The Effect of Current Variation on MMA Welding to Mechanical Properties and Microstructure of Mild Steel

Industrial development is increasingly rapid, demanding technological progress. One of the necessary technologies in the manufacturing industry is welding technology. Welding on low carbon steel is often used in the construction, furniture and furniture industries. MMA welding is the most commonly used welding in connecting low carbon steel. Low carbon steel which is often used in this case is St. 37. To find out the best MMA welding results on low carbon steel connections, it is necessary to observe the variation of current used, namely 65 Ampere, 70 Ampere, 75 Ampere, 80 Ampere, and 85 Ampere. The electrode used is E7016 Ø 2.6. The results showed that the testing of the composition of the raw material contained levels of C= 0.1068%. The lowest tensile strength is in the current of 65 A, which is 35.097 N/mm2 and the highest tensile strength is at the current of 75 A which is 36.636 N/mm2. In testing the microstructure image, it is also seen that in welding with a current strength of 75 A, there is a slight presence of porosity or welding defects, because of sufficient heat input so that the arc flame is stable. A stable arc will cause good penetration.