Method of rolling metal billet

FIELD: process engineering.

SUBSTANCE: invention relates to production of rolled stock and may be used in rolling of long-sized billets including those with superplastic properties. Method of rolling between shaping rolls comprises selection of forming roll working surface shape by computer simulation at steady-state plastic yielding of metal in deformation zone with due allowance for superplasticity. Billet is formed at forming rolls with variation of forming rate at every stand owing to selection of forming roll working surface shape of next stand proceeding from optimum shape at previous stand. Note here that forming roll working surface shape is selected with due allowance for distribution of billet metal plastic yielding in deformation zone in directions perpendicular to rolling direction and plastic yielding rate in direction of rolling related therewith to be computed by mathematical relationship.

EFFECT: higher quality of finished product, power saving.

2 dwg

 

The invention relates to a method of production of steel and can be used when rolling long metal blanks between the rollers, including the manifestation of the workpiece material superplastic properties.

When rolling lengthy preparations, having a simple configuration in cross-section, long semi-finished products with a more complex final cross-sectional configuration, the workpiece is processed by a certain number of pairs of rolls in rolling mill). For each pair of such rolls, rolling stands, is part of the total deformation of the workpiece or tackle the cross-section for subsequent processing (rolling) to obtain the desired defect-free semi-finished products. The most inefficient and time-consuming operation in this technology is the choice of the profile of the deforming contour tool (rolls) on the first operation rolling.

The use of modern methods of computer simulation of the deformation process for interactive optimization of technological parameters and purpose of selecting the optimal geometry of the deforming tool should provide high quality products and to reduce the energy consumption for its production.

There is a method of die forging blanks in the state corplast is knosti, published article - Chumachenko, Sergeant G.A., Makarova LT, Solomatin B.C. - Definition of rational speed limits stamping under superplastic conditions. "Forging and Stamping Production, engineering, 1987, No. 3, 16-17.

In accordance with the known method of die forging blanks in a state of superplasticity based on the analysis of the stress-strain state of the workpiece and power parameters of process of deformation modelling impose criteria functional relationship between changes in the velocity of deformation, the rate and degree of metal deformation in the deformation zone, the structural parameter and the degree of change efforts deformation. All criteria are linked functionally mathematical expressions, allowing, using step-by-step iteration, to carry out computer modeling, which allows to determine the changes of speed of deformation of the workpiece, which will enable superplastic flow of her material.

The disadvantages of this method are:

- impossibility to determine the velocity field of the flow of the metal of the workpiece in the direction perpendicular to the main plane of motion of the deforming tool and, thus, the inability to determine the optimal configuration de is armirujushchego tool through computer modeling in 3-dimensional space of the deformation zone;

- used in similar mathematical method of compilation of the simulation algorithm cannot be applied to 3-dimensional space of the deformation zone at the established stage of metal flow in the deformation zone.

The closest to the technical nature of the claimed invention is a method of rolling a metal workpiece between the rollers (J.J.Park, S.I.Oh " Application of three dimensional finite elements to shape rolling processes." Published in the journal - Transaction of the ASME J. Engg. Ind. - 1990. - Vol.112. - FEBRUARY. - p.36-46 - "Application of 3-dimensional finite elements in the simulation of rolling processes"). In this method, the determination of technological parameters defining the geometry of the working surface of the deforming tool, the distribution of stresses and velocities of the material in the deformation zone is carried out through computer simulation modeling of plastic flow of metal in the deformation zone, including:

- the choice of a computer program to simulate the configuration of the deforming contour of the tool and its optimization processing of the input data;

the choice of empirical configuration of the deforming contour of the rolls start rolling stands and putting it in the modeling and optimization;

- select and enter the program for the modeling and optimization algorithm, is defining the scope of the current deformation simulation step, the number of steps in the deformation zone and the precision parameter of the optimization emitting in the deformation of the two directions of the simulation along the direction of the rolling axis Z and perpendicular to the direction of rolling - plane X-Y;

input to a computer program algorithm that determines at each step of the modeling of the stress strain state of the environment in the form of functionality;

input to the simulation program algorithm in the scope of each simulation step and the total deformation zone, at first, the initial operation, the N - dimensional finite elements with properties of a solid plastic material and their reconstruction at each step of the simulation and optimization of the configuration of the working surface of the rolls, and including the modeling and optimization of the configuration of the working surface of the rolls on subsequent rolling of the workpiece to obtain the finished product, when used as the initial configuration of the mill roll, the optimal path obtained in the previous operation of the simulated rolling of the workpiece, with the possibility of changing the rolling speed through the changes in the geometric parameters of the deforming tool and dynamic parameters of the drive.

