Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
  • B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
  • B21B1/463—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a continuous process, i.e. the cast not being cut before rolling

Definitions

• the invention relates to a method for producing a metal strip by casting rolls, in which first in a casting machine a slab with nominal slab thickness is poured by discharging metal at a nominal casting speed from a mold, wherein the slab in the region of a strand guide by a number rollers are subjected to a thickness reduction, wherein the slab is then tempered in a furnace of defined length, wherein the slab is rolled behind the furnace in a rolling train and wherein in particular the slab behind the casting machine and in front of the furnace in a roughing mill of a reduction in thickness to a nominal deformed slab thickness or Vorbanddicke is subjected. Furthermore, the invention relates to a casting rolling mill.
• the slabs or pre-strips are separated into individual slabs or individual pre-slats so that coils of the desired size are produced after hot-rolling.
• Thin slab plants mainly work as a slab process.
• the slab process it is characteristic that the conservation of energy and the required heating of the slab, for example in a roller hearth furnace, which is longer than the maximum slab length. This allows all slabs to be separated in such a way that the individual slab is completely in the oven within a certain period of time, ie neither in the casting machine nor in the casting machine.
• nen Scheme still in the rolling range of the finishing train is engaged.
• Typical thicknesses of the slabs are between 40 mm and 100 mm.
• the so-called ISP process works with smaller intermediate strip thicknesses, which are typically in the range between 10 and 20 mm.
• the individual intermediate belts are always engaged either in the casting area or in the rolling area of the finishing train.
• the intermediate buffering of the pre-bands is carried out by means of two heated coiling ovens, which conserves the temperature of the pre-bands after reheating.
• ESP process also known is the so-called ESP process. This is an endless process that originated from the ISP process. Since the ESP process must operate without a thermal intermediate buffer, all distances between the individual devices of the plant must be minimized in order to avoid the unprotected radiation of the heat of the intermediate strips to the environment. This inevitably results in small distances between the facilities.
• the advantages and disadvantages of the ESP process are as follows:
• the disadvantage is as follows: It is difficult to adhere to the final rolling temperature, since the rolling speed in the finishing train is coupled directly to the mass flow from the casting machine. This can only be achieved by a consistently high casting performance and by reheating the intermediate belt to very high temperatures after roughing. Furthermore, the required final rolling temperatures can not be achieved for all steel grades, so that certain grades can not be produced in continuous operation. Then it is disadvantageous that in a required roll change, the sequence must be completely stopped. In case of faults, for example, in the casting operation, the continuous operation is interrupted, it must then be converted to batch mode. be switched.
• DE 10 2008 020 412 A1 describes a method for producing a metal strip by casting rolls, in which first a thin slab is cast in a casting machine. This is then rolled in a rolling mill using the primary heat of the casting process.
• a first mode of operation can be carried out by direct coupling of the casting machine with the at least one rolling train, a continuous production of the metal strip (endless rolling);
• a discontinuous production of the metal strip can take place by decoupling the casting machine from the at least one rolling train (batch operation).
• the removed slabs or pre-bands can be brought to a desired temperature or kept at a desired temperature prior to being transported back into the main transport line.
• an additional slab storage area - accessible by ferry - is created next to the main transport line.
• the invention has for its object to provide a method of the type mentioned so or to create a corresponding device with which it is possible, without great effort on the one hand a sufficient buffer memory in the event of roll interruptions, z. B. due to a roll change, on the other hand to ensure the smallest possible furnace length to work optimally in continuous operation can.
• a combined continuous / batch process is to be provided which overcomes the above disadvantages of the ESP process with cost effective means.
• additional storage ovens adjacent to the transport line or oven extensions should be avoided.
• the solution of this problem by the invention according to the method is characterized in that for temporary reduction, in particular for temporary interruption, the supply of rolling stock in the rolling mill at least one of the measures is performed: a) Increase the slab thickness behind the casting machine by reducing the thickness reduction of the slab in the field of strand guidance; b) lowering the casting speed from the nominal casting speed to a reduced value;
• At least two of the measures a), b) or c) can also be used in combination in order to increase the desired effect.
• the slab may be cut (separated) on a pair of shears located in front of the furnace.
• the inlet velocity of the slab into the furnace is preferably reduced by at least a factor of 2 compared to the nominal value.
• the thickness reduction of the slab in the area of the strand guide is preferably reduced by up to 40 mm.
