Casting and forging are two different metal forming process for aluminum alloy.
Aluminum forging is thermal molding forming process. High external force make the hot aluminum blank deformation in the die forging mould.
Through forging pressure, aluminum alloy can get the internal structure grain refining, and the internal fiber is continuous. So the aluminum forging part is always with higher strength. at the same time, aluminum forging part is easy to be done with surface oxidation treatment. When we need high strength and surface beautiful aluminum parts, the designer is usually choose forging process from the beginning.
Aluminum casting, no matter gravity casting, die casting, low pressure casting, is a metal forming process from melt aluminum to solid aluminum in the casting moulds.
Because there is a phase changing process of solidification. some casting defects usually appear, such as shrinkage. So the aluminum casting parts is lower strength than forging parts. But Aluminum casting process can make complex shape and thin wall structure, which the forging process can not make it.