The disadvantages of this method of rolling process optimization to the hence, adaptation rolling tool roll through modeling should include:

low efficacy of simulation as applied to industrial processes due to a material increase in the cost of machine and operating time for the following reasons:

- large dimensionality of the system of the governing equations and, as a consequence, a large number of unknowns requires to get the result or enter additional assumptions required to achieve the desired result by reducing its accuracy, or significantly increased time adjustment 3-dimensional finite element (TCE) at each simulation step in the whole volume of the deformation zone and processing tasks on each node TCA;

the assumption in the separation of the flow of the workpiece material in the deformation zone along two independent directions of the simulation so that the component of velocity of movement of any point of the metal in the deformation does not depend on its coordinates in the transverse direction, which will require additional processing time of the algorithm for matching the simulation results to the whole deformation zone.

The next disadvantage is the acceptance in the simulation the maximum value of friction in the deformation zone, which may lead to distortion of the results of optimization of the profile of the working surface of the mill roll.

When rolling in the deformation zone is the zone of contact of the metal with the surface of the rolls with significant relative slippage, i.e. a coefficient of friction less than 1.0. This area of the grip roller metal billet and the exit area of the metal billet from the deformation zone. The third zone located between these areas is the so-called neutral section, which has the effect of adhesion of the metal workpiece to the surface of the roll by equalizing the linear velocity of each point of the working profile of the mill roll and the rolled blank. Geometrical parameters and the location of the third zone of deformation relative to the center of rotation of the rolls well developed in the works of the rolling member. Ahicelebi, which shows the significance of the influence of geometrical parameters of the roll and the dynamics of his drive on the geometry of the neutral zone sections and control the distribution of velocities of the particles of metal in the deformation zone. The latter factors are not used in the analog prototype for modeling the optimal configuration of the deforming contour mill roll.

Technical problem on which the invention is directed, is the optimization of technological modes of deformation of providing a high-quality semi-finished product is the products view and reduction of energy consumption for its production through optimal geometry of the working profile mill roll each rolling stand.

The technical problem is solved in the method of rolling a metal workpiece between the profile rolls in consistently stand rolling mill, including the selection of a profile of the working surface of the rolls by means of simulation computer simulation at the steady state stage of plastic flow of metal in the deformation zone, taking into account the state of superplasticity, and the deformation of the workpiece in the forming rolls installed in series of rolling stands with a velocity change of deformation of the workpiece in each of the rolling stands by choosing the profile of the working surface of the roll subsequent rolling stands based on the optimal profile previous roll rolling stands. While the profile of the working surface of the mill roll is chosen taking into account the distribution of velocities (VxVy)kflow of the metal billet in the deformation zone in the direction perpendicular to the rolling direction and interconnected with these velocities velocity (Vz)kflow of the metal of the workpiece in the direction of rolling, which is calculated by the mathematical expression:

providedZΔZk,

where:

Ck, received the needful for the constant value of ε/zthe strain rate in the direction of rolling for each elementary volume ∆ kdetermine on minimoa mathematical expression:

Sσzdxdy+2(tgα±η)GσndG-σzHSξprovided Z∈∆k,

where:

- ξ - low, front selectable number tending to zero, but not zero;

X, Y coordinates, perpendicular to the direction of rolling;

Z - coordinate coincides with the direction of rolling;

- K is the number of elementary volume ∆ kthat break volume deformation zone;

- ∈ - means belonging Z elementary volume ∆ kdeformation zone;

-σzH- tension the tension of the metal workpiece at the outlet of the deformation zone, when it occurs;

- S - the current size poperechnov the cross-section of the workpiece relative to the elementary volume ∆ kdeformation zone;

- G - side surface of the elementary volume ∆ kdeformation zone;

- 2(tgα±η) is a multiplier that takes into account the friction at the boundary of metal

the workpiece - tool, where: η is the coefficient of the Coulomb law, and α is the contact angle of the metal workpiece with the tool for each elementary volume ∆ kdeformation zone;

- σn- normal stress acting on the side surface G of the elementary volume ∆ kdeformation zone;

- σzthe stress acting along the direction of the rolling axis Z, in the elementary volume ∆ kthe deformation zone, depending on the configuration of the side surface of the elementary volume ∆ kthe deformation zone, the magnitude of the accumulated therein hydrostatic pressure σ* and index of compressibility of the material of the workpiece;

- fk- term used as an amendment defined velocity (Vz)kparticles of a particle ΔZkdeformation zone relative to the speed of movement of particles of the metal billet in neutral cross section of the deformation zone, the step of determining the velocity, for each elementary volume ∆ kthe deformation zone, for each rolling mill stand is determined from the interval:

10<ZBΔZk <300,

where ZB- the length of the deformation zone in the direction of rolling.

