Research on Effects of Arc Excited Ultrasonic on Fusion and Heat Affected Zone in Submerged Arc Welding

Abstract:

This paper proposes an investigation of arc ultrasonic excitation technique in 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 pulse current at ultrasonic frequencies. During the tests were employed two ultrasonic excitation current amplitudes, 25 A and 50 A, each one in three different pulse frequencies, 20 kHz, 50 kHz 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 the information available in 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.

Key-words:
Submerged arc welding; Ultrasonic arc excitation; Ultrasonic frequencies; Molten pool geometry; Heat affected zone