Patent ID: 6810943
Filing Date: 2004-11-02
Classification: B22D

Abstract:
A process for producing a thin slab having broad faces with a predetermined convexity in a continuous casting installation, in which a spade-shaped immersion nozzle protrudes into a mold composed of broad and narrow faces followed by a strand guiding means for guiding the slab which comprises a strand shell surrounding a liquid sump, said process comprising the steps of:a) forming broad faces of the strand shell to have planar surfaces in a region of the spade-shaped immersion nozzle using central parts of the mold broad face, wherein widths of the planar surfaces extend in parallel directions and lengths of the planar surfaces taper conically toward a slab guiding direction; b) shaping said broad faces of the strand shell with planar side surfaces of the mold broad face that taper conically to the narrow faces, in which the side surfaces of the mold broad face are at an angle to the central parts; c) in a strand casting direction, feeding parts of the slab broad faces shaped with planar surfaces conically to each other up to 40 to 60% of the mold length to such a degree that lateral edges of the faces adapt themselves to ends of the planar side surfaces of the slab, wherein the mold broad faces tapering conically with respect to narrow faces of the slab, includes wedge-shaped connecting pieces joined with the central parts and side parts of the broad faces, and wherein the central part extends past sides of the spade-shaped immersion nozzle; and d) subsequently, in a mouth region of the mold at a slab exit end of the mold and after leaving the mold, maintaining convexity formed by in each case three planar surface parts of the broad faces of the strand shell constant in its form as far as a lowest point of a liquid crater of the slab.