PENGARUH LAMA WAKTU TAHAN NORMALIZING PADA BAJA ST 41 PENGELASAN FRICTION WELDING TERHADAP SIFAT MEKANIS

Abstract

The development and application of science and technology, especially in the industrial world, is currently experiencing very rapid progress, especially in the world of welding. Welding is the process of joining two or more metal parts using heat energy. In the current era, welding developments are increasingly developing, such as liquid welding, resistance welding, solid welding, and forging welding. For solid welding, there are friction welding and cold welding. The joining process using friction welding involves friction factors, pressing force, and surface quality. To improve the mechanical properties of steel after welding, Normalizing heat treatment is carried out, namely a heat treatment process on steel which aims to refine the grain, homogenize the structure and obtain steel with mechanical properties as desired, or called normalization. This research method uses the Experimental Testing method. This sample was obtained from the normalizing friction welding process which was tensile tested, namely samples with varying holding times of 15 minutes, 30 minutes and 45 minutes with an engine speed of 2100 rpm and a pressure of 35 MPa with tensile testing of the material and microphotographs. The results of the friction welding research are as follows. The normalizing holding time of 15 minutes produces a maximum tensile stress value of 325.16 N/mm2, the fracture that occurs is in the form of a ductile fracture, the normalizing holding time of 30 minutes produces a maximum tensile stress value of 327.66 N/mm2, the fracture that occurs is in the form of a fracture ductile, the normalizing holding time of 45 minutes produces a maximum tensile stress value of 329.53 N/mm2, the fracture that occurs is in the form of a ductile fracture. The long holding time of normalizing will increase the tensile strength of the steel and tensile test fractures mostly occur in the weld area