Control method for short circuit arc for welding

Abstract

A control method of a short-circuit arc for welding, the short-circuit arc including a short-circuit phase and a burn phase, wherein the control method includes outputting a first current for a first length of time upon detection of the burn phase after the short-circuit phase, the first current being a difference between a welding current at the burn phase and a first current compensation amount.

Description

Technical Field

[0001] The embodiments of this disclosure relate to the field of welding, and more specifically, to a method for controlling a short-circuit arc for welding. Background Technology

[0002] With the successful application of refining technologies such as AOD, VOD, and SS-VOD in the stainless steel smelting process, the modern stainless steel grade system has become increasingly complete, meeting the needs of industries such as automobile manufacturing, rail passenger vehicles, and stainless steel products. The widespread use of stainless steel has also made stainless steel welding technology a popular field.

[0003] The most commonly used welding process for MIG welding of thin stainless steel sheets is short-circuit welding. Due to the special properties of stainless steel itself, such as its magnetism, high content of alloying elements, low thermal conductivity, and large coefficient of linear expansion, arc control of stainless steel also faces many problems. Summary of the Invention

[0004] In at least one embodiment of this disclosure, a method for controlling a short-circuit arc for welding is provided, the short-circuit arc including a short-circuit stage and an arc-ignition stage, wherein the control method includes:

[0005] When arcing is detected during the short circuit phase, a first current is output within the first time period. The first current is the difference between the welding current during arcing and the first current compensation amount.

[0006] In one embodiment of this disclosure, the method for controlling the short-circuit arc for welding further includes:

[0007] Detect abnormal voltages during the arcing stage;

[0008] In response to the detection of an abnormal voltage, a fixed current is output; and

[0009] Under preset conditions, the welding current is switched to be controlled by an electronic reactor.

[0010] In one embodiment of this disclosure, outputting a fixed current in response to detecting an abnormal voltage includes:

[0011] In response to detecting that the difference between the average welding voltage and the first reference voltage in the last sampling period within the second time length of the output arc current is greater than the first voltage threshold, the output arc current continues after the second time length.

[0012] In one embodiment of this disclosure, switching the welding current to be controlled by an electronic reactor when preset conditions are met includes:

[0013] At the end of the second time period, if the difference between the average welding voltage and the first reference voltage during the last sampling period of the second time period is less than or equal to the first voltage threshold, the welding current will be switched to be controlled by the electronic reactor; or

[0014] If the difference between the average welding voltage and the first reference voltage within the third time period is less than or equal to the first voltage threshold, the welding current is switched to be controlled by the electronic reactor; or

[0015] At the end of the third time period, the welding current is switched to be controlled by the electronic reactor.

[0016] In one embodiment of this disclosure, the method of outputting a fixed current in response to detecting an abnormal voltage further includes:

[0017] In response to the detection of a short circuit within a fourth time period, a second current is output within a fifth time period, wherein the second current is greater than the welding current at the time of the short circuit by a second current compensation amount.

[0018] In one embodiment of this disclosure, the fourth time length is less than 0.5ms and the fifth time length is equal to 0.5ms.

[0019] In one embodiment of this disclosure, the method for controlling the short-circuit arc for welding further includes:

[0020] At the end of the fifth time period, if the difference between the welding average voltage and the second reference voltage in the last sampling cycle of the fifth time period is greater than the second voltage threshold, the second current continues to be output in the sixth time period.

[0021] In one embodiment of this disclosure, switching the welding current to be controlled by an electronic reactor when preset conditions are met includes:

[0022] At the end of the fifth time period, if the difference between the average welding voltage and the second reference voltage during the last sampling period of the fifth time period is less than or equal to the second voltage threshold, the welding current will be switched to be controlled by the electronic reactor; or

[0023] If the difference between the average welding voltage and the second reference voltage in the last sampling period within the sixth time length is less than or equal to the second voltage threshold, the welding current will be switched to be controlled by the electronic reactor; or

[0024] At the end of the sixth time period, the welding current is switched to be controlled by the electronic reactor.

