Automatic Welding Current Adjustment Unit for Welding Machine, Welding Machine and Usage Method

Abstract

The present invention discloses an automatic welding current regulating unit for a welding machine, a welding machine and a using method, belonging to the technical field of gas shielded welding equipment. An automatic welding current regulating unit for a gas shielded welding machine of the present invention includes a plurality of resistors connected in parallel, and a time relay is respectively connected in series on each resistor. When the present invention is adopted, thanks to the design of "a plurality of resistors connected in parallel, and a time relay is respectively connected in series on each resistor" of the present invention, as the time relays are successively disconnected one by one, the resistance of the welding current regulating unit gradually increases, the resistance of the welding current regulating unit in parallel with the welding current potentiometer gradually increases, the welding current can automatically decrease, and the welding heat input automatically decreases, thereby avoiding defects caused by too high molten pool temperature.

Description

Technical Field

[0001] The present invention relates to an automatic welding current regulating unit for a welding machine, a welding machine and a using method thereof, belonging to the technical field of gas shielded welding equipment. Background Art

[0002] Gas shielded welding is an arc welding that uses gas as the arc medium and protects the arc and the welding area, which is called gas shielded arc welding.

[0003] Gas shielded welding is usually divided into non-consumable electrode (tungsten electrode) inert gas shielded welding (TIG) and consumable electrode gas shielded welding (GMAW) according to whether the electrode melts and the different shielding gases. Consumable electrode gas shielded welding includes inert gas shielded welding (MIG), oxidizing mixed gas shielded welding (MAG), CO2 gas shielded welding, and flux cored wire gas shielded welding (FCAW).

[0004] In the prior art, a hollow metal sphere is usually formed by welding two hemispherical hollow hemispheres together, adopting the welding process of GMAW with one-side welding and two-side forming. The full spelling of GMAW is gas metal arc welding (consumable electrode gas shielded welding), which is a welding method that, under gas shielding, uses the arc between the welding wire and the welded part to melt the continuously fed welding wire to form a molten pool and a weld seam.

[0005] As Figure 1 shown, during the welding operation, on the welding fixture 7, the two metal hemispheres to be welded are made to face each other to form the metal sphere 6 to be welded. The welding groove can be I-shaped, V-shaped, Y-shaped, U-shaped groove, etc.; then the welding machine is started, and the welding machine conveys the welding wire and melts and fuses it with the base material. The welding fixture rotates the sphere to be welded continuously, and continuously welds the sphere to be welded. After welding, the two hollow hemispheres are connected by a weld seam to form a hollow sphere.

[0006] During the welding operation, when the welding process parameters (welding current, welding voltage, welding speed) are set, the welding heat input is basically determined. Welding heat input refers to the heat energy input by the welding energy to the unit length of the weld during fusion welding. The welding heat input is equal to the product of the welding current, arc voltage, heat efficiency coefficient and the ratio of the welding speed (the rotation speed of the sphere to be welded). The welding heat input E = IUη / V. Where I represents the welding current; U represents the arc voltage; V represents the welding speed; η represents the heat efficiency coefficient. Among them: the heat efficiency coefficient is classified according to the welding method, 0.5 for tungsten inert gas welding (TIG), 0.6 - 0.8 for consumable electrode gas shielded welding (GMAW), and 0.8 - 0.9 for submerged arc welding (SAW).

[0007] Welding heat input is a technical parameter of the welding process. Excessive heat input will increase unnecessary power consumption and is also likely to cause welding defects such as "undercut". Insufficient heat input will also cause welding defects such as "incomplete penetration", affecting the strength of the welding point, which is not allowed.

[0008] The diameter of the metal balls to be welded is often small (10mm - 150mm in diameter). The heat of the previously welded part will be transferred to the unwelded part (preheated by high temperature), making the molten pool temperature of the later welded part too high (more obvious for smaller diameter metal balls), extremely likely to cause overheating of the weld, resulting in defects such as pits, undercut or burn-through, affecting the welding quality and causing the welded metal balls not to meet the requirements.

[0009] During the welding process, if the welding heat input can automatically decrease, then the defects caused by too high molten pool temperature can be avoided. Therefore, the present invention designs a welding current automatic adjustment unit. For a gas shielded arc welding machine using this welding current automatic adjustment unit, during the welding process, the welding current can automatically decrease, making the welding heat input automatically decrease, thereby avoiding the defects caused by too high molten pool temperature. Summary of the Invention

[0010] The object of the present invention is to provide a welding current automatic adjustment unit for a welding machine, a welding machine and a usage method. When using the present invention, during the welding process, the welding current can automatically decrease, making the welding heat input automatically decrease, thereby avoiding the defects caused by too high molten pool temperature.

