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"Badan kendaraan taktis umumnya menggunakan material baja yang memiliki densitas tinggi sehingga menyebabkan mobilitas kendaraan taktis yang rendah dan konsumsi bahan bakar yang tinggi. Untuk itu, material utama badan kendaraan taktis harus disubtitusi dengan material yang lebih ringan, seperti komposit bermatriks paduan alumunium. Namun komposit ini perlu dimanufaktur dengan baik untuk memastikan dapat diperolehnya pelat tebal sesuai dimensi yang dibutuhkan.Pada penelitian ini dilakukan perancangan cetakan komposit dengan dimensi 30x30x2.5cm dengan 4 buah lubang rivet Ø1.5cm. Perancangan dilakukan dengan menggunakan aplikasi Solidworks dan Z-Cast. Simulasi diverifikasi dengan menggunakan proses squeeze casting menggunakan material paduan Al-6Si-6Zn-5Mg-1Cu berpenguat 10% vol. SiC.Hasil pengamatan didapatkan beberapa jenis cacat pengecoran pada hasil pengecoran, yaitu cacat cold shots, void, retak makro, mikro porositas, dan shrinkage.Cacat-cacat tersebut terjadi dikarenakan terdapat beberapa kesalahan teknis pada proses pengeocran. Cacat cold shots terjadi dikarenakan proses penuangan yang kurang tepat, sehingga memantulkan lelehan logam dan akan menempel pada dinding cetakan dan akan membeku terlebih dahulu. Void dan mikro porositas terjadi dikarenakan kurangnya proses degassing, dan retak makro terjadi dikarenakan kurang tepatnya perlakuan pemeberian tekanan pada saat proses pengecoran.

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Most of tactical vehicle body structure consist of steel which has high density, that resulting low mobility and high fuel consumption. Therefore, the base material for tactical vehicle body should be substituted with lighter material, such as aluminium alloys matrix composite. However,this composite have to be manufactured carefully to obtain thick plate composite with the obvious dimension. In this research, the dimension of designed composite plate is 30x30x2.5 cm including four rivet holes with diameter of 1.5 cm. Casting design done with Solidworks™ and Z-Cast™. Simulation was verified using squeeze casting process with Al-6Si-6Zn-5Mg-1Cu alloy strengthened by 10% vol. SiC.

There are some casting defects which are not predicted in the simulation, such as cold shots, void, macro crack, micro porosity, and shrinkage. Cold shots were caused by pouring position which right at the top of rivet position that spread molten metal in the mold. Void and micro porosity were due to lack of degassing process, and macro crack may be resulted by imperfect pressing process during solidification."

"[ABSTRAKPengelasan merupakan metode yang sering digunakan pada proses manufaktur darikendaraan taktis. Pengelasan dengan menggunakan metode gas metal arcwelding(GMAW) umum dilakukan pada paduan aluminium, dikarenakan minimnyakontaminasi dari udara dan memiliki kecepatan pengelasan yang tinggi karenaelektroda terumpan secara kontinyu.Pada penelitian ini dilakukan pengelasan dengan metode GMAW pada pelatkomposit Al-10Zn-6Mg-3Si yang diperkuat oleh 10 %Vol. SiC dengan menggunakanmetode squeeze casting. Parameter yang digunakan adalah arus, yaitu sebesar 180, 210,dan 240 A, dengan variabel tetap tegangan sebesar 22 V, dan kecepatan pengelasansebesar 180 mm/menit. Didapatkan variasi heat input sebesar 1.32, 1.54, dan 1.76kJ/mm. Pengujian yang dilakukan antara lain uji tekuk, uji keras, SEM, danmetalografi.Hasil yang didapatkan adalah dengan penambahan heat input pada proses pengelasan,kekerasan yang didapatkan semakin menurun karena dengan penambahan heat inputakan memperlambat pendinginan sehingga memperbesar butir.Ditemukan fasa Al4C3pada pengujian SEM, yang mengakibatkan penurunan kekuatan dari produkpengelasan. Fasa tersebut didapatkan dari reaksi Al dengan SiC pada temperaturdiatas 700oC, sedangkan temperatur pengelasan mencapai 2000o C.

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ABSTRACTWelding is one of the most common method used in joining ballistic vehicle bodystructure. Welding with gas metal arc welding (GMAW) is widely used for joiningaluminium alloy because of its low atmosphere contamination and continouslyfeeding electrode that results in high welding velocityThis research studied GMAW of Al-10Zn-6Mg-3Sicomposite reinforced by 10 %vol.SiC, produced by squeeze casting method. In GMAW, the current is varied to 180,210, and 240 A, with constant voltage and velocity of 22 V and 180mm/min,respectively. Therefore heat input used in this research is varied to 1.32, 1.54, 1.76kJ/mm. The characterization included bending test, microhardness test, danmetallography observation.The result shows that the higher heat input will decrease the hardness because itslowed down the cooling rate so that increased the grain size. Al4C3 was found onSEM observation, which decreased the strength of the weld products. Al4C3 wasproduced by the reaction of Al with SiC at 700 oC, which was lower than the weldingtemperature that exceed 2000 oC.;Welding is one of the most common method used in joining ballistic vehicle bodystructure. Welding with gas metal arc welding (GMAW) is widely used for joiningaluminium alloy because of its low atmosphere contamination and continouslyfeeding electrode that results in high welding velocityThis research studied GMAW of Al-10Zn-6Mg-3Sicomposite reinforced by 10 %vol.SiC, produced by squeeze casting method. In GMAW, the current is varied to 180,210, and 240 A, with constant voltage and velocity of 22 V and 180mm/min,respectively. Therefore heat input used in this research is varied to 1.32, 1.54, 1.76kJ/mm. The characterization included bending test, microhardness test, danmetallography observation.The result shows that the higher heat input will decrease the hardness because itslowed down the cooling rate so that increased the grain size. Al4C3 was found onSEM observation, which decreased the strength of the weld products. Al4C3 wasproduced by the reaction of Al with SiC at 700 oC, which was lower than the weldingtemperature that exceed 2000 oC., Welding is one of the most common method used in joining ballistic vehicle bodystructure. Welding with gas metal arc welding (GMAW) is widely used for joiningaluminium alloy because of its low atmosphere contamination and continouslyfeeding electrode that results in high welding velocityThis research studied GMAW of Al-10Zn-6Mg-3Sicomposite reinforced by 10 %vol.SiC, produced by squeeze casting method. In GMAW, the current is varied to 180,210, and 240 A, with constant voltage and velocity of 22 V and 180mm/min,respectively. Therefore heat input used in this research is varied to 1.32, 1.54, 1.76kJ/mm. The characterization included bending test, microhardness test, danmetallography observation.The result shows that the higher heat input will decrease the hardness because itslowed down the cooling rate so that increased the grain size. Al4C3 was found onSEM observation, which decreased the strength of the weld products. Al4C3 wasproduced by the reaction of Al with SiC at 700 oC, which was lower than the weldingtemperature that exceed 2000 oC.]"