Estudo dos sinais elétricos no processo de soldagem por revestimento com arame tubular pulsado, visando determinar a estabilidade do arco elétrico

Abstract

This dissertation aims to analyze the electric arc signals in the process of coating welding with pulsed tubular wire, with SAE 1020 base metal and AWS EC410NiMo MC filler metal with 1.2mm diameter, where the signals were obtained simultaneously of current, voltage and acceleration. The influencing variables adopted were the average current, the pulse frequency, the welding speed and the nozzle-to-piece distance, each variable being tested at three different levels. As response variables, acceleration, pulse frequency obtained, number of peaks, power and amplitude of acceleration were analyzed. Therefore, to achieve the purpose of the work, some statistical tools were used, in the first phase, the Taguchi method was used, to establish which combinations of parameters would be performed in each trial, providing us with an L9 matrix. In the second phase, analysis of variance was used to statistically prove which welding parameter influenced the response variables, where it was possible to verify that the average current affected the response variables (acceleration, power and amplitude of acceleration). the pulsation frequency affected the response variables (acceleration, pulse frequency obtained and peak quantity), the welding speed affected the variables (acceleration, power and acceleration amplitude) and the contact tip distance did not affect any of the variables. Analyzing the values found by the signals, it was possible to observe that the average current of 230 A presented a lower acceleration RMS, remaining between 0.140 and 0.172 m/s2 and, consequently, a better stability of the system. And using Fourier analysis, the frequencies of the three signals were identified, and the number of peaks was also analyzed to verify synchronism.