• the thickness reduction of the slab in the roughing mill can be reduced to zero.
• the temporary reduction, in particular the temporary interruption, the supply of rolling stock in the rolling train can be made while in the rolling mill a roll change is made or there is a different production delay in the rolling mill.
• the slab After making the temporary reduction in the supply of rolling stock in the rolling mill, the slab can be processed in batch batch operation. This is due to the process for the first slab after a Walzun- break.
• the slab can, as long as a temporary reduction of the supply of rolling stock in the rolling train is not carried out, be processed in the continuous rolling process.
• the method is applicable to a rolling mill, which is operated in continuous mode or in batch mode.
• a), b) or c) such a buffer time or rolling interruption in the rolling train can be created or made possible, so that no casting breakage must take place in the casting machine, with a short furnace being used in particular.
• the slab may also be subjected to heating by means of induction heating in front of or behind the furnace.
• the casting rolling mill which comprises a casting machine, an oven and a rolling mill connected downstream of the furnace, wherein the furnace has a number of heating elements in order to temper a cast slab, is inventively characterized in that the furnace has a total length between 30 and 120 m ,
• the furnace is preferably formed as a roller hearth furnace or as roller-skating encapsulation, wherein it preferably has insulated roller conveyor rollers.
• heating elements for heating the slab may be arranged, in particular inductive heating elements.
• a roughing mill or multiple roughing mills can be arranged.
• the heating elements of the furnace are preferably arranged out of the transport line.
• insulation elements may be present, which can be retracted as needed in the area of the furnace instead of the heating elements.
• the proposed method allows maximizing the slab puff mass or buffer time in a furnace (preferably in a roller hearth furnace or a walking beam furnace) by increasing the casting thickness in comparison with the (nominal) production thickness. Furthermore, alternatively or additionally, a lowering of the casting speed can be provided in comparison with the (nominal) production speed.
• the method further provides alternatively or additionally that a reduction of the decrease in an in-line roughing stand or Vorgerüsten behind the casting plant and in front of the furnace in comparison with the (nominal) decrease takes place during regular production.
• the method may provide for maximizing the oven bake time (in a hot strip and continuous hot rolling mill) where the feed rate of the slabs into the oven in the buffer phase is at least a factor of 2 over the nominal (normal) feed rate in the case of normal production is reduced.
• the casting thickness can be adjusted by LCR (liquid core reduction) of preferably 0 to 40 mm in order to influence the slab segment length in the furnace, preferably with the same ring weight.
• the finished strip is changed to a desired practical finished strip thickness.
• the process provides buffering time for a roll change or for bridging other production delays.
• the proposed casting mill allows the combined batch and final rolling of hot strip.
• the oven - preferably designed as a roller hearth furnace - is preferably between 30 and 120 m long.
• the use of an inline roughing stand is preferred, but not mandatory.
• the use of the change in thickness in the caster and in the in-line scaffold for the purpose of increasing the buffer time or shortening the kiln length can be provided in a single-strand caster rolling mill, but also in a multi-strand caster rolling mill.
• the roller hearth furnace can be designed as a temperature holding furnace or alternatively serve for heating the slabs or intermediate bands.
• roller table cover (roller table encapsulation) can also be used partially or instead of a roller hearth furnace.
• An induction heater which is preferably arranged behind it, brings the pre-strip or the slab in front of the rolling train to the desired inlet temperature.
• the induction heaters can be displaced laterally or upwards out of the line in order to be able to heat at a thin strip and to be able to drive out the induction heaters with a thick strip, in order to replace them with insulation elements (insulating elements, roller shutter encapsulation).
• At least one inductive heating can also be provided between the stands of the finishing train.
• a buffer time can be created or a rolling interruption can be realized in the rolling train (For example, to change a roller in the finishing train), without a casting demolition must be done in the casting machine.
• FIG. 1 is a schematic side view of a casting and rolling plant according to a first embodiment of the invention
• FIG. 2 shows in the illustration according to FIG. 1 a cast roll mill according to an alternative embodiment of the invention and in the illustration according to FIG. 1 a cast roll mill according to the alternative embodiment of the invention.
• FIGS. 1 to 3 each show a cast roll plant in which a metal strip 1 is produced.
• the cast strand is deflected by means of a strand guide 5 from the vertical to the horizontal.
• rollers which are arranged in the strand guide 5 and exert a normal force on both sides of the slab surface.
