The effects of process variables on weld quality are being studied for the Flash Butt Welding of SPFH 590 steel. The resulting welded metal and heat affected zones were characterized by tensile testing, bending testing, Rockwell hardness testing and microstructural analyzed by optical microscopy, and scanning electron microscopy. The results indicated a transformation of the metal joint from ferrite laminar to acicular ferrite. During the welding process, the long-shaped grains grew and became rounded-shaped, and through the cooling process, some side plate Widmanstatten ferrite structure is formed. The significance of process factor levels on microstructure, weld zone strength, and fracture characteristics were analyzed. The welding process parameters, 5V (voltage), 2.3 mm (upset), and 2 s (flashing time), displayed the best properties combination (strength and ductility) of all the test performed.