[0025] In one embodiment of this disclosure, outputting a fixed current in response to detecting an abnormal voltage includes:

[0026] During the arc-burning stage of electronic reactor control, the welding voltage change rate is continuously monitored. When the welding voltage change rate is greater than or equal to a threshold value, an abnormal voltage is detected.

[0027] In response to the detection of an abnormal voltage, the welding current at the time of the abnormal voltage is output within a seventh time period.

[0028] In one embodiment of this disclosure, switching the welding current to be controlled by an electronic reactor when preset conditions are met includes:

[0029] When the difference between the average welding voltage and the third reference voltage within a sampling period of the seventh time length is less than or equal to the third voltage threshold, the welding current is switched to be controlled by the electronic reactor; or

[0030] At the end of the seventh time period, the welding current is switched to be controlled by the electronic reactor.

[0031] In at least one embodiment of this disclosure, a non-volatile storage medium is also provided, on which a processor-executable computer program is stored, wherein the processor is configured to perform operations in any of the above-described methods for controlling a short-circuit arc for welding.

[0032] In at least one embodiment of this disclosure, a computer program product is also provided, the computer program product including a processor-executable computer program, wherein when the computer program is executed by a processor, the processor is configured to perform the operations in any of the above-described methods for controlling a short-circuit arc for welding.

[0033] In the control method for short-circuit arc welding according to the embodiments of the present disclosure, a fixed current is output during the arc ignition stage after short circuit. At the same time, detection, identification methods and handling measures are provided for three abnormal voltages that may occur during stainless steel short-circuit welding, effectively avoiding and reducing the impact of abnormal voltages on welding during stainless steel short-circuit welding, and improving arc stability. Attached Figure Description

[0034] Figure 1 A flowchart is shown for a method of controlling a short-circuit arc for welding according to an embodiment of the present disclosure;

[0035] Figure 2 A schematic diagram is shown illustrating a method for controlling a short-circuit arc in welding according to an embodiment of the present disclosure, which processes abnormal voltage after a normal short circuit.

[0036] Figure 3 A schematic diagram is shown of a method for controlling a short-circuit arc in welding according to an embodiment of the present disclosure, which processes abnormal voltages following a minor short circuit.

[0037] Figure 4 A schematic diagram is shown illustrating the handling of abnormal voltages occurring during the electronic reactor control process in the arc-burning stage of a welding short-circuit arc control method according to an embodiment of the present disclosure. Detailed Implementation

[0038] The present disclosure will be further described in detail below with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present disclosure will become clearer and more apparent.

[0039] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0040] Furthermore, the technical features involved in the different embodiments of this disclosure described below can be combined with each other as long as they do not conflict with each other.

[0041] Welding technology for stainless steel has emerged with the widespread application of stainless steel to meet the needs of stainless steel products in various industries.

[0042] MIG welding of thin stainless steel sheets commonly employs short-circuit welding, a process that presents numerous challenges due to the inherent properties of stainless steel, such as its magnetic properties, high alloy content, low thermal conductivity, and high coefficient of linear expansion. One key difficulty lies in controlling abnormal voltages that occur during the welding process. The timing, frequency, magnitude, and duration of these abnormal voltages directly impact the stability of the welding arc and the overall weld quality.

[0043] In typical short-circuit arc welding, the short-circuit arc is controlled by an electronic reactor, but abnormal voltages are not handled. When the pulse output voltage exceeds the set voltage Va, the arc length is determined to increase, and the electronic reactor rapidly reduces the welding current, thereby reducing the welding voltage and arc length. When the actual voltage is lower than the set voltage Va, the arc length is determined to decrease, and the electronic reactor increases the welding current, thus increasing the welding arc length and voltage to achieve a suitable arc length.

[0044] However, during welding, it was found that if no abnormal voltage occurred during the welding process, the electronic reactor could accurately reflect the arc length and make adjustments, resulting in a stable welding process. But when there was an abnormal voltage during the welding process, the actual voltage could not accurately reflect the arc length. This was especially true when welding ferritic stainless steel. If an abnormal voltage occurred, the actual arc length would be lower than the actual voltage. If the electronic reactor continued to reduce the welding current, the arc length would be further shortened, leading to a larger short circuit or wire breakage, thus affecting the arc stability and weld formation.

