Effects of ultrasonic pulsation of the welding current on the geometry of the fusion zone and heat-affected zone in submerged arc welding

摘要

This paper proposes investigation of an arc ultrasonic excitation technique in the SAW process in order to evaluate the main parameters'influence associated with pulsed current on weld beads, such as the frequency and amplitude of ultrasonic excitation current. Therefore, an experimental bench was assembled, which consists of two power sources: a conventional welding source and another able to provide pulse current at ultrasonic frequencies. During the tests two ultrasonic excitation current amplitudes were employed, 25 A and 50 A, each one in three different pulse frequencies, 20,50 and 80 kHz. Macrographs of these welds are observed, and width, penetration, molten area and heat affected zone area (HAZ) are measured. As a result, contrary to information available in the literature, there were no significant changes in weld bead geometry, as well as in the HAZ, that could be attributed to the current excitation in studied frequencies.