Effects of Tandem Side-by-side GTAW Welds on Centerline Solidification Cracking of AA2024

Abstract

Welding techniques such as gas tungsten arc welding (GTAW) can induce solidification cracking owing to the wide solidification temperature range. Riveting or mechanical fastening are plausible alternatives, but can create problems like material loss, overall weight increase, corrosion, and introduction of high stress concentration areas. This study proposes a new welding method to improve and minimize centerline solidification cracking in GTAW called “tandem side-by-side GTAW welds”. AA2024 is fusion welded using GTAW, and its solidification cracking behavior is investigated and compared for two weld pool motions (straight and weaving) and the proposed method. The fishbone test was used to assess centerline solidification cracking susceptibility. The results of welding AA2024 autogenously proved that the tandem weld pool motion is superior to the other two GTAW methods. As a result, the proposed method showed lower stress concentration areas by forming less concave weld shapes, lower heat input, formation of preferable grain size and orientation thus shorter centerline solidification crack lengths with a tortuous crack path motion obtained in comparison with the straight and weave.