Method and apparatus for welding thick and thin plate using 1.6 mm diameter aluminum alloy welding wire

Abstract

The application provides a welding method and device for a 1.6mm diameter aluminum alloy welding wire for thick and thin plates, relates to the technical field of aluminum alloy welding, and the welding method for the 1.6mm diameter aluminum alloy welding wire for thick and thin plates is used for welding a first aluminum alloy plate and a second aluminum alloy plate, wherein the plate thickness of the first aluminum alloy plate is greater than that of the second aluminum alloy plate, the welding method comprises a plurality of continuous welding cycles, each welding cycle comprises a high-frequency pulse welding cycle for welding the first aluminum alloy plate and a low-frequency pulse welding cycle for welding the second aluminum alloy plate; the high-frequency pulse welding cycle comprises a high-frequency pulse welding period and an arc thrust control period formed after the high-frequency pulse welding period, and the low-frequency pulse welding cycle comprises a low-frequency pulse welding period and an arc length control period formed after the low-frequency pulse welding period.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum alloy welding, in particular to a welding method and device for 1.6mm diameter aluminum alloy welding wire for thick-thin plate. BACKGROUND

[0002] Metal Inert Gas (MIG) welding technology for aluminum alloy is widely used in the fields of aerospace, rail vehicles and new energy vehicle manufacturing. It realizes the fusion of welding wire and workpiece under the protection of argon by using direct current arc as heat source, and automatically removes the surface oxide film to ensure the welding quality and avoid damage to the workpiece. Because the aluminum alloy material is relatively soft, the welding wire is prone to scratching and difficult to feed, so the industry generally uses 1.2mm diameter welding wire for welding. In contrast, 1.6mm diameter aluminum alloy welding wire exhibits the advantages of small heat input, fast welding speed and large penetration during welding, especially suitable for the manufacturing of battery box and other new energy vehicle components. However, in the thick-thin plate combination welding scene, for the aluminum alloy profile joints with significant thickness difference, the traditional process faces serious challenges. The thick plate area has insufficient penetration due to insufficient current, which leads to poor structural strength, while the thin plate area is prone to back penetration, welding breakage or undercut due to excessive current. SUMMARY

[0003] The present application aims to solve the problems of insufficient penetration in thick plate area and easy back penetration, welding breakage or undercut in thin plate area.

[0004] To solve the above problems, the present application provides a welding method and device for 1.6mm diameter aluminum alloy welding wire for thick-thin plate.

[0005] In a first aspect, the present application provides a welding method for 1.6mm diameter aluminum alloy welding wire for thick-thin plate, which is used for welding a first aluminum alloy plate and a second aluminum alloy plate, wherein the thickness of the first aluminum alloy plate is greater than that of the second aluminum alloy plate; the welding method includes a plurality of continuous welding cycles, each welding cycle includes a high-frequency pulse welding cycle for welding the first aluminum alloy plate and a low-frequency pulse welding cycle for welding the second aluminum alloy plate.

[0006] The high-frequency pulse welding cycle includes the high-frequency pulse welding period and the arc thrust control period that follows the high-frequency pulse welding period. During the arc thrust control period, the welding wire is fed forward at a first constant speed. The welding wire forms a molten droplet under the welding current. After the molten droplet forms a neck, the welding current drops to the droplet separation current. The welding wire continues to feed forward until the molten droplet contacts the first aluminum alloy plate, forming a short circuit. Then, the welding wire is fed forward at a second constant speed, and the molten droplet and the first aluminum alloy plate remain in a short circuit state. Afterward, the welding current is increased to accelerate the entry of the molten droplet into the molten pool. The welding wire is retracted to separate from the molten droplet. The arc thrust is controlled by controlling the welding current and time during the wire retraction. The second constant speed is less than the first constant speed.

[0007] The low-frequency pulse welding cycle includes the low-frequency pulse welding period and the arc length control period formed after the low-frequency pulse welding period. During the arc length control period, the welding wire is fed forward at a third constant speed. The welding wire forms a molten droplet under the welding current. After the molten droplet forms a neck, the welding current drops to 0. The welding wire continues to be fed forward until the molten droplet contacts the first aluminum alloy plate, forming a short circuit. Then, the welding wire is fed forward at a fourth constant speed, and the molten droplet and the first aluminum alloy plate remain in a short circuit state while cooling. Afterward, the welding current is increased to the molten droplet separation current to re-ignite the arc. The welding wire is retracted to separate from the molten droplet. The pulse arc length is controlled by controlling the welding wire retraction time. The fourth constant speed is less than the third constant speed.

[0008] Optionally, the droplet separation current is 40% to 60% of the peak current.

[0009] Optionally, the pulse frequency of the high-frequency pulse welding cycle is 50 to 300 Hz, and the pulse frequency of the low-frequency pulse welding cycle is 0.5 to 10 Hz.

[0010] Optionally, in the step of controlling the arc thrust by controlling the welding current and time during wire retraction, the welding current during wire retraction is set to 20% to 50% of the peak current.

[0011] Optionally, in the subsequent step of increasing the welding current to the droplet separation current to re-ignite the arc, the welding current is 30% to 50% of the peak current.

[0012] Optionally, the ratio of the number of pulses during high-frequency pulse welding to the number of pulses during arc thrust control is 1:2 to 4:1.

[0013] Optionally, the cooling process includes setting a cooling time, with a voltage drop signal set as the start of the cooling time.

[0014] In a second aspect, the present invention provides a welding device for 1.6mm diameter aluminum alloy welding wire for thick and thin plates, for operating the welding method of 1.6mm diameter aluminum alloy welding wire for thick and thin plates as described above. The welding device includes a welding control circuit and a servo motor-controlled wire drawing welding gun respectively connected to the electrode.

