplet, promoting the molten droplet transition and realizing the adjustment of the molten droplet transition frequency; wherein the heat source can adopt a TIG welding or pulsed TIG welding device.

[0029] A welding device adopts the above-mentioned low heat input arc welding control method, and includes an arc welding torch 10, an image acquisition module 20, a data processing module 30, a molten droplet control module 40 and a molten droplet adjustment module 50. The arc welding torch 10 is arranged above the welding workpiece for starting arc welding. The image acquisition module 20 is used for acquiring the welding parameters of the arc and the molten pool. The data processing module 30 is used for processing the welding parameters. The molten droplet control module 40 is used for judging and controlling the start and stop of the molten droplet adjustment module 50. The molten droplet adjustment module 50 is used for cutting off the molten droplet and adjusting the molten droplet transition frequency.

[0030] Preferably, the image acquisition module adopts a high-speed camera.

[0031] Combined with the above-mentioned low heat input arc welding control method, specifically, a high-speed camera is used to monitor and acquire images of the arc and the molten pool of the arc welding torch, and the data is transmitted to the data processing module; the data processing module processes the acquired images and transmits the image processing result to the molten droplet control module; the molten droplet control module receives the above-mentioned image processing result, and the molten droplet transition frequency is adjusted in real time through the molten droplet adjustment module, and the welding state is observed in real time to realize the stable welding of the welding workpiece. The heat of the auxiliary device adopted by the molten droplet adjustment module is relatively small, and at the same time, the heat directly acts on the welding wire and the molten droplet, and does not directly act on the welding workpiece, effectively reducing the heat input of the welding workpiece, and at the same time ensuring the original or better welding quality of the workpiece.

[0032] Based on the above technical solution, the molten droplet adjustment module includes a laser gun head 501. The arc welding torch 10 is located on one side of the laser gun head 501, and the laser gun head 501 is correspondingly arranged above the welding wire of the arc welding torch 10.

[0033] Based on the above technical solution, the output of the laser gun head 501 is pulsed laser.

[0034] Different from the traditional composite welding method that combines laser welding and arc welding, the traditional laser-arc hybrid welding method is to make the energy of two heat sources, namely laser and arc, act on the workpiece together through a certain way to generate the same welding molten pool, and realize high-quality and efficient welding of materials through the interaction between the two. Compared with laser-arc hybrid welding, laser-induced arc welding adds a low-power laser and uses the suppression effect of the laser on the arc to achieve the transformation of the arc from "free and loose arc" to "high-energy density arc". In other combinations of multiple heat sources, multiple heat sources act on the same molten pool together, and high-efficiency welding is achieved through the heat input and interaction of multiple heat sources.

[0035] The essential difference between this device and laser-arc hybrid welding, laser-induced arc welding, or other forms of combined welding with multiple heat sources is that laser-arc hybrid welding, laser-induced arc welding, or other forms of combined welding with multiple heat sources introduce a new heat source, and this new heat source acts on the workpiece together with the arc welding power source, thus generating a stronger effect to achieve high-efficiency welding. However, the device of the present invention acts on the welding wire and the molten droplet. The heat of the additional molten droplet auxiliary module itself is relatively low, and this heat does not directly act on the welded workpiece. By promoting the molten droplet transfer, the technical effect of low heat input is achieved, and at the same time, the same or better welding effect is ensured.

[0036] In a preferred embodiment, the molten droplet transfer frequency is adjusted by using pulsed laser to cut off the molten droplet. The arc welding torch 10 is arranged on one side of the laser gun head 501, and the laser gun head 501 is correspondingly arranged above the welding wire. That is, during the arc welding process, the pulsed laser acts on the welding wire and the molten droplet to cut off the molten droplet to promote the smooth entry of the molten droplet into the molten pool, and the pulsed laser parameters of the laser gun head are controlled according to the welding state data.

[0037] More preferably, the parameters of the pulsed laser are set as above to achieve the matching of the pulsed laser and the arc, and then the welding of the workpiece is completed. In particular, the pulsed laser frequency directly affects the welding quality and efficiency. High-frequency pulses mean more energy outputs in the same time, which helps to improve the welding speed and maintain the continuity and consistency of the weld seam. For thin-walled materials or precision parts, using a higher frequency can reduce the heat-affected zone and avoid deformation or damage caused by excessive heating.

[0038] Embodiment 2 Based on the above technical solution, the molten droplet adjustment module includes a vibration generator 502 and a horn 503. The vibration generator 502 is arranged at the top of the arc welding torch 10 through a fixture 504, and the horn 503 is arranged between the vibration generator 502 and the fixture 504.

[0039] In another preferred embodiment, the method of cutting molten droplets by mechanical vibration is adopted to adjust the molten droplet transfer frequency. Specifically, the arc welding torch 10 is arranged directly above the welding workpiece. The arc welding torch 10 is fixedly arranged on the micro motor 506 through the fixture 504. Vibration is generated by the vibration generator 502 and then transmitted to the arc welding torch 10 and the welding wire, promoting the transfer of molten droplets through mechanical vibration. Meanwhile, by arranging a horn 503, the vibration is transmitted to the fixture 504 through the transducer 507, and the vibration amplitude can be amplified or reduced, and adjusted in real time according to the welding state, promoting better transfer of molten droplets and better cooperation with the arc welding assembly. Further, the vibration of the molten droplets can produce a stirring effect on the molten pool, promoting the escape of gas in the molten pool and reducing the porosity of the weld seam.

