RU2325241C2 - Method of continuous cold rolling of thin strips on multiple-stand rolling mill - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention is intended for rolling of strips on four-stand wide-strip rolling mills. During rolling, a number of parameters are monitored by measuring and/or calculating using mathematical models: reduction of cross-sectional area for stands, geometric parameters of semi-finished and finished rolled stock, tension of the strip between the stands. For each stand, the neutral section position in the deformation region is determined using a mathematical model, reductions of cross-sectional area in the stands and the strip tension between the stands are corrected. Decrease of power consumption while maintaining the required finished strip surface finish is achieved due to the fact that the 1^st stand main drive motor power is monitored additionally, by measuring or calculating, and the reduction of cross-sectional area in the first stand is set based on the power loading of its main drive within a range of 80-95% of the maximum rated power of its motor. The reduction of cross-sectional area in the 4^th stand is set within a range of 5-15%, and the remaining part of the total reduction of cross-sectional area is distributed equally between the 2^nd and 3^rd stands; for the 3^rd stand, the allowable upward deviation of the reduction of cross-sectional area from this condition is no more than 15% of the total reduction of cross-sectional area in the 2^nd and 3^rd stands.

EFFECT: decrease in power consumption.

6 cl; 7 tbl

Description

The invention relates to technology for rolling production, specifically to technology for continuous rolling of thin strips, and can be used on four-stand wide-band cold rolling mills.

характеризующего положение нейтрального сечения в очаге деформации, корректировку на основе и по результатам этих действий относительных обжатий в клетях и натяжений полосы между клетями до достижения, прежде всего, в последней клети максимально возможного приближения к значению X_i=1 (патент РФ №2238809, МПК⁷ В21В 1/28, 2004 г.) [1].A known method for the continuous rolling of thin strips on a multi-bench mill, comprising compressing the strip in several passes with associated control by measuring and / or calculating, using mathematical models, a number of rolling parameters: relative compressions by stands, geometric parameters of the roll and finished roll, strip tension between stands, determination for each i-stand using a mathematical model of the deformation zone, the length of the plastic section X _pl , the length of the lag zone X _pl.otst in this section and their relations

characterizing the position of the neutral section in the deformation zone, the adjustment based on and based on the results of these actions of the relative compressions in the stands and the strip tension between the stands until, in the last stand, reaches the maximum possible approximation to the value of X _i = 1 (RF patent No. 2238809, IPC ⁷ B21B 1/28, 2004) [1].

This method is the closest analogue of the invention.

The known method, to some extent solving the problem of improving the quality (surface cleanliness) of the obtained strips, however, has its drawbacks.

In the known method, it is shown that the larger the value of X _i in the stand with number “i”, the greater the part of the deformation zone is the lag zone, in which the tangential forces applied to the strip from the side of the rolls are directed forward along the rolling direction, as a result of which these forces effectively remove mechanical and fatty contaminants from the deformation zone. Moreover, the smaller the length of the advance zone, in which the tangential forces are directed in the opposite direction, the less obstacles these impurities encounter in their path and the more efficient the self-cleaning of the deformation zone from dirt. At the limiting value of the value X _i = 1, when the entire deformation zone consists only of the lag zone, the contaminants are removed from such a zone without hindrance, and the strip surface is the cleanest.

The value of X _i , according to [1], is affected by the redistribution between the stands of the relative reductions and interstand tension, however, the possibilities of this redistribution are limited by technological and operational factors (the maximum allowable rolling force and the maximum allowable maximum and minimum values of interstand tension), therefore, in practice rarely achieved in the stands of the maximum value of X _i = 1, first of all seek to maximize the X _i in the final stand, which he leaves to the mill ready TVOC.

Studies have established that increasing X _i , improving the cleanliness of the strip surface, at the same time increases the energy consumption spent on the rolling process, since this energy is spent only in the lag zone, and in the advance zone the strip returns part of the energy expended to the rolls. Therefore, the task of saving energy comes into conflict with the task of improving the cleanliness of the surface of the strips (Garber E.A. Cold rolling mills (theory, equipment, technology). M: Chermetinformation. Cherepovets: GOU VPO ChGU, 2004, p. 92- 103; 200-208) [2].