[0015] The welding control circuit is used to provide welding current to the electrodes in each welding cycle;

[0016] The servo motor controls the wire drawing welding torch to control the feed speed and feed direction of the welding wire;

[0017] Electrodes are used to apply current to the welding area via welding wire;

[0018] The servo motor controls the wire-drawing welding torch, which is connected to the welding torch control circuit. The welding torch control circuit controls the welding torch to swing sinusoidally along the welding direction. When the welding torch swings to the first aluminum alloy plate area, the welding control circuit switches to a high-frequency pulse welding cycle; when the welding torch swings to the second aluminum alloy plate area, the welding control circuit switches to a low-frequency pulse welding cycle.

[0019] Optionally, the welding torch control circuit includes:

[0020] The welding torch oscillation position signal module is used to detect and provide the position information of the welding torch;

[0021] The welding torch oscillation output module is used to control the sinusoidal oscillation of the welding torch.

[0022] Optionally, the welding control circuit includes:

[0023] The pulse welding current output module is used to output a welding current with a preset peak current, base current, pulse duty cycle and pulse frequency to the electrode during pulse welding, so as to achieve stable welding with one pulse at a time.

[0024] The arc thrust and arc length control module is used to control the welding current and time during wire retraction in the high-frequency pulse welding cycle to control the arc thrust; and to control the wire retraction time in the low-frequency pulse welding cycle to control the pulse arc length.

[0025] The beneficial effects of the welding method and apparatus for 1.6mm diameter aluminum alloy welding wire in the present invention are as follows: By setting the arc thrust control period during the high-frequency pulse welding cycle, a strategy of different wire feeding speeds (first constant speed and second constant speed) combined with current maintenance is adopted for the thick plate area to stabilize the arc and enhance the penetration depth, while improving the arc stiffness and reducing arc drift and product undercut. Simultaneously, during the low-frequency pulse welding cycle, a method combining current reduction to zero and cooling control is adopted for the thin plate area to reduce heat input and prevent back penetration. This method, by distinguishing the welding cycle characteristics of different plate thickness areas and combining independent control of wire feeding speed, current changes, and retraction parameters, achieves dynamic matching of heat input, thereby effectively solving the technical problems of thin plate weld breakage, back penetration, and insufficient penetration depth in thick plate welding. Specifically, during the high-frequency pulse cycle, setting the wire retraction time during the wire retraction to separate from the molten droplet can control the molten droplet separation speed, achieving rapid droplet transition during the welding process and reducing the problems of wire sticking and welding failure caused by excessively rapid cooling of the 1.6mm diameter welding wire pool. During droplet separation, increasing the welding current melts the welding wire, allowing the droplet to detach from it. Setting the welding current and time controls the droplet thrust, accelerating droplet transfer, increasing welding speed, and enhancing arc stability. Arc length control is applied during low-frequency pulse cycles. The lack of current cooling ensures low-energy welding on thin plates. Furthermore, the re-ignition of the arc ensures it remains aligned with the wire direction, preventing arc deviation. The arc-free and non-undercut characteristics during low-frequency pulses are suitable for thin-plate welding. Multiple arc length control pulses within a single low-frequency pulse cycle significantly reduce the risk of wire sticking due to feed resistance, improve molten pool consistency, and allow for high-speed arc length adjustment to automatically compensate for arc instability caused by wire extension changes. This also reduces low-frequency pulse heat input, significantly decreasing penetration and weld deviation. After the droplet contacts the molten pool, the voltage reduction signal primarily determines that the wire and droplet have made contact, providing an initial position reset for the arc length in the next pulse cycle and creating conditions for adaptive arc length control. If the wire feeding system has high resistance, the welding arc length can be directly reduced during this cycle to return it to the initial setting of pulse welding. Attached Figure Description

[0026] Figure 1 This is a waveform diagram of the wire feed rate, welding current, and welding voltage during a high-frequency pulse welding cycle for welding a first aluminum alloy plate, according to an embodiment of the present invention.

[0027] Figure 2 This is a waveform diagram of the wire feed rate, welding current, and welding voltage during a low-frequency pulse welding cycle for welding a second aluminum alloy plate, according to an embodiment of the present invention.

[0028] Figure 3This is a schematic diagram of the welding device for using 1.6mm diameter aluminum alloy welding wire for thick and thin plates according to an embodiment of the present invention;

[0029] Figure 4 This is a waveform diagram showing the welding torch forward direction corresponding to the high-energy cycle and low-energy cycle in an embodiment of the present invention. Detailed Implementation

[0030] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0031] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this invention's description is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0032] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0033] In related technologies, the uneven heat input distribution is significantly exposed when using 1.6mm diameter welding wire to weld thick and thin plates in traditional aluminum alloy welding techniques. Thick plates require high current to achieve sufficient penetration, while thin plates require low current to avoid heat accumulation. However, the existing dual-pulse welding process has a simplistic arc control mechanism, leading to frequent arc drift during welding. Furthermore, the stability of the molten pool is affected by the wire feed resistance and the gap between the weld and the base material. When the gap exceeds a critical value, the arc cannot be maintained stably, causing molten pool deviation. Consequently, thin plates experience back penetration or weld fracture defects due to excessive heat input, while thick plates suffer from insufficient penetration due to insufficient heat input, ultimately resulting in reduced weld joint strength and deterioration of product consistency.

[0034] To address the problems existing in the aforementioned related technologies, embodiments of the present invention provide a welding method and apparatus for using 1.6mm diameter aluminum alloy welding wire for both thick and thin plates.

