Control method for an arc welding machine for steel structure welding

Abstract

The present invention relates to the technical field of welding equipment, and particularly relates to a control method for an arc welding machine used for welding steel structures. During the welding process, the melting speed of the welding rod and the depth of the weld seam are obtained. According to the welding standard, the melting speed of the welding rod has a first preset range, and the depth of the weld seam has a second preset range. When the melting speed of the welding rod is within the first preset range and the depth of the weld seam is within the second preset range, the welded part completed at this time meets the standard. If the melting speed of the welding rod is not within the first preset range, or the depth of the weld seam is within the second preset range, an adjustment program is used to adjust the heat input ratio between the welding rod and the welded part, and to adjust the total heat input of the welding rod and the welded part, so as to ensure that the welded part completed by welding meets the standard.

Description

Technical Field

[0001] The present invention relates to the technical field of welding equipment, and particularly to a control method for an arc welding machine used in steel structure welding. Background Art

[0002] Welding, as a key connection technology in the industrial manufacturing field, realizes the combination between metal atoms through heating, high temperature or high pressure. Its process stability directly determines the product quality. There are many energy sources for modern welding, including gas flame, arc, laser, electron beam, friction, and ultrasonic wave, etc. During the arc welding process, the positive pole of the direct current is connected to the workpiece or the electrode, and the negative pole of the direct current is connected to the electrode or the workpiece. Continuously maintaining the straight polarity or reverse polarity of the direct current will cause excessive heat input concentration on the electrode or the welded part, which may lead to an excessive temperature gradient between the electrode and the welded part, causing local thermal stress concentration, resulting in electrode spatter or excessive penetration, or even thermal cracks in the weld seam, damaging the strength and reliability of the welded structure, and making the welding quality unqualified. Summary of the Invention

[0003] The present invention provides a control method for an arc welding machine used in steel structure welding to solve the problem of unstable welding quality during the welding process of the existing welding machine for workpieces.

[0004] The control method for an arc welding machine used in steel structure welding of the present invention adopts the following technical solutions:

[0005] A control method for an arc welding machine used in steel structure welding includes the following steps:

[0006] S100: Determine the welding current and welding voltage;

[0007] S200: Obtain the heat input ratio of the electrode to the welded part;

[0008] S300: Obtain the melting speed of the electrode and the depth of the weld seam;

[0009] S400: If the melting speed of the electrode is not within the first preset range, or / and, if the depth of the weld seam is not within the second preset range, then execute the adjustment program to adjust the heat input ratio of the electrode to the welded part, and at the same time, the adjustment program can adjust the total heat input of the electrode to the welded part.

[0010] Furthermore, the adjustment program in step S400 is divided into a first adjustment program, a second adjustment program, and a third adjustment program. The first adjustment program is used to adjust the heat input ratio of the electrode to the welded part; the second adjustment program adjusts the total heat input of the electrode to the welded part; the third adjustment program can both adjust the heat input ratio of the electrode to the welded part and adjust the total heat input of the electrode to the welded part.

[0011] Further, step S400 further includes:

[0012] S410: If the melting speed of the welding rod is greater than the maximum value of the first preset range and the depth of the weld seam is less than the minimum value of the second preset range, or if the melting speed of the welding rod is less than the minimum value of the first preset range and the depth of the weld seam is greater than the maximum value of the second preset range, then execute the first adjustment program to adjust the heat input ratio between the welding rod and the welded part.

[0013] Further, step S400 further includes:

[0014] S420: If the melting speed of the welding rod is greater than the maximum value of the first preset range and the depth of the weld seam is greater than the maximum value of the second preset range, or if the melting speed of the welding rod is less than the minimum value of the first preset range and the depth of the weld seam is less than the minimum value of the second preset range, then execute the second adjustment program to adjust the total heat input of the welding rod and the welded part.

[0015] Further, step S400 further includes:

[0016] S430: If the melting speed of the welding rod is within the first preset range and the depth of the weld seam is greater than the maximum value or less than the minimum value of the second preset range, or if the melting speed of the welding rod is greater than the maximum value or less than the minimum value of the first preset range and the depth of the weld seam is within the second preset range, then execute the third adjustment program to first adjust the heat input ratio between the welding rod and the welded part, and then adjust the total heat input of the welding rod and the welded part again.

