The method of controlling the profile of the rolls of sheet rolling mill

 

(57) Abstract:

The invention relates to the field of rolling mills and for the profiling of the sheet mill rolls with the use of mathematical models. The inventive process management profile roll take into account a number of new technological factors that enter into the mathematical model, and parallel to form a more mathematical model of calculation of machine profiling rolls all the mill stands. This model uses the predicted values of the rolling forces, actually measured values of the transverse thickness variation and temperature strips, roughness of the rolls, thermophysical properties of the coolant and determine the estimated sizing of convexity given the costs of the emulsion in the system section cooling rolls. Procedure select the desired values of grinding protuberances depending on the projected and actual costs of the emulsion in the sectional cooling system: first at 50 - 60% of the predicted maximum flow rate, then by varying in the range of 40 to 80% of the predicted maximum flow rate, and when rolling the rolls are replaced with the actual output p is ucaeoy strip. 2 C.p. f-crystals.

The invention relates to the field of metallurgy, specifically, to rolling production, and relates to methods of profiling rolls of sheet rolling mills and correction of this profiling with the aid of mathematical models.

A known method of controlling the profile of the rolls of sheet rolling mill, including the determination using mathematical models estimated profile of the rolls as a function of range and parameters of the rolling mode, the adjustment of the profile on the measured actual values of the rolling speed, tension and thickness of the strip, the temperature of the rolled stock, strategy flow of coolant along the length of the roll barrel, by varying and regulating the actual strategy of consumption (see, for example, USSR author's certificate N 710705, class B 21 B 37/32, 1980).

The disadvantage of this method is the omission in the calculation model of the influence of several factors, in particular, the actual transverse profile strips, grinding bulges, rolls, roughness of the rolls, the rolling forces and factors work hardening. This reduces the accuracy of the control.

A particular problem was the sizing rolls profiling. The choice of this profiling (size vychodni grinding rolls profiling (see, for example, A. C. Tretyakov, E. A. Garber, gg Davletbaev. Calculation and investigation rolls. M.: metallurgy, 1976, S. 216-217), but this method takes into account the deflection, deterioration, flattening and heat bulge and roll are not linked to this parameter controls the profile of the rolls, as a strategy, the flow of coolant along the length of the barrel, forming the actual thermal profile along with thermal expansion of the roll.

Meanwhile, the original (pre) grinding profiling roll plays a significant role in shaping his work profile and, consequently, to control them. If the original profile is selected successfully, the control range of the flow rate of the coolant when the work rolls narrows, management of the work roll profile is simplified. Conversely, if the original ground profile is far from optimal, the desired control range flow rate of the coolant expands and could, in principle, to go beyond the limits of the cooling system. In this regard, it is important not only to consider the source of grinding profiled rolls in close contact with thermal profiling carried out by strategy the coolant, but also to provide for adjustment of ishodovanja also become limited, and control system loses the necessary flexibility. As to change the cooling system is significantly harder and more difficult than to change rolls new, with a different grinding profile (Park rolls with different profile is prepared in the shop in advance), there is the problem of determining the desired optimal source profiling given the limited range of flow control cooler in system cooling strategy rolls and taking into account other significant factors of the rolling process.

The objective of the invention is to improve the flatness of rolled strip (sheet) by increasing the accuracy of the system management profile rolls by considering and correcting the influence of the initial grinding rolls profiling, as well as accounting in mathematical models of the maximum possible number of factors affecting the profile of the roll.

This problem is solved by the fact that in the method of controlling the profile of the rolls of sheet rolling mill, including the determination using mathematical models estimated profile of the rolls as a function of range and parameters of the rolling mode, the adjustment of the profile on the measured actual values of the rolling speed, tension and casinolibre actual strategy of consumption, according to the invention is introduced into the model values of grinding protuberances rolls, as well as the actual measured values of roughness of the rolls before they are installed in the mill, the actual transverse thickness of the rolled stock, the cooler temperature and the actual rolling force, in addition enter in the model according to the deformation resistance of rolled metal from the relative compression for different steel grades (work hardening curves), in parallel form the mathematical model of calculation of machine profiling rolls all mill using it predicted value of the rolling load and the measured value of the actual lateral thickness variation and temperature strips, roughness of the rolls, thermophysical properties of the coolant, determine the estimated sizing of convexity in the cost of the cooler, is equal to 50-60% of the maximum in each of the cooling sections, the calculated values of grinding protuberances on the train rounded up to multiples of 0.05 mm, compare them with the actual set empirically the values of grinding protuberances, when the mismatch varies sectional expenses cooler in the range of 40-80% of the maximum, minimizing the difference between calculated and empirical vypuklosti equality empirical and computational convexity use rollers, having calculated the value of grinding convexity.