[0011] The technical solution adopted by the present invention is as follows:

[0012] A welding current automatic adjustment unit for a gas shielded arc welding machine includes a plurality of resistors connected in parallel, and a time relay is respectively connected in series on each resistor.

[0013] Resistors and time relays are electronic components in the prior art. Resistors are generally directly called resistors in daily life and are current-limiting components. After connecting a resistor in a circuit, it can limit the magnitude of the current passing through the circuit it is connected to. A time relay refers to a relay that, after adding (or removing) an input action signal, its output circuit will produce a jump change (or contact action) after a specified accurate time, and it is an electronic component used to connect or disconnect a circuit.

[0014] The automatic welding current adjustment unit of the present invention is used for a gas shielded welding machine. When in use, the automatic welding current adjustment unit is connected in parallel to the welding current potentiometer inside the gas shielded welding machine. In the prior art, a gas shielded welding machine has a welding current potentiometer, which is the potentiometer inside the gas shielded welding machine used to adjust and set the welding current. Its working principle is as follows: First, in the initial state, each time relay is in the on state. The initial welding current is set through the gas shielded welding machine, and the action trigger time of each time relay is set respectively. The action trigger times of each time relay are not equal. In the initial state, the total resistance of the automatic welding current adjustment unit is the smallest. As time goes by, the time relays are successively disconnected one by one, making the total resistance of the automatic welding current adjustment unit gradually increase. For the current automatic adjustment unit, its theoretical basis is: 1 / R of the automatic welding current adjustment unit = 1 / R1 + 1 / R2 +... + 1 / Rn, where R1, R2... Rn represent the resistance values of each resistor; when the corresponding time relay is disconnected, the resistor in series with it is no longer connected in parallel to the circuit. The automatic adjustment unit is connected in parallel to the welding current potentiometer, that is, 1 / R of the total parallel connection = 1 / R of the automatic welding current adjustment unit + 1 / R of the welding current potentiometer; since R of the automatic welding current adjustment unit is gradually increasing while R of the welding current potentiometer remains unchanged (after the initial setting, R of the welding current potentiometer will be a fixed value), then the total parallel resistance R of the automatic adjustment unit and the welding current potentiometer will gradually increase, so the welding current will gradually decrease, making the heat input during welding gradually decrease, thereby avoiding defects caused by excessive molten pool temperature. That is, when the present invention is adopted, during the welding process, as the time relays are successively disconnected one by one, the resistance of the automatic welding current adjustment unit gradually increases, the total parallel resistance of the automatic welding current adjustment unit and the welding current potentiometer gradually increases, the welding current can automatically decrease, and the heat input during welding can automatically decrease, thereby avoiding defects caused by excessive molten pool temperature. Of course, by the same token, if necessary, the initial state of the time relay is set to be off, and the action trigger time is set so that as time goes by, each time relay closes successively, then the resistance of the automatic welding current adjustment unit will gradually decrease, the total parallel resistance of the automatic welding current adjustment unit and the welding current potentiometer will gradually decrease, the welding current can automatically increase, and the heat input during welding can automatically increase. This can be achieved by using the automatic welding current adjustment unit of the present invention and is also within the scope of protection required by the present invention.

[0015] Based on the above working principle (the welding current gradually decreases), when the welding current potentiometer in the gas shielded welding machine is connected in parallel with the automatic welding current adjustment unit of the present invention, during the welding process, as time goes by, the welding current automatically and gradually decreases from large to small, and the welding heat input automatically and gradually decreases from large to small; it can avoid defects caused by the excessive temperature of the molten pool of the metal ball to be welded, and ensure the welding quality of the metal ball. Of course, the gas shielded welding machine using the automatic welding current adjustment unit of the present invention can also be used to weld other types of products.

[0016] Preferably, a time relay is connected in series after a plurality of the resistors are connected in parallel. After the action trigger time of the time relay is set, it can make the entire automatic welding current adjustment unit open circuit when the set time arrives. Of course, it is also feasible not to adopt this design.

[0017] Preferably, the resistance value of the resistor is 5Ω - 50Ω. For example, the resistance values of the resistors are 5Ω, 10Ω, 15Ω, 20Ω, 25Ω, 30Ω, 35Ω, 40Ω, 45Ω, 50Ω. Select according to actual requirements, and the resistance values of each resistor can be equal or unequal. Of course, the resistance value of the resistor can also be greater than 50Ω or less than 5Ω.