[0017] Further, the first adjustment program in step S410 includes:

[0018] S411: Obtain the DC connection method between the welded part and the welding rod;

[0019] S412: Control the total heat input to the welding rod and the welded part to remain unchanged;

[0020] S413: Adjust the time ratio of AC connection to DC connection between the welded part and the welding rod.

[0021] Further, the second adjustment program in step S420 includes:

[0022] S421: Adjust the output voltage or output current of the welding power source when welding the welded part and the welding rod.

[0023] Further, the third adjustment program in step S430 includes:

[0024] S431: Adjust the time ratio of AC connection to DC connection between the welded part and the welding rod;

[0025] S432: Adjust the total heat input of the welding electrode and the weldment according to the adjusted time ratio of the AC connection to the DC connection.

[0026] Further, in step S300, the melting speed of the welding electrode and the depth of the weld seam are both obtained by a distance sensor.

[0027] Further, in step S100, an inverter is provided on the welding power source. The inverter can change the output polarity of the welding power source and can also change the current mode output by the welding power source.

[0028] The beneficial effects of the present invention are as follows: When the control method of an arc welding machine for steel structure welding of the present invention is executed, first, the welding voltage and welding current of the initial welding power source are determined. During the welding process, the way the welding electrode and the weldment are connected to the welding power source can change the heat input ratio between the welding electrode and the weldment. During conventional welding, the DC connection method is usually used for welding. When the positive pole of the welding power source is connected to the welding electrode and when the positive pole is connected to the weldment, the heat input ratio between the welding electrode and the weldment is different. During the welding process, the melting speed of the welding electrode and the depth of the weld seam are obtained. According to the welding standard, the melting speed of the welding electrode has a first preset range, and the depth of the weld seam has a second preset range. When the melting speed of the welding electrode is within the first preset range and the depth of the weld seam is within the second preset range, the weldment completed by welding meets the standard at this time. If the melting speed of the welding electrode is not within the first preset range, or the depth of the weld seam is within the second preset range, an adjustment program is used to adjust the heat input ratio between the welding electrode and the weldment, and to adjust the total heat input of the welding electrode and the weldment, so as to ensure that the weldment completed by welding meets the standard. Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a flowchart of a control method for an arc welding machine for steel structure welding provided by an embodiment of the present invention. Detailed Embodiments

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the described objects and do not have any sequential or technical meanings. The "connection" and "coupling" mentioned in this application, unless otherwise specified, both include direct and indirect connections (couplings). In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0033] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature may mean that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0034] As Figure 1 shown, a control method for an arc welding machine for steel structure welding provided by an embodiment of the present invention includes the following steps:

[0035] S100: Determine the welding current and welding voltage. The output current of the welding power source is the welding current, and the output voltage of the welding power source is the welding voltage.

[0036] S200: Obtain the heat input ratio between the welding electrode and the welded part. The heat input refers to the total energy delivered from the electrical energy in the welding power source to the welding electrode and the welded part during the welding process. When the direct current is straight polarity, the heat input ratio between the welding electrode and the welded part is generally 3:7; when the direct current is reverse polarity, the heat input ratio between the welding electrode and the welded part is generally 7:3; when the alternating current is connected to the welding electrode and the welded part, the heat input ratio between the welding electrode and the welded part is generally 1:1.

[0037] S300: Obtain the melting speed of the welding electrode and the depth of the weld seam. The melting speed of the welding electrode and the depth of the weld seam are both obtained through a distance sensor. A distance sensor is provided on the welding electrode, and the distance sensor is used to detect the length change of the welding electrode per unit time, so as to obtain the melting speed of the welding electrode, and set the melting speed of the welding electrode as V a A distance sensor is also provided at the weld position of the welded part. The distance sensor can obtain the depth of the weld seam, and set the depth of the weld seam as H a .

