Abstract :
As the development, the metal processing and forming grows and varies, one
of which is the casting. The metal casting process is a process of manufacturing the
product in which the metal is melted in a melting furnace then is poured into a mold
cavity similar to the original form of the cast product to be manufactured.
The casting in this research applied aluminum alloys derived from used
aluminum-based propellers with variation of casting temperature at 680ºC, 710ºC,
740ºC and with mold temperature at 100ºC. This study aimed to dentify the effect of
temperature variation of pouring using metal molds to the tensile strength, hardness,
and micro structure. The tensile of casting aluminum was tested by ASTM E8/E8M-
09 standard and the hardness value used Vikers hardness tester with loading of 150
kg.
The test results showed that the largest tensile strength was found at 710ºC
casting temperature with a tensile strength value of 14.75 kgf/mm2 and the lowest
tensile strength was at 740ºC with a value of 7.86 kgf/mm2. Meanwhile, in the
hardness testing, the largest hardness value was at 710ºC casting temperature with
the hardness value of 90,98 HV and the lowest hardness was at the casting
temperature of 740ºC with the value of 63,19 HV. In the micro structure testing, the
casting temperature was 710ºC obtained by the change of micro structure due to
precipitate formation. This made specimen B with the casting temperature of 710ºC
had better mechanical properties than other specimens, with precipitate value of
49.8%, then at 680 ºC the precipitate value was 28.7% and at 740 ºC the precipitate
value was 27.2%. Based on the test that has been done is could be concluded that the
higher the pouring temperature reduced the tensile strength and the hardness of
aluminum castings.