[0035] An embodiment of the present invention provides a welding method for using 1.6mm diameter aluminum alloy welding wire for welding thick and thin plates, for welding a first aluminum alloy plate and a second aluminum alloy plate, wherein the thickness of the first aluminum alloy plate is greater than that of the second aluminum alloy plate; the welding method includes multiple consecutive welding cycles, each welding cycle including a high-frequency pulse welding cycle for welding the first aluminum alloy plate and a low-frequency pulse welding cycle for welding the second aluminum alloy plate.

[0036] The high-frequency pulse welding cycle includes the high-frequency pulse welding period and the arc thrust control period that follows the high-frequency pulse welding period. During the arc thrust control period, the welding wire is fed forward at a first constant speed. The welding wire forms a molten droplet under the welding current. After the molten droplet forms a neck, the welding current drops to the droplet separation current. The welding wire continues to feed forward until the molten droplet contacts the first aluminum alloy plate, forming a short circuit. Then, the welding wire is fed forward at a second constant speed, and the molten droplet and the first aluminum alloy plate remain in a short circuit state. Afterward, the welding current is increased to accelerate the entry of the molten droplet into the molten pool. The welding wire is retracted to separate from the molten droplet. The arc thrust is controlled by controlling the welding current and time during the wire retraction. The second constant speed is less than the first constant speed.

[0037] The low-frequency pulse welding cycle includes the low-frequency pulse welding period and the arc length control period formed after the low-frequency pulse welding period. During the arc length control period, the welding wire is fed forward at a third constant speed. The welding wire forms a molten droplet under the welding current. After the molten droplet forms a neck, the welding current drops to 0. The welding wire continues to be fed forward until the molten droplet contacts the first aluminum alloy plate, forming a short circuit. Then, the welding wire is fed forward at a fourth constant speed. The molten droplet and the first aluminum alloy plate remain in a short circuit state and cool simultaneously. Afterward, the welding current is increased to the molten droplet separation current to re-ignite the arc. The welding wire is retracted to separate from the molten droplet. The pulse arc length is controlled by controlling the welding wire retraction time. The fourth constant speed is less than the third constant speed.

[0038] Specifically, such as Figure 1 As shown, the high-frequency pulse welding cycle (Pc) includes the high-frequency pulse welding period (Tp) and the arc thrust control period (Ts). The welding cycle T starts at the beginning time Pst of the high-frequency pulse welding period Tp. During the high-frequency pulse welding cycle Tp, the welding current is pulsed with preset pulse parameters such as peak current Ipp, base current Ipb, pulse duty cycle and pulse frequency to form a high-energy welding input.

[0039] During the arc thrust control period (Ts), the following are included:

[0040] During the forward feed period (Tb) of the high-frequency welding wire, the welding wire is fed forward at a first constant speed. Under the welding current, the welding wire forms a molten droplet, which then forms a necking. The first constant speed is greater than 0. The first constant speed refers to the uniform feeding speed of the high-frequency welding wire during the forward feed period. It can be achieved by servo motor control. Its function is to form a stable molten droplet and promote necking under pulsed current. The first constant speed being greater than 0 means that the forward feed direction of the welding wire is defined as the positive direction.

[0041] During the first arc thrust control period (Ts1), the welding current drops to the droplet separation current (Isr), and the welding wire continues to feed forward until the droplet contacts the first aluminum alloy plate, forming a short circuit. At this time, the welding current cannot melt the welding wire.

[0042] During the second arc thrust control period (Ts2), the welding wire is fed forward at a second constant speed, and the molten droplet and the first aluminum alloy plate are kept in a short-circuit state. The welding current is increased to accelerate the entry of the molten droplet into the molten pool. Here, 0 < second constant speed < first constant speed. The second constant speed refers to the wire feeding speed during the second arc thrust control period, which is less than the first constant speed. This can be achieved by reducing the motor speed to maintain the short-circuit contact time and ensure sufficient droplet transition.

[0043] The high-frequency welding wire retraction period (Ts3) involves retracting the welding wire to separate it from the molten droplet. During separation, the welding current is set to be maintained at the droplet separation current. The arc thrust is controlled by setting the welding current and time during the wire retraction.

[0044] In some specific embodiments, during the arc thrust control period (Ts), the welding wire is fed forward at a constant rate. To achieve rapid contact between the welding wire and the base material during the arc thrust control period (Ts), the forward feed rate of the welding wire needs to be rapidly increased to the set forward feed rate value Ws1 at the beginning of the first arc thrust control period (Ts1) and maintained. When the arc thrust control period (Ts) enters the high-frequency welding wire retraction period (Ts3), the retraction speed of the welding wire increases to the retraction speed set value Ws3 and is maintained. In some specific embodiments, after the welding wire contacts the molten pool and forms a short circuit (i.e., entering the second arc thrust control period Ts2), constant current control is adopted, that is, the output current set for both the second arc thrust control period Ts2 and the high-frequency welding wire retraction period Ts3 is Is2. At this time, during the high-frequency welding wire retraction period Ts3, affected by the welding wire retraction speed, the welding current will decrease from the set output current Is2 to the droplet thrust current Isr.

[0045] Specifically, such as Figure 2 As shown, the low-frequency pulse welding cycle (Pc) includes the low-frequency pulse welding period (Tp) and the arc length control period (Ts). The welding cycle T starts at the beginning time Pst of the low-frequency pulse welding period Tp. During the low-frequency pulse welding cycle Tp, the welding current is pulsed with preset pulse parameters such as peak current Ipp, base current Ipb, pulse duty cycle and pulse frequency to form a low-energy welding input.

[0046] During the arc length control period (Ts), the following are included:

[0047] During the forward feed period (Tb) of low-frequency welding wire, the welding wire is fed forward at a third constant speed. The welding wire forms a molten droplet under the welding current, and the molten droplet forms a necking. The third constant speed is >0.

