Gravity casting is the process refers to the liquid metal in the earth under the action of gravity, into the mold, also known as casting. The generalized gravity casting including sand casting, metal casting, investment casting, lost foam casting, such as clay mold casting; narrow sense of the gravity casting refers specifically to the metal casting.
In the die casting process, liquid or “molten” metal is forced into a die under high pressure. In this case, “die” refers to the steel mold created to shape the actual product that will be made. Following the pour and injection into the mold, the molten metal solidifies and is removed from the mold. When the metal cools, the gating material gets removed and a product has been manufactured Gravity casting usually used for the products with complicated outer shapes, and die casting usually used for the products with complicated internal shapes but simple outer shapes.