Pengaruh Variasi Suhu Artificial Aging (150°C, 175°C, dan 200°C) Terhadap Hasil Coran Aluminium (Al) Menggunakan Cetakan Pasir Hitam Dengan Bentonit 7%

The use of aluminum and aluminum alloys in the industrial world continues to grow, demanding people to carry out engineering in order to meet the increasingly complex needs of basic materials to make aluminum very limited and its processing requires large funds. So it is done recycling from aluminum waste. One way to recycle is to do the casting process. For better casting results, treatment needs to be done to improve the properties of aluminum so that the casting results are more resilient and harder by means of artificial aging. In this study using the method of artificial aging. Artificial aging is aging for aluminum alloys that are aged hardening in a hot state. Artificial aging takes place at temperatures between 100°C-200°C and holding time between 1 to 24 hours. So in this study the artificial aging stage uses variations in artificial aging temperature (150ºC, 175ºC, and 200ºC) holding time of 2 hour and compares it with raw material. The purpose of this study was to determine the chemical composition of the material to be treated artificially by aging, to know the value of material hardness before and after artificial aging. From the results of testing the chemical composition there are 13 elements, namely Al (84.84%), Si (9.2655%), Cu (1.7669%), Fe (2.07%), Ni (0.93%), Mg (0.91%), Ti (0.08%), Zn (0.05%), Mn (0.047%), Cr (0.03%), Sn (0.0074%), Pb (0, 0049%), and P (0.0019%). From the results of rockwell hardness testing on specimens with aging 200ºC has the highest hardness value of an average of 80.36 HRB harder than specimens with aging 150ºC and aging 175ºC due to more Cu deposition than others