In recent days, the conventional gas metal arc welding (GMAW) process is employed for joining higher thickness (>12 mm) high strength low alloy (HSLA) steel plates in various applications.

However, during welding, continuous thermal cycles (heating and cooling) and non-linear elastic strains are developed in welded joints due to higher heat input to the joints through multi pass welding procedures.

This phenomenon hinders the strength properties and fatigue behaviour of welded joints. The above-mentioned problems can be minimised by the rotating arc welding process. Because the arc rotation greatly reduces the heat input and minimises the number of passes required during welding.

This investigation compares the fatigue performance of stationary arc gas metal arc welded (SA-GMAW) and rotating arc gas metal arc welded (RA-GMAW) 12 mm thickness HSLA steel joints.

This study revealed that the RA-GMAW joint shows 18 % higher fatigue strength than the SA-GMAW joint. This is attributed to the presence of a greater volume percentage of fine acicular ferrite (29.17%) in the RA-GMAW joint weld metal region.

Furthermore, the acicular ferrite morphology in the SA-GMAW joint is polygon, whereas it is needle shape in the RA-GMAW joint. This may be one of the reasons behind the increased fatigue performance of RA- GMAW joints.

This article is shared by N. Sankar, S. Malarvizhi and V. Balasubramanian