Abstract: A mold for the continuous casting of beam blanks has a central casting passage bounded by a pair of parallel walls. On either side of the central casting passage is an expanding casting passage which widens in a direction away from the central casting passage and is bounded by a pair of inclined walls diverging from respective ones of the walls of the central casting passage. A terminal casting passage bounded by a pair of side walls parallel to the walls of the central casting passage is located outwardly adjacent to each expanding casting passage. The various casting passages cooperate to define a dogbone-shaped mold cavity. The inclined walls have an angle of inclination no smaller than arc tangent (y/z) where y is the distance from a point on an inclined wall to a transverse center line of the transverse cross section of the mold and z is the distance from such point to a longitudinal center line of the transverse cross section of the mold.