Wrought-aluminum and -magnesium alloys are mostly produced by a semicontinuous casting method called direct-chill (DC) casting. Invented in the late 1930s, it quickly became the dominant technology of producing round (billets) and flat (ingots) large-scale castings intended for further deformation (extrusion and rolling). Sometimes large billets are made for forgings and flat ingots, intended for further remelting (as master alloys).