[0038] S400: If the melting speed of the welding electrode is not within the first preset range, or / and, if the depth of the weld seam is not within the second preset range, then execute the adjustment program to adjust the heat input ratio of the welding electrode and the welded part, and at the same time the adjustment program can adjust the total heat input of the welding electrode and the welded part. Specifically, during the welding process, the melting speed of the welding electrode has a first preset range. When the melting speed of the welding electrode is within the first preset range, the slag of the welding electrode does not splash. The depth of the weld seam has a second preset range. When the depth of the weld seam is within the second preset range, the welded part after welding is stable and reliable. The first preset range of the melting speed of the welding electrode is set as V min to V max , and the second preset range of the depth of the weld seam is set as H min to H max . When the melting speed of the welding electrode is not within the first preset range, the adjustment program needs to adjust the heat input ratio of the welding electrode and the welded part, and at the same time adjust the total heat input of the welding electrode and the welded part; when the depth of the weld seam is not within the second preset range, the adjustment program needs to adjust the heat input ratio of the welding electrode and the welded part, and at the same time adjust the total heat input of the welding electrode and the welded part. That is, according to the actual value V a of the melting speed of the welding electrode and the actual value H a of the depth of the weld seam, judge whether the inequality V min <V a <V max holds, and at the same time judge whether the inequality H min <H a <H max holds. If one of the inequalities does not hold or both inequalities do not hold, then use the adjustment program to adjust the heat input ratio of the welding electrode and the welded part, and at the same time adjust the total heat input of the welding electrode and the welded part.

[0039] Specifically, the adjustment program in step S400 is divided into a first adjustment program, a second adjustment program and a third adjustment program. The first adjustment program is used to adjust the heat input ratio of the welding electrode and the welded part; the second adjustment program adjusts the total heat input of the welding electrode and the welded part; the third adjustment program can both adjust the heat input ratio of the welding electrode and the welded part and adjust the total heat input of the welding electrode and the welded part.

[0040] In one of the embodiments, step S400 further includes:

[0041] S410: If the melting speed of the welding electrode is greater than the maximum value of the first preset range and the depth of the weld seam is less than the minimum value of the second preset range. In other words, the actually measured melting speed V of the welding electrode a > V max , and the actually measured depth H of the weld seam a < H min ; or, the melting speed of the welding electrode is less than the minimum value of the first preset range and the depth of the weld seam is greater than the maximum value of the second preset range. In other words, the actually measured melting speed V of the welding electrode a < V min , and the actually measured depth H of the weld seam a > H max ; If the melting speed of the welding electrode and the depth of the weld seam meet the above two conditions, then execute the first adjustment program to adjust the heat input ratio between the welding electrode and the welded part.

[0042] In this embodiment, the first adjustment program in step S410 includes:

[0043] S411: Obtain the DC connection method between the welded part and the welding electrode. Before welding, connect the positive pole of the welding power supply to the welded part or the welding electrode. When the positive pole of the welding power supply is connected to the welded part, the welding electrode is connected to the negative pole of the welding power supply. At this time, it is DC straight polarity. When using DC straight polarity, the welded part is heated more and is suitable for welding thick welded parts. When the negative pole of the welding power supply is connected to the welded part, the welding electrode is connected to the positive pole of the welding power supply. At this time, it is DC reverse polarity. When using DC reverse polarity, the welded part is heated less and is suitable for welding thin welded parts.

[0044] S412: Control the total heat input to the welding electrode and the welded part to remain unchanged. Ensure that the output voltage and output current of the welding power supply remain unchanged, then the total output power of the welding power supply remains unchanged. On the premise that the connection method of the welded part and the welding electrode to the welding power supply remains unchanged, the total heat input of the welding electrode and the welded part remains unchanged.

[0045] S413: Adjust the time ratio of AC connection and DC connection between the welded part and the welding electrode. There is an inverter on the welding power supply. The inverter can change the output polarity of the welding power supply and can also change the way of the output current of the welding power supply. Specifically, the way of the output current of the welding power supply is divided into DC and AC. When the welding power supply uses AC to connect the welded part and the welding electrode, the heat input ratio between the welding electrode and the welded part is 1:1. Then after connecting the welded part and the welding electrode with AC, the heat input ratio between the welding electrode and the welded part changes. On the premise that the total heat input of the welding electrode and the welded part remains unchanged, the actually measured melting speed V of the welding electrode a and the actually measured depth H of the weld seam aAll change to ensure that V min <V a <V max is established, and at the same time H min <H a <H max is established, thus ensuring that the welded parts after welding meet the standards.