In addition, when an increase or decrease in the regulatory process in one of the mill the actual flow rate of the coolant supplied to the middle of the roll barrel, respectively, to less than 30% or more than 80% of the maximum, the rollers in the cage change on the rolls with grinding the bulge, respectively, at 0.05 mm or more to 0.05 mm smaller than the changed set.

Additional measurement and accounting (introduction to the model) of a number of process parameters can significantly improve the accuracy of the model. The actual cross section of the rolled affects the distribution of reductions across the width of the strip, therefore, partial (width) of the drawing areas of the strip. Inequality such extracts directly affects the flatness of the strip leaving the mill stand. Thus, the actual cross section of the rolled responsible for hereditary transverse profile of the strip and its associated characteristics flatness. Grinding the convexity of the rolls is the original database, which formed the actual profile of the roll barrel. The load determines an amount of elastic deformation (deflection) of the roll and the elastic flattening f is on the roughness of the rolls, their value is determined by the contact friction in the deformation, and hence the computational load. So, these parameters being entered in the model, tell her higher accuracy, approximate mathematical description of the actual painting process. The fact of the influence of these factors was known previously, but the correct account in the model was represented by the well-known problems. Currently, the model taking into account these parameters with a sufficient degree of accuracy, developed and used in the present invention.

When rolling on a continuous strip mills a significant impact on the characteristics of the process provides the change in process value of deformation resistance of the metal associated (in addition to previously taken into account the temperature factor) with the phenomenon of work hardening during the compression of the metal. The invention provides for additional consideration of this factor. A preliminary research can be installed for different steel grades according to the deformation resistance of the relative compression, these dependencies are also introduced into the model, further increasing its accuracy.

However, the most basic feature of this invention is that is offered by the (ground) profiling rolls in the mill, given the ranges of the flow rate of coolant (emulsion) in the sectional system of cooling rolls. This model involves the use of measured values of the transverse thickness variation and temperature strips, roughness of the rolls, the temperature of the emulsion to select grinding rolls profiles. Previously these values, except for temperature of the emulsion, used to control thermal profile, and not to select grinding profiles. In this way define specific ranges of costs emulsion and is determined using a mathematical model of grinding the convexity of the rolls to provide the best flatness of the strip.

Grinding profiling rolls actually depends on all of the above measured values, however, no previous procedure, how to remember them in the profiling was chosen empirically without measuring these quantities, and this led to the inevitable errors in the result: increased percent of sorting out the box and wave, unscheduled handling for the replacement of the rolls with lost productivity and increased consumption of rolls due to unnecessary re-grinding.

Create procedure taking into account all these measured values increases the accuracy opredeleniya the number of transshipments, increasing the productivity of the mill, will decrease the flow rate of the rolls.

Because there is a procedure of accounting values, in the way provided by their dimension, which is to select the roll forming machine is essentially a new action.

The choice of grinding rolls profiling from the condition that the expenditure in the sectional cooling is equal to 50-60% of maximum, while rolling on such rolls the opportunity to increase and decrease thermal camber of the rolls, which allows to eliminate waviness and karabatos strip. At a cost of < 50% > 60% of this can be significantly narrowed: adjustment ranges of deviations from flatness are reduced.

The rounding of calculated values of grinding protuberances to 0.05 mm is a common practice, due to limited fleet of rolls. For example, the mill 1700 JSC "Severstal", the work rolls are polished with knobs: +0,10; +0,05;0; -0,05; -0,10 mm, i.e., 0.05 mm

In this regard, after the rolls are ground and installed in the mill, it is impossible to keep the costs of the emulsion in a narrow range of 50-60% of maximum. Therefore, actual management process acceptable range 40-80% of maximum flow rate. The output from this range de is lifemojo bulge on one step (0.05 mm), so the cost of the emulsion will be included in the working range of 40-80% of the maximum. This procedure is performed at the stage of selection profiles.

When the mill due to possible perturbations of the technological process for regulation will require the full range of costs emulsion (1-100% of max). However, if a long time consumption necessary to keep < 30% of maximum and > 80% of the maximum, it means that the profiling rolls does not match this particular range and the rolling mode (for example, some part of the hot-rolled coils was more amount of resistance to deformation, more heat is emitted, and the cooling roll has exceeded the limit (80%). In this case, replacement of the rolls (see PP 2 and 3 formulas).

When the mill rate range in the lower side can be expanded from 40 to 30% of the maximum, because the reduction of thermal profile is more sensitive than increase consumption.

The combination and sequence of action when implementing the method according to the invention is as follows.

1. Form in the computer automatic control system (ACS) mill database:

A. On the relative compression) for each grade of steel;

- preset modes rolling for each mercaptotetrazole gauge steel;

- forecast for each mercaptotetrazole (statistical) value of the rolling forces on the stands, the transverse thickness variation tackle, temperature strips.

