The method used in this study is an experiment which aims to determine the effect of preheating temperature variations in Shielded Metal Arc Welding (SMAW) on the tensile strength of low carbon steel ASTM A283 Grade C. There are four specimens used in this study, one specimen without preheating. And three specimens with temperatures of preheating 100ºC, 150ºC and 200ºC. The results of this s…