[0046] Further, after connecting the welded part and the welding electrode with alternating current, the heat input ratio between the welding electrode and the welded part changes. In unit time, the heat input ratio of the welding electrode and the welded part during DC welding multiplied by the DC welding time, plus the heat input ratio of the welding electrode and the welded part during AC welding multiplied by the AC welding time, is equal to the adjusted heat input ratio of the welding electrode and the welded part multiplied by the unit time; when calculating, preset an adjusted heat input ratio between the welding electrode and the welded part, calculate the AC welding time according to the preset heat input ratio between the welding electrode and the welded part, and perform trial welding according to the calculated time, and measure the melting speed V of the welding electrode during the welding process a and the depth H of the weld a , and judge the inequality V min <V a <V max and H min <H a <H max whether it holds. If it does not hold, preset an adjusted heat input ratio between the welding electrode and the welded part again, and repeat this process until V min <V a <V max and H min <H a <H max holds.

[0047] In one embodiment, step S400 further includes:

[0048] S420: If the melting speed of the welding electrode is greater than the maximum value of the first preset range, and the depth of the weld is greater than the maximum value of the second preset range. In other words, the actually measured melting speed V of the welding electrode a >V max , and the actually measured depth H of the weld a >H max ; or, the melting speed of the welding electrode is less than the minimum value of the first preset range, and the depth of the weld is less than the minimum value of the second preset range. In other words, the actually measured melting speed V of the welding electrode a <V min , and the actually measured depth H of the weld a <H min ; If the melting speed of the welding electrode and the depth of the weld belong to the above two conditions, then execute the second adjustment program to adjust the total heat input of the welding electrode and the welded part.

[0049] In this embodiment, the second adjustment program in step S420 includes:

[0050] S421: Adjust the output voltage or output current of the welding power source during the welding of the welded part and the welding electrode. On the premise that the connection method between the welded part and the welding electrode to the welding power source remains unchanged, by adjusting the output voltage or output current of the welding power source, the total heat input of the welded part and the heat input of the welding electrode during welding are changed, and the actually measured melting speed V of the welding electrode a and the actually measured depth H of the weld a both change, ensuring that V min <V a <V max is established, and at the same time H min <H a <H max is established, so as to ensure that the welded part after welding meets the standards.

[0051] In one of the embodiments, step S400 further includes:

[0052] S430: If the melting speed of the welding electrode is within the first preset interval, and the depth of the weld is greater than the maximum value of the second preset interval or less than the minimum value of the second preset interval. In other words, the actually measured melting speed of the welding electrode makes V min <V a <V max established, and the actually measured depth H of the weld a <H min or H a >H max ; or, the melting speed of the welding electrode is greater than the maximum value of the first preset interval or less than the minimum value of the first preset interval, and the depth of the weld is within the second preset interval. In other words, the actually measured melting speed of the welding electrode V a <V min or V a >V max , and the actually measured depth of the weld makes H min <H a <H max established; if the melting speed of the welding electrode and the depth of the weld belong to the above two conditions, then execute the third adjustment program to first adjust the heat input ratio of the welding electrode and the welded part, and then adjust the total heat input of the welding electrode and the welded part.

[0053] In this embodiment, the third adjustment program in step S430 includes:

[0054] S431: Adjust the time ratio between the AC connection and the DC connection between the welded part and the welding electrode. During the DC welding process, when switching to AC welding, the heat input ratio between the welded part and the welding electrode will change. Without adjusting the total heat input of the welding electrode and the welded part, the heat input of both the welded part and the welding electrode will change. The actually measured melting speed V of the welding electrode a and the actually measured weld depth H a both change. Within a unit time, the heat input ratio of the welding electrode and the welded part during DC welding multiplied by the DC welding time, plus the heat input ratio of the welding electrode and the welded part during AC welding multiplied by the AC welding time, is equal to the adjusted heat input ratio of the welding electrode and the welded part multiplied by the unit time. When calculating, preset an adjusted heat input ratio between the welding electrode and the welded part, and calculate the AC welding time based on the preset heat input ratio between the welding electrode and the welded part. During this process, one of the ratios of the welding electrode or the welded part in the preset adjusted heat input ratio between the welding electrode and the welded part remains unchanged. For example, when the DC connection heat input ratio between the welding electrode and the welded part is 3:7, the preset adjusted heat input ratio between the welding electrode and the welded part is 3:8.

