Influence of Nickel Powder on Microstructure of Carbon Steel Weld using GMAW

The purpose of this research was studied overlay weld of ASTM A36 carbon steel using gas metal arc welding (GMAW) without and with nickel powder adding. ER 70S-6 filler metal consumable electrode was used in diameter 2 mm. Metallurgical structure was examined using an optical microscope (OM). In addition, the mechanical property of the weldment evaluated by micro vickers hardness was measured by means of the variation in the percentage of nickel powder adding. The weldment without and with adding nickel powder 4.25, 7.25 and 15.75 g/min were produced and carried out to the metallography analysis, The experimental result showed that defect-free of all welded-specimens. The highest value of microhardness was 527.4 Hv with the nickel powder 15.75 g/min. Moreover, the hardness of weld metal tends to decrease with decreasing of the weight fraction of nickel adding.