PENGARUH HEAT TREATMENT NORMALIZING DENGAN VARIASI HOLDING TIME TERHADAP KEKUATAN TARIK DAN MIKROSTRUKTUR BAJA AISI 1045

AISI 1045 steel is one type of medium carbon steel that is often used as a component of motorcycle vehicles. Like a bolts on connecting rods that require mechanical properties with a dynamic tensile load. With the Heat Treatment and holding time with several variations and continued to the normalizing process which is then carried out tensile testing, it produces different tensile strenght (σT) and yield strenght (σy). The maximum value found in the specimens is given a holding time of 20 minutes with tensile strenght of 695.213 MPa, and yield structure of 475.3032 MPa. The minimum value is found in 30 minute holding time specimens with tensile strenght 672.8590 Mpa, and yield yield 459.7238 MPa. Furthermore, microstructure testing using SEM obtained the pearlite (dark) phase and ferrite (bright) phase and specimens with 20 minutes holding, resulting in a homogeneous pearlite phase compared to the others. Whereas for holding 25 and 30 minutes the appearance of new grain boundaries appears and rise the accicular ferrite phase between ferrite and pearlite formed, therefore reducing the value of the toughness of a material