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

Giovanni Coassin

Andrea Carboni

Alfredo Lavazza

Gianni Gensini

Bruno Di Giusto

Mirco Striuli

Fulvio Fasano

Wogler D Ruzza

Umberto Meroni

Fausto Drigani

Gianpietro Benedetti

Kjell Bergman

Fausto De Marco

Pietro Morasca

Staffan Granstrom

Corrado De Cecco

Gianni Rattierri

Franco Driussi

Kenneth Lundstrom

Luciano Morello

Gensini Gianni

Ricardo Fragiacomo

Bruno Gosparini

Sergio Gerussi

Method to transform a rolling mill in order to revamp an old-type rolling line (,) fed by slabs with a thickness greater than 160 mm and arriving from an accumulation store (,) and to insert a segment of new line comprising at least a continuous casting machine (,) to produce thin and medium slabs, with attached relative operating assemblies such as extraction, straightening, shearing devices etc., the old line (,) comprising a roughing unit with one or more stands and a terminal segment (,) with a finishing train (,), a cooling area (,), systems to collect the product (,) etc., the segment of new line (,) being achieved and installed in a position near the old line (,) while the old line (,) continues working, the segment of new line (,) being equipped substantially at the terminal end with a movable element (,) in order to be at least temporarily connected to the terminal end (,) of the old line (,).

Method to transform a rolling plant

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

The casting line for slabs comprises at least a mould (11), an assembly of foot rolls (12) located at the outlet of the mould (11), a plurality of containing and guide assemblies (13) associated with the vertical segment of the line, a possible extraction assembly cooperating downstream with the last containing and guide assembly (13) and a drawing assembly (16) associated with the horizontal segment of the line, the containing and guide assemblies (13) covering at least the whole vertical segment of the casting line, at least part of the rolls (14) of the containing and guide assemblies (13) cooperating with an actuator (19) governed by a data processing unit (20) to obtain a controlled soft-reduction pre-rolling at least in the second part of the vertical segment of the casting line.

Casting line for slabs

Discharge nozzle (10) for continuous casting of slabs having narrow sides between about 30 and about 300 mm. wide, which is employed to distribute liquid metal in a continuous casting mould and is of a type comprising a substantially vertical discharge pipe (11), which is closed at its lower end and includes lateral terminal discharge holes (14) facing towards the narrow sides of the mould and cooperating with means (13) that distribute and deflect the flow of liquid metal, the discharge pipe (11) comprising a first segment (11a) having a downwardly converging circular cross-section and a second downwardly diverging segment (11b) with a cross-section which can be varied progressively from circular to substantially rectangular at least with rounded short sides, the distribution and deflection means (13) consisting of two distribution chambers (15), one per each lateral discharge hole (14), the chambers (15) being open at their upper (16a) and lower (16b) portions and being defined by a sidewall (17) which, at the opposite side of the lateral discharge hole (14), is conformed as a downwardly diverging deflector (18) forming an angle '.alpha.' with the vertical between 10.degree. and 35.degree., the lateral discharge holes (14) being adjacent to a bottom end wall (12) and having an overall section about equal to the section of the outlet of the second segment (11b) of the discharge pipe (11), each distribution chamber (15) defining an upper discharge outlet (16a) and a lower discharge outlet (16b).

Discharge nozzle for continuous casting

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.

Line to produce strip and/or sheet or a combined line for strip/sheet, starting from at least one plant for the continuous casting of thin or medium slabs, the continuous casting plant comprising in sequence a continuous casting machine (12), at least one assembly (13) for shearing to size, a temperature restoration system, a rolling train (17-117) and a possible assembly (19) for the cooling of strip/sheet. A device to accelerate the speed of feed of the slabs is included downstream of the assembly (13) for shearing to size. The temperature-restoration system includes an induction furnace (14) with at least one working frequency to heat the surface and edges of the slabs, the induction furnace (14) being followed by a low-speed descaler (115) and by a tunnel furnace (16). An emergency shears (24) and high-speed descaler (15) is included between the tunnel furnace (16) and the rolling train (17-117).

Line to produce strip and/or sheet

Method for the storage and controlled supply of electric energy for discontinuous loads in steelworks and in particular for metal melting systems and rolling mills, the method comprising at least one main supply line (18) connected to a main supply source (11) of electric energy and a plurality of loads (12-13-14-114-20), whereby the level of maximum active power supplied by that main supply source (11) to the steelworks is limited by a sub-station (27) to a level 'P.sub.0 ' lower than the peaks of maximum absorption by those loads (12-13-14-114-20), the method comprising at least one accumulation line (16) connected in parallel to the main supply line (18) and supplying at least one storage assembly (17), which is connected to the loads (12-13-14-114-20) through a secondary supply line (19).

