Effect of spray angle toward microstructure morphology and hardness of Al-Mg powder produced from a single orifice nozzle water atomizing

Aluminum alloy is the basic raw material to produce powder metallurgy by implementing a device called as water atomization. Aluminum alloy is melted at a temperature of 1300 °C to melt aluminum material. After melt the aluminum alloy is cooled about 15 minutes on the surround air while being cleaned from dirt on the hot liquid material surface thoroughly. Furthermore, the hot liquid material in the kowi is then poured into the atomization tube through a hopper which is then sprayed with water comes out from a twin nozzle with an Ø9 mm diameter nozzle hole. This the granulation process, with a spray pressure about P = 30 psi, a spraying angle variation of: L20°, L30°, and L40° and a constant water rate discharge of (Q) = 15 L/S. The water spraying distance was also varied for the L20°, the spraying distance is taken 2.5 cm; for L30°, the spraying distance was taken 3.5 cm and the spraying distance for the L40 ° is 4.5 cm. From the research, L30 ° with a spraying distance of 3.5 cm may have the best result, with a better metallurgical powder amount and resulted about 295 grams of aluminum powder material. The aluminum weight before melted is about 300 grams. Finally the aluminum powder hardness (HV) was tested; for the L20° process the HV was 55.94 kgm/s², for the L30° process the HV was 50.07 kgm/s², and for the L40° process the HV was 45.73 kgm/s². From the three angle variation observed, the L20° got the highest Vickers Hardness Number.