Process Stability Evaluation of Manual Metal Arc Welding Using Digital Signals

Abstract:

The experimental investigation has been carried out to evaluate process stability for two rutile types of electrode supplied with two types of DC power sources: traditional 3 phase thyristor and inverter type. Initially to understand the maximum range of outcomes high quality and defective electrodes, with lower arc stability, were selected for both. During welding tests current and voltage signals were recorded separately with the aid of A/D converter and 5 kHz of sampling frequency. On the basis of digital signals obtained from each electrode type and power sources, a number of statistical indicators have been computed. Furthermore voltage and current histograms have been determined (defined as a density distribution of welding arc voltage and current values). Statistical indicators of voltage signals have proved to be more useful for process stability evaluation, particularly mean voltage (U_śr) and histograms as well as voltage coefficient of variation (K_vU).

• Periodical: Materials Science Forum (Volumes 730-732)
• Pages: 847-852
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.730-732.847
• Online since: November 2012
• Authors: B. Slazak, J. Slania, T. Węgrzyn, Abílio P. Silva
• Keywords: Arc Welding, Digital Signals, Voltage Coefficient

References

[1] J. Slania, Objective methods for assessing the performance of welding power sources via a computer recording device and data processing, a general discussion, Welding Institute Bulletin (1991), N. 2-3 (in Polish).

[2] J. Slania, An objective method of evaluating the energy in robotized welding electric arc welding, Welding Institute Bulletin (1992), N. 4 (in Polish).

[3] J. Wegrzyn, Physics and metallurgy of welding, Politechnika Slaska, Katowice, 1990 (in Polish).

[4] E. Dobaj, Welding Machinery and Equipment, WNT, Varsóvia, 1994 (in Polish).

[5] B.C. Sharma, Process stability evaluation of basic coated MMAW electrodes, using statistical analysis, mechanical properties and hydrogen content, Journal of Production Engineering, Institution of Engineers (India) (2006), 86.

DOI: 10.22486/iwj.v39i3.178459

[6] B. Slazak, W. Malewski, A. Krysztafkiewicz, T. Jesionowski, Evaluation of welding electrode obtained from lithium oxide-modified water glass, Polish J. of Chemical Technology (2006), 3.

[7] B Slazak, J. Slania, Comparative studies of high-coated electrodes ERWS 19-9 L produced using a new water-glass modified with lithium oxide, Welding Inst. Bull. (2006), N. 6 (in Polish).

[8] M. Weglowski, A. Kolasa, P. Cegielski, Evaluation of the stability of the manual arc welding process with covered electrodes, Welding Overview (2006), 1 (in Polish).

[9] M. Weglowski, A. Kolasa, P. Cegielski, Study of technological properties of inverter welding power supplies, Welding Overview (2006), 9-10 (in Polish).

[10] M. Weglowski, Testing of welding power sources with internal frequency conversion, Doctoral Thesis, University of Warsaw, 2008 (in Polish).

[11] J.C. Dutra, MIG/MAG - short circuit metal transfer - welding power sources versus arc gases, Welding International, 23 (2009), pp.231-236.

DOI: 10.1080/09507110802543302

[12] Wegrzyn T, Miroslawski J, Silva AP, Pinto DG, Miros M, Oxide inclusions in steel welds of car body, Materials Science Forum, Vol. 636-637 (2010), pp.585-591.

DOI: 10.4028/www.scientific.net/msf.636-637.585