[0018] A gas shielded welding machine includes a welding machine body and the above-mentioned automatic welding current adjustment unit, and the automatic welding current adjustment unit is connected in parallel to the welding current potentiometer in the welding machine body. For the gas shielded welding machine of the present invention, the welding machine body is a welding machine in the prior art. The present invention is a modification of the existing welding machine and does not make too much change to the existing welding machine; only an automatic welding current adjustment unit is connected in parallel to the welding current potentiometer in the welding machine body. When using the gas shielded welding machine of the present invention to weld metal balls, during the welding process, the welding current can automatically decrease, making the welding heat input automatically decrease, avoiding defects caused by excessive molten pool temperature, and thus ensuring the welding quality of the metal balls, and the welding quality of the metal balls is high.

[0019] Furthermore, the automatic welding current adjustment unit is assembled inside the housing of the welding machine body. The gas shielded welding machine is more beautiful. The automatic welding current adjustment unit can also be assembled outside the housing of the welding machine body. In this case, the wire connecting the automatic welding current adjustment unit and the welding current potentiometer passes through the housing of the welding machine body.

[0020] Optionally, all the time relays are electrically connected to a relay controller located outside the housing of the welding machine body to facilitate setting each time relay. The action trigger time of each time relay is set through the relay controller.

[0021] Alternatively, the control panels of all the time relays are embedded and exposed outside the housing of the welding machine body for easy setting of each time relay.

[0022] The time relay has a control panel for setting the action trigger time. When the welding current automatic adjustment unit is located inside the housing of the welding machine body, it is necessary to solve the problem of how to set the action trigger time on the control panel of the time relay. Therefore, the present invention proposes two technical solutions. The first is to electrically connect each time relay to a relay controller located outside the housing of the welding machine body, and set the action trigger time of each time relay through the relay controller. The second is to expose the control panel of each time relay outside the housing of the welding machine body for easy operation.

[0023] Alternatively, the gas shielded arc welding machine is a gas metal arc welding machine.

[0024] Alternatively, the gas shielded arc welding machine is a DC welding machine.

[0025] A method for using a gas shielded arc welding machine, using the above gas shielded arc welding machine, includes the following steps:

[0026] Each time relay is in the on state, and the action trigger time of each time relay is set. The action trigger times of each time relay are not equal. The welding current and welding voltage of the welding machine body are set.

[0027] Two hollow metal hemispheres are clamped opposite to each other on the welding fixture to form a metal ball to be welded.

[0028] Weld the metal ball to be welded. The welding fixture rotates the metal ball to be welded continuously, and the rotation speed of the metal ball to be welded is the welding speed.

[0029] During the welding process, as time goes by, the time relays are disconnected one by one in sequence, so that the resistance of the welding current automatic adjustment unit gradually increases, the resistance of the welding current automatic adjustment unit in parallel with the welding current potentiometer gradually increases, the welding current gradually decreases, and the welding heat input gradually decreases to avoid defects caused by too high a molten pool temperature.

[0030] After welding is completed, the two metal hemispheres are connected by a weld seam to form a welded metal ball.

[0031] When this method is adopted, the welding quality of the metal ball is high, the weld formation is beautiful, and defects such as pits, undercut or burn-through can be avoided.

[0032] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are:

[0033] An automatic welding current adjustment unit for a welding machine, a welding machine, and a usage method thereof according to the present invention, specifically, an automatic welding current adjustment unit for a gas shielded arc welding machine, a gas shielded arc welding machine, and a usage method thereof. The structure of the automatic welding current adjustment unit is simple and ingenious. Thanks to the design of "a plurality of resistors connected in parallel, with a time relay connected in series on each resistor" in the present invention, as the time relays are successively disconnected one by one, the resistance of the automatic welding current adjustment unit gradually increases, the resistance of the automatic welding current adjustment unit in parallel with the welding current potentiometer gradually increases, the welding current can automatically decrease, and the welding heat input can automatically decrease, thereby avoiding defects caused by too high a molten pool temperature. When using the gas shielded arc welding machine of the present invention to weld steel balls, welding defects caused by too high a molten pool temperature can be avoided, ensuring the welding quality of the metal balls, and the welding quality of the metal balls is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be described by way of examples with reference to the accompanying drawings, wherein:

[0035] Figure 1 is a schematic diagram of a gas shielded arc welding machine in the prior art when welding steel balls;

[0036] Figure 2 is a schematic circuit diagram of the automatic welding current adjustment unit;

[0037] Figure 3 is a schematic circuit diagram of a parallel connection between an automatic welding current adjustment unit and a welding current potentiometer;

[0038] Figure 4 is Figure 3 a schematic diagram of the approximate position of the automatic welding current adjustment unit;

[0039] Figure 5 is another schematic circuit diagram of a parallel connection between an automatic welding current adjustment unit and a welding current potentiometer, and all time relays are electrically connected to a relay controller;

[0040] Figure 6 is Figure 5 a schematic diagram of the approximate position of the automatic welding current adjustment unit.