To overcome this contradiction, it is recommended in [2] in the intermediate stands of a multi-cage mill (on a five-cage mill — stands No. 2 and No. 3), where the energy consumption is usually greater than in other stands, to reduce the indicator X _i , thereby saving energy , and in the last stands, where the energy consumption is usually less (on a five-stand mill - stands No. 4 and No. 5), increase the indicator X, thereby improving the cleanliness of the strip surface directly at the exit from the continuous multi-stand mill. Such a method with a number of working stands of 5 or more provides a positive result: energy saving in the intermediate stands overlaps its somewhat increased consumption in the last stands, resulting in a camp average energy savings of 4 to 8%, with a slight deterioration in the surface finish of the strip of the intermediate stands is compensated by its improvement in the last stands, as a result, the finished strip has a surface cleanliness that meets the requirements of standards [2, p.205-208]. It is clear that the quality (cleanliness) of the surface of the finished strip is of interest: the surface cleanliness obtained at the exit from the intermediate stands of the mill is only one of the factors determining this final cleanliness of the surface of the strip emerging from the last stand of the mill.

However, for a mill with a number of stands less than five, in particular for a four-stand mill, this rolling method, as established, does not give the desired effect, because stand No. 3 of this mill, on the one hand, is intermediate, therefore, according to this method, it is necessary to reduce the indicator X _{i in} order to save energy, and on the other hand, this stand is clean and in it to improve the cleanliness of the strip surface, according to in the same way, you need to increase the indicator X _i .

Therefore, in order to simultaneously save energy and roll a strip with a surface meeting the cleanliness requirements on a four-stand mill, a different approach is needed: using the recommendations given in well-known sources [1, 2], this problem cannot be solved.

The method [1] leaves some other possibilities for its improvement, including with reference specifically to the four-stand cold strip rolling mill.

Firstly, in the known method, the possibilities of saving energy due to a more complete loading of the first stand of a continuous mill are not considered, for which relative compression is set on many mills in the same limits as in subsequent stands (from 20 to 32%), not taking into account Moreover, that the deformation resistance of the metal, which did not have time to get riveting, in the first stand is 30-50% less than in subsequent stands.

Secondly, it does not specify specific for each inter-span gap ranges of specific inter-span tension, allowing not only to reduce the probability of breaks in strips, but also to save energy when obtaining the proper cleanliness of the surface of the strips. In [2, p.142], a recommendation was made regarding the used range of specific inter-stand tension:

where σ _i is the specific tension at the exit of the i-stand;

σ _0.2i is the deformation resistance of the strip at the exit of the i-stand (as a measure of deformation resistance during cold rolling, σ _0.2i , the conditional yield strength, is used).

However, this recommendation is general in nature and is not tied to specific intercellular gaps, although the work experience of mills and calculations by mathematical models have shown that it is advisable to set the tension close to the lower boundary of the expression to save energy consumption and improve the cleanliness of the strip surfaces in the first interstand space (1) , and in the latter, close to the upper boundary of expression (1).

The technical result of the invention is to reduce energy consumption during cold rolling of strips on a four-stand continuous mill, while ensuring the proper cleanliness of the surface of the strips and reducing the likelihood of breaks.

