Morphological and Microstructural Evaluation of Welding Beads Manufactured by SAW Process with Thermal Pulsing

Abstract

The thermal current pulsation is a technique widely used mainly in the GTAW process. The advantages of this technique range from operational gains in the process to metallurgical weld improvements. However, despite the advantages already reported in several studies that employ the GTAW and GMAW processes, there is no reference in the literature to the use of this technique in the submerged arc process. From this perspective, an investigation was carried out regarding the use of the current pulsation technique at low frequencies. Bead-on-plate tests were performed, varying the pulsation times from 0.5 to 2.0 s for two different welding speed (18 and 36 cm/min). The results showed that, besides being viable, the application of the thermal pulsation technique in SAW welding resulted in greater process efficiency. This result was obtained without causing instabilities or problems related to the inclusion of slag. However, unlike what is reported in the literature for the GTAW process, thermal pulsation did not show significant metallurgical improvements for any of the operating conditions used.

Key-words:
Submerged arc; Thermal pulsation; Low frequency