METHOD AND APPARATUS FOR REDUCING CROP LOSSES DURING SLAB AND INGOT ROLLING

A method and apparatus for reducing crop losses during slab and ingot rollin g concerns the formation of a slab ingot having a specially configured or shap ed butt end and optionally a head end as well. A special shape is formed by machining, forging or preferably by casting. The special shape at the butt e nd is imparted during casting by a specially shaped bottom block or starter block. The special shape of the bottom block is imparted to the cast ingot butt end. The specially shaped butt end of a slab shaped ingot is generally rectangular in shape and has longitudinally outwardly extending, enlarged portions (24), which slope downwardly toward a depressed central valley regi on (26). The lateral sides of the enlarged end portions and the depressed valle y region carry transversely extending, tapered or curved edges. A similar shap e may be imparted to the head end of the ingot at the conclusion of a casting run through the use of a specially shaped hot top mold or by way of machinin g or forging the cast head end. During subsequent hot rolling in a reversing roughing mill, the specially shaped slab ingot minimizes the formation of overlap and tongue so as to improve material recovery by reducing end crop losses and to increase rolling mill efficiency by increasing metal throughpu t in the mill.