[0040] Embodiment 3 On the basis of the above technical solution, the molten droplet adjustment module includes a vibration generator 502, a horn 503 and a TIG torch 505. The vibration generator 502 is arranged at the top of the TIG torch 505 through the fixture 504. The horn 503 is arranged between the vibration generator 502 and the fixture 504. The arc welding torch 10 is arranged on one side of the TIG torch 505, and the TIG torch 505 is correspondingly arranged above the welding wire of the arc welding torch 10.

[0041] In yet another preferred embodiment, the method of jointly cooperating mechanical vibration and heat source is adopted to cut molten droplets to adjust the molten droplet transfer frequency; wherein the heat source adopts a TIG welding or pulsed TIG welding device.

[0042] Different from Embodiment 2, in this application, on the basis of adopting the vibration generator 502 and the horn 503, a TIG torch 505 is further arranged; the TIG torch 505 is arranged directly above the welding workpiece, and the heat generated by the tungsten electrode and the mechanical vibration cooperate to promote the transfer of molten droplets. Meanwhile, the addition of the heat of the tungsten needle can increase the welding speed, and the added heat acts completely on the welding wire and the molten droplets, without causing an increase in the heat input of the workpiece.

[0043] Further, the TIG auxiliary device can be optimized into a pulsed TIG auxiliary device, that is, a controllable pulsed current is used to heat the tungsten needle. When each pulsed current passes, a dot-like heat source is generated on the tungsten needle to promote the transfer of molten droplets. When the pulsed current stops, the heat source on the tungsten needle cools. By reasonably adjusting the pulse interval time, a good weld seam can be obtained.

[0044] Based on the above technical solution, the droplet adjustment module further includes a height adjustment component disposed on the fixture 504 for adjusting the height of the welding torch. The adjustment of the height of the arc welding wire is achieved, and by adjusting the distance between the wire and the workpiece, the adjustment of the arc voltage, droplet transfer frequency, etc. is realized, and further the adjustment of the welding effect is realized. Preferably, the height adjustment component adopts a cylinder

[32] .

[0045] In a more preferred embodiment, a micro motor 506 is disposed on the fixture 504. By providing the micro motor 506, vibration can be assisted to help the droplets transfer smoothly.

[0046] The above has shown and described the basic principles and main features of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments. Therefore, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention.

[0047] In addition, it should be understood that although this specification is described according to the embodiments, not every embodiment only includes an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A low heat input arc welding control method, characterized in that It includes the following steps: Step 1: Start the arc welding assembly, and the arc welding torch starts arc ignition. Step 2: Collect the welding parameters of the arc of the arc welding torch and the molten pool during the welding process. Step 3: Perform data processing based on the obtained welding parameters of the arc and the molten pool to obtain welding state data. Step 4: According to the welding state data, assist in adjusting the droplet transfer frequency to achieve stable welding under low heat input.

2. The low heat input arc welding control method according to claim 1, wherein The judgment method for assisting in adjusting the droplet transfer frequency in Step 4 includes: judging whether the data conforms to the historical data according to the welding state data, and if it conforms, correspondingly adjusting the corresponding droplet transfer frequency.

3. A low heat input arc welding control method according to claim 1, characterized in that, The method for assisting in adjusting the droplet transfer frequency includes: Using pulsed laser to cut off droplets; or using mechanical vibration to cut off droplets; or using mechanical vibration and heat source to cut off droplets; to achieve smooth transfer of droplets.

4. A low heat input arc welding control method according to claim 3, characterized in that, The power of the pulsed laser is 100 - 500W, the pulse width of the pulsed laser is in nanoseconds, and the pulsed laser frequency is 30 - 300Hz; the mechanical vibration frequency is 20 - 300Hz.

5. A welding device, which adopts the low heat input arc welding control method according to any one of claims 1 to 4, is characterized in that, It includes an arc welding torch (10), an image acquisition module (20), a data processing module (30), a droplet control module (40), and a droplet adjustment module (50). The arc welding torch (10) is arranged above the welding workpiece and is used for arc ignition welding. The image acquisition module (20) is used to collect the welding parameters of the arc and the molten pool. The data processing module (30) is used to perform data processing on the welding parameters. The droplet control module (40) is used to judge and control the start and stop of the droplet adjustment module (50). The droplet adjustment module (50) is used to cut off droplets and adjust the droplet transfer frequency.

6. A welding device according to claim 5, wherein, The droplet adjustment module includes a laser gun head (501). The arc welding torch (10) is located on one side of the laser gun head (501), and the laser gun head (501) is correspondingly arranged above the welding wire of the arc welding torch (10).

7. A welding device according to claim 6, characterized in that, The output of the laser gun head (20) is pulsed laser.

8. A welding device according to claim 5, characterized in that, The droplet adjustment module includes a vibration generator (502) and a horn (503). The vibration generator (502) is arranged at the top of the arc welding torch (10) through a fixture (504), and the horn (503) is arranged between the vibration generator (502) and the fixture (504).

9. A welding device according to claim 5, characterized in that, The droplet adjustment module includes a vibration generator (502), a horn (503), and a TIG welding torch (505). The vibration generator (502) is arranged at the top of the TIG welding torch (505) through a fixture (504), and the horn (503) is arranged between the vibration generator (502) and the fixture (504). The arc welding torch (10) is arranged on one side of the TIG welding torch (505), and the TIG welding torch (505) is correspondingly arranged above the welding wire of the arc welding torch (10).

10. A welding device according to claim 8 or 9, characterized in that, The droplet adjustment module further includes a height adjustment assembly arranged on the fixture (504) for adjusting the height of the welding torch.

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