[0048] During the first arc length control period (Ts1), the welding current drops to 0, and the welding wire continues to feed forward until the molten droplet contacts the first aluminum alloy plate, forming a short circuit state.

[0049] During the second arc length control period (Ts2), the welding wire is fed forward at the fourth constant speed, the molten droplet and the first aluminum alloy plate are kept in a short circuit state and cooled at the same time, and the welding current is increased to the droplet separation current to re-ignite the arc; where 0 < fourth constant speed < third constant speed.

[0050] The low-frequency wire retraction period (Ts3) involves retracting the wire to separate it from the molten droplet. The pulse arc length is controlled by setting the wire retraction time.

[0051] In some specific embodiments, during the arc length control period (Ts), the welding wire is fed forward at a constant rate. To achieve rapid contact between the welding wire and the base material during the arc length control period (Ts), the forward feed rate of the welding wire needs to be rapidly increased to the forward feed rate set value Ws1 at the beginning of the first arc length control period (Ts1) and maintained. When the arc length control period (Ts) enters the low-frequency welding wire retraction period (Ts3), the retraction speed of the welding wire increases to the retraction speed set value Ws3 and remains maintained.

[0052] In some specific embodiments, after the welding wire contacts the molten pool and forms a short circuit (i.e., enters the second arc length control period Ts2), constant current control is adopted. That is, the output current during the second arc length control period Ts2 is 0, and the output current during the low-frequency welding wire retraction period Ts3 is Is2. At this time, during the low-frequency welding wire retraction period Ts3, the welding current will drop from the set output current Is2 to the droplet arc ignition current Isr due to the influence of the welding wire retraction speed.

[0053] In some specific embodiments, reducing the welding current to the droplet separation current refers to adjusting the current to the minimum threshold required for the droplet to separate from the welding wire. This can be achieved automatically by a current regulation module based on a preset program, such as by using a fixed current reduction range or setting a target value based on historical welding data, or by dynamically adjusting the current parameters through a real-time feedback control system. This is primarily to achieve stable control of the droplet separation process. Further, wire retraction refers to the action of the welding wire moving in the opposite direction to separate from the droplet. This can be controlled by a servo drive system to control the retraction displacement and speed, such as by using a stepper motor to precisely set the retraction distance, or by using a pneumatic actuator to achieve rapid reverse movement. This is primarily to achieve precise adjustment of the arc thrust or pulse arc length. Specifically, maintaining a short-circuit state while cooling during arc length control refers to reducing heat input to promote molten pool cooling while the welding wire is in contact with the droplet. This can be achieved by extending the short-circuit duration or reducing the wire feed rate, such as by setting a fixed cooling time interval or adjusting cooling parameters based on the molten pool temperature feedback signal. This is primarily to effectively suppress heat accumulation in thin plate areas.

[0054] In some specific embodiments, when the thickness of the first aluminum alloy plate is 6 mm and the thickness of the second aluminum alloy plate is 2 mm, a high-frequency pulse welding cycle is activated for welding the area of ​​the first aluminum alloy plate. During the arc thrust control, the welding wire is fed forward at a first constant speed, which can be set to 5 m / min to achieve stable wire feeding. After the droplet necks, the welding current is reduced to the droplet separation current. The welding wire continues to feed to form a short circuit and switches to a second constant speed (e.g., 3 m / min) to maintain the short circuit. Subsequently, the welding current is increased and the welding wire retraction parameter is controlled to adjust the arc thrust. At the same time, a low-frequency pulse welding cycle is used for welding the area of ​​the second aluminum alloy plate. During the arc length control, the welding wire is fed forward at a third constant speed (e.g., 4 m / min). After the droplet necks, the welding current is reduced to zero. The welding wire continues to feed to form a short circuit and switches to a fourth constant speed (e.g., 2 m / min) to maintain the short circuit and cooling. Afterward, the welding current is increased and the welding wire retraction time is set to control the arc length. Thus, by adjusting the wire feeding speed in stages, controlling the timing of current changes, and setting the retraction parameters in a coordinated manner, the droplet transition process is precisely managed, allowing the thick plate area to achieve sufficient melting depth while preventing overheating in the thin plate area.

[0055] In this embodiment, during the arc thrust control period in the high-frequency pulse welding cycle, a strategy of different wire feeding speeds (first constant speed and second constant speed) combined with current maintenance is used for thick plate areas to stabilize the arc and enhance penetration depth, while also improving arc stiffness and reducing arc drift and undercut. Simultaneously, during the arc length control period in the low-frequency pulse welding cycle, a combination of current reduction to zero and cooling control is used for thin plate areas to reduce heat input and prevent back penetration. This method, by differentiating the welding cycle characteristics of different plate thickness areas and combining independent control of wire feeding speed, current changes, and retraction parameters, achieves dynamic matching of heat input, effectively solving the technical problems of weld breakage and back penetration in thin plate welding and insufficient penetration in thick plate welding. Specifically, during the high-frequency pulse cycle, setting the wire retraction time during the wire retraction to separate from the molten droplet can control the droplet separation speed, achieving rapid droplet transition during welding and reducing the problems of wire sticking and welding failure caused by excessively rapid cooling of the 1.6mm wire molten pool. During droplet separation, increasing the welding current melts the welding wire, allowing the droplet to detach from it. Setting the welding current and time controls the droplet thrust, accelerating droplet transfer, increasing welding speed, and enhancing arc stability. Arc length control is applied during low-frequency pulse cycles. The lack of current cooling ensures low-energy welding on thin plates. Furthermore, the re-ignition of the arc ensures it remains aligned with the wire direction, preventing arc deviation. The arc-free and non-undercut characteristics during low-frequency pulses are suitable for thin-plate welding. Multiple arc length control pulses within a single low-frequency pulse cycle significantly reduce the risk of wire sticking due to feed resistance, improve molten pool consistency, and allow for high-speed arc length adjustment to automatically compensate for arc instability caused by wire extension changes. This also reduces low-frequency pulse heat input, significantly decreasing penetration and weld deviation. After the droplet contacts the molten pool, the voltage reduction signal primarily determines that the wire and droplet have made contact, providing an initial position reset for the arc length in the next pulse cycle and creating conditions for adaptive arc length control. If the wire feeding system has high resistance, the welding arc length can be directly reduced during this cycle to return it to the initial setting of pulse welding.

