| Nowday the demand for fuel-efficient and safe vehichles is very high, there is been a lot innovation has been made in automotive industrial, one of the others was using double phase steel as car body’s material. Combination between ferit and martensit create an uniq mechanical properties,that have high strenght but still have capability easy for forming and can permeate high energy too. Welding process has been selected for continiuation body in automotive industrial. Vehicle assembly has been dominated by spot welding, but there’s still lack of research about how nugget created during spot welding procces on double phase material. Double phase steel on this research is comercial C-Mn Steel that already through Intercritical Annealing Process that have composition 0.39% C, 0.11% Si, dan 1.74% Mn with strenght 1 Gpa. The result of this experiment says somepoint like : the strenght of continuation when converted to maximum tensile force is not stress, the strenght of continuation more smaller it’s about 5,8 Kn when we compare it with workpiece material that have 27,56 kN, the diameter of nugget getting bigger/smaller depend on the pressure force and how long that force have been applied when welding procces, the bigger diameter of the nugget doesn’t always followed by enchanment strenght of welding connection like on parameter when the welding process use 6 seconds with 90 N pressure force and 4 seconds welding process with 105 N pressure force. |