[0045] During short-circuit welding, abnormal voltages can be classified into three types based on the timing of their generation: 1. Abnormal voltages may be generated during arc ignition after a normal short circuit; 2. Abnormal voltages may be generated during arc ignition after a minor short circuit; and 3. Abnormal voltages may suddenly occur during arc ignition.

[0046] Embodiments of this disclosure provide a method and apparatus for controlling a short-circuit arc in welding, thereby eliminating the influence of the aforementioned abnormal voltage on the arc.

[0047] At least one embodiment of this disclosure provides a method for controlling a short-circuit arc for welding, the short-circuit arc including a short-circuit stage and an arc-ignition stage, the control method comprising:

[0048] When arcing is detected during the short circuit phase, a first current is output within the first time period. The first current is the difference between the welding current during arcing and the first current compensation amount.

[0049] By outputting the first current when arc ignition begins after the short-circuit phase, abnormal voltage in the arc can be effectively controlled.

[0050] In one embodiment of this disclosure, such as Figure 1 As shown, the control method further includes

[0051] S01, detects abnormal voltage during the arcing stage;

[0052] S02, in response to detecting an abnormal voltage, outputs a fixed current; and

[0053] S03, under the condition that the preset conditions are met, the welding current is switched to be controlled by the electronic reactor.

[0054] Figure 2 A schematic diagram is shown in one embodiment of this disclosure, illustrating the elimination of the influence of abnormal voltage on the electric arc through constant current control.

[0055] As described above, the generation timing of abnormal voltage can be divided into three types: 1. After normal short circuit, abnormal voltage may be generated during the arcing stage; 2. After a minor short circuit, abnormal voltage may be generated during arcing; and 3. During the arcing process, abnormal voltage may suddenly occur.

[0056] Figure 2 It shows the processing of abnormal voltage after normal short circuit in the control method of short - circuit arc for welding according to an embodiment of the present disclosure.

[0057] As Figure 2 shown, after normal short circuit, to prevent abnormal voltage during arcing, during arcing, a first current is output within a first time length. According to the control method of short - circuit arc for welding of the present disclosure, a first current is output within the first time length T1. The first current is smaller than the welding current at the time of abnormal voltage occurrence by a first current compensation amount to effectively suppress the abnormal voltage generated instantaneously during arcing.

[0058] After the first time length, a sustaining - arc current SPI is output within a second time length. During the output of the sustaining - arc current SPI, the welding average voltage IPV1 is measured in real time. At the end of the second time length, the welding average voltage IPV1 in the last sampling period during the output of the sustaining - arc current SPI is compared with a first reference voltage Va. If the difference between the welding average voltage IPV1 in the last sampling period and the first reference voltage Va is greater than a first voltage threshold, that is, IPV1 Va>K1, then the sustaining - arc current SPI is continuously output within a third time length after the second time length until the difference between the welding average voltage IPV1 in one sampling period within the third time length and the first reference voltage Va is less than the first voltage threshold, that is, IPV1 Va<K1, or the sustaining - arc current SPI is continuously output until the end of the third time length T3. After that, the arc output is controlled by an electronic reactor. During the operation of the welding machine, one sampling period can be 200 us. The welding average voltage IPV1 in the last sampling period during the output of the sustaining - arc current SPI at the end of the second time length mentioned above refers to the welding average voltage IPV1 in the sampling period from 200 us before the end of the second time length to the end of the second time length.

[0059] Therefore, in an embodiment of the present disclosure, when the preset conditions are met, controlling the arc output by an electronic reactor includes:

[0060] At the end of the second time length T2, when the welding average voltage IPV1 in the last sampling period within the second time length and the first reference voltage Va are less than the first voltage threshold, the welding current is switched to be controlled by the electronic reactor. <s

[0061] In another embodiment of this disclosure, switching the welding current to be controlled by an electronic reactor when preset conditions are met includes:

[0062] Within the third time length T3, if the difference between the average welding voltage and the first reference voltage within one sampling period of the third time length is less than or equal to the first voltage threshold, the welding current is switched to be controlled by the electronic reactor.