• the slab 3 leaves the casting machine 2 with the nominal thickness d 0 and speed v 0 in the belt conveying direction F.
• the nominal values for the casting speed v 0 and the slab thickness d 0 are those values which are present in the scheduled production of the metal strip 1.
• an in-line roughing stand 8 (rough rolling mill) is directly arranged, with which the slab 3 is further reduced in thickness.
• a pair of scissors 9 Behind the pair of scissors 9, there follows an oven 6, which is designed, for example, as a roller hearth oven.
• an oven 6 which is designed, for example, as a roller hearth oven.
• At the position of the furnace 6 is also optionally the arrangement of a roller table cover or encapsulation preferably with insulated roller table rollers conceivable.
• the cast rolling mill still has various other elements, which are shown in the three embodiments.
• Fig. 1 is located behind the furnace 6, an induction heater 10.
• This induction heating can optionally be arranged laterally displaced orWhenhebbar from the working position.
• the tape can be heated by the induction heater; then be provided with thicker slabs that the induction heater is moved out of the working position and replaced by insulating elements to reduce the heat radiation from the slab.
• the exemplary six rolling mills of the finishing train 7 are designated F1 to F6.
• further induction heaters 1 1 can be provided between the rolling stands.
• Behind the finishing train 7 are a cooling section 12 and reels 13. Further scissors 14 and 15 are provided.
• Fig. 2 is a heat-insulating hood in the field of cold strand disposal 16 behind the roughing mill 8 and the scissors 9 mentioned. It can be equipped with a swiveling thermal insulation hood and insulated furnace rollers be. When casting the tape is observable here (pivoting the employment of the framework).
• An induction heater 10 is provided here in front of the roller hearth furnace 6. In the solution according to FIG. 3 no induction heating is provided in the region of the furnace 6, however, in this embodiment the furnace 6 is made slightly longer.
• the intermediate thickness or the inlet thickness in the roller hearth furnace 6 can be flexibly adjusted.
• the buffer time results from the Ofen Pilllzeit given boundary conditions minus the rolling time in the finishing mill for the previously produced slab minus a reserve distance.
• a final thickness is selected such that a high draw-in speed results in the finishing train.
• the finished strip thickness is also increased accordingly to a desired practical finished strip thickness.
• the stator windows are to be dimensioned sufficiently, it is a large stroke of the thickness adjustment (long-stroke cylinder or additional mechanical employment in the front scaffolding or a wedge adjustment) provided further, the engine speed ranges are provided in the finishing mill accordingly.
• the roller hearth furnace is designed for the mode of operation and the maximum and minimum thin slab thicknesses of, for example, 120 or 20 (25) mm, and corresponding roller spacings and diameters are used.
• the furnace length between the roughing stand 8 and the finishing train 7 is short and is preferably between 30 m and 120 m, depending on the required boundary conditions.
• the kiln length is shorter than with conventional CSP plants (where it is between 200 and 240 m).
• the shorter oven advantageously reduces the energy losses.
• the heating of the (transformed) slab 3 can take place with a roller hearth furnace or the roller hearth furnace is operated as a temperature holding furnace and assisted by inductive heaters upstream and / or behind or inside the roller hearth furnace (see the three exemplary embodiments according to FIGS.
• Parts of the furnace or the entire furnace may alternatively be designed in the form of a rolling cover or encapsulation with insulated roller table rollers.
• the above procedure applies to continuous and batch operation in a 1-line system. In order to make better use of the production capacity of the finishing train, it may be useful to integrate a second casting strand in the case of batch operation. In the case of a 2-line system, the above procedure of batch operation is also carried out on the second line in order to reduce the roller hearth furnace length in total.
• a flexible two-part ferry can be provided.
• the half parallel ferry transports the thick slabs and the whole double ferry is intended for the normal thinner, longer slabs.
• the ring weight of the slabs can be the same.
• the slab 3 is understood to be the cast slab behind the casting machine 2 or else the deformed slab behind the rough rolling mill 8.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Metal Rolling (AREA)

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• 2011
  • 2011-02-16 DE DE201110004245 patent/DE102011004245A1/de not_active Withdrawn
  • 2011-09-28 EP EP11763652.2A patent/EP2624971B1/de active Active
  • 2011-09-28 WO PCT/EP2011/066889 patent/WO2012045629A2/de active Application Filing
  • 2011-09-28 RU RU2013120545/02A patent/RU2537629C2/ru active

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