Drawings illustrating the invention:

- figure 1 shows a diagram of the deformation zone (spatial schema one-quarter of the workpiece) for longitudinal rolling with a part of the working surface of the roll;

figure 2 shows a diagram of stress distribution on the surface of a particle ΔZkin the deformation zone.

The method is as follows.

When the simulation computer simulation of volume distribution in the deformation velocities of the particles of the metal billet deformation zone software is divided into two interrelated and orthogonal directions:

first direction in the plane X-Y perpendicular to the rolling direction is the Z axis, and having an elementary increment in the Z axis direction of thickness ΔZkforming an elementary volume ∆ kthe deformation zone, characterized by constant quasi-static over the metal of the workpiece corresponding to the viscous plastic medium, and in the plane of this direction through the software code, is meshed 2-dimensional finite elements (DCE) for computer modelling of the distribution of velocities VxVydefined by the algorithm of course-lemental approximation, and located in the deformation zone in the direction of rolling with Zkrelative to the center of rotation of the roll, projected on the Z axis as the origin, where k is the number of particle deformation zone;

the second - direction coinciding with the direction of the Z axis, the direction of rolling, which features relative speed of movement of the metal particles in the elementary volume ∆ kthe deformation zone is taken equal to a constant value, expressed analytically as functions.

A complete picture of the distribution in the amount of deformation relative velocities of the particles are deformable metal and voltage obtained after the computer integration of the stress strain States for each elementary volume ∆ kdistributed in the length of the deformation zone with a pre-selected step. The results are used to build the simulated configuration of the working profile of the rolls of each rolling stand.

Comparing the results of computer simulation with the requirements of the defect-free filling metal working profile rolls of each rolling mill stand, evaluate the optimality of the simulated circuit.

Where the requirements defect-free filling of simulated work profile rolling Valk is in each rolling mill stand metal workpiece, modeling the workflow configuration profile rolls of each rolling mill stand goes for a second simulation step when changing or empirically selected contour of the rolls, or the characteristic size of the rolls on the element of the path, or the speed setting of the drive rolls, or at the same time all these parameters.

When performing a defect-free filling of the metal billet simulated working profile rolls, contour accept optimally designed for this activity and consider the original circuit for simulation by the same algorithm subsequent operations rolling the workpiece to obtain the desired semi-finished product output from the last stand.

Thus, without significant loss of precision calculations, setting one of the relative movements of the metal in the deformation zone in analytical form, receive a small number of unknown parameters, which reduces the resolving equations and allowing to reduce the solution volume problem to a sequence of solutions of generalized two-dimensional problems.

For the sake of simplicity, the essence of the claimed invention, consider the solution of the problem on the example of longitudinal rolling of a metal strip (based on the symmetry seen a quarter of what ecene deformation zone of rolling strip - figure 1).

The problem of deformation in the deformation zone is solved in the velocities with the adoption of a number of assumptions:

- in forming the deformation zone is slow, quasi-static process, i.e. dynamic effects are neglected and the flow of the metal particles in the deformation zone is considered established when the time interval is divided into sub - intervals Δt, in which the change of speed of movement does not occur;

- consider an infinitely small elementary volume deformation zone - ΔZkat a distance of Zkfrom the projection on the Z-axis coordinates of the center of the mill roll;

on the basis of semi-analytical finite element method (FEM), for an elementary volume ∆ kthe value of the strain rateε/zalong the Z-axis is equal to a constant value, namely:

εZ/|Z=Z=Ckprovided Z∈[Zk, Zk+ΔZk],

where ∈ denotes the identity variable Z to the interval - [Zk, Zk+ΔZk].

Hence, the distance between the first point (x, y, z) of the deformation zone, at any time t, must be found the function Vzk(x, y, z, t), describing the rate of movement of material in an arbitrarily selected point. Thus, each end of the elementary volume ∆ kcross-section of the deformation zone component of velocity of moving particles of material will be determined by the following functions:

Vx=Vx(x,y); Vy=Vy(x,y); Vz=Ckz.

