KR20130099091A - Method for producing steel strips by continuous rolling or semi-continuous rolling - Google Patents

Abstract

In the present invention, the slab 3 is first cast in a casting plant 2, which is rolled in a rolling mill train 4 to form a rough strip 3 ′. The temper strip 3 'is heated in a furnace 7 and the heated temper strip 3' is finish rolled in a finish mill row 5 to a predetermined final thickness and a predetermined final rolling temperature. A method for producing steel strips 1 by rolling or semi-continuous rolling. In order to ensure the desired final thickness and final rolling temperature of the steel strip, when changing the entry temperature T2 and / or the inlet mass flow of the crude strip, a new pass sequence is selected, whereby the desired final The thickness and the desired final rolling temperature are obtained, and the rolling stand which is finally engaged in the finishing mill row 5 is roll-unlocked or the rolling stand of the finishing mill row connected downstream of the last engaged rolling stand is roll-engaged, And further allows for minimization of the energy supplied to the furnace 7 and / or finishing mill rows 5.

Description

Method for manufacturing steel strips by continuous rolling or semi-continuous rolling {METHOD FOR PRODUCING STEEL STRIPS BY CONTINUOUS ROLLING OR SEMI-CONTINUOUS ROLLING}

In the present invention, the slab is first cast in a casting plant and the slab is rolled in a rolling mill train to form a rough strip, which is heated in a furnace, and heated heated strip This method relates to a method for producing steel strips by continuous rolling or semi continuous rolling, which is finish rolled in a finishing mill row at a predetermined final thickness and a predetermined final rolling temperature.

"Continuous rolling" means that the casting plant is rolled so that the slab cast in the casting plant-without separation from the recently cast slab portion and without intermediate storage-is passed directly into the rolling plant and rolled to the final thickness in the plant. If connected to a facility. This allows the casting facility to continue casting on the same slab, ie there is no end of the slab, while the beginning of the slab to be finished finish rolled now allows the formation of a steel strip of final thickness. This is also known as direct coupled operation or continuous operation of casting and rolling equipment.

In so-called "semi-continuous rolling", after casting, the cast slabs are split up and the separated slabs are fed to the rolling mill without intermediate storage and without cooling to ambient temperature.

Slabs made from the casting plant are generally descaled, rough-rolled, and the resulting strips are heated in a furnace and finish rolled in a finish mill row. Hot-rolling generally takes place in the finish mill row, ie during the rolling process, the rolled material has a temperature that exceeds the recrystallization temperature of the material. In steel, this temperature is in the range exceeding approximately 720 ° C., and hot rolling generally occurs at a temperature of 1200 ° C. or less.

When hot rolling a steel, the metal is generally in an austenite state, in which iron atoms are arranged in a face-centered cubic structure. This is called austenite rolling when both the initial and final rolling temperatures are in the austenitic range of the respective steel. The austenite range of the steel depends on the steel composition but is generally above 800 ° C. In order to reliably execute the entire finish rolling procedure in the austenitic state, the corresponding high finish rolling temperature is generally predetermined in the pass sequences.

Continuous or semi continuous rolling of steel strips is well known from the prior art, as well as the resulting disadvantages; In particular, it is well known from the prior art that during continuous rolling, all fluctuations in the casting processor are transferred to the rolling process by direct coupling of the casting equipment and the rolling equipment. During casting, fluctuating casting speeds and interruptions to casting equipment can cause fluctuations in temperature and speed of the crude strip, thus affecting the finish rolling of the steel strip and causing fluctuations in quality. . In particular, the mass flow and / or volumetric flow of the crude strip can be altered and / or the temperature of the crude strip can be altered. Mass flows and / or volumetric flows may have a thickness, for example, where the thickness and width of the crude strip remain the same, or when the speed of the crude strip changes, or while the width and speed of the crude strip remain the same. It changes if it changes. In the rolling technique, instead of the volumetric flow, a width-specific volumetric flow is often used, i.e. a flow such as a volumetric flow per unit width (1 meter), in particular the width of the strip is under consideration. If it does not play a particularly important role in the process, it can be expressed as the product of the strip thickness and strip speed. This is frequently the case when the width is at least 7 to 10 times greater than the thickness. In a known manner, the (width-specific) mass flow is obtained by multiplying the (width-specific) volumetric flow by the thickness of the strip.