Method for the storage and controlled supply of electric energy for

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.

The mold has movable sidewalls (13) to adjust the width of the slab and an enlarged casting chamber (11) extending along the length of the crystallizer of the mold (10). Located immediately downstream of the mold (10) are containing plates (24) and transverse rolls (18) defining a possible first assembly (19) of rolls, a second assembly (28) of rolls and a third assembly (29) of rolls. The casting chamber (11) has an enlargement provided by a central curve defined by a first equivalent radius R, the central curve at the inlet (16) of the casting chamber (11) being defined by the specific first equivalent radius R' and by a width L of at least 500 mm. with a value of the lateral half-enlargement A between 30 mm. and 90 mm., the casting chamber (11) comprising within its length a first segment (26) and a terminal segment (27), a zone of curved connection (23) being included between the first segment (26) and the terminal segment (27), the terminal segment (27) being equal to between about one quarter and one sixth of the overall length of the crystallizer (10), the terminal segment (27) comprising a first terminal portion (27') defined by the respective curved connection zone (23) and a second terminal portion (27'), the second terminal portion (27') having a constant section of its passage with a lateral half-enlargement B having a value between 1 mm. and 12.5 mm. and defined by a central curve with a specific first equivalent radius R'.

Method of and mold for the continuous casting of thin slabs

Electric arc furnace with alternative sources of energy, which functions with direct current or alternating current and comprises at least one lance (12) to inject pure or combined oxygen above the bath (16) and a plurality of tuyeres (13) positioned in the hearth of the furnace (10) to inject oxygen below the bath, the tuyeres (13) being cooled by a peripheral movement of a cooling mixture consisting of at least one gas having a high cooling power (methane, butane, inert gases, etc.) and of at least one diluting gas (nitrogen, carbon dioxide), pipes (15) being included to introduce additives and powdered coal, post-combustion burners (28) possibly being comprised, the tuyeres (13) including an oxygen delivery pipe (18) having a diameter greater than 8 mm., the oxygen pressure being capable of being modulated according to the working steps, there being a constant minimum pressure of delivery. Melting operating method associated with such an electric furnace, wherein the charging operation with each single charge (skip) is divided into defined periods, with which are associated a pressure of delivery of oxygen through the tuyeres (13) and a percentage of gas having a high cooling power and proportioned to the rate of flow of the oxygen, there being a minimum pressure of delivery of oxygen in each moment of the working of the furnace (10).

Electric arc furnace with alternative sources of energy and operating

Descaling device employing water to descale blooms, thin slabs, billets, etc., which cooperates with a mould and the zone immediately downstream therefrom, or with an induction furnace or rolling mill stands, the slabs or blooms (11-24) being fed in cooperation with the descaling device at a speed of feed of the order of 1.5-20 meters per minute, but advantageously between 4 and 10 meters per minute, the device consisting of at least one movable arm (12-13) bearing nozzle means (14) delivering descaling water, the movable arm (12-13) being associated with the face of the slab or bloom (11-24) to be descaled and having a working phase, in which the descaling water acts on the surface of the slab or bloom (11-24), and a shut-off phase, in which the descaling water does not act on the surface of the slab or bloom (11-24).

Descaling device employing water

Direct-current smelting furnace with control of deflection of the electric arc, which comprises an upper electrode (13) with relative return-flow lines and a plurality of bottom electrodes (11) positioned on the hearth of the furnace (12) and arranged in two or more assemblies, each assembly having its own controlled supply line connected to its own transformer (16), there being included downstream of each transformer (16) its own thyristor rectifier assembly (17) associated with its own means to control voltage (26), current (24) and firing angle (23), at least the lines supplying the bottom conductors (32) being at least partly screened in the vicinity of the melting furnace (12)

Direct current melting furnace with control of deflection of the

Method to feed a three-phase direct-arc electric furnace with controlled current and also a three-phase electric furnace thus fed for the smelting of metals, e.g. iron-based alloys, the furnace comprising means (GI) for regulation of the length of the arc by means of action on the height of the electrodes, the mains supply of the furnace including at least one medium voltage line and a transformer to serve the arc furnace, an element to regulate the arc current being comprised in each phase in the segment connecting the medium voltage line and the transformer and consisting of at least one inductor (L1), a thyristor-controlled valve (T) or alternatively a regulation element consisting of a saturable reactor being included in parallel with at least part of the inductor, one or the other of these regulation elements cooperating with a device (s1) to measure the intensity of the arc current and with an assembly (GC) that controls the arc current of the furnace by means of action on the overall value of the equivalent series reactance. The method includes feeding current to the furnace through the mains supply and varying the value of a series reactance of the segment connecting the medium voltage line and the transformer.

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Pordenone, Italy

Giovanni Coassin