[0041] Reference numerals in the drawings: 1 - resistor, 2 - time relay, 3 - welding machine body, 31 - welding current potentiometer, 32 - welding machine body housing, 4 - automatic welding current adjustment unit, 5 - relay controller, 6 - metal ball, 7 - welding fixture. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] All features disclosed in this specification, or steps in all methods or processes disclosed, can be combined in any way, except for mutually exclusive features and / or steps.

[0043] Any feature disclosed in this specification, unless specifically described, can be replaced by other equivalent or similar-purpose alternative features. That is, unless specifically described, each feature is only an example in a series of equivalent or similar features.

[0044] Embodiment 1

[0045] As Figure 2 shown, a welding current automatic adjustment unit for a gas shielded welding machine in Embodiment 1 includes a plurality of resistors 1 connected in parallel, and a time relay 2 is respectively connected in series on each resistor 1.

[0046] The resistor 1 and the time relay 2 are both electronic components in the prior art. The resistor 1 is generally directly called a resistor in daily life and is a current-limiting component. After connecting the resistor to the circuit, it can limit the magnitude of the current passing through the circuit it is connected to. The time relay 2 refers to a relay that, when an input action signal is added (or removed), its output circuit takes a specified accurate time to produce a jump change (or contact action), and it is an electronic component used to connect or disconnect a circuit.

[0047] The welding current automatic adjustment unit of the present invention is used for a gas shielded welding machine. When in use, the welding current automatic adjustment unit 4 is connected in parallel to the welding current potentiometer 31 in the gas shielded welding machine. In the prior art, the gas shielded welding machine has a welding current potentiometer 31, and this welding current potentiometer 31 is a potentiometer used to adjust and set the welding current in the gas shielded welding machine. As Figure 3 、 Figure 4As shown, its working principle is as follows: First, in the initial state, each time relay 2 is in the on state. The initial welding current is set through a gas shielded arc welding machine, and the action trigger time of each time relay 2 is set respectively, and the action trigger times of each time relay 2 are not equal. In the initial state, the total resistance of the welding current automatic adjustment unit 4 is the smallest. As time goes by, the time relays 2 are successively disconnected one by one, making the total resistance of the welding current automatic adjustment unit 4 gradually increase. For the current automatic adjustment unit, its theoretical basis is: 1 / R of the welding current automatic adjustment unit = 1 / R1 + 1 / R2 + …… + 1 / Rn, where R1, R2 …… Rn represent the resistance values of each resistor 1; when the corresponding time relay 2 is disconnected, the resistor 1 in series with it is no longer paralleled into the circuit. The automatic adjustment unit 4 is paralleled with the welding current potentiometer 31, that is, 1 / R of the total parallel = 1 / R of the welding current automatic adjustment unit + 1 / R of the welding current potentiometer; since R of the welding current automatic adjustment unit gradually increases while R of the welding current potentiometer remains unchanged (after the initial setting, R of the welding current potentiometer will be a fixed value), then the total parallel resistance R of the automatic adjustment unit 4 paralleled with the welding current potentiometer 31 will gradually increase, so the welding current gradually decreases, making the welding heat input gradually decrease, thereby avoiding defects caused by too high a molten pool temperature. That is, when using the present invention, during the welding process, as the time relays 2 are successively disconnected one by one, the resistance of the welding current automatic adjustment unit 4 gradually increases, the total parallel resistance of the welding current automatic adjustment unit 4 and the welding current potentiometer 31 gradually increases, the welding current can automatically decrease, and the welding heat input can automatically decrease, thereby avoiding defects caused by too high a molten pool temperature. Of course, by the same token, if necessary, the initial state of the time relay 2 is set to be off, and the action trigger time is set so that as time goes by, each time relay 2 is successively closed, then the resistance of the welding current automatic adjustment unit will gradually decrease, the total parallel resistance of the welding current automatic adjustment unit and the welding current potentiometer 31 will gradually decrease, the welding current can automatically increase, and the welding heat input can automatically increase. This can be achieved by using the welding current automatic adjustment unit of the present invention and is also within the scope of protection required by the present invention.

