Pengaruh Permeabilitas Cetakan Pasir dan Penambahan Silikon(Si) pada Proses Pengecoran Terhadap Kekerasan, Porositas dan Struktur Mikro Alumunium Silikon (Al-Si) - Siagian, Sihar J.; Sugita, I Ketut Gede; Kencanawati, Cok Istri Putri Kusuma (Teknik Desain Mekanika; Vol 6 No 4 (2017): Oktober 2017 : Teknik Desain Mekanika, 2018)
Abstrak Pengecoran merupakan proses pencairan logam yang selanjutnya di tuangkan ke dalam rongga cetakan dan dibiarkan membeku. Proses pengecoran logam dengan variasi permeabilitas dan variasi silikon dilakukan untuk mengetahui pengaruhnya terhadap kekerasan, porositas dan struktur mikro. Variasi permeabilitas dilakukan dengan perbedaan ukuran pasir yaitu: 0,180 mm, 0,250 mm dan 0,315 mm, dan variasi silikon terhadap alumunium dilakukan dengan perbedaan persentase silikon yaitu: 5% ;7% dan 10%. Hasil permeabilitas dengan ukuran pasir 0,180 mm adalah 22,29 cm3/min, dengan ukuran pasir 0,250 mm adalah 27,06 cm3/min dan dengan ukuran pasir 0,315 mm adalah 31,62 cm3/min. Pengujian yang dilakukan yaitu: uji permeabilitas, uji kekerasan vikers, uji densitas untuk mengetahui nilai porositas. Permeabilitas 22,29 cm3/min dan silikon 5% didapati nilai kekerasan 29,195 Kg/mm2 dan nilai porositas 1,46%, permeabilitas 27,06 cm3/min dan silikon 5% didapati nilai kekerasan 29,428 Kg/mm2 dan nilai porositas 1,27%, permeabilitas 31,62 cm3/min dan silikon 5% didapati nilai kekerasan 33,859 Kg/mm2 dan nilai porositas 0,68%, permeabilitas 22,29 cm3/min dan silikon 7% didapati nilai kekerasan 29,428 Kg/mm2 dan nilai porositas 3,41%, permeabilitas 27,06 cm3/min dan silikon 7% didapati nilai kekerasan 29,902 Kg/mm2 dan nilai porositas 2,10%, permeabilitas 31,62 cm3/min dan silikon 7% didapati nilai kekerasan 34,445 Kg/mm2 dan nilai porositas 1,88%, permeabilitas 22,29 cm3/min dan silikon 10% didapati nilai kekerasan 37,618 Kg/mm2 dan nilai porositas 4,70%, permeabilitas 27,06 cm3/min dan silikon 10% didapati nilai kekerasan 39,372 Kg/mm2 dan nilai porositas 4,17%, permeabilitas 31,62 cm3/min dan silikon 10% didapati nilai kekerasan 42,040 Kg/mm2 dan nilai porositas 3,09%. Variasi permebilitas dan silikon berpengaruh terhadap struktur mikro. Kata Kunci: permeabilitas, alumunium silikon, pengecoran, kekerasan, porositas, struktur mikro Abstract Casting is a process of melting metal then poured into the mold cavity and left to freeze. The process of casting metals with permeability variations and silicon variations is done to determine the effect on hardness, porosity and microstructure. The permeability variations was done by difference of sand size that is: 0,180 mm, 0,250 mm and 0,315 mm, and silicon variations to alumunium was done with different percentage of silicon that is: 5%, 7% and 10%. The result of permeability with sand size 0,180 mm is 22,29 cm3/min, with sand size 0,250 mm is 27,06 cm3/min and with sand size 0,315 mm is 31,62 cm3/min. Tests conducted are: permeability test, vikers hardness test, and density test to determine the value of porosity. Permeability of 22,29 cm3/min and 5% silicon was found to be hardness value 29,195 Kg/mm2 and porosity value 1,46%, permeability of 27,06 cm3/min and 5% silicon was found to be hardness value 29,428 Kg/mm2 and porosity value 1,27%, permeability of 31,62 cm3/min and 5% silicon was found to be hardness value 33,859 Kg/mm2 and porosity value 0,68%, permeability of 22,29 cm3/min and 7% silicon was found to be hardness value 29,428 Kg/mm2 and porosity value 3,41%, permeability of 27,06 cm3/min and 7% silicon was found to be hardness value 29,902 Kg/mm2 and porosity value 2,10%, permeability of 31,62 cm3/min and 7% silicon was found to be hardness value 34,445 Kg/mm2 and porosity value 1,88%, permeability of 22,29 cm3/min and 10% silicon was found to be hardness value 37,618 Kg/mm2 and porosity value 4,70%, permeability of 27,06 cm3/min and 10% silicon was found to be hardness value 39,372 Kg/mm2 and porosity value 4,17%, permeability of 31,62 cm3/min and 10% silicon was found to be hardness value 42,040 Kg/mm2 and porosity value 3,09%. Variations of permebility and silicon affect the micro structure. Keywords : permeability, aluminum silicon, casting, porosity hardness and microstructure