Welding process based on two types of steel together in multiple industry categories. Found that the Shielded Metal Arc Welding (SMAW) is most appropriate. Because welding working structures have to change positions regularly. If the gas metal arc welding applications in structural welding may be appropriate for less. Because the gas metal arc welding machine series cover consists of several parts, welding equipment and make it difficult to move the position of a given connection. This research aims study effect of butter to affect micro structure and property of But joint carbon steel AISI 1015 with stainless steel AISI 304 to Shielded Metal Arc Welding (SMAW). Best work piece width 75 mm, length 150 mm number of 15 pieces. Under the condition of welding wire connected to the bump is used E 308 and wire connects primer, E 307 E 309 E 312 to stream of fire in 80, 90, 100, 110, 120 ampere. When completed, the welding workpiece to impact test, test hardness Test and metallurgical structure. Study results found a piece of a welding wire 309 E with a primer that 100 Ampere is the maximum energy absorption. The study of the structure elements are comma found that when increasing power on the seam of the dilution. But when adding stream too high will cause the value to lower energy absorption.