характеризующего положение нейтрального сечения в очаге деформации, корректировку на основе и по результатам этих действий относительных обжатий в клетях и натяжений полосы между клетями до достижения, прежде всего, в последней клети максимально возможного приближения к значению Х_i=1, согласно изобретению при прокатке на четырехклетевом стане дополнительно контролируют путем измерения и/или расчета фактическую рабочую мощность электродвигателя главного привода первой клети, и относительное обжатие в этой клети устанавливают, исходя из условия загрузки этого электродвигателя в диапазоне 80-95% от максимального паспортного значения его мощности, дифференцируют это обжатие в зависимости от диапазонов толщин и суммарных относительных обжатий прокатываемых полос, относительное обжатие в четвертой клети устанавливают в пределах 5-15%, а оставшуюся часть суммарного относительного обжатия распределяют между второй и третьей клетями поровну, допуская для третьей клети отклонение от этого условия в сторону увеличения в ней относительного обжатия не более чем на 15% от суммарного обжатия во второй и третьей клетях.The technical result is achieved by the fact that in the method of continuous cold rolling of thin strips on a multi-bench mill, including the compression of the strip in several passes with concomitant control by measuring and / or calculating by mathematical models a number of rolling parameters: relative compressions by stands, geometrical parameters of rolling and finished rolling , tension of the strip between stands, resistance to deformation of the strip at the entrance to the mill and exit from each stand, determination for each i-stand using a mathematical model of the source deformations of the length of the plastic portion X _Sq lag zone length X _pl.otst in this area and their relationship

characterizing the position of the neutral section in the deformation zone, the adjustment based on and based on the results of these actions of the relative compressions in the stands and the tension of the strip between the stands until, in the last stand, reaches the maximum possible approximation to the value of X _i = 1, according to the invention when rolling on a four-stand the mill is additionally controlled by measuring and / or calculating the actual operating power of the electric motor of the main drive of the first stand, and the relative compression in this stand is established, the outcome from the loading condition of this electric motor in the range of 80-95% of the maximum rated value of its power, this compression is differentiated depending on the thickness ranges and the total relative reductions of the rolled strips, the relative compression in the fourth stand is set within 5-15%, and the rest of the total the relative compression is distributed equally between the second and third stands, allowing for the third stand deviation from this condition in the direction of increasing the relative compression in it by no more than 15% of the total th compression in the second and third stands.

In addition, when rolling with a total relative compression of 70-79% of the strips up to 0.6 mm thick, the relative compression in the first stand is set within 36-38%.

In addition, when rolling with a total relative compression of 60-69% of the strips with a thickness of 0.6 to 1.4 mm, the relative compression in the first stand is set within 26-28%.

In addition, when rolling with a total relative compression of 50-59% of the strips with a thickness of more than 1.4 mm, the relative compression in the first stand is set within 18-20%.

где

- условный предел текучести полосы после первой клети.In addition, the specific tension of the strip at the exit of the first stand is set in the range

Where

- the conditional yield strength of the strip after the first stand.

In addition, the specific tension of the strip at the exit of the second and third stands is set in the range σ _i = (0.21-0.22) σ _0.2i .

The invention consists in the following.

The quantitative values of the relative compressions and inter-stand tension of the strip indicated in it are obtained using a new mathematical model of the cold rolling process, described and justified in [2, pp. 30-115]. Its advantage consists in determining the rolling effort and power with an error of 5-7%, 4-6 times less than with most other known, including classic models.

Such high accuracy of this model is achieved due to the following features that distinguish it from most other models:

1. Contact stresses in the deformation zone are determined taking into account not only plastic but also elastic sections of the deformation zone, in which the elasticity equation is used instead of the plasticity equation.

2. The energy consumption and power of the rolling process are determined taking into account the work of both normal and tangential forces, oppositely directed in the areas of lag and lead.

3. The friction coefficient in the deformation zone is more reliably determined taking into account the real properties of the cutting fluid, the level of contact stresses, roll roughness and rolling speed.

The high accuracy of this model, proven by reliable statistical methods, allows using it to more reliably determine the indicator X _i characterizing the position of the neutral section in the deformation zone of each working stand, and due to this, varying between compression and tension stands, affect this indicator in such a way so that in the fourth stand it was as close as possible to the value of X _i = 1; in the third stand, select its value so that, on the one hand, it is relatively high and ensures that a sufficiently clean band enters the fourth stand, and on the other hand, that in the third stand this figure does not reach the maximum possible value, which would cause consumption in this stands of excess energy; in the second stand - to set the indicator X _i as low as possible, since this stand is very energy-intensive and the reduction in energy costs in it will more than compensate for some increase in these costs in other stands, and some deterioration in the degree of cleaning of the strip surface in it will be eliminated in the third and fourth stands .