[0056] Optionally, the droplet separation current is 40% to 60% of the peak current.

[0057] Specifically, pulse welding achieves welding through periodically alternating peak current (Ipp) and base current (Ipb). The droplet separation current refers to the current value below the welding wire melting threshold, which can be 40%-60% of the peak current (Ipp). It is output through the constant current module of the welding power supply and is used to suppress arc reignition during the short circuit stage.

[0058] In this optional embodiment, during arc thrust control, the welding current is reduced during the formation of pulsed welding droplets, the wire melting speed is decreased, the wire is fed, and the droplets contact the molten pool to form a short circuit. The welding current is 40% to 60% of the peak current, so the heat input during welding is still high. This current range allows for precise control of the timing and speed of droplet separation, avoiding problems such as excessively fast droplet transition and excessive heat input caused by excessive current. This prevents back penetration or weld breakage in thin plate areas due to concentrated heat input. At the same time, it avoids the phenomenon of delayed droplet transition and insufficient penetration caused by excessively low current, ensuring sufficient penetration in thick plate areas. During arc thrust control, this current range maintains the stability of the short circuit state between the droplets and the base material, while improving the stiffness of the arc and reducing arc drift and product undercut.

[0059] Optionally, the pulse frequency of the high-frequency pulse welding cycle is 50 to 300 Hz, and the pulse frequency of the low-frequency pulse welding cycle is 0.5 to 10 Hz.

[0060] Specifically, the pulse frequency of the high-frequency pulse welding cycle refers to the repetition frequency of the pulse current when welding the first aluminum alloy plate. It can be achieved by dynamically adjusting the inverter switching frequency using a digital signal processor. The purpose is to provide stable and sufficient heat input to achieve a large penetration depth, while avoiding excessive heat input due to excessive frequency or insufficient penetration due to excessive frequency. The pulse frequency of the low-frequency pulse welding cycle refers to the repetition frequency of the pulse current when welding the second aluminum alloy plate. It can be achieved by setting the pulse interval time using a programmable timer module. The purpose is to extend the cooling time of the molten pool and reduce the heat input, preventing the thin plate from breaking due to excessive heat input, while maintaining the stability of the arc length control.

[0061] In this optional embodiment, by limiting the pulse frequency of the high-frequency pulse welding cycle to the range of 50 to 300 Hz, sufficient heat input from the arc is ensured to achieve a large penetration depth when welding the first aluminum alloy plate, while suppressing the risk of undercut in thin plates caused by excessively high frequencies or insufficient penetration depth caused by excessively low frequencies. By limiting the pulse frequency of the low-frequency pulse welding cycle to the range of 0.5 to 10 Hz, heat input is significantly reduced and the cooling time of the molten pool is extended when welding the second aluminum alloy plate, preventing the thin plate from breaking through the weld, while avoiding insufficient cooling due to excessively high frequencies or welding interruptions caused by excessively low frequencies. The setting of the frequency range allows for more precise control of the arc thrust, reducing arc drift, thereby synergistically optimizing penetration depth control in thick plate areas and suppressing heat input in thin plate areas.

[0062] Optionally, in the step of controlling the arc thrust by controlling the welding current and time during wire retraction, the welding current during wire retraction is set to 20% to 50% of the peak current.

[0063] Specifically, the welding current setting range during wire retraction refers to the precise proportional control range of current output during the wire retraction stage. This can be achieved using a current proportional adjustment module in the welding control system. This module analyzes the peak current signal in real time and generates dynamic current commands according to a preset ratio. Its purpose is to establish an adaptive correlation between current parameters and the physical characteristics of droplet transfer, avoiding process fluctuations caused by the setting of the absolute value of the current. Among them, the peak current refers to the maximum current value output during high-frequency pulse welding. It can be understood as the current peak reference point that appears periodically during the welding process. Specifically, it can be collected in real time by a current sensor and stored in the control system. Its purpose is to provide a dynamic reference for proportional current setting.

[0064] In this optional embodiment, by strictly limiting the welding current during wire retraction to a range of 20% to 50% of the peak current, dynamic matching between arc thrust and droplet separation is achieved. After the wire retraction is initiated, the welding current is set according to this proportional range, ensuring that the arc thrust is sufficient to overcome the surface tension of the droplets for reliable separation, while preventing excessive thrust from causing disturbance to the molten pool. Since the peak current serves as a dynamic reference in the proportional calculation, this setting method establishes an intrinsic link between arc thrust control and the current welding state. When the peak current changes due to process fluctuations, the current during the retraction phase is automatically adjusted proportionally, thereby maintaining thrust stability. Based on this proportional setting mechanism, the adaptability defects caused by setting a fixed current value under different welding conditions are effectively avoided, ensuring the controllability of the droplet separation process in both thick and thin plate welding scenarios. It effectively improves the accuracy and adaptability of arc thrust control, maintains dynamic stability of the molten pool during the welding of thick and thin plates, avoids undercut or weld breakage caused by uncontrolled heat input in the thin plate area, and ensures sufficient penetration in the thick plate area, thereby significantly enhancing the reliability of the welding process under conditions of significant thickness difference.

