2017 №08 (08) DOI of Article
2017 №08 (02)

Automatic Welding 2017 #08
Avtomaticheskaya Svarka (Automatic Welding), #8, 2017, pp. 3-14
Effective values of electrodynamic characteristics of the process of nonconsumable electrode welding with pulse modulation of arc current

V.F. Demchenko, U. Boi, I.V. Krivtsun and I.V. Shuba
E.O. Paton Electric Welding Institute, NASU 11 Kazimir Malevich Str., 03680, Kiev, Ukraine. E-mail: office@paton.kiev.ua
The paper is devoted to analysis of the influence of pulse modulation of welding current on effective values of electrodynamic characteristics of the process of nonconsumable electrode welding. The first part of the paper provides analysis of the possibilities for increasing the effective value of arc current through selection of optimum time and current parameters of pulse modulation. A quite general case of current modulation by pulses of trapezoidal shape is considered (rectangular and triangular pulses are treated as particular cases). In the second part distribution of effective values of electromagnetic and dynamic characteristics of modulated current in the weld pool is studied, proceeding from a nonstationary model of arc discharge and model of electromagnetic processes in the metal being welded. Force impact of modulated current on weld pool metal at current modulation by triangular pulses with pauses at 10 kHz frequency is considered as a characteristic example. Influence of dynamic effects in the pulsed arc on distribution of effective values of electromagnetic characteristics, namely centripetal component of Lorenz force and magnetic pressure, is analyzed. A conclusion is made that with optimum shape of current pulses dynamic effects arising in nonstationary arc are capable of essentially enhancing its force impact on weld pool metal in nonconsumable electrode welding with high-frequency current modulation, compared to welding by constant current coinciding in magnitude with effective value of modulated current. 19 Ref., 13 Figures.
Keywords: nonconsumable electrode welding, pulse current modulation, electrodynamic characteristics, effective value, weld pool metal, mathematical models
Received:                03.07.17
Published:               01.08.17
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