Pengaruh Perbedaan Diameter Saluran Penambah (Riser) 15 mm, 17 mm, 19 mm Terhadap Hasil Coran Eye Material Aluminium Dengan Media Cetakan Pasir

This research aim to know the chemical composition of aluminum material and the influence of the riser size to shrinkage, density, porosity defect, hardness and microstructure. The material of this research is aluminum from sparepart motor that is breakshoe used. In this research, the riser used are tubular with the variation of riser I height 60mm and diameter 15mm, variation of riser II height 60mm and diameter 17mm, variation of riser III height 60mm and diameter 19mm. Tests to be performed include testing depreciation, density, porosity observation, chemical composition, brinell hardness, and microstructure of material. The results of this study show the highest percentage shrinkage found on riser III variation is 2,91%, while riser variation I is 0,97% and the riser variation II is 1,94%. The highest density result found on the riser variation III of 2.83 and riser variation II of 2.76, the lowest density found on the riser variation I of 2.62. The result of chemical composition found chemical elements, namely Aluminum (Al) 86.79% as the main material, and Silicon (Si) 9.49%, so this material elements categorized as aluminum alloy silicon (Al-Si). The highest hardness price found on the riser variation III 76.71 BHN, while the riser variation II 71.81 BHN and the riser variation I 70.45 BHN