Danieli & C. Officine Meccaniche S.p.a.

Mirco Striuli

Giovanni Coassin

Andrea Carboni

Wogler D Ruzza

Alfredo Lavazza

Bruno Di Giusto

Fulvio Fasano

Umberto Meroni

Fabio Borlina

The controlled pre-rolling of a slab, leaving a continuous casting plant is carried out with pairs of pre-rolling elements (14, 114, 16) assembled in at least one pre-rolling assembly (10), the first of these pre-rolling assemblies (10) being positioned immediately downstream of the foot rolls (12) of a crystalliser (11). At least one data processing and controlling unit (21) governs the positioning and the adjustment of the pre-rolling elements (14, 114, 16), the final pre-rolling zone being pre-defined by a specific pair (No. X) of pre-rolling elements positioned along the path of extraction of the slab (20), the data processing and controlling unit (21) having access to an inner memorised archive where there is a plurality of pre-defined tables or technological cards (27) containing the map of the desired values of reduction in thickness in the pre-rolling step as a function of the working parameters pre-set and/or monitored and/or detected continuously, each significant variation of at least two of these parameters causing a new table or technological card (27) to be selected with a resulting re-definition of the position and/or action of the pre-rolling elements (14, 114, 16).

Method for the controlled pre-rolling of thin slabs leaving a continuous

Method for the controlled pre-rolling of thin slabs (20) leaving a continuous casting plant, whereby the pre-rolling is carried out with a plurality of pairs of rolls (14-16), a first pre-rolling assembly (10) being positioned immediately downstream of foot rolls (12) of a mold (11), at least one displaceable roll (16) being included in the pairs of rolls (14-16), the pairs of rolls (14-16) being associated with pressure transducer (18) and hydraulic capsule (17), position transducer (24) being included. The pressure transducer (18) and position transducer (24) can be associated with a data processing unit (21), at least the first of the pairs of rolls (14-16) processing a slab (20) which has just emerged from the mold (11) with a thin solidified skin. The method achieves a pre-rolling with a reduction of the thickness of the slab (20) leaving the last pair of pre-rolling rolls (14-16) by at least 10% so as to eliminate the liquid core and to bring into contact the zones in a two-phase condition in order that the central solidification structure be refined and the central separation be minimized. Device suitable to carry out the controlled pre-rolling of thin slabs according to the above method, which comprises an element (25a) to monitor the temperature of the liquid bath in a tundish, an element (25b) to monitor the temperature of a slab (20), an element (26) to monitor the speed of the slab (20) and an element (28) to monitor the inclusion of a liquid cone.

Method for the controlled pre-rolling of thin slabs (20) leaving a continuous casting plant, whereby the pre-rolling is carried out with a plurality of pairs of rolls (14-16) grouped together in one or more pre-rolling assemblies (10), the first of the pre-rolling assemblies (10) being positioned immediately downstream of foot rolls (12) of a mold (11), at least one displaceable roll (16) being included in the pairs of rolls (14-16), the pairs of rolls (14-16) being associated with pressure transducer means (18) and hydraulic capsule means (17), position transducer means (24) being included. The pressure transducer means (18) and position transducer means (24) can be associated with a data processing unit (21), at least the first of the pairs of rolls (14-16) processing a slab (20) which has just emerged from the mold (11) with a thin solidified skin. The method achieves a pre-rolling with a reduction of the thickness of the slab (20) leaving the last pair of pre-rolling rolls (14-16) by at least 10% so as to eliminate the liquid core and to bring into contact the zones in a two-phase condition in order that the central solidification structure be refined and the central separation be minimized. Device suitable to carry out the controlled pre-rolling of thin slabs according to the above method, which comprises means (25a) to monitor the temperature of the liquid bath in a tundish, means (25b) to monitor the temperature of a slab (20), means (26) to monitor the speed of the slab (20) and means (28) to monitor the inclusion of a liquid cone.

Crystallizer, or inner portion, of a mold for the continuous curved casting of thin slabs, which has at least its outer curved extrados plate (10) containing a substantially central enlargement hollow (11) starting from the upper surface (13) of the outer plate (10) and being reduced progressively, to zero in the curved inner surface (12) of the plate (10) for sliding of the molten metal, the enlargement hollow (11) being defined by a determined profile, the profile being determined lengthwise by an angle '.alpha.' and crosswise by an angle '.beta.', wherein the angle '.alpha.' should not exceed a maximum value of 5.degree. and may vary, from the center line to the sides of the hollow (11), according to a linear development contained within a field limited at its upper end by that maximum value and at its lower end by zero.

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Mirco Striuli