Apparatus for changing width of slab in continuous casting

A variable-width type composite continuous casting mold apparatus comprising:

• two broad faces in opposing spaced apart relation;
• at least one narrow face movable between said broad faces to change the width of a slab under continuous casting conditions;
• horizontal driving means for transversely moving said narrow face;
• rotary driving means operable independently of said horizontal driving means for rotationally moving said narrow face;
• and,
• control means for dividing the period of width changing operation into a forward taper changing period and a rearward taper changing period, determining, by means of allowable shell deformation resistance as a parameter, the accceleration .alpha..sub.s of horizontal moving velocity of said narrow face in each period, determining the angular velocity .omega. of said rotary driving means in accordance with the following formula (4), and actuating said horizontal driving means and said rotary driving means to cause a predetermining change in the width of said slab while maintaining said acceleration .alpha..sub.s and said angular velocity .omega. at constant levels in said respective taper changing periods:
• .omega.=.alpha..sub.s /Uc (4)
• where,
• .omega.:
• angular velocity of rotary drive (rad/min),
• .alpha..sub.s :
• acceleration of horizontal moving velocity, of narrow face (mm/min.sup.2), and
• Uc:
• casting speed (mm/min).