[0065] Optionally, in the subsequent step of increasing the welding current to the droplet separation current to re-ignite the arc, the welding current is 30% to 50% of the peak current.

[0066] Specifically, the welding current being 30% to 50% of the peak current refers to a precise proportional limit on the welding current during the re-arc ignition stage. This can be achieved using a current adjustment algorithm based on dynamic calculation of the peak current. Specifically, the current value can be set through the proportional adjustment module built into the welding control system. The purpose of introducing this feature is to establish a dynamic correlation between the welding current and the peak current, avoid the problem of insufficient process adaptability caused by a fixed current value, and ensure that the current parameter is adjusted synchronously with the overall welding conditions, thereby accurately controlling the heat input while ensuring the reliability of arc ignition.

[0067] In this optional embodiment, by strictly limiting the welding current in the re-arc-ignition step to within 30% to 50% of the peak current, dynamic matching of the current parameter with the current welding state is achieved. Since the peak current, as a core parameter of the welding process, directly reflects the overall heat input level and the energy state of the molten pool, using it as a benchmark ensures that the re-arc-ignition current is coordinated with the thermodynamic characteristics of the welding cycle. Furthermore, this range limitation avoids the risk of excessive melting of thin plates caused by excessive heat input when the current exceeds 50%, and also prevents arc instability caused by insufficient arc-ignition energy when the current is below 30%. By setting this specific ratio range, a stable energy transfer link is formed between droplet separation and the re-arc-ignition process, effectively suppressing arc drift and maintaining a stable molten pool morphology during the arc length control of the low-frequency pulse welding cycle. Precise control of heat input in the thin plate area is achieved during the welding of thick and thin plates, effectively avoiding defects such as undercut, weld breakage, and back penetration caused by improper current parameters, significantly improving the stability of the welding process and the quality of joint formation.

[0068] Optionally, the ratio of the number of pulses during high-frequency pulse welding to the number of pulses during arc thrust control is 1:2 to 4:1.

[0069] Specifically, the ratio of the number of pulses during high-frequency pulse welding to the number of pulses during arc thrust control refers to the proportional relationship between the number of pulses generated during the high-frequency pulse welding stage and the number of pulses generated during the arc thrust control stage within the welding cycle. This can be achieved using a programmable pulse counting module in the welding control system. By setting a pulse counting threshold, the stage switching is automatically triggered. The purpose is to dynamically adjust the arc thrust action time to match the heat input requirements of different plate thickness areas and avoid problems such as molten pool deviation or heat accumulation caused by excessive or insufficient thrust.

[0070] In this optional embodiment, the ratio range is set to create a dynamic complementary relationship between the high-frequency pulse welding period and the arc thrust control period: when the ratio is 1:2, the number of pulses during the arc thrust control period is relatively large, prolonging the action time of the arc thrust on the molten pool and enhancing the stirring effect on the molten pool in the thick plate area, thereby effectively avoiding penetration defects caused by insufficient heat input; when the ratio is 4:1, the high-frequency pulse welding period dominates, but the arc thrust control period still retains a sufficient number of pulses to ensure timely intervention of thrust adjustment in the thin plate area, suppressing heat accumulation and preventing molten pool displacement or weld breakage caused by excessive arc thrust during wire retraction. This precise control of the ratio allows the arc thrust to adaptively adjust its intensity and duration according to the plate thickness difference, achieving a balance between large penetration depth in thick plates and low heat input in thin plates, while reducing arc drift. This effectively solves the problem of molten pool stability caused by uneven heat input distribution in the welding of thick and thin plates, significantly reducing the occurrence of insufficient penetration depth in thick plates and weld breakage in thin plates, and improving the reliability of the welding process and product quality.

[0071] Optionally, the cooling process includes setting a cooling time, with a voltage drop signal set as the start of the cooling time.

[0072] Specifically, setting the cooling time refers to pre-determining the duration of the cooling process. This can be achieved by using a fixed time value or by dynamically calculating based on welding current and plate thickness parameters. The purpose is to enable the welding system to adjust the cooling period according to the plate thickness and heat sensitivity, avoiding excessive or insufficient heat accumulation. Setting the voltage drop signal as the start of the cooling time means using a sudden voltage drop during welding as a trigger signal. This can be achieved by using a voltage sensor to monitor the welding voltage in real time and setting a voltage threshold as the trigger condition. The purpose is to accurately capture the moment when the molten droplet contacts the workpiece and forms a short circuit, ensuring that the cooling process is strictly synchronized with the short circuit state.

[0073] In this optional embodiment, dynamic matching between cooling control and welding status is achieved by using the voltage drop signal as the precise start trigger point for cooling time. During the arc length control of the low-frequency pulse welding cycle, when the molten droplet forms a short circuit upon contact with the first aluminum alloy plate after necking, the welding voltage drops significantly due to changes in circuit impedance. This voltage drop signal is detected in real time and used as the start trigger point for cooling timing, followed by the execution of the cooling operation according to the set cooling time. This mechanism avoids the lag of fixed time settings, precisely synchronizing the cooling process with the short circuit state, effectively suppressing molten pool disturbances, stabilizing heat input distribution, and thus achieving precise thermal management in the thin plate area. It achieves precise synchronization between cooling timing and welding status, effectively preventing defects such as overheating, weld breakage, or back penetration caused by improper cooling timing, and improving the quality and stability of welding aluminum alloys of different thicknesses.

[0074] like Figure 3 As shown, another embodiment of the present invention provides a welding device for 1.6mm diameter aluminum alloy welding wire for thick and thin plates, used to operate and implement the welding method of 1.6mm diameter aluminum alloy welding wire for thick and thin plates as described above. The welding device includes a welding control circuit and a servo motor-controlled wire drawing welding gun respectively connected to the electrode.

