Effect of parameters of welding circuit on formation of welding current pulses

Abstract

This work studies a poorly investigated effect of welding arc parameters on amplitude of welding current pulses in consumable electrode gas-shielded pulsed arc welding (PAW). A welding circuit is considered as a frequency-selective system, which passes the pulses in undistorted form only in specific frequency band. The pulses out of this band are significantly suppressed, that can result in rapid decrease of PAW efficiency. The main aim of the work is to determine a width of welding circuit pass band and possibility of its increase. In scope of developed mathematical model a criterion was obtained, which sets in algebraic form one of the necessary conditions of PAW efficient application. From practical point of view, this criterion allows, using known parameters of welding circuit, carrying out a fairly simple evaluation of pass band upper boundary, inside which a set amplitude of welding current pulses is ensured. From the other side, indicated criterion can be used for solving an inverse problem, i.e. to determine the allowable values of some parameters of welding circuit using preliminary selected frequency of welding current pulse passing. Besides, due to its «analytical property» the indicated criterion can be useful for theoretical investigations of pulse-arc processes taking place in the welding circuit. 19 Ref., 5 Figures. K e y w o r d s : pulsed arc welding, consumable electrode, welding circuit, welding current amplitude, pulse repetition frequency, mathematical modelOne of the most efficient welding technologies, developed back in the 1960s and received further propagation in our country and abroad [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15], is a consumable electrode gas-shielded pulsed arc welding (PAW). The rising interest to its application in the last time is to large extent related with robotization of arc welding and coming into industry of improved welding equipment, including the sources of pulsed welding current. These sources are characterized by new possibilities in welding mode regulation and, in particular, possibility of program setting of current amplitude in the pulse, pulse duration, background current and pulse setting frequency. It is well known fact that the optimum transfer of electrode metal during PAW is achieved at specific combination of indicated parameters.A lot of publications were dedicated to the problems of stabilizing, adaptive regulation and practical realization of PAW [4,6,8,9]. But, at the same time, particularly important question, related with effect of welding circuit parameters on formation of the pulses of welding current, have almost no description in the reference literature. The matter is that the welding circuit in dynamic relationship represents itself a frequency-selective system which passes the undistorted pulses only in specific frequency band [12]. Out of this band the pulses will be significantly suppressed, that can result in rapid decrease of PAW efficiency.Meanwhile, it is difficult to say what the width of indicated frequency band is an...

Synthesis of structure of system for self-regulation of electrode melting rate

“…Что касается случая, когда g(t) ≠ const, то при v e (t) = v e0 скорость v m (t), как видно из структурной схемы спэ, будет «следить» за изменением dg/dt. это замечательное свойство широко используется в импульсно-дуговых технологиях сварки [10][11][12][13].…”