Casting of molten metal in an open ended mold cavity

In combination,

• an apparatus defining an open ended mold cavity having an entry end portion, a discharge end opening, and an axis extending between the discharge end opening and the entry end portion of the cavity, and wherein molten metal is cast into a form-sustaining body of metal by forcing the molten metal into the entry end portion of the cavity while a starter block telescopically engaged in the discharge end opening of the cavity is reciprocated relatively outwardly from the cavity along the axis thereof, a body of startup material interposed between the starter block and a first cross sectional plane of the cavity extending relatively transverse the axis thereof is reciprocated in tandem with the starter block through a series of second cross sectional planes of the cavity extending relatively transverse the axis thereof, and successive layers of molten metal are relatively superimposed on the body of startup material adjacent the first cross sectional plane of the cavity so as to have inherent splaying forces therein acting to distend the layers relatively peripherally outwardly from the axis of the cavity adjacent the first cross sectional plane thereof,
• means for confining the relatively peripheral outward distention of respective layers of the molten metal to a first cross sectional area of the cavity in the first cross sectional plane thereof, while permitting the respective layers to distend relatively peripherally outwardly from the circumferential outline of the first cross sectional area at relatively peripherally outwardly inclined angles to the axis of the cavity in which the layers assume progressively relatively peripherally outwardly greater second cross sectional areas of the cavity in second cross sectional planes thereof,
• means for generating thermal contraction forces in the respective layers as the layers assume the second cross sectional areas, and
• means for controlling the magnitude of the thermal contraction forces in the respective layers so that the thermal contraction forces counterbalance the splaying forces in the respective layers at one of the second cross sectional planes of the cavity and thereby confer a free-formed circumferential outline on the body of metal as the body of metal becomes form-sustaining.