Another advantage of the new model of the cold rolling process used in the invention is that it takes into account, more accurately than other models, the effect of interstand tension on the rolling power. The established general ranges of specific interstand stresses, not exceeding 22% of the strip deformation resistance, guarantee the absence of breaks (due to at least five-fold supply of tensile stresses relative to their tensile strength). At the same time, the invention differentiates the ranges of tension across the stands: after the first stand (0.18-0.20) σ _0.2i after the second and third stands (0.21-0.22) σ _0.2i , which allows indicators X _i , these stands, reaching the above optimal values of these indicators.

Thus, the invention implements a fundamentally new high-tech technology for cold rolling strips on a continuous four-stand mill, which would be impossible without the use of a new mathematical model of the rolling process. The method according to the invention allows to realize such advantages in terms of saving energy, cleaning the surface of the strips and reducing the likelihood of breaks, which would not be possible to implement by other rolling methods.

These advantages are explained on a specific example of the implementation of the method of continuous cold rolling on a four-stand mill "1700" strip of steel grade 08kp 1000 mm wide, 0.6 mm thick from rolled 2.0 mm thick.

The general ranges of relative reductions in the first stand of this mill, recommended in the claims, are summarized in table 1.

Table 1 Relative compression ranges for the first mill stand Assortment group Thickness, mm The total relative compression,% The relative compression in the stand No. 1,% I 0.38-0.6 70-79 36-38 II 0.7-1.4 60-69 26-28 III 1.5-2.0 50-59 18-20

The relative compression in the first stand, set within the limits indicated in table 1, allows you to ensure the loading of the electric motors of the main line of the drive of this stand by 80-95%.

удельное натяжение на выходе из второй клети

удельное натяжение на выходе из третьей клети составляет

Table 2 shows a specific example of a rolling regime that implements all the features of the invention: the relative compression in the first stand ε ₁ = 38% corresponds to the range 36-38%, the relative compression in the fourth stand ε ₄ = 5% is in the range 5-15%, the remaining part of the total reduction is distributed approximately equally between stands No. 2 and No. 3: ε ₂ = 28.23%, ε ₃ = 28.99%, a slight excess of reduction in the third stand does not go beyond 15% of the total reduction of these two stands; specific tension at the exit of the first stand

specific tension at the exit from the second stand

the specific tension at the exit from the third stand is

table 2
The rolling mode of the strip of steel 08kp size 2.0 × 0.6 × 1000 mm, corresponding to the claims Crate No. V _i , m / s h _i-1 , mm h _i mm σ _0.2i , MPa σ _i-1 , MPa σ _i , MPa ε _i ,% ε _Σi ,% X _i P _i , MH N _{double calculation} , kW one 5.81 2 1.24 524 fifteen 94 38 38 0.9705 8.16 4554 2 8.09 1.24 0.89 673 94 148 28.23 55.5 0.7857 9.63 2166 3 11.39 0.89 0.632 733 148 161 28,99 68,4 0.8061 9.45 2497 four 12 0.632 0.6 758 161 94 5 70 0.7988 6.16 889 N _dvΣ = 10106 kW.

Table 2 shows: V _i - rolling speed, h _i-1 and h _i - strip thicknesses at the entrance and exit of the i-th stand, ε _i - partial relative compression in the i-th stand, ε _Σi - total relative compression in of the i-th stand, Р _i - rolling force in the i-th stand, σ _0,2i - deformation resistance (conditional yield strength) of the strip at the exit of the i-th stand, N _double calculation - calculated power of the main drive engine of the i-th crates.

All the calculated values are listed in Table 2 and in all subsequent tables (σ _{i-1, σ i, σ 0,2i, X} i, P i, N _dv.raschi), prepared according to a new model of the rolling process, and because this model takes into account additional factors previously not taken into account, these values are closer to real ones.

When the compression in the first stand ε ₁ = 38%, the engine load of its main drive is 4554 kW, that is, about 95% of the rated power equal to 4800 kW, and the total power of all engines is N _dΣ = 10106 kW.