[0048] Based on the above working principle (the welding current gradually decreases), when the welding current potentiometer 31 in the gas shielded arc welding machine is paralleled with the welding current automatic adjustment unit of the present invention, during the welding process, as time goes by, the welding current automatically gradually decreases from large to small, and the welding heat input automatically gradually decreases from large to small; it can avoid defects caused by too high a molten pool temperature of the metal ball to be welded and ensure the welding quality of the metal ball. Of course, the gas shielded arc welding machine using the welding current automatic adjustment unit of the present invention can also be used to weld other types of products.

[0049] Preferably, as Figure 2 shown, after multiple resistors 1 are connected in parallel, a time relay 2 is connected in series. After the action trigger time of the time relay 2 is set, when the set time arrives, the entire welding current automatic adjustment unit can be opened. Of course, it is also feasible not to adopt this design.

[0050] Preferably, the resistance value of the resistor 1 is 5Ω - 50Ω. For example, the resistance values of the resistor 1 are 5Ω, 10Ω, 15Ω, 20Ω, 25Ω, 30Ω, 35Ω, 40Ω, 45Ω, 50Ω. Select according to actual requirements, and the resistance values of each resistor 1 can be equal or not equal. Of course, the resistance value of the resistor 1 can also be greater than 50Ω or less than 5Ω.

[0051] Embodiment 2

[0052] As Figures 3 to 6 shown, a gas shielded arc welding machine in Embodiment 2 includes a welding machine body 3 and the welding current automatic adjustment unit of Embodiment 1. The welding current automatic adjustment unit 4 is connected in parallel to the welding current potentiometer 31 in the welding machine body 3. For the gas shielded arc welding machine of the present invention, the welding machine body 3 is a welding machine in the prior art. The present invention is a modification of the existing welding machine and does not make too much change to the existing welding machine; only the welding current automatic adjustment unit 4 is connected in parallel to the welding current potentiometer 31 in the welding machine body 3, and its working principle is detailed in Embodiment 1. When using the gas shielded arc welding machine of the present invention to weld metal balls, during the welding process, the welding current can automatically become smaller, so that the welding heat input automatically becomes smaller, avoiding defects caused by too high a molten pool temperature, thereby ensuring the welding quality of the metal balls, and the welding quality of the metal balls is high.

[0053] Further, in another embodiment, as Figure 4 、 Figure 6 shown, the welding current automatic adjustment unit 4 is assembled in the welding machine body housing 32. The gas shielded arc welding machine is more beautiful. The welding current automatic adjustment unit 4 can also be assembled outside the welding machine body housing 32. In this case, the wire connecting the welding current automatic adjustment unit 4 and the welding current potentiometer 31 passes through the welding machine body housing 32.

[0054] Optionally, in one embodiment, as Figure 5 、 Figure 6 shown, all time relays 2 are electrically connected to a relay controller 5 located outside the welding machine body housing 32 to facilitate setting each time relay. The action trigger time of each time relay 2 is set through the relay controller 5.

[0055] Optionally, in another embodiment, as Figure 3, Figure 4 As shown in Figure 4 , the control panels of all the time relays 2 are inlaid and exposed outside the housing 32 of the welding machine body, so as to facilitate the setting of each time relay.

[0056] The time relay 2 has a control panel for setting the action trigger time. When the welding current automatic adjustment unit 4 is located inside the housing 32 of the welding machine body, it is necessary to solve the problem of how to set the action trigger time on the control panel of the time relay 2. Therefore, the present invention proposes two technical solutions. The first is to electrically connect each time relay 2 to a relay controller 5 located outside the housing 32 of the welding machine body, and set the action trigger time of each time relay 2 through the relay controller 5, as shown in Figure 5 , Figure 6 As shown. The second is to expose the control panels of each time relay 2 outside the housing 32 of the welding machine body for easy operation, as shown in Figure 3 , Figure 4 As shown.

[0057] Optionally, in one embodiment, the gas shielded welding machine is a gas metal arc welding machine.

[0058] Optionally, in one embodiment, the gas shielded welding machine is a DC welding machine.

