Pengaruh Variasi Sudut Kemiringan Saluran Turun (Sprue) 90˚, 65˚ Dan 45˚ Terhadap Hasil Coran Aluminium (Al) Pada Produk Handle Rem Dengan Cetakan Pasir

The aim of this research is to know about the effect of decrease of descending channel slope to shrinkage, porosity defect, hardness and micro photo. The raw materials of this research are used aluminum or rosok from various components which are re-casted. In this study we will examine the variation of the slope of the channel down by 90º, 65º, 45º. Tests carried out include chemical composition test, porosity observation, depreciation test, density test, brinell hardness test (ASTM standard E - 10), and microscope metallographic microscope. The results showed that the result of chemical composition found found chemical element (Al) 89,32%, (Si) 5,56%. So from the existing elements of this material include aluminum alloy silicon (Al - Si). The highest mean shrinkage result is in the in-gate of one of 2.03%, while the in-gate two are 1.94% and the in-gate 3 is 1.93%. This is due to by the amount of metal shrinking during freezing. The highest density result is in in-gate three amount 2,81, while in-gate two equal to 2,75, and in-gate one 2,66, higher density value hence higher density of specimen. The highest hardness price was in the amount of in-gate three of 104,47 BHN, while the in-gate two of 81,87 BHN, and the in-gate one of 61,26 BHN, it happened because porosity defect caused hardness of metal decreasing, other factor influencing hardness that is density , the higher the density value the higher the value of hardness