[0063] During the above process, at the end of the second time period of the arc current SPI output, if the difference between the average welding voltage IPV1 and the first reference voltage Va during the second time period is less than or equal to the first voltage threshold, the welding current is switched to be controlled by the electronic reactor. If the average voltage IPV1 and the first reference voltage Va during the last sampling period of the second time period are greater than the first voltage threshold, the arc current SPI continues to be output during the next third time period T3 until the average welding voltage and the first reference voltage Va during one sampling period of the third time period are less than or equal to the first voltage threshold, or until the end of the third time period, at which point the welding current is switched to be controlled by the electronic reactor. Since the welding voltage will return to normal after an abnormal voltage occurs, i.e., the welding voltage will gradually decrease, in any sampling period of the third time period, if the average welding voltage decreases to a level where the difference between it and the first reference voltage Va is less than or equal to the first voltage threshold, the difference between the average welding voltage and the first reference voltage Va after that sampling period will definitely be less than or equal to the first voltage threshold. At this point, the continued output of the arc current SPI can be stopped.

[0064] Figure 3 A method for controlling a short-circuit arc in welding according to an embodiment of the present disclosure is shown for handling abnormal voltages that appear during arcing after a minor short circuit.

[0065] like Figure 3 As shown, a minor short circuit occurred during the short-circuit welding process, specifically, a short circuit occurred within the fourth time length T4, which is less than 0.5 ms. An abnormal voltage appeared after this minor short circuit. At this time, according to the short-circuit arc control method of this embodiment, constant current control is performed after arc ignition. That is, when igniting the arc after the short circuit, the welding current is first increased, and a second current is output within the fifth time length T5. The second current is larger than the welding current at the time of the short circuit by a second current compensation amount. The fifth time length T5 can be 0.5 ms. At the end of the fifth time length T5, the second average welding voltage IPV2 within the last sampling period of the fifth time length T5 is calculated, and the second average welding voltage IPV2 is compared with the second reference voltage Vb. If the difference between the average welding voltage IPV2 and the second reference voltage Vb is less than or equal to a second voltage threshold, i.e., IPV2... Vb If the voltage is ≤K2, the welding current will be switched to be controlled by the electronic reactor. If the difference between the second average arc voltage IPV2 and the second reference voltage Vb is greater than the second voltage threshold, i.e., IPV2-V b K2 continues constant current control, that is, it continues to output the second current, specifically, it continues to output the second current within the sixth time length T6, until IPV2-V. b ≤K2, or, at the end of the sixth time length T6, the welding current is switched to be controlled by the electronic reactor. During the operation of the welding machine, a sampling period can be 200µs. The last sampling period within the fifth time length T5 refers to the sampling period from 200µs before the end of the fifth time length to the end of the fifth time length.

[0066] Therefore, in one embodiment of this disclosure, outputting a fixed current in response to detecting an abnormal voltage includes:

[0067] In response to the detection that the time of the short circuit is less than the fourth time length, a second current is output during the fifth time length while the arc is ignited, wherein the second current is greater than the welding current at the time of the short circuit by a second current compensation amount.

[0068] In one embodiment of this disclosure, the fourth time length is less than 0.5 ms, and the fifth time length is 0.5 ms.

[0069] In one embodiment of this disclosure, if the difference between the second welding average voltage IPV2 and the second reference voltage Vb in the last sampling period within the fifth time length is greater than the second voltage threshold, the second current continues to be output after the sixth time length.