Thus, spatial, three-dimensional velocity field of a moving particle material in the deformation zone, including in the elementary volume ∆ kcross-section of the deformation zone is divided into two field components:

(VxVy)k- velocity field in the plane X-Y perpendicular to the Z-axis for each elementary volume ∆ kthe deformation zone, calculated according to the generalized flat, two-dimensional problem using FEM or course element approximation;

(Vz)k- velocity field along the Z-axis, calculated from the condition of minimization of the functional is calculated based on the equilibrium equations for each elementary volume ∆ kthe deformation zone at the appropriate time.

Considering the conditions of balance of all the forces acting in the direction of rolling at the elementary volume ∆ khighlighted sections of Zkand Zk+dz, Paul is given the General expression for the functional

F(Ck)=SσZdxdy+2(tgα±η)GσndG-σzHS,

which is determined by computer simulation, for each k-th elementary volume ∆ kdeformation zone with regard to the working profile mill roll obtained by k-1 simulation step, is assumed constant, equivalent strain rate in the form -εZ/|Z=Z=Ckand contains the following influencing parameters:

σn- normal stress acting on the side surface of the elementary volume ∆ kthe contour of the surface G (Fig 1)defined by the expression

σn=[2μV xx+(KΔt-23μ)(Vxx+Vyy)+σ*]nx+μ(Vxx+Vyy)ny,

where

μ=μ(εu,εu,T)function determined experimentally and characterizing the physical properties of the rolled material, depending on the strain εu, strain rateεuand temperature T;

K - coefficient of volumetric compression (constant material);

nxand ny- direction cosines of the normal to the strip in the zone of contact with the rollers are determined for the k-th step, the solution at the k-1 step);

Δt - step solutions determined from (Vz)kΔt=ΔZkhowever, depending on the required accuracy of the simulation, the value of ΔZkchoose from a ratio of10<ZBΔZk<300or taking into account recommendationsZBΔZk=100in which ZBthe geometric size of the deformation zone in the direction of rolling;

σ* - accumulated hydrostatic stress in the elementary volume ∆ kthe deformation zone, which is determined from the expression -σ*=K[-θΔt+0tθdt]=Ki=0k-1Δtiθiwhereθ= Vxx+Vyy+Vzz;

σzthe stress acting along the Z-axis, perpendicular to the surface S of the elementary volume ∆ k- depends on the operating profile of the mill roll in the area of elementary volume ∆ kand the amount of the accrued hydrostatic pressure σ* ∆ kthe deformation zone, defined by the equation:

σz=(KΔt-23μ)(Vxx+Vyy)+σ*;

σzH- possible tension bands due to the mismatch of speeds of adjacent rolls in the pass band in the system calibers;

2(tgα±η) is a multiplier that takes into account the friction η according to the Coulomb law on the border of the metal workpiece - tool and the angle α of the meta contact the La blanks with roller for each elementary volume ∆ kthe deformation zone.

However, the use of the sign ±in relation to the longitudinal rolling due to meet emerging compressive stresses along the Z-axis near the input section of the deformation zone and tensile stresses near the output section of the hearth relatively neutral section in it.

At least the same module functionality outlined above and allows you to find the value (Vz)kfor each elementary volume ∆ kthe deformation zone, is defined as

|F(Ck)|≤ξ,

where

ξ is small, predetermined number tending to zero, but not zero, and to ensure the required accuracy of the solution when defining Ckin the process of computer modeling for optimization, for example, empirically selected deforming contour mill roll (tool).

Velocity field (VxVy)kdetermine, taking into account the initial and boundary conditions, the solution below presents differential equations:

{σij,j=0σij=μ(Vxx+Vyy )+[(KΔt-23μ)up,p+σ*]δij,

where

δijis the Kronecker symbol.

Coordinate placement Z* neutral section, with respect to rolling, the length of the deformation zone depends on the geometry of the deforming contour of the tool, the angle of the rolling contact of the roller with the rolled material for each elementary volume ∆ k, the speed of rotation of the rolls and is determined from the expression

Z*=R2(ZBR-1-R+h-HRη),

where

R is the radius of the roller;

H, h, respectively height of the car at the entrance and at the exit of the rolls;

After the obtained solution is functional in all k-th elementary volume ∆ kdeformation zone pass to the determination of the velocities of the workpiece material across the deformation zone in on the managing rolling (V z)k.