Any deviations from the ranges of compression and tension specified in the distinguishing features of the invention, reduce the effectiveness of the rolling mode shown in table 2.

So, if the relative compression in the first stand is set to more than 38%, for example, 39%, then the load of the stand motor will exceed 95% of the rated power, which will not allow you to compensate for the fluctuations in the compression, tension and speed during rolling, which make up 5- 10% of the set values. As a result, in cases of such fluctuations, engine overload can occur, which is unacceptable.

If the relative compression in the first stand is set to less than 36%, for example, 35.5%, then it will be necessary to increase the compression in the second and third stands (a variant of this mode is presented in table 3). This will lead to an increase in engine power in stands No. 2 and No. 3, as a result of which the total power consumed by the mill will increase by 84 kW or 0.82%, which is economically disadvantageous.

If you set the relative compression in the fourth stand is more than 15%, for example, 16%, then we get a decrease in X _i in the second, third, fourth stands, which will lead to an increase in the contamination of the strip surface (this version of the rolling mode is shown in table 4).

If you set the relative reduction in the 4th stand less than 5%, for example, 4%, then you need to increase the reduction in the second and third stands, which will lead to an increase in their capacity, as a result, the total power consumed by the mill and the energy consumption in the whole mill will increase compared with the optimal mode (table 2) by 0.8-1%, which is economically disadvantageous.

Table 3
The rolling mode of the strip of steel 08kp size 2.0 × 0.6 × 1000 mm with a relative reduction in stand No. 1 35.5% Crate No. V _i , m / s h _i-1 , mm h _i mm σ _i-1 , MPa σ _i , MPa ε _i ,% ε _Σi ,% X _i P _i , MH N _{double calculation} , kW one 5.71 2 1.29 fifteen 94 35.5 35.5 0.9721 7.95 4507 2 8.08 1.29 0.91 94 148 29.4 54.5 0.792 9.83 2289 3 11.39 0.91 0.632 148 161 30.05 68,4 0.8064 9.47 2505 four 12 0.632 0.6 161 94 5.06 70 0.7988 6.16 889 N _dvΣ = 10190 kW.

Table 4
The rolling mode of the strip of steel 08kp size 2.0 × 0.6 × 1000 mm with a relative reduction in stand No. 4 16% Crate No. V _i , m / s h _i-1 , mm h _i mm σ _i-1 , MPa σ _i , MPa ε _i ,% ε _Σi ,% X _i P _i , MH N _{double calculation} , kW one 5.81 2 1.24 fifteen 94 38 38 0.9705 8.16 4554 2 7.64 1.24 0.942 94 148 24.03 52.9 0.7699 8.59 1719 3 10.07 0.942 0.715 148 161 24.1 64.25 0,8001 8.16 1984 four 12 0.715 0.6 161 94 16.08 70 0.7962 9.86 1851 N _dvΣ = 10108 kW.

If, instead of distributing the relative reductions between the second and third stands equally, as provided for in the optimal mode (Table 2), increase the reduction in the second stand by reducing the reduction in the third stand (a variant of this mode is presented in Table 5), then we obtain a significant decrease in the indicator X _i in the final third stand, which will lead to the entry of a strip with a dirtier surface into the fourth stand and, as a result, to a deterioration in the surface cleanliness of the strip at the mill exit. At the same time, the total power consumed by the mill will also increase slightly (by 0.3%).

Table 5
The rolling mode of a strip of 08kp steel 2.0 × 0.6 × 1000 mm in size with reductions in stands No. 2 and No. 3: 36% and 20%, respectively Crate No. V _i , m / s h _i-1 , mm h _i mm σ _i-1 , MPa σ _i , MPa ε _i ,% ε _Σi ,% X _i P _i , MH N _{double calculation} , kW one 5.81 2 1.24 fifteen 94 38 38 0,9996 7.57 4554 2 9.11 1.24 0.79 94 148 36.29 60.5 0.8094 11.93 3122 3 11.39 0.79 0.632 148 161 twenty 68,4 0.7694 7.72 1571 four 12 0.632 0.6 161 94 5.06 70 0.7988 6.16 889 N _dvΣ = 10136 kW.