[0059] Embodiment Three

[0060] As Figures 1 to 6 shown, a method for using a gas shielded welding machine according to Embodiment Three, using the gas shielded welding machine of Embodiment Two, includes the following steps:

[0061] Each time relay 2 is in the on state, and the action trigger time of each time relay 2 is set. The action trigger times of each time relay 2 are not equal. The welding current and welding voltage of the welding machine body 3 are set;

[0062] Two hollow metal hemispheres are clamped opposite to each other on the welding fixture 7 to form a metal ball 6 to be welded;

[0063] Weld the metal ball 6 to be welded. The welding fixture 7 rotates the metal ball 6 to be welded continuously, and the rotation speed of the metal ball 6 to be welded is the welding speed;

[0064] During the welding process, as time goes by, the time relays 6 are disconnected one by one in sequence, so that the resistance of the welding current automatic adjustment unit 4 gradually increases, so that the resistance of the welding current automatic adjustment unit 4 in parallel with the welding current potentiometer 31 gradually increases, so that the welding current gradually decreases, so that the welding heat input gradually decreases, so as to avoid defects caused by too high a molten pool temperature;

[0065] After welding is completed, the two metal hemispheres are connected by a weld seam to form a welded metal sphere 6.

[0066] When this method is adopted, the welding quality of the metal sphere is high, the weld seam is beautifully formed, and defects such as pits, undercuts or burn-throughs can be avoided.

[0067] In summary, by using the automatic welding current adjustment unit and the welding machine and the usage method of the present invention for the welding machine, the structure of the automatic welding current adjustment unit is simple and ingeniously conceived. Thanks to the design of "a plurality of resistors connected in parallel, with a time relay connected in series on each resistor" of the present invention, as the time relays are successively disconnected one by one, the resistance of the automatic welding current adjustment unit gradually increases, the resistance of the automatic welding current adjustment unit in parallel with the welding current potentiometer gradually increases, the welding current can automatically decrease, and the welding heat input automatically decreases, thereby avoiding defects caused by too high a molten pool temperature. When using the gas shielded welding machine of the present invention to weld steel balls, welding defects caused by too high a molten pool temperature can be avoided, ensuring the welding quality of the metal balls, and the welding quality of the metal balls is high.

[0068] The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature or any new combination disclosed in this specification, as well as any new method or process step or any new combination disclosed.

Claims

1. A method for welding metal balls using a gas shielded welding machine, characterized in that: The gas shielded welding machine includes a welding machine body (3) and a welding current automatic adjustment unit. The welding current automatic adjustment unit (4) is connected in parallel to the welding current potentiometer (31) inside the welding machine body (3); The welding current automatic adjustment unit includes a plurality of resistors (1) connected in parallel, and each resistor (1) is respectively connected in series with a time relay (2); It includes the following steps: Each time relay (2) is in the on state, set the action trigger time of each time relay (2), the action trigger times of each time relay (2) are not equal, and set the welding current and welding voltage of the welding machine body (3); Clamp two hollow metal hemispheres facing each other on the welding fixture (7) to form a metal ball to be welded (6); Weld the metal ball to be welded (6). The welding fixture (7) rotates the metal ball to be welded (6) continuously, and the rotation speed of the metal ball to be welded (6) is the welding speed; During the welding process, as time goes by, the time relays (6) are successively disconnected one by one, so that the resistance of the welding current automatic adjustment unit (4) gradually increases, so that the resistance of the welding current automatic adjustment unit (4) connected in parallel with the welding current potentiometer (31) gradually increases, so that the welding current gradually decreases, so that the welding heat input gradually decreases, to avoid defects caused by too high a molten pool temperature; After welding, the two metal hemispheres are connected by a weld to form a welded metal ball (6).

2. The method according to claim 1, characterized in that: A time relay (2) is connected in series after a plurality of the resistors (1) are connected in parallel.

3. The method according to claim 1, characterized in that: The resistance value of the resistor (1) is 5Ω - 50Ω.

4. The method according to claim 1, characterized in that: The welding current automatic adjustment unit (4) is assembled inside the welding machine body housing (32).

5. The method according to claim 4, characterized in that: All the time relays (2) are electrically connected to a relay controller (5) located outside the welding machine body housing (32) for facilitating the setting of each time relay.

6. The method according to claim 4, characterized in that: The control panels of all the time relays (2) are inlaid and exposed outside the welding machine body housing (32) for facilitating the setting of each time relay.

7. The method according to claim 1, characterized in that: The gas shielded welding machine is a gas metal arc welding machine.

8. The method according to claim 1, characterized in that: The gas shielded welding machine is a DC welding machine.

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