Values of the velocity (Vz)kcalculate for each elementary volume ∆ kratio

(Vz)k=CkZ+fk(z)providedZΔZk,

where: fk(z) - velocity of a particle ΔZkin the deformation zone, defined by:

fk(z)=f0+n=1k-1CnZn,

where:

k is the number of the cross-section of the deformation zone;

f0the entrance velocity of the strip in the rolling mill rolls, determined by the speed of a neutral section in the deformation - Z*, the angular velocity of the rolls Ω and radius R by the expression

fm(z* )=f0+n=1mCnZ*=ΩRsinβ,

where m is the number of a particle cross-section, which is the neutral section with coordinate Z*;

β=arcsinZ*R- the angle that defines a neutral section in the deformation during rolling (corresponding to the Z position* relative to the center of the roll).

Thus, make the determination of the velocity distribution throughout the volume of the deformation zone of the workpiece relative to the current operation. However, with respect to the longitudinal rolling, for the current solution relative to the current stand, the initial configuration of the deforming contour tool is the profile of the deforming contour of the tool received in the previous stand rolling mill.

In the implementation of computer simulation and optimization of the workflow configuration profile rolls on subsequent deformation of the workpiece as the initial configuration of the deforming contour tool use the optimal path, the floor is built on previous modeling operation rolling of the workpiece, with the possibility of changing the rolling speed by changing the geometric parameters of rolls and dynamic parameters of the drive.

Example of the effectiveness of the proposed method by computer simulation of the optimal configuration of the caliber of the deforming tool - rolls rolling mill in comparison with the method of computer-aided design configuration same instrument based on 3-dimensional finite element (TCE).

In the prototype presented a three-dimensional model for computer simulation of rolling in calibers using three-dimensional finite elements and using SHPROL. Using TCA of the program that set the configuration profile of the roll and, in the process of computer simulation of the rolling process, the strip, has traced the gradual deform as desired profile. The simulation was performed with the conditions of isothermal deformation.

The claimed invention were delivered similar numerical experiments (computer simulation) rolling in calibers using the software package SPLEN (Caliber), which applied the FEM method with two-dimensional finite elements. Numerical experiments sang and danced with the same product as the authors of the article - prototype - band rectangular cross section of 50× 50,8 mm

Comparative numerical analysis was carried out as in smooth and profiled rolls. The material strip 45 is similar steel AISI - 1045, which was used in the article of the prototype. The heating temperature for the simulation was set to 1100°C and temperature conditions of isothermal deformation.

In the calculations using SHPROL made, due to the axial symmetry of the cross section of the strip, on a quarter-section, used the split model 640 spatial, three-dimensional elements 1025 nodes. In this case, the calculations were done on the computer VAX-11/750, to obtain solutions took 2600 iterations, which took about 175 hours of computing.

Numerical experiments on modeling the configuration of the rolls during rolling with SPLEN (Caliber) using the proposed method. It was selected one hundred sections of the deformation zone (k=1÷100) 352 final item in each section. The computation time on a Pentium 4 took about 100 minutes calculation Errors did not exceed 6...8%.

To obtain the normal stress distribution on the rolled strip in the calculations of the authors [2] required: 1000 TCE with 1476 nodes and 3200 iterations that resulted in 470 hours of computer VAX-11/750 (powerful enough computer engineering).

Receipt of similar information in numerical experiments by the present method, using the program SPLEN (Caliber) to which the user's computer Pentium 4 took no more than 5 minutes The examples of computer equipment on the basic system requirements had almost the same performance.

The inventive method of rolling a metal workpiece between the rollers allows the optimization of technological modes of rolling with the provision of high quality semi-finished products and to reduce the energy consumption for its production by selecting, using computer simulation, the optimal geometry of the working surface of the rolls of each rolling stand.

Method of rolling a metal workpiece between the profile rolls in consistently stand rolling mill, including the selection of a profile of the working surface of the rolls by means of simulation computer simulation at the steady state stage of plastic flow of metal in the deformation based on the status of superplasticity and deformation of the workpiece in the forming rolls installed in series of rolling stands with a velocity change of deformation of the workpiece in each of the rolling stands by choosing the profile of the working surface of the roll subsequent rolling stands on the basis of the optimum profile of the preceding rolling stand, wherein the profile of the working surface of the mill roll is chosen taking into account the distribution of velocities (VxVy)sub> kflow of the metal billet in the deformation zone in the direction perpendicular to the rolling direction and are correlated with these velocities velocity (Vz)kflow of the metal of the workpiece in the direction of rolling, which is calