PENGARUH VARIASI SUHU TUANG TERHADAP KEKERASAN DAN STRUKTUR MIKRO PADA HASIL REMELTING ALUMINIUM TROMOL SUPRA X DENGAN CETAKAN LOGAM

Abstract

The  objective  of  this  research  is  to  investigate  the  optimal  casting  temperature  to produce  the  best  molding  on  the  hardness  and  microstructure  of  the  aluminum  remelting product of Supra X motorcycle drum brake with metal mould.This  research  used  three  casting  temperature  variations,  namely:  7000C,  7250C,  and 7500C. The aluminum material  used in this molding was used back drum brake aluminum of Supra X motorcycle.This  research  used  the  experimental  method  with  the  descriptive  data  analysis.  The data of the research were gathered through the calculation of the hardness of each specimen and the microstructure photograph-taking of each specimen. The result of the calculation of the hardness was then displayed in graphs for analysis.The  result  of  the  research  shows  that  the  highest  molding  hardness  is  found  in  the casting  temperature  variation  of  7000C  with  the  value  of  86.17  BHN,  whereas  the  lowest molding  hardness  is  found  in  the  casting  temperature  variation  of  7500C  with  the  value  of 83.03  BHN,  and  the  hardness  of  the  drum  brake  aluminum  of  Supra  X  aluminum  itself  is 90.36BHN. Based on the microstructure photograph, the casting temperature variation of 7000C  results  in  the  best  structure  granules  as  indicated  by  the  tiny  size  of  Al-si  granules, compared  to  the  results  of  the  other  casting  temperature  variations  of  7250C,  and  7500C respectively of which the size of granules become larger along with the increase of the casting temperature variations. Thus,  based  on  the  result  of  the  research,  a  conclusion  is  drawn  that  the  casting temperature variation of 7000C results in the most optimal hardness and good microstructure, and among the tree casting temperature variations the casting temperature variation of 7000C results  in  casting  temperature  of  which  the  quality  of  the  aluminum  remelting  product approaches the quality of back aluminum drum brake of Supra X motorcycle. The hardness of the aluminum remelting product decreases along with the increase of the casting temperature variations, and the size of microstructure of the granules also becomes larger along with the increase of the casting temperature variations.