If the compression in the third stand is increased by more than 15% of the total compression in the second and third stands due to the reduction in compression in the second stand (a variant of this mode is presented in Table 6), then the total power consumed by the mill engines will increase by 19 kW (or by 0 , 2%), which is economically disadvantageous. At the same time, a slight increase in the indicator X _i in the third stand is compensated by a corresponding decrease in the indicator X _i in the 2nd stand, and in general, the surface cleanliness of the strip at the outlet of the mill will not change.

Table 6
The rolling mode of a strip of 08kp steel 2.0 × 0.6 × 1000 mm in size, with reductions in stands No. 2 and No. 3: 20% and 36%, respectively Crate No. V _i , m / s h _i-1 , mm h _i mm σ _i-1 , MPa σ _i , MPa ε _i ,% ε _Σi ,% X _i P _i , MH N _{double calculation} , kW one 5.81 2 1.24 fifteen 94 38 38 0,9996 7.57 4554 2 7.27 1.24 0.99 94 148 20.16 50,5 0.7523 7.67 1336 3 11.39 0.99 0.632 148 161 36.16 68,4 0.8368 10.75 3346 four 12 0.632 0.6 161 94 5.06 70 0.7988 6.16 889 N _dvΣ = 10125 kW.

Thus, the compression distribution option presented in table 2, corresponding to the features of the invention, is the most advantageous, since it provides a minimum of energy costs and proper cleanliness of the strip surface.

Next, we consider variants of the rolling modes in which the relative reductions are distributed optimally, according to table 2, and the interstand tension are set with deviations from the ranges indicated in the features of the invention and in table 2.

например, 90 МПа, вместо 94 МПа, это будет иметь два негативных последствия. Во-первых, как показывает опыт многих станов, при удельных натяжениях, меньших 18% от сопротивления деформации полосы, полоса теряет осевую устойчивость: возможны ее отклонения влево или вправо от оси прокатки, что может приводить к аварийным ситуациям на стане (порезам валков, обрывам полосы и так далее). Во-вторых, чем меньше переднее натяжение полосы, тем больше расход энергии двигателя главного привода i-й клети, который, как показано выше, загружен до 95% паспортной мощности, и еще большая загрузка его недопустима.If after the first stand the specific tension is set lower than

for example, 90 MPa, instead of 94 MPa, this will have two negative consequences. Firstly, as the experience of many mills shows, with specific tensions less than 18% of the strip deformation resistance, the strip loses axial stability: it can deviate to the left or right from the rolling axis, which can lead to emergency situations on the mill (roll cuts, breaks stripes and so on). Secondly, the lower the front tension of the strip, the greater the energy consumption of the engine of the main drive of the i-th stand, which, as shown above, is loaded up to 95% of the rated power, and its even greater load is unacceptable.

то в этой клети мощность двигателя снизится с 4554 кВт до 4487 кВт, но во второй клети мощность возрастет с 2166 кВт до 2323 кВт (так как переднее натяжение в первой клети для второй клети является задним натяжением, рост которого существенно увеличивает энергозатраты). В результате суммарная мощность, потребляемая станом, увеличится на 90 кВт, или на 0,9%, что экономически невыгодно.If after the first stand to set the specific tension of the strip is more than 20% of the value

then in this stand the engine power will decrease from 4554 kW to 4487 kW, but in the second stand the power will increase from 2166 kW to 2323 kW (since the front tension in the first stand for the second stand is the rear tension, the growth of which significantly increases energy costs). As a result, the total power consumed by the mill will increase by 90 kW, or 0.9%, which is economically disadvantageous.

указанных в отличительных признаках изобретения, то возрастет вероятность порывов полос (22% от сопротивления деформации полосы - предельно допустимое значение удельного натяжения, установленное технологическим регламентом многих современных станов).If the specific tension of the strip in the second and third interstand spaces (after the second and third stands) set more limit values

indicated in the distinguishing features of the invention, the likelihood of gusting strips will increase (22% of the strip deformation resistance is the maximum allowable value of specific tension established by the technological regulations of many modern mills).

