Application of Fast Fourier Transform (FFT) in the Analysis of a Welding Current Instantaneous Values Waveforms during Welding with a Covered Electrode

Abstract The article presents the process of production of coated electrodes and their welding properties. The factors concerning the welding properties and the currently applied method of assessing are given. The methodology of the testing based on the measuring and recording of instantaneous values of welding current and welding arc voltage is discussed. Algorithm for creation of reference data base of the expert system is shown, aiding the assessment of covered electrodes welding properties. The stability of voltage–current characteristics was discussed. Statistical factors of instantaneous values of welding current and welding arc voltage waveforms used for determining of welding process stability are presented. The results of coated electrodes welding properties are compared. The article presents the results of linear regression as well as the impact of the independent variables on the welding process performance. Finally the conclusions drawn from the research are given.

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Oscillography Based Analysis of the Arc Stability in Manual Welding with Coated Electrode in Pulsed Current

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1128.209 ◽

2015 ◽

Vol 1128 ◽

pp. 209-216

Author(s):

Mircea Burcă ◽

Ioan Lucaciu

Keyword(s):

Low Frequency ◽

Welding Current ◽

Pulsed Current ◽

Metal Bath ◽

Arc Voltage ◽

Transfer Mode ◽

Coated Electrode ◽

Points Of View ◽

Different Levels ◽

Coated Electrodes

Welding in pulsed current is specific to welding procedures carried out in MIG / MAG and WIG shielding gases environment, and which is appealling from both technological and process quality points of view because of the advantages this procedure provides, especially controlling the transfer mode and the power introduced into components. Making use of pulsed current in manual welding with coated electrodes is a new challenge to modern inverter based sources with potential technological advantages. In this case the advantage of pulsed current is linked to controlling the molten metal bath, its volume as a result of partial solidification, similar to the manual WIG welding using low frequency pulsed current < 5 Hz. The paper presents some technological issues related to the use of pulsed current in the case of manual welding with coated electrodes by arc oscillograpy. Experimental research aimed at recording the shapes of current pulses for different brands of electrodes and diameters, and for different parameters of welding current, different levels of pulses frequency respectively, and the oscillograms analysis through the variation of welding current and arc voltage in order to explain phenomena occurring in the arc when welding. This will allow also a better understanding of the technological issues in the case of manual welding with coated electrode in pulsed current.

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