[0075] The welding control circuit is used to provide welding current to the electrodes in each welding cycle;

[0076] The servo motor controls the wire drawing welding torch to control the feed speed and feed direction of the welding wire;

[0077] Electrodes are used to apply current to the welding area via welding wire;

[0078] Among them, such as Figure 4As shown, the servo motor controls the wire-drawing welding torch connected to the welding torch control circuit. The welding torch control circuit is used to control the welding torch to swing sinusoidally along the welding direction. When the welding torch swings to the first aluminum alloy plate area, the welding control circuit switches to a high-frequency pulse welding cycle; when the welding torch swings to the second aluminum alloy plate area, the welding control circuit switches to a low-frequency pulse welding cycle.

[0079] Specifically, a servo motor is a closed-loop drive device that can achieve high-precision position, speed and acceleration control. It can be implemented using a DC servo motor, an AC servo motor or a stepper servo motor. Specifically, it can form a closed-loop adjustment system with the controller through encoder feedback signals. Its purpose is to provide wire feeding adjustment capabilities with fast dynamic response and high control accuracy to adapt to the differentiated requirements of wire feeding behavior in different welding cycles.

[0080] In this embodiment, the sinusoidal oscillation of the welding torch combined with a position-aware dynamic switching mechanism for the welding cycle enables real-time and precise control of welding parameters. The sinusoidal oscillation trajectory of the welding torch along the welding direction provides continuous and accurate position feedback signals to the welding control system. When the welding torch oscillates to the first aluminum alloy plate area, the high-frequency pulse welding cycle is activated, providing high heat input and strong arc thrust through the arc thrust control mechanism. This ensures sufficient penetration in the thick plate area while effectively suppressing arc drift and maintaining molten pool stability. When the welding torch oscillates to the second aluminum alloy plate area, the low-frequency pulse welding cycle is activated, providing low heat input and gentle molten pool stirring through the arc length control mechanism. This prevents back penetration or weld breakage in the thin plate area due to heat accumulation. Through the above technical solution, the heat input distribution is specifically optimized, fundamentally solving the problems of arc drift, molten pool instability, insufficient penetration in thick plates, and weld breakage in thin plates when welding aluminum alloy plates with large thickness differences using 1.6mm diameter aluminum alloy welding wire. This significantly improves the reliability of the welded joint and product consistency.

[0081] Optionally, the welding torch control circuit includes:

[0082] The welding torch oscillation position signal module is used to detect and provide the position information of the welding torch;

[0083] The welding torch oscillation output module is used to control the sinusoidal oscillation of the welding torch.

[0084] In this optional embodiment, the welding torch oscillation output module controls the welding torch to oscillate sinusoidally along the welding direction, the welding torch oscillation position signal module provides the welding torch position, and different welding conditions are set according to the different action positions of the welding torch. For thick plates, high-frequency pulse welding and variable thrust pulse are output, and for thin plates, high-frequency pulse welding and small thrust pulse are output. At the same time, different welding arc thrust is set for different phases of the welding torch.

[0085] Optionally, the welding control circuit includes:

[0086] The pulse welding current output module is used to output a welding current with a preset peak current, base current, pulse duty cycle and pulse frequency to the electrode during pulse welding, so as to achieve stable welding with one pulse at a time.

[0087] The arc thrust and arc length control module is used to control the welding current and time during wire retraction in the high-frequency pulse welding cycle to control the arc thrust; and to control the wire retraction time in the low-frequency pulse welding cycle to control the pulse arc length.

[0088] Specifically, peak current refers to the maximum current value reached during pulse welding. It can be achieved using a programmable DC power supply or an inverter welding power supply. Its purpose is to ensure smooth separation of the molten droplet after necking, avoiding transition abnormalities and spatter caused by current fluctuations. Base current refers to the minimum current value that maintains arc continuity during the pulse gap. It can be achieved using a constant current feedback control circuit or a digital adjustment module. Its purpose is to prevent the arc from accidentally extinguishing during low-frequency pulses, and it is especially suitable for fine control of heat input in thin plate areas. Pulse duty cycle refers to the ratio of high current time to the total pulse period. It can be achieved using a pulse width modulation controller or software algorithm. Its purpose is to adapt the heat input to different plate thickness requirements by adjusting the time distribution of high and low currents. Pulse frequency refers to the number of times the pulse signal is repeated per unit time. It can be achieved using a frequency synthesizer or an adjustable clock circuit. Its purpose is to match the sinusoidal oscillation period of the welding torch, ensuring that high-frequency and low-frequency welding conditions are applied in thick and thin plate areas respectively.

[0089] In this optional embodiment, after the welding wire is retracted and the distance between it and the base material during the high-frequency pulse welding cycle of thick plates, the arc thrust is adjusted by adjusting the magnitude and time of the welding current, thereby adjusting the stirring ability of the molten droplets in the molten pool. Combined with the number of pulse welding cycles within the cycle, the size and shape of the weld penetration can be effectively controlled. This control of the weld penetration is completely independent of the control of parameters during the pulse welding cycle. During welding, as long as the welding current parameter is controlled before the end of the arc thrust period, the weld penetration can be controlled, which greatly improves the stability of the arc length control and significantly reduces the risk of wire sticking and burnt contact tip of 1.6 welding wire. During the arc length control period added in the low-frequency pulse welding cycle of thin plates, the welding current decreases and the welding wire continues to melt. The molten droplets contact the base material and the welding current decreases to 0. Therefore, no heat input is formed during this period. As the welding arc is extinguished, the molten pool is rapidly cooled, realizing a rapid transition of the arc from thick plate welding to thin plate welding, reducing the arc length and reducing the risk of undercut. In addition, the welding current is set to 0 during the cooling period. When the welding wire is retracted and detached from the base material, the molten droplets detach rapidly due to the increased retraction of the welding wire, and the welding wire is quickly re-ignited, resulting in very fast and stable arc ignition with minimal spatter.

