Microstructure analysis of dissmilar metals weld between S690Q and S355J2+N steel under flame straightening treatment

Abstract

Flame straightening process is needed to improve joint alignments due to the distortions induced by welding heat. This research shows that flame straightening can be applied safely on the weld of dissimilar metals such as S690Q and S355J2+N steel. The results indicated an increase in hardness of the flame straightened base metal, heat affected zone (HAZ), and weld metal due to pearlite transformation in these areas. Furthermore, the two metals were welded in accordance to the welding procedure standard (WPS) and then straightened by applying heat. It was then cooled rapidly with an air jet along the root of the weld joint. Lastly, microstructure investigation and hardness test were carried out on the area which was flame straightened.

Keywords

• S690Q
• S355J2+N
• flame straightening
• dissimilar metals weld
• microstructure