[0070] In one embodiment of this disclosure, switching the welding current to be controlled by an electronic reactor when preset conditions are met includes:

[0071] At the end of the fifth time period, if the difference between the second average welding voltage IPV2 and the second reference voltage Vb in the last sampling period of the fifth time period is less than or equal to the second voltage threshold, the welding current will be switched to be controlled by the electronic reactor; or

[0072] If, within the sixth time period, the difference between the second average welding voltage IPV2 and the second reference voltage Vb within one sampling period of the sixth time period is less than or equal to the second voltage threshold, the welding current is switched to be controlled by the electronic reactor; or

[0073] At the end of the sixth time period, the welding current is switched to be controlled by the electronic reactor.

[0074] After an abnormal voltage occurs, the welding voltage will gradually return to normal, meaning the welding voltage will gradually decrease. Within one sampling period of the sixth time length, if the difference between the second average welding voltage IPV2 and the second reference voltage Vb is less than or equal to the second voltage threshold, then the difference between the second average welding voltage IPV2 and the second reference voltage Vb after that sampling period will also be less than or equal to the second voltage threshold. At this point, the output of the second current can be terminated. Figure 4 The present disclosure illustrates a method for controlling a short-circuit arc in welding according to an embodiment of the present disclosure, which addresses the handling of abnormal voltages during the control process of an electronic reactor in the arc-burning stage.

[0075] During short-circuit welding, in the arc-burning stage, the electronic reactor continuously monitors the welding voltage change rate dv / dt. When the welding voltage change rate dv / dt is greater than or equal to the change rate threshold K3, i.e., dv / dt≥K3, an abnormal voltage is determined. In response to the determination of an abnormal voltage, the welding current at the time of the abnormal voltage is output within the seventh time length until the difference between the welding average voltage IPV3 and the third voltage reference value Vc within the seventh time length is less than or equal to the third voltage threshold K4, or at the end of the seventh time length, the welding current is switched to be controlled by the electronic reactor.

[0076] In one embodiment of this disclosure, detecting abnormal voltage includes: continuously detecting the rate of change of welding voltage during the arc-burning stage electronic reactor control process, and determining that an abnormal voltage has been detected when the rate of change of welding voltage is greater than or equal to a rate of change threshold.

[0077] In one embodiment of this disclosure, outputting a fixed current in response to detecting an abnormal voltage includes:

[0078] In response to the detection of an abnormal voltage, the welding current at the time of the abnormal voltage is output within a seventh time period.

[0079] In one embodiment of this disclosure, switching the welding current to be controlled by an electronic reactor when preset conditions are met includes:

[0080] Within the seventh time period, if the difference between the average welding voltage IPV3 and the third reference voltage Vc within one sampling period is less than or equal to the third voltage threshold, the welding current will be switched to be controlled by the electronic reactor; or

[0081] At the end of the seventh time period, the welding current is switched to be controlled by the electronic reactor.

[0082] The foregoing description and explanation of the short-circuit arc control method for welding according to embodiments of this disclosure, in conjunction with three types of abnormal voltages that may occur during stainless steel short-circuit welding, have provided an explanation. The parameters involved, such as the first current compensation amount, the second current compensation amount, the first reference voltage, the first voltage threshold, the second reference voltage, the second voltage threshold, the third reference voltage, the third voltage threshold, the rate of change threshold, the first time length, the second time length, the third time length, the fourth time length, the fifth time length, the sixth time length, and the seventh time length, are related to the welding conditions and vary with the welding conditions (e.g., wire diameter, shielding gas, or current value).

[0083] By using the short-circuit arc control method for welding according to the embodiments of this disclosure, three abnormal voltages that may occur during stainless steel short-circuit welding can be detected, identified, and dealt with, effectively avoiding and reducing the impact of abnormal voltages on welding during stainless steel short-circuit welding and improving arc stability.

[0084] At least one embodiment of this disclosure also provides a non-volatile storage medium having a processor-executable computer program stored thereon, the processor being configured to perform operations in any of the above-described methods for controlling a short-circuit arc for welding, in response to the processor executing the computer program.

[0085] At least one embodiment of this disclosure also provides a computer program product including a processor-executable computer program, wherein when the computer program is executed by a processor, the processor is configured to perform the operations in any of the above-described control methods for short-circuit arcs used in welding.