[0090] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A welding method for thick and thin plates using 1.6mm diameter aluminum alloy welding wire, characterized in that, The welding method is used for welding a first aluminum alloy plate and a second aluminum alloy plate, wherein the thickness of the first aluminum alloy plate is greater than that of the second aluminum alloy plate; the welding method includes a series of welding cycles, each welding cycle including a high-frequency pulse welding cycle for welding the first aluminum alloy plate and a low-frequency pulse welding cycle for welding the second aluminum alloy plate. The high-frequency pulse welding cycle includes a high-frequency pulse welding period and an arc thrust control period following the high-frequency pulse welding period. During the arc thrust control period, the welding wire is fed forward at a first constant speed. The welding wire forms a molten droplet under the welding current. After the molten droplet necks, the welding current drops to the droplet separation current. The welding wire continues to be fed forward until the molten droplet contacts the first aluminum alloy plate, forming a short circuit. Then, the welding wire is fed forward at a second constant speed, and the molten droplet and the first aluminum alloy plate maintain the short circuit state. Afterward, the welding current is increased to accelerate the entry of the molten droplet into the molten pool. The welding wire is retracted to separate from the molten droplet. The arc thrust is controlled by controlling the welding current and time during the wire retraction. The second constant speed is less than the first constant speed. The low-frequency pulse welding cycle includes a low-frequency pulse welding period and an arc length control period following the low-frequency pulse welding period. During the arc length control period, the welding wire is fed forward at a third constant speed. The welding wire forms a molten droplet under the welding current. After the molten droplet forms a neck, the welding current drops to 0. The welding wire continues to be fed forward until the molten droplet contacts the first aluminum alloy plate, forming a short circuit. Then, the welding wire is fed forward at a fourth constant speed. The molten droplet and the first aluminum alloy plate maintain the short circuit state while cooling. Afterward, the welding current is increased to the molten droplet separation current to re-ignite the arc. The welding wire is retracted to separate from the molten droplet. The pulse arc length is controlled by controlling the welding wire retraction time. The fourth constant speed is less than the third constant speed.

2. The welding method for thick and thin plates using 1.6mm diameter aluminum alloy welding wire according to claim 1, characterized in that, The droplet separation current is 40% to 60% of the peak current.

3. The welding method for thick and thin plates using 1.6mm diameter aluminum alloy welding wire according to claim 1, characterized in that, The pulse frequency of the high-frequency pulse welding cycle is 50 to 300 Hz, and the pulse frequency of the low-frequency pulse welding cycle is 0.5 to 10 Hz.

4. The welding method for thick and thin plates using 1.6mm diameter aluminum alloy welding wire according to claim 1, characterized in that, In the step of controlling the arc thrust by controlling the welding current and time during the wire retraction, the welding current during the wire retraction is set to 20% to 50% of the peak current.

5. The welding method for thick and thin plates using 1.6mm diameter aluminum alloy welding wire according to claim 1, characterized in that, In the subsequent step of increasing the welding current to the droplet separation current to re-ignite the arc, the welding current is 30% to 50% of the peak current.

6. The welding method for thick and thin plates using 1.6mm diameter aluminum alloy welding wire according to claim 1, characterized in that, The ratio of the number of pulses during the high-frequency pulse welding period to the number of pulses during the arc thrust control period is 1:2 to 4:

1.

7. The welding method for thick and thin plates using 1.6mm diameter aluminum alloy welding wire according to claim 1, characterized in that, The simultaneous cooling step includes: setting a cooling time, with a voltage reduction signal set as the start of the cooling time.

8. A welding apparatus for using 1.6mm diameter aluminum alloy welding wire for thick and thin plates, used to operate and implement the welding method for using 1.6mm diameter aluminum alloy welding wire for thick and thin plates as described in any one of claims 1-7, characterized in that, The welding device includes a welding control circuit connected to the electrodes and a servo motor-controlled wire-drawing welding gun. The welding control circuit is used to provide welding current to the electrode in each welding cycle; The servo motor controls the wire drawing welding gun to control the feeding speed and feeding direction of the welding wire; The electrode is used to apply current to the welding area through the welding wire; The servo motor controls the wire-drawing welding torch, which is connected to the welding torch control circuit. The welding torch control circuit controls the welding torch to swing sinusoidally along the welding direction. When the welding torch swings to the first aluminum alloy plate area, the welding control circuit switches to a high-frequency pulse welding cycle. When the welding torch swings to the second aluminum alloy plate area, the welding control circuit switches to a low-frequency pulse welding cycle.

9. The welding apparatus for using 1.6mm diameter aluminum alloy welding wire for thick and thin plates according to claim 8, characterized in that, The welding torch control circuit includes: A welding torch oscillation position signal module is used to detect and provide the position information of the welding torch; The welding torch oscillation output module is used to control the sinusoidal oscillation of the welding torch.

10. The welding apparatus for using 1.6mm diameter aluminum alloy welding wire for thick and thin plates according to claim 8, characterized in that, The welding control circuit includes: The pulse welding current output module is used to output a welding current with a preset peak current, base current, pulse duty cycle and pulse frequency to the electrode during pulse welding, so as to achieve stable welding with one pulse at a time. The arc thrust and arc length control module is used to control the welding current and time during wire retraction in the high-frequency pulse welding cycle to control the arc thrust; and to control the wire retraction time in the low-frequency pulse welding cycle to control the pulse arc length.

Images