The effect of welding electric current strength on the tensile strength of the 3 kg capacity gas cylinder material welding joint has been studied. The welding carried out in this study is a damping arc welding with variations in electric current of 40A, 60A, 80 A, 100 A, and 120 A. The results show that: The maximum tensile stress is found in the welded specimen with an electric current of 40 A with a tensile strength of 13 kg/mm2, 60 A with a tensile strength of 12 kg/mm2, 80 A with a tensile strength of 28 kg/mm2, 100 A with a tensile strength of 46 kg/mm2. The maximum tensile stress is the test object which is welded with 120 A electric current with a tensile strength of 39 kg/mm2. With the above results, it can be seen that the highest tensile strength of maximum is the sample that is welded with 100 A electric current. The highest maximum tensile strength reaches 46 kg/mm2. The results of observations of micro structures in welded and HAZ matrix areas are Ferrite and Perlite.