Variations in temperature and / or width-specific mass and / or volumetric flows can be attributed to the actual final rolling temperature, i.e., the temperature of the steel strip after the last rolling stand of the finishing mill row, which may be associated with quality impairment. It may have consequences that deviate from the temperature. Thereby, as an essential characteristic of the product, the microstructure of the steel strip can escape the desired microstructure, ie austenite microstructure. However, this can also lead to deviations from the desired profile or the desired thickness of the steel strip. However, the quality of the finished steel strip may also be poor enough to be treated as waste.

In the prior art hot rolling of slabs or coarse strips cut from the casting train, in general, an alteration to the final thickness of the steel strip is from the next slab from only one slab and / or the coarse strip. And / or only the next strip is allowed. Similarly, the fixed entry rolling temperature (on the last rolling stand) for the volumetric flow curves (thickness change, width change) as well as the slab and / or the temper strips, as well as the temporary entry temperature curves of the temper strips in the finish mill row, It is always established in advance. When rolling the same slab and / or the same rough strip, deviations from the intended and / or expected curves are generally not accepted. Nevertheless, the entry temperatures of the crude strip which are slowly reduced when entering the finish mill row, such that the pass reduction distribution for each rolling stand and the final rolling temperature are generally maintained, are the speed of the crude strip. Is compensated by increasing (speed up). Changes to the pass sequence, ie the distribution of pass cross-sectional reductions for the respective rolling stands, are carried out at idle time between the exit of either finished steel strip and the entry of the next temper strip. In this case, as the intrinsic mill control has already been previously determined for each temper strip, important operating conditions are not made in the finish mill row. Sudden changes to the entry temperature of the crude strip in the finish mill row lead to an increase in waste, and abrupt changes to the volumetric flow when the crude strip enters the finish mill row are thereby excluded.

During semi-continuous rolling, slabs with large excess sizes are cut from the heat of the casting plant, and the newly entering slab is due to changes in the characteristics (temperature, width, thickness, speed of the slab and / or crude strip) or Due to the adjustment of the new final thickness, it can be braked to recalculate the pass sequence of the finishing mill train.

During full continuous rolling, the downtimes between the respective metal strips and / or slabs are removed and during the load operation, ie when the steel strip is rolled in the finish mill row, the operating state of the combined plant Any changes to must be made.

In order to ensure a sufficiently high final rolling temperature for the relevant methods, DE 10 2007 058 709 A1 determines the functional connection between the casting speed or mass flow, on the one hand the final rolling temperature, and on the other hand, the active rolling stand. For a particular number of teeth and for various final thicknesses, it is proposed to determine the optimal number when determining a particular casting speed and / or mass flow, whereby the desired final rolling temperature is reached and optionally the number of rolling stands By increasing only the optimal number of rolling stands is activated.

However, it cannot be guaranteed that a specific final thickness of the steel strip is simply obtained by reaching the desired final rolling temperature. This is also not even desirable according to DE 10 2007 058 709 A1, paragraph 20.

Accordingly, it is an object of the present invention that the fluctuations in mass flow and / or volumetric flow and / or speed of the crude strip, if technically possible, reach the desired final thickness and in any case the desired of the steel strip. When the final rolling temperature is reached, it is to specify a method which can be obtained without the above-mentioned fluctuations in the uninterrupted operation of the continuous combined installation and ensures that the desired final thickness and / or final rolling temperature is reached. This method can be further applied when only the width-specific mass flow and / or volumetric flow of the crude strip increase slowly when switching on a continuous combined installation.

