M. E. Aalami-Aleagha* and A. M. Rashidi
The Journal of Mechanical Science and Technology, vol. 26, no. 1, pp.181-185, 2012

Abstract : The present research investigated the effect of increased weld current on the apparent discontinuities, macrostructure, and hardness in the shielded metal arc welding of pipes. Thin, small pipes were butt welded, and the section view of the weld was observed using an optical microscope equipped with an image analyzer. Vickers hardness measurements were also made. The results indicated that the area of the melting zone and the width of the weld at the midpoint of pipe thickness were the appropriate parameters for assessing the weld current. In contrast, the lengths of the columnar grain zone and hardness values were not correlated with the current levels. A moderate current level caused the mechanical properties of the melting zone to become closer to those of the parent metal.

Keyword : Welding; Steel pipe; Hardness; Macrostructure; Melting zone