Method for testing arc welding device

Abstract

The invention discloses a method for testing an electric arc welding device, and in the electric arc welding device testing method based on the quality of a welding seam, welding parameters are recorded by recording current and voltage oscillogram of the actual electric arc welding device when the electric arc welding device performs welding on a sample. And the recorded parameters are compared with corresponding welding parameters when the reference arc welding device is used, and the welding seam quality and the welding performance of the actual arc welding device are evaluated according to the comparison result. According to the electric arc welding equipment testing method, equipment which cannot guarantee the welding joint quality and the welding work quality can be excluded, and the reliability of testing the electric arc welding equipment when the welding performance of the electric arc welding equipment is determined is improved.

Description

Technical Field

[0001] The invention relates to the field of welding production and can be used for the certification of welding equipment in various industrial fields. Background Art

[0002] Currently, modern welding production places increasingly complex tasks on welding equipment manufacturers, requiring the development of new welding methods to increase the speed and quality of welding work. To solve these problems, welding equipment developers have launched new welding devices that implement various welding methods on the Russian and international markets. However, in order to obtain high-quality welded joints, welding devices need to be tested (certified). However, currently available methods for evaluating the welding performance of arc welding equipment cannot fully evaluate the welding performance of the equipment, because the evaluation is performed by experts, which means that the evaluation is subjective.

[0003] Existing welding technology solutions around the world mainly focus on the control of the welding process, and rarely involve testing of welding equipment, such as evaluating welding performance that affects the quality of welded joints, or only partially evaluating welding performance (for example, evaluating the stability of the process only through statistical characteristics, or only evaluating the quality of electrode metal transfer without involving the quality of the welded joint itself) (see: ГладковЭ.Α. "Process and Equipment Management in Welding Process". - Moscow: Αкадемия Publishing House, 2006).

[0004] A technology for controlling and managing an electric welding process is known, which is characterized by creating a reference database of current spectra for a welding power source and directly acquiring the current spectrum during the welding process, and performing a comprehensive instantaneous evaluation of the welding quality by extracting harmonics of the short-circuit current from the acquired spectrum, which harmonics characterize the spectrum of the welding power source (Russian Patent 2319586, Classification No. Β23К9 / 10, 2005).

[0005] This technical solution can partially evaluate the welding performance of welding equipment, that is, only evaluate the stability of the welding process.

[0006] In terms of technical essence and implementation effect, the technical solution closest to the present invention is a method for testing arc welding devices based on weld quality. This method records welding parameters by recording the current and voltage waveforms of an actual arc welding device when welding on a sample, and compares the recorded parameters with the corresponding welding parameters when using a reference arc welding device, and evaluates the weld quality and the welding performance of the actual arc welding device based on the comparison results (see Russian National Standard 25615 (GOST 25616) "Arc welding power source. Welding performance test method").

[0007] Yet, known technical scheme can only subjectively assess the performance of welding equipment.In addition, this assessment is only carried out after the welding process is completely finished, and the welding performance and weld quality of arc welding device cannot be assessed in real time. Summary of the invention

[0008] The technical problem that the present invention aims to solve is to improve the quality of welded joints and welding work by means of a more comprehensive, objective and expert-independent testing method for arc welding equipment.

[0009] The above technical effects are achieved in the following ways: the arc welding device testing method proposed in the present invention adds a statistical processing method for welding mode parameters, thereby improving the reliability of the test and being able to more accurately determine the welding performance of the arc welding equipment.

[0010] Implementation method: In the arc welding device testing method based on weld quality, the welding parameters are recorded by recording the current and voltage waveforms of the actual arc welding device when welding on the sample, and the recorded parameters are compared with the corresponding welding parameters when using the reference arc welding device, and the weld quality and the welding performance of the actual arc welding device are evaluated according to the comparison results. In addition, the present invention also adds a reference to the actual device.

[0011] High frequency range (500–5000 Hz): characterizes the spatial stability of the arc;

[0012] Medium frequency range (10–500 Hz): characterizes the transfer of electrode metal;

[0013] Low frequency range (0.1–10 Hz): Characterizes the oscillation frequency of the welding pool and the quality of weld formation.

[0014] Then, the actual arc welding device and the reference arc welding device are determined according to the following formula:

[0015]

[0016] K vi : Coefficient of variation of a parameter of welding mode;

[0017] σ i : Standard deviation of a parameter of welding mode;

[0018] M(π i ): The mathematical expectation value of a parameter of the welding mode.

[0019] The quality of the weld is determined by comparing the obtained coefficients and the comparison results are used to test the arc welding device.