[0055] S432: Adjust the total heat input of the welding electrode and the welded part according to the adjusted time ratio between the AC connection and the DC connection. During the DC welding process, if the actually measured melting speed of the welding electrode makes V min <V a <V max hold, or the actually measured weld depth makes H min <H a <H max hold, then calculate the heat input of the qualified welding electrode or welded part according to the proportion of the qualified welding electrode or welded part in the total heat input. Subsequently, based on the preset adjusted heat input ratio between the welding electrode and the welded part in step S431, calculate the adjusted total heat input of the welding electrode and the welded part. The time ratio of DC welding and AC welding calculated in step S431 is used to attempt welding simultaneously with the adjusted total heat input of the welding electrode and the welded part calculated in step S432, and measure the melting speed V of the welding electrode a and the weld depth H a during the welding process, and determine whether the inequalities V min <V a <V max and H min <H a <H max hold. If not, preset an adjusted heat input ratio between the welding electrode and the welded part again, and repeat this process until V min <V a <V max and H min <H a <H max hold.

[0056] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An intelligent control method for a steel structure welding machine, characterized in that: It includes the following steps: S100: Determine the welding current and welding voltage; An inverter is provided on the welding power source, which can change the output polarity of the welding power source and can also change the current mode output by the welding power source; S200: Obtain the heat input ratio of the welding rod to the welded part; S300: Obtain the melting speed of the welding rod and the depth of the weld; S400: If the melting speed of the welding rod is not within the first preset range, or / and, if the depth of the weld is not within the second preset range, then execute an adjustment program to adjust the heat input ratio of the welding rod and the welded part. At the same time, the adjustment program can adjust the total heat input of the welding rod and the welded part. Among them, within the first preset range, the welding slag of the welding rod does not splash; within the second preset range, the welded part after welding is stable and reliable; The adjustment program is divided into a first adjustment program, a second adjustment program, and a third adjustment program. The first adjustment program is used to adjust the heat input ratio of the welding rod and the welded part; The second adjustment program adjusts the total heat input of the welding rod and the welded part; The third adjustment program can both adjust the heat input ratio of the welding rod and the welded part and adjust the total heat input of the welding rod and the welded part; S410: If the melting speed of the welding rod is greater than the maximum value of the first preset range and the depth of the weld is less than the minimum value of the second preset range, or the melting speed of the welding rod is less than the minimum value of the first preset range and the depth of the weld is greater than the maximum value of the second preset range, then execute the first adjustment program to adjust the heat input ratio of the welding rod and the welded part; S420: If the melting speed of the welding rod is greater than the maximum value of the first preset range and the depth of the weld is greater than the maximum value of the second preset range, or the melting speed of the welding rod is less than the minimum value of the first preset range and the depth of the weld is less than the minimum value of the second preset range, then execute the second adjustment program to adjust the total heat input of the welding rod and the welded part; S430: If the melting speed of the welding rod is within the first preset range and the depth of the weld is greater than the maximum value or less than the minimum value of the second preset range, or the melting speed of the welding rod is greater than the maximum value or less than the minimum value of the first preset range and the depth of the weld is within the second preset range, then execute the third adjustment program to first adjust the heat input ratio of the welding rod and the welded part, and then adjust the total heat input of the welding rod and the welded part again; The first adjustment program includes: S411: Obtain the DC connection method between the welded part and the welding rod; S412: Control the total heat input of the welding rod and the welded part to remain unchanged; S413: Adjust the time ratio of AC connection to DC connection between the welded part and the welding rod; The second adjustment program includes: S421: Adjust the output voltage or output current of the welding power source when welding the welded part and the welding rod; The third adjustment program includes: S431: Adjust the time ratio of AC connection to DC connection between the welded part and the welding rod; S432: Adjust the total heat input of the welding rod and the welded part according to the adjusted time ratio of AC connection to DC connection.

2. The intelligent control method of a steel structure welding machine according to claim 1, characterized in that: In step S300, both the melting speed of the welding rod and the depth of the weld are obtained by a distance sensor.

Images