B. About the structural parameters of the camp, and his work stands.

Century About the options section cooling system of the mill (maximum costs, values of heat transfer coefficients and other thermophysical coefficients)

Was About empirical values of grinding protuberances rolls in groups of assortment.

2. Enter in the computer automatic control system of the mill mathematical model:

- power calculation of the rolling process;

- thermal profile of the rolls and expenses sectional cooling options gauge and rolling mode;

elastic deformation of the rolls;

- wear the middle of the back-up roll barrel as a function of time of its operation;

- machine rolls profiling as a function of range, mode, rolling, elastic, thermal deformation and wear of the rolls, transverse profile and temperature strips.

3. Measure:

the roughness of the rolls - before installing into the camp;

- the temperature of the emulsion in the system's sectional 4. Introducing the computer as the operational source data all measured parameters specified in paragraph 3.

5. Determined using the model of machine rolls profiling calculated values of grinding protuberances rolls all mill stands, using as input the predicted values of the rolling load and the measured values of the transverse thickness variation and temperature strips, roughness of the rolls, the temperature and thermophysical properties of the emulsion, and the calculation of the components of the grinding profiling lead to models specified in paragraph 2, and thermal profile of the rolls expect when spending emulsion equal to 50-60% of the maximum in each of the cooling sections.

6. Calculated values of grinding protuberances rolls on the train rounded up to 0.05 mm and compare them with the empirical values.

7. If the calculated and empirical convexity of the rolls in any crate does not match, then the variation of the sectional expenses in the range of 40-80% of the maximum minimize by using a model of thermal profile of the difference between the estimated and empirical bumps.

8. If after the minimization procedure (p. 7) the estimated and empirical convexity matched, polished and set not equal to zero the difference between the empirical and the estimated convexity, as specified for the execution of the values of grinding convexity take its calculated value.

10. After installing the cage rolls, grinding profiling which is made in accordance with PP 8 and 9, when rolling perform the following steps:

and additionally measure:

- the actual modes of rolling (thickness, velocity, compression, tension on stands);

- the actual costs of the emulsion in the system section cooling;

b) controlling the shape (flatness) of the strip at the outlet of each stand (visually or using sensors);

C) introducing the computer as the operational source data for mathematical models in addition to the measured parameters, specified in paragraph 3, the measured parameters specified in paragraph 10A;

g) using the parameters listed in PP 3 and 10A, b, in the models specified in paragraph 2, shall be calculated in pace with the rolling of thermal profile of the rolls and costs sectional cooling;

d) establish the actual costs of the emulsion in the sectional cooling system is equal to the settlement and adjust their values depending on the inspection results form strips;

(e) if the actual flow rate of the emulsion supplied to the sulfur is more in this crate a new set of work rolls with grinding the bulge, 0.05 mm larger than the previous set;

g) if the actual flow rate of the emulsion supplied to the middle of the barrel, turned out to be more than 80% of the maximum, do the transfer and establish in this crate a new set of work rolls with grinding the bulge, 0.05 mm smaller than the previous set.

1. The method of controlling the profile of the rolls of sheet rolling mill, including the determination using mathematical models estimated profile of the rolls as a function of range and parameters of the rolling mode, the adjustment of the profile on the measured actual values of the rolling speed, tension and thickness of the strip, the temperature of the rolled stock, strategy flow of coolant along the length of the roll barrel by varying and regulating the actual strategy of consumption, characterized in that enter into the model values of grinding protuberances rolls, as well as the actual measured values of roughness of the rolls prior to installation in the mill, the actual transverse thickness of the rolled stock, the cooler temperature and the actual rolling force, additionally injected into the model dependence of the deformation resistance of rolled metal from the relative compression for different Maro is all mill stands, using it predicted value of the rolling force and the measured value of the actual lateral thickness variation and temperature strips, roughness of the rolls, thermophysical properties of the coolant, and determine the calculated grinding convexity in the cost of the cooler 50 - 60% of

the maximum in each of the cooling sections, the calculated values of grinding protuberances on the train rounded up to multiples of 0.05 mm, compare them with the actual set empirically the values of grinding protuberances, when the mismatch varies sectional expenses cooler in the range of 40 - 80% of maximum, minimizing the difference between calculated and empirical bumps, the coincidence of their values, polished and set into the cage rolls with empirical bulge, as if no equality empirical and computational convexity use rolls having a design value of the ground bumps.

2. The method according to p. 1, characterized in that when the reduction in the regulatory process in one of the mill the actual flow rate of the coolant supplied to the middle of the roll barrel, to less than 30% of the maximum, the rollers in the cage change on the rolls with grinding the bulge, 0.05 mm greater than the Oia in one of the mill's actual consumption, applied to the middle of the roll barrel, up to more than 80% of the maximum, the rollers in the cage change on the rolls with grinding the bulge, 0.05 mm less than replaced the kit.

 

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