[0020] In addition, the proposed method determines the corresponding welding mode according to the information processing frequency range and process characteristics. After frequency processing the current and voltage waveforms in the range of 500-5000 Hz, the coefficient of variation of the welding mode parameters - arcing current, arcing time, short-circuit current, short-circuit frequency, short-circuit time, arc current, and arc current are determined. After frequency processing of the current and voltage waveforms in the range of 10-500 Hz, the coefficients of variation of the welding mode parameters – arc current, arc time, short-circuit current, short-circuit frequency, short-circuit time, arc voltage – were determined.

[0021] After frequency processing within the range, the arc power and its corresponding coefficient of variation within a specific time period are determined.

[0022] Next, the proposed method suggests using an inverter as the power source for the arc welding equipment and performing welding by short-circuiting arc gap, controlled dripping electrode metal transfer or pulse welding, wherein the coefficient of variation of the welding mode parameters within each information frequency range is determined - pulse current, pulse time, pulse frequency, pulse voltage, arc current, arc time, arc voltage, as well as welding current, arc voltage, arc power within a given time period.

[0023] The proposed arc welding equipment testing method can exclude the use of equipment that cannot guarantee the quality of welded joints and welding work, and improves the reliability of arc welding equipment testing when determining its welding performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below with reference to the accompanying drawings.

[0025] Figure 1 A is the current waveform diagram in Example 1, and B is the voltage waveform diagram in Example 1.

[0026] Figure 2 This is a signal diagram after the voltage waveform is filtered in Example 1.

[0027] Figure 3 This is the appearance of the weld obtained during welding in Example 1.

[0028] Figure 4 A is the current waveform diagram in Example 2, and B is the voltage waveform diagram in Example 2.

[0029] Figure 5 This is a signal diagram after the voltage waveform is filtered in Example 2.

[0030] Figure 6 This is the appearance of the weld obtained during welding in Example 2. DETAILED DESCRIPTION

[0031] On the prepared samples, welding is performed in the optimal mode using the reference equipment and the actual arc welding equipment. During the welding process, the waveforms of the arc current and voltage are recorded using an oscilloscope or a dedicated welding parameter recorder, and the recording frequency should be sufficient for subsequent waveform processing. Subsequently, the current and voltage waveforms are frequency processed in the range of 0.1 to 5000 Hz, and the information frequency ranges - high frequency (500–5000 Hz), medium frequency (10–500 Hz) and low frequency (0.1–10 Hz) are separated by filters. The range of 0.1 to 5000 Hz is selected because this frequency range contains information on the spatial position of the anode and cathode spots, the fluid dynamics of the welding pool, and the electrode metal transfer process. Frequencies below 0.1 Hz cannot evaluate the weld formation quality in real time because the welding and molten pool crystallization processes occur faster. It is unreasonable to process waveforms at frequencies above 5000 Hz because all processes at these frequencies cannot affect the weldability of the equipment and the weld formation quality. Then, the coefficient of variation of the welding mode parameters of the actual and reference arc welding equipment is determined according to the formula, at least for a selected information frequency range:

[0032]

[0033] K vi : Coefficient of variation of welding mode parameters;

[0034] σ i : Standard deviation of a parameter of welding mode;

[0035] M(π i ): Mathematical expectation value of welding mode parameters.

[0036] It is necessary to illustrate the determination of the coefficient of variation of welding mode parameters by comparing the welding current waveforms. When comparing the current waveforms of the actual equipment and the reference equipment, the instantaneous values ​​at the same moment are usually compared, rather than the complete welding stages that directly affect the weld quality (such as the droplet formation stage, the droplet transition to the molten pool stage, etc.). By using the coefficient of variation, the current stability of each stage of the welding process can be evaluated separately, thereby evaluating the weld quality over the entire welding time.

[0037] According to the proposed method, the coefficients of variation of the welding mode parameters are determined when welding samples using the reference equipment and the actual equipment. The obtained coefficients of variation that determine the weld quality are compared, and the welding performance of the arc welding equipment is evaluated based on the comparison results.

[0038] Therefore, instead of comparing waveforms directly, comparing the coefficients of variation mentioned above is the most accurate and reliable way to test arc welding equipment and evaluate its welding performance.

[0039] According to the present invention, the frequency processing range is divided into three information frequency ranges:

[0040] High frequency range (500–5000 Hz): Characterizes the spatial stability of the arc, i.e. the movement of the anode and cathode spots. Determines the coefficient of variation of the following parameters: arcing current, arcing time, short-circuit current, short-circuit frequency, short-circuit time, arc voltage.

[0041] Medium frequency range (10–500 Hz): Characterizes the transfer of electrode metal. Determines the coefficient of variation of the following parameters: arc current, arc time, short-circuit current, short-circuit frequency, short-circuit time, arc voltage.

[0042] Low frequency range (0.1–10 Hz): Characterizes the vibration frequency of the weld pool and contains signals about the quality of the weld formation. Determination of the coefficient of variation of the following parameters: welding current, arc voltage, arc power in a given time period and their coefficient of variation. The determination of arc power is used to evaluate the geometry of the weld.