[0086] In the description of this disclosure, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "back", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship in the working state of this disclosure, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0087] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. Those skilled in the art can understand the specific meaning of these terms in this disclosure based on the specific circumstances.

[0088] The present disclosure has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present disclosure based on these embodiments, all of which fall within the protection scope of the present disclosure.

Claims

1. A method for controlling a short-circuit arc for welding, wherein the short-circuit arc includes a short-circuit stage and an arc-ignition stage, wherein, The control method includes: When detecting arcing during the short-circuit phase, the first current is output within the first time length. The first current is the difference between the welding current during arcing and the first current compensation amount. This also includes: Detect abnormal voltages during the arcing stage; In response to the detection of an abnormal voltage, a fixed current is output; and Under preset conditions, the welding current is switched to be controlled by the electronic reactor; The function of outputting a fixed current in response to the detection of an abnormal voltage includes: In response to detecting that the difference between the average welding voltage and the first reference voltage in the last sampling period within the second time length of the output arc current is greater than the first voltage threshold, the output arc current continues after the second time length. Among these measures, switching the welding current to be controlled by the electronic reactor, under preset conditions, includes: At the end of the second time period, if the difference between the average welding voltage and the first reference voltage during the last sampling period of the second time period is less than or equal to the first voltage threshold, the welding current will be switched to be controlled by the electronic reactor; or If the difference between the average welding voltage and the first reference voltage within a sampling period in the third time length is less than or equal to the first voltage threshold, the welding current will be switched to be controlled by the electronic reactor; or At the end of the third time period, the welding current is switched to be controlled by the electronic reactor.

2. The method for controlling a short-circuit arc for welding according to claim 1, wherein, In response to the detection of an abnormal voltage, the output of a fixed current also includes: In response to the detection of a short circuit within a fourth time period, a second current is output within a fifth time period, wherein the second current is greater than the welding current at the time of the short circuit by a second current compensation amount. The fourth time interval is less than 0.5ms, and the fifth time interval is equal to 0.5ms.

3. The method for controlling a short-circuit arc for welding according to claim 2, further comprising: At the end of the fifth time period, if the difference between the welding average voltage and the second reference voltage in the last sampling cycle of the fifth time period is greater than the second voltage threshold, the second current continues to be output in the sixth time period.

4. The method for controlling a short-circuit arc for welding according to claim 2, wherein, Under preset conditions, switching the welding current to be controlled by the electronic reactor includes: At the end of the fifth time period, if the difference between the average welding voltage and the second reference voltage during the last sampling period of the fifth time period is less than or equal to the second voltage threshold, the welding current will be switched to be controlled by the electronic reactor; or If the difference between the average welding voltage and the second reference voltage within a sampling period over the sixth time period is less than or equal to the second voltage threshold, the welding current will be switched to be controlled by the electronic reactor; or At the end of the sixth time period, the welding current is switched to be controlled by the electronic reactor.

5. The method for controlling a short-circuit arc for welding according to claim 1, wherein, In response to the detection of an abnormal voltage, a fixed current is output, including: During the arc-burning stage of electronic reactor control, the welding voltage change rate is continuously monitored. When the welding voltage change rate is greater than or equal to a threshold value, an abnormal voltage is detected. In response to the detection of an abnormal voltage, the welding current at the time of the abnormal voltage is output within the seventh time period; Among these measures, switching the welding current to be controlled by the electronic reactor, under preset conditions, includes: When the difference between the average welding voltage and the third reference voltage within a sampling period of the seventh time length is less than or equal to the third voltage threshold, the welding current is switched to be controlled by the electronic reactor; or At the end of the seventh time period, the welding current is switched to be controlled by the electronic reactor.

6. A non-volatile storage medium having a processor-executable computer program stored thereon, the processor being configured to perform operations in the control method for a short-circuit arc for welding as described in any one of claims 1 to 5, in response to the processor executing the computer program.

7. A computer program product comprising a processor-executable computer program, wherein when the computer program is executed by a processor, the processor is configured to perform operations in the control method for a short-circuit arc for welding as described in any one of claims 1 to 5.

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