SUMMARY OF THE INVENTION [0006]

When entering the finish mill row, by more than 1 K / sec, in particular by more than 5 K / sec, when changing the entry temperature of the crude strip, and / or

When entering the finishing mill row, by changing the entering mass flow of the crude strip by more than 0.2% / second, in particular by more than 1.5% / second,

A new pass sequence is selected, whereby the desired final thickness and the desired final rolling temperature are obtained, and the last engaged rolling stand in the finish mill row is de-rolled or the energy supplied to the furnace and / or finish mill rows With the -essential-minimized second condition being minimized, the rolling stands of the finishing mill row arranged downstream of the last engaged rolling stand are rolled engaged,

The entry temperature of the crude strip is obtained by adjusting the furnace and rolling stands according to the new pass sequence.

Changes to the entry temperature and / or entry mass flow are detected through the measuring devices, and conventional measures are taken to ensure the validity and accuracy of the signals, which are sometimes already present in the measuring devices. This is done when preparing the integrated or measured values based on statistics. In particular, in this case, only measured values which are statistically significant and without the usual signal noise are required to assess the current constancy or changeability of the entry mass flow and / or entry temperature. To be used, so-called filtering methods are used.

Thus, if significant changes occur in the temperature and / or mass flow of the temper strip when entering the finish mill row, then a new pass sequence must be used to achieve the desired final thickness and final rolling temperature of the steel strip. Changes to the entry temperature of the temper strip and / or entry mass flow by more than 0.2% / second when entering the finishing mill heat by more than 1 K / sec correspond to the ratios when switching on the combined cast rolling mill, Constant or slow changes to the entry temperature and entry mass flow. Values above 5 K / sec and / or above 1.5% / sec correspond to the values of the interruption of the combined cast rolling equipment and represent a significant and generally also sudden change in entry temperature and entry mass flow.

When determining a new pass sequence, an attempt is made to reach the desired final thickness and final rolling temperature of the steel strip by minimizing the energy used for this in the furnace and / or in the finish mill row.

Energy may be saved when the rolling stand which is not necessary is raised and no longer meshes with the steel strip, and where the steel strip passes through the rolling stand without changing thickness. However, in this case, when changing the pass sequence, only one rolling stand which was previously engaged with the steel strip is raised. Thus, if only the first five of the six rolling stands of the finishing mill row are engaged with the steel strip, i.e. active, according to the invention, only the fifth rolling stand can be selectively raised, but the fourth rolling stand is no.

However, it may also be necessary to engage the rolling stand, because even in the case of causing the required energy increase, the desired final thickness and final rolling temperature cannot be reached. In this case, for each change to the pass sequence, only one rolling stand that was last engaged and placed directly downstream is engaged. Of the six rolling stands in the finishing mill row-before the pass sequence change-if only the first four are engaged with the steel strip ("active"), only the fifth rolling stand can be engaged, but the sixth is Or in this case the sixth rolling stand is the last rolling stand of the finishing mill row. Thus, in minimizing energy, the desired final rolling thickness is invariably reached, i.e., by formulating the corresponding boundary conditions in the mathematical process model.

However, energy can also be saved if the entry temperature is reduced, i.e., the temperature at which the crude strip exits the furnace and enters the finish mill heat is reduced. This means, in particular, that the number of active rolling stands in the finishing mill row is reduced by one, and that in the remaining active rolling stands, the thickness reduction of the steel strip is at the maximum possible level of cross-sectional reduction (steel strip downstream and upstream of the rolling stand). And a relatively dissipative deformation heat that further heats the steel strip is then generated for each rolling stand. The maximum possible cross-sectional reduction levels are determined on the one hand by the material properties of the steel strip itself and on the other hand by a rolling stand which can only apply a finite rolling load.

