????????????????????????????????????????????????????????? A356 ?????????????????????????????

Abstract

This research study examines the study of optimum state of turning machinability of A356 aluminum alloy and study the effect of the number of castings on surface roughness, which is formed a casting process using a graphite mold that can be shaped into a 1-inch round shaft. The temperature used cast at 850 degrees Celsius. Heat treatment T6, which is heat at 540 degrees Celsius for 10 hours and then immediately cooled in water. Artificial heat at 160 degrees Celsius for 5 hours and immediately cooled in water. The hardness of the workpiece was tested with an average hardness of 53.24 HRB and the tensile test was an average ultimate strength of 226.49 MPa. In addition, turning test process were a total of 3 factors at 3 levels, including spindle speed of 320, 450 and 900 rpm, feed rates of 0.1, 0.2 and 0.4 mm/rev, and depth of cut of 0.5 1 and 1.5 mm, it was found that optimum state were spindle speed of 320 rpm, feed rate of 0.1 mm/rev, depth of cut of 1 mm, resulting in surface roughness of 0.864 Ra. From to study the effect of the number of castings on surface roughness. It was found that the surface roughness in turning process was at spindle speed of 320 rev/min, feed rate of 0.1 mm/rev and depth of cut 1 mm compared with the 10th of casting process had average surface roughness was 2.703 Ra, which has a decrease to 68.05%. It was also found that the 1st round of casting compared with the 10th round of casting had average hardness of 12.10 HRB and average tensile strength of 142.84 MPa. The hardness to decrease to 77.27% and the average tensile strength decreased by 36.93%.

????????????????????????????????????????????????????????????????????? A356????????????????????????????????????????????????????? ????????????????????????????????????????????????????????????????????????????????????????? 1 ???? ????????????????????????????? 850 ???????????? ???????????????????????????????????????? T6 ?????????????????????? 540 ???????????? ???????????? 10 ??????? ?????????????????????????????????????????????????????????? ??????????????????????????????? 160 ???????????? ???????????? 5 ??????? ?????????????????????????????????????????????????????????? ????????????????????????????????????????????????????????????????????????????????? 53.24 HRB ????????????????????????????????????????????????????????????? 226.49 MPa ???????????????????????????????????????????????????????????????????? 3 ?????? 3 ????? ????????????????????????????????? 320,450 ??? 900 rpm ,???????????????? 0.1 ,0.2 ??? 0.4 mm/rev ?????????????????????? 0.5 1 ???1.5 mm ???????????????????????????????????????????????????? 320 rpm ????????????? 0.1 mm/rev ?????????????????????? 1 mm ?????????????????????????? 0.864 Ra ????????????????????????????????????? ?????????????????????????????????????????????????????????????? 320 rev/min ???????????????? 0.1 mm/rev?????????????????????? 1 mm ???????????????????????????? 10 ?????????????????????????????? 2.703 Ra ??????????????????????????? 68.05% ????????????????????????? 1 ???????????????????? 53.24 HRB ???????????????????????????????? 10 ?????????????????????????? 12.10 HRB ????????????????????????????????????? 77.27% ???????????????? 1 ??????????????????????????? 226.49 MPa ????????????? 10 ??????????????????????????? 142.84 MPa ??????????????????????????????????????????? 36.93%