PERLAKUAN PANAS PADUAN AL-SI PADA PROTOTIPE PISTON BERBASIS MATERIAL PISTON BEKAS

Abstract

The use of aluminum in the automotive industry continues increasing since 1980, in particular aluminum alloy is used for the manufacture of pistons, engine blocks, cylinder heads and valves. In this study the use of former gasoline engine piston waste was recycled (remelted) to the piston Daihatsu Hi-Jet 1000 with the addition of ADC 12. The former Piston having composition 87.82 wt% Al, 7, 76 wt% Si, 0.775 wt% Fe, 1.40 wt% Cu, 0.368 wt% Mg plus ADC 12 material was casted by gravity process at pouring temperature of 700oC, 750oC and 800oC. Research activities include the test composition, microstructure, and hardness The results showed that the addition of 75%, ADC 12 has the greatest percentage of Si at the average of 8.70% Si. The addition of 50%, of ADC 12 resulted in very minor differences os Si composition compared with the addition of 75%, of ADC 12 ( 8.61% Si difference 0.09%). So for the effectiveness and efficiency in the process of heat treatment, the composition of the former Piston material with a ratio of 50% PB + 50% ADC 12 was selected in this study After the heat treatment process of piston material hardness value of 50% PB + 50% ADC12 can be improved and some test results have the same hardness value and even some are over the original piston Daihatsu that is 76 HRB. The result of heat treatment produced hardness value over the hardness that exceeds the value of the original piston Daihatsu heat treatment temperature of 155 0C aging with aging time 2, 4 and 5 hours. Keywords: Heat treatment, Artificial aging, Holding time