[0043] When pulse welding in the high and medium frequency range, determine the coefficient of variation of the following parameters: pulse current, pulse time, pulse frequency, pulse voltage, arc current, arc time, arc voltage, as well as the coefficient of variation of welding current and arc voltage within a given time period.

[0044] When implementing the proposed invention, short-circuit arc gap welding or controlled drip electrode metal transfer welding can be used, and the power supply for all welding processes can use an inverter power supply.

[0045] The following is an example of a partial test of the TransPuls Synergic 3200CMT arc welding equipment produced by Fronius, Austria, according to the proposed invention. This example focuses on comparing the weld formation quality (geometric dimensions of the weld joint) of different welding modes in the low frequency range.

[0046] Example 1

[0047] like Figure 1 and Figure 2 The figure shows an unstable working mode of a simulated arc welding device with a base current of 70 A. The welding is performed using a controlled droplet electrode metal transfer with a welding speed of 1 m / min.

[0048] When the basic current is 70A, the arc power variation coefficient is 0.402 and the weld width variation coefficient is 0.411. Figure 3 It shows that the weld formation is not ideal, the quality of the weld joint is not ideal, and the coefficient of variation of the weld geometry is high, indicating that the test equipment does not have the required welding performance, so it is necessary to adjust the welding mode or improve the equipment design.

[0049] Example 2

[0050] like Figure 4 and Figure 5 The figure shows a simulated steady operation of an arc welding device with a base current of 170 A. The welding is carried out using a controlled drop electrode metal transfer with a welding speed of 1 m / min.

[0051] When the basic current is 170A, the arc power variation coefficient is 0.110 and the weld width variation coefficient is 0.113. Figure 6 It shows that the weld formation is ideal, the weld quality is good, and the coefficient of variation of the weld geometry is low, indicating that the tested equipment has the required welding performance and can be considered as a reference standard.

[0052] By comparing the quality of the welded joints of Example 1 and Example 2, the coefficient of variation was used to successfully identify high-quality and low-quality equipment, thereby completing the testing of the arc welding equipment.

[0053] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent replacements or modifications made based on the present invention to solve basically the same technical problems and achieve basically the same technical effects are all included in the protection scope of the present invention.

Claims

1. A method for testing an arc welding device, characterized in that The method comprises the following steps: performing welding on a sample using an actual arc welding device and a reference arc welding device, recording welding parameters by recording waveforms of current and voltage, comparing the recorded parameters, and evaluating weld quality and welding performance of the actual arc welding device based on the comparison results.

2. A method for testing an arc welding device according to claim 1, characterized in that: The current and voltage waveforms of the actual device and the reference device are frequency processed in the frequency range of 0.1 to 5000 Hz, and at least three information frequency ranges including high frequency range, medium frequency range and low frequency range are extracted. The parameter variation coefficients are calculated, and the weld quality is determined by comparing the obtained coefficients. The comparison results are used to test the arc welding device.

3. A method for testing an arc welding device according to claim 2, characterized in that: The parameter variation coefficient calculation formula is as follows Among them, K vi is the coefficient of variation of the welding mode parameters, σ i is the standard deviation of the welding mode parameters, M(π i ) is the mathematical expectation value of the welding mode parameters.

4. A method for testing an arc welding device according to claim 2, characterized in that: The high frequency range is 500-5000 Hz, and the coefficients of variation of welding mode parameters determined within the high frequency range include arc current, arc time, short circuit current, short circuit frequency, short circuit time, and arc voltage.

5. A method for testing an arc welding device according to claim 2, characterized in that: The intermediate frequency range is 10-500 Hz, and the coefficients of variation of welding mode parameters determined within the intermediate frequency range include arc current, arc time, short-circuit current, short-circuit frequency, short-circuit time, and arc voltage.

6. A method for testing an arc welding device according to claim 2, characterized in that: The low frequency range is 0.1-10 Hz, and the power of the arc within a specific time interval and its corresponding coefficient of variation are determined within the low frequency range.

7. A method for testing an arc welding device according to any one of claims 1 to 6, characterized in that: Determine the coefficient of variation of welding mode parameters including: welding current and arc voltage values ​​within a given time interval.

8. A method for testing an arc welding device according to claim 1, characterized in that: An inverter power supply is used as a power supply for an arc welding device. The welding includes arc gap short circuit welding and controlled droplet electrode metal transfer welding.

9. A method for testing an arc welding device according to claim 1, characterized in that: Pulse welding was performed, where the coefficient of variation of the welding mode parameters was determined for each frequency range of the signal, including: Pulse current, pulse time, pulse frequency, pulse voltage, arcing current, arcing time, arcing voltage.

10. A method for testing an arc welding device according to claim 9, characterized in that: In pulse welding, the coefficient of variation of the welding mode parameters is determined, including: welding current, arc voltage, and arc power in a given time interval.

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