указанных в отличительных признаках изобретения, то показатель X_i в последней клети существенно снизится, то есть со стана будет выходить менее чистая полоса, кроме того, несколько возрастет суммарная мощность, потребляемая станом.If the specific tension of the strip after the second and / or third stand is set to less than the minimum values

indicated in the distinguishing features of the invention, the indicator X _i in the last stand will significantly decrease, that is, a less clean band will leave the mill, in addition, the total power consumed by the mill will increase slightly.

A variant of such a regime is presented in table 7. In it, the specific tension at the exit from the second and third stands is set by values that make up 20% of the corresponding yield strengths: σ ₂ = 135 MPa, σ ₃ = 147 MPa. As a result, the indicator X _i in the fourth stand decreased from 0.7988 to 0.7841, and the total power increased from 10106 kW to 10115 kW.

Table 7
The rolling mode of a strip of 08kp steel 2.0 × 0.6 × 1000 mm in size with specific strains σ ₂ and σ ₃ reduced to 0.2σ _0.2i Crate No. V _i , m / s h _i-1 , mm h _i mm σ _i-1 , MPa σ _i , MPa ε _i ,% ε _Σi ,% X _i P _i , MH N _{double calculation} , kW one 5.81 2 1.24 fifteen 94 38 38 0.9705 8.16 4554 2 8.09 1.24 0.89 94 135 28.23 55.5 0.7972 9.8 2270 3 11.39 0.89 0.632 135 147 28,99 68,4 0.8074 9.86 2507 four 12 0.632 0.6 147 94 5 70 0.7841 6.31 784 N _dvΣ = 10115 kW.

Thus, it is shown that the technical result of the invention (reduction of energy consumption when obtaining the proper cleanliness of the surface of the rolled strip) is achieved by using technological parameters of rolling in the recommended ranges, and only in these ranges.

Claims (6)

1. The method of continuous cold rolling of thin strips on a four-stand mill, comprising compressing the strip in several passes with associated control by measuring and / or calculating, using mathematical models, a number of rolling parameters: relative compressions by stands, geometric parameters of the roll and finished roll, strip tension between stands , strain resistance strip entering the mill and out of each stand, determining for each i-th stand using a mathematical model for the focus of plastic deformation portion of length X _n , The lag length of the zone X _pl.otst in this area and their relationship

characterizing the position of the neutral cross section in the deformation zone, the adjustment based on and based on the results of these actions of the relative reductions in the stands and the tension of the strip between the stands until, in the last stand, reaches the maximum possible approximation to the value of X _i = 1, characterized in that control by measuring and / or calculating the actual operating power of the electric motor of the main drive of the first stand, while the relative compression in this stand is set based on the loading condition of this electric motor in the range of 80-95% of the maximum rated value of its power and differentiate this compression depending on the ranges of thicknesses and the total relative compressions of the rolled strips, the relative compression in the fourth stand is set within 5-15%, and the remainder of the total relative compression is distributed between the second and third stands equally, allowing the third stand to deviate from this condition in the direction of increasing the relative compression in it by no more than 15% of the total compression in the intermediate glue s. 2. The method according to claim 1, characterized in that when rolling with a total relative compression of 70-79% of the strips up to 0.6 mm thick, the relative compression in the first stand is set within 36-38%. 3. The method according to claim 1, characterized in that when rolling with a total relative compression of 60-69% of strips with a thickness of from 0.6 to 1.4 mm, the relative compression in the first stand is set within 26-28%. 4. The method according to claim 1, characterized in that when rolling with a total relative compression of 50-59% of strips with a thickness of more than 1.4 mm, the relative compression in the first stand is set within 18-20%. 5. The method according to any one of claims 2 to 4, characterized in that the specific tension of the strip at the outlet of the first stand is set in the range

Where

- the conditional yield strength of the strip after the first stand. 6. The method according to any one of claims 2 to 4, characterized in that the specific tension of the strip at the outlet of the second and third stands is set in the range

where σ _0,2i is the conditional yield strength of the strip at the exit from the stand with the number "i".