In the method according to the invention, it goes without saying that the adjustments of the rolling stands within predetermined limit values do not damage the combined equipment, in particular the finishing mill heat. Accordingly, the maximum allowable rolling load and bending force are predetermined for rolling stands, and if exceeded, there is a possibility of causing breakage of rolling stands or breakage of rollers. In addition, there are limit values for the maximum possible speed of the steel strip, which can be set by both the rolling stand and / or the drive of the coilers and the properties of the steel strip, i.

However, if the respective active rolling stands of the finishing mill row have not yet reached the limit values, according to the invention, the last active rolling stand is raised and passes to the remaining active rolling stands if the mass flow of the crude strip increases. Distributing cross-sectional reductions is provided. As a result, more energy in the form of conversion heat can be introduced into the steel strip by changing the thickness for each rolling stand to be larger, so that the energy for the furnace can be saved as the steel strip is heated.

In the detail for the purpose to be achieved by the present invention, the phrase "technically possible" (more specifically, if possible within the limit values for the technical specifications of the installation), means that the original desired final thickness is effective for the finishing mill row. It is understood that it can only be sought if possible within the limit values, in particular the limit values for the maximum allowable rolling load and bending force. This is generally possible when the entry temperature and / or entry mass flow rises and additional rolling stands engage. However, this may in some cases, in turn, potentially reduce the original desired final thickness, as the rolling load and bending force of the finishing mill train required to maintain the final thickness may exceed those limits. The entry temperature and / or entry mass flow may decrease and may not be maintained when the rolling stand is raised. Thus, in any rolling program, when in any case a larger final thickness must be subsequently rolled, a larger final thickness which is not a problem should be approved.

In any case, when the rolling stand is lowered or raised, pass cross-sectional reductions, ie thickness changes for each rolling stand, must be redistributed to the respective and active rolling stands. The distribution of path cross-sectional reductions for each rolling stand is what those skilled in the art refer to as a "pass sequence". However, the pass sequence includes additional information for the rolling process, as is well known to those skilled in the art.

The rolled material, ie the steel strip, is at any time in the rolling process, and thus also in the pass sequence, described at least by the following variables (speed, thickness, temperature and relative profile (the thickness of the strip at the center to the edge)). . Each rolling stand is at least characterized by the following variables (peripheral speed, rolling load and bending force of the operating rollers) which simultaneously indicate the control variables of the rolling stand-even in the pass sequence.

It may be provided that a new pass sequence is determined during the current rolling process. In this case, the new pass sequence can be recalculated particularly with reference to the current measured data of the rolling process and accordingly. Naturally, it may also be possible to calculate different pass sequences in advance before the rolling process using different data of the rolling process, and to store the pass sequences in a data bank, so that there is a considerable By modification, a suitable new pass sequence can be selected from the stored pass sequences. However, as only a limited number of pass sequences can be precomputed and stored in the data bank, and these sequences are not always appropriate for a given rolling process, this method can calculate a new pass sequence during the current rolling process. Results in relatively worse results than online ones.

Ideally, the new pass sequence according to the invention is determined by a mathematical process model that simulates the rolling process of at least all rolling stands of the finishing mill row. During the current rolling process, the rolling process in the finishing mill row can be recalculated several times a minute using a mathematical process model.

In this case, the final rolling temperature, final thickness, rolling force and bending force required for each stand, as well as the energy requirements of the finishing mill heat and furnace can be calculated in each calculation step. have. Thereafter, the distribution of the rolling load for each rolling stand and also the number of active rolling stands are changed, and it is determined whether the active rolling stand can be less advantageous in terms of energy by maintaining the equipment limitations and the operating limitations. .

Such mathematical process models are known to those skilled in the art, several examples of which are cited in the EP 1 014 239 A1 publication, which generally includes a plurality of partial models, such as rolling load models, velocity models, Temperature models and profile models are used.

In order to minimize the energy supplied to the furnace and / or finishing mill heat, so-called target functions are formed which are subjected to mathematical optimization, for example in the form of extreme values, in which the function values of the target functions determined in this way are formed. Are used to determine the pass sequence.

The function values of the target function determined by mathematical optimization can be used directly as parameters of the pass sequence, for example. It is one embodiment where the target function is a function of the state variables of the rolling material such as speed, thickness, temperature, relative profile and / or control variables such as peripheral speed, rolling load, bending force.

Within the scope of the present invention, since the target function is the energy supplied to the furnace and / or finishing mill heat, a pass sequence is calculated, for example using particularly low energy. As one or more conditions set for the pass sequence in the form of limit values are considered as secondary conditions during optimization, limit values or technical limit values related to the technical specification of the installation are readily included in the optimization. In addition, one or more conditions that provide a fixed value for a control variable or state variable are considered as secondary conditions during optimization. As a result, fixed values, ie the desired final thickness and final rolling temperature, can be integrated into the optimization.

Decisions on the mathematical methods actually used for optimization are within the skill of the art and are not described in more detail herein. Several applicable methods are described in EP 1 014 239 A1 above.

When it is not possible to find a new pass sequence with the desired final thickness and the final rolling temperature, there is a solution to breakage for at least secondary conditions, under predetermined secondary conditions. When such a product can later be produced in any way according to the production plan, a change from the desired final thickness can be approved. However, the final rolling temperature can be at least when the metal is in the austenite state,

In practice, using the process model of the pass sequence, at least the final rolling temperature of the steel strip, the final thickness of the steel strip and the common energy requirements of the finishing mill heat and furnace are calculated, the number of rolling stands is varied, the rolling stands and If the associated energy for the furnace is determined, and during deformation, by maintaining predetermined values for the adjustments of the rolling stands and the furnace, if a reduction in the common energy demand is caused, this may be provided based on a new pass sequence. .

However, also simple may be required to minimize furnace energy, and accordingly, using the process model of the pass sequence, at least the final rolling temperature of the steel strip, the final thickness of the steel strip as well as the energy requirements of the furnace. Is calculated, the number of rolling stands is varied, the associated energy for the rolling stands and the furnace is determined, and during deformation, by maintaining predetermined values for the adjustment of the rolling stands and the furnace, If a reduction is caused, this is provided based on the new pass sequence.

A further possibility to minimize the energy required for the furnace is to change the thickness of the crude strip. In this case, the rolling stands of the rolling mill row must also be integrated into the newly calculated pass sequence. Thereby, the thinner the crude strip, the less energy is required to heat the crude strip in the furnace. However, it is an object of the present application to select the crude strip thickness as large as possible within predetermined values for the inlet mass flow, the final strip thickness and the final rolling temperature, so as to convert the energy stored in the furnace into a dissipating strain heat, which is the active rolling of the finishing mill row. Stands operate as close as possible to the maximum possible reduction levels. The temperature of the steel strip upon exiting the furnace in proportion to the energy supplied to the furnace should generally not exceed 1250 ° C., preferably below 1220 ° C. However, if the cross-sectional reduction levels are increased in the rolling stands of the finishing mill row, the temperature of the steel strip upon exiting the furnace can be reduced to, for example, approximately 1090 ° C.

The method according to the invention can be used for both continuous rolling or semi continuous rolling. In particular, the present invention provides for starting up and switching on a combined cast rolling plant after the casting rolling interruption, i.e. not immediately after the plant is stopped due to the actual restart and failure of the plant. Can be used for If used for semi-continuous rolling, then in principle there are two options, the case where the pass sequence is changed and thus the rolling stand is engaged or raised in order to implement a new pass sequence.

When the rolling stand is brought into rolling engagement or rolled out of engagement, the crude strip to be rolled may already be positioned in the finishing mill row. This corresponds to the method during continuous rolling in which the continuous steel strip passes through all rolling stands. During semi-continuous rolling, from the separated slabs, a plurality, which is generally relatively close behind one another at a time interval of only less than 20 seconds, preferably less than 10 seconds, in particular less than 5 seconds, into the finishing mill row Crude strips are prepared. In a first variant, the engagement or rise of the rolling stand is carried out without considering whether the steel strip is in the finish mill row. Thus, this is likely to occur when the steel strip is in the associated rolling stand.

In a second variant, the crude strip to be rolled during semi continuous rolling is provided to move only into the finishing mill row when the rolling stand is raised or lowered according to a new pass sequence. This allows parts already in the finishing mill row to pass from the finishing mill row in an accelerated manner, while parts not yet positioned in the finishing mill row pass into the finishing mill row until the corresponding rolling stand is adjusted according to the new pass sequence. This means that shears should be placed upstream of the finishing mill row which are cut through the crude strip so as to avoid (or at least not pass into the rolling stand to be displaced). Cutting of the temper strip is not a problem because the finished strip is generally not very long for the coil, and therefore must be cut at least once after the finish mill row in order to wind up the strip into two or more coils. . Thus, the cutting of the steel strip can be performed upstream of the finishing rolling stand instead of downstream of the finishing rolling stand, thus at the same time providing a block for the required transition to a new pass sequence.

When the rolling stand is raised or engaged, the gap between the rolls may increase and / or decrease by approximately 5 mm per second.

The method according to the invention can be implemented by a computer program product that, when loaded on a computer and implemented on a computer, determines a pass sequence as claimed in one of the method claims.

By means of the method according to the invention, finish rolling is most viable in spite of a significant or sudden decrease in entry temperature and / or width specific entry mass flow, for example due to interruptions in furnaces, descaling operations or casting equipment. It can be ensured that what can be caused by great operational safety.

Either the total energy consumption of the furnace and finishing mill heat or just the energy consumption of the furnace can be minimized, in particular, by changing the initial state (entry temperature and inlet mass flow) consistently or slowly.

The method according to the invention requires only a small cost for the adjustment of the actuators for the strip temperature (furnace, cooling).

The method according to the invention permits to start the finish rolling immediately after the start of the casting process, even when the entering mass flow is relatively low. By engaging the rolling stands sequentially in the finish mill row, the strip thickness can be gradually reduced as the entry mass flow and / or the heating power of the furnace gradually increases.

The invention is illustrated by way of example with reference to the schematic drawings.

1 shows a side view of a combined cast-rolling plant.

1 schematically shows an embodiment of a combined cast-rolling installation, in which the method according to the invention can be implemented for producing steel strips 1. There is provided a vertical casting installation 2 in which slabs 3, for example 70 mm thick, are cast. During semi-continuous rolling, cutting to the desired slab length can be made by shears 12. The slab 3 is brought to a rough-rolling temperature T1 of approximately 1000 ° C. to 1200 ° C., followed by a first furnace 6 in which a predetermined temperature compensation is caused in the width direction. However, the furnace 6 can also be removed.

The rough rolling then takes place in a rough-rolling mill train 4, which may be composed of one or more stands-as in this case-and the rough rolling mill. In the row the slab 3 is rolled to a medium or rough strip thickness. During the rough rolling process, a conversion from cast tissue to fine-grained rolled tissue occurs. This can also be done without the use of additional equipment or descaling nebulizer 13 for descaling upstream of the crude mill row 4.

Downstream of the stands of the crude mill row 4, an additional furnace 7 is arranged for the crude strip 3 ′. The furnace 7 can preferably be designed not only as an induction furnace but also as an existing furnace or high temperature furnace using flame application. In the furnace, the crude strip 3 'is relatively uniform over the cross section of the strip with the desired entry temperature T2 for entry into the finishing mill row 5, the entry temperature T2 being generally the type of steel. And 1090 ° C. to 1250 ° C. according to the subsequent rolling process in the finish mill row 5.

Downstream during heating in the furnace 7, finish rolling takes place at the desired final thickness and final rolling temperature in the multi-stand finishing mill row 5, after which the cooling of the strip takes place in the cooling stage 14 as well as Finally, the windings by the coilers 15 occur. This may also be done without the use of descaling nebulizers 13 upstream of the rolling stands 51 to 56 and / or between the rolling stands 51 to 56.

When switching on the combined casting rolling plant, i.e. after break in operation, if the entry mass flow of the temper strip 3 'in the finishing mill row 5 is still relatively low (the entry mass flow during normal operation) Less than 70%), rolling is carried out using only the first three rolling stands 51 to 53. In order to achieve the desired final thickness and final rolling temperature, if the inlet mass flow continues to increase, firstly up to the fourth rolling stand 54, then in a further step the fifth rolling stand 55 and optionally also the sixth rolling Stand 56 is lowered, ie activated. Prior to engagement with the further rolling stand, with the entry mass flow increasing, the temperature in the furnace 7 and thereby the entry temperature T2 of the crude strip 3 ′ will decrease. As soon as the additional stand is engaged and / or lowered, the entry temperature should rise significantly, typically 35-55K, but for reasons of economic and / or production quality, the surface temperature exceeds 1250 ° C, preferably 1220 ° C. It should not be.

In addition, in each case where additional rolling stands 51 to 56 are engaged or elevated in order to obtain the desired final thickness and final rolling temperature, a sudden unexpected change in the entry mass flow or entry temperature (e.g. Attention should be paid to partial failures in 7).

However, according to the present invention, both for continuous and abrupt changes to the entry variables (temperature, mass flow), only for using the actual number of rolling stands 51 to 56 required. Attention must be taken. In this case, in particular, the crude strip thickness should be chosen sufficiently large using the lowest possible entry temperature, for example 1090 ° C., and three, four or five rolling stands, which are still active, are at maximum cross-sectional reduction levels, The desired steel strip can still be produced in the technical limitations of the rolling stands.

An example of a 1570 mm wide strip product with a finish mill heat-entry thickness of 15 mm and a width-specific entry mass flow of 440 mm m / min is detailed below. When only four rolling stands are used instead of five rolling stands, a reduction in the overall energy demand, as well as variations in the rolling forces of the rolling stands, pass reductions and A decrease in furnace energy can be seen.

Active stands
(51 to 55) Active stands
(51-54) Inlet temperature
Quench strip 1069 ℃ 992 ℃ Ingress thickness
Quench strip 15 mm 15 mm Inlet mass flow
Quench strip 440 mm m / min 440 mm m / min Total energy requirements
(No + finish rolling mill)
[kWh / t] 125 102 Energy requirements
furnace
[kWh / t] 91.5 61.5

Active stands
(51 to 55) Active stands
(51-54) pass
Reduced section
[%] Rolling
weight
[MN] Total energy requirements
[kWh / t] pass
Reduced section
[%] Rolling
weight
[MN] Total energy
demand
[kWh / t] Rolling
Stand 51 43 22.5 33.5 53 33 40.5 Rolling
Stand 52 41 25 49 33 Rolling
Stand 53 36 22.5 37 23 Rolling
Stand 54 30 21 20 14 Rolling
Stand 55 20 14 0 0 0

1: steel strip
2: casting equipment
3: slab
3 ': rough strip
4: rough-rolling mill train
5: finish rolling mill
51: the first rolling stand of the finishing rolling mill
52: second rolling stand of finishing rolling mill
53: third rolling stand of finishing rolling mill
54: fourth rolling stand of finishing rolling mill
55: fifth rolling stand of finishing rolling mill
56: 6th rolling stand of the finishing rolling mill
6: Furnace for slab
7: furnace for temper strip
12: shears
13: descaling sprayer
14: cooling stage
15: coiler
F: feed direction
T1: crude rolling temperature
T2: Entry temperature of steel strip when entering finish mill heat

Claims (10)

Method for producing steel strips (1) by continuous rolling or semi continuous rolling,
The slab 3 is first cast in a casting plant 2, and the slab 3 is rolled in a rolling mill train 4 to form a rough strip 3 ′, The crude strip 3 'is heated in the furnace 7 and is continuously rolled or semi-rolled in which the heated crude strip 3' is finish rolled in the finishing mill row 5 to a predetermined final thickness and a predetermined final rolling temperature. In the method of manufacturing the steel strips (1) by continuous rolling,

When entering the finishing mill row 5, when changing the entry temperature T2 of the crude strip 3 'by more than 1K / sec, in particular by more than 5K / sec, and / or
When entering the finishing mill heat, changing the mass flow of the crude strip by more than 0.2% / second, in particular by more than 1.5% / second,

A new pass sequence is selected, whereby the desired final thickness and the desired final rolling temperature are obtained, and the last engaged rolling stand of the finishing mill row 5 is roll unengaged, or the furnace 7 and / or Due to the second condition that the energy supplied to the finish mill row 5 is minimized, the rolling stands of the finish mill row disposed downstream of the last engaged rolling stand are roll-engaged,
The entry temperature T2 of the temper strip 3 'is set by adjusting the furnace 7 and rolling stands 5 according to the new pass sequence,
Method for producing steel strips by continuous rolling or semi continuous rolling.
The method of claim 1,
Wherein the new pass sequence is determined during a current rolling process,
Method for producing steel strips by continuous rolling or semi continuous rolling.
3. The method according to claim 1 or 2,
The new pass sequence is characterized by a mathematical process model which simulates the rolling process of at least all rolling stands 51 to 56 of the finishing mill row 5,
Method for producing steel strips by continuous rolling or semi continuous rolling.
The method of claim 3, wherein
Using the process model of the pass sequence, at least the final rolling temperature of the steel strip, the final thickness of the steel strip and the common energy requirements of the finishing mill rows 5 and the furnace 7 are calculated and the rolling stands 51-56. If the number of beams is varied, the associated energy for the rolling stands and the furnace is determined, and during deformation, when maintaining the predetermined limit values for the adjustment of the rolling stands and the furnace, a reduction in the common energy requirement is caused, Characterized in that it is based on the new pass sequence,
Method for producing steel strips by continuous rolling or semi continuous rolling.
5. The method of claim 4,
Using the process model of the pass sequence, at least the final rolling temperature of the steel strip of the furnace 7, the final thickness of the steel strip as well as the energy requirements are calculated, the number of rolling stands 51 to 56 is varied, Is determined based on the new pass sequence, if the reduction in energy for the furnace is caused by maintaining the predetermined limits for the adjustment of the rolling stands and the furnace during deformation.
Method for producing steel strips by continuous rolling or semi continuous rolling.
6. The method according to any one of claims 1 to 5,
It is characterized in that the thickness of the crude strip 3 'is varied to minimize the energy required for the furnace 7,
Method for producing steel strips by continuous rolling or semi continuous rolling.
7. The method according to any one of claims 1 to 6,
After casting rolling interruption, the starting up and switching on the combined cast rolling facility is characterized by causing continuous rolling or semi-continuous rolling,
Method for producing steel strips by continuous rolling or semi continuous rolling.
The method according to any one of claims 1 to 7,
During the semi-continuous rolling, when the rolling stands 51 to 56 are brought into rolling engagement or rolled out of engagement, the crude strip 3 'to be rolled is already positioned in the rolling mill train 5. Characterized in that
Method for producing steel strips by continuous rolling or semi continuous rolling.
The method according to any one of claims 1 to 7,
Characterized in that the crude strip 3 ′ to be rolled during semi-continuous rolling only moves into the finishing mill row 5 when the rolling stands 51 to 56 are raised or lowered according to a new pass sequence.
Method for producing steel strips by continuous rolling or semi continuous rolling.
When loaded on a computer and implemented on a computer, determining the pass sequence as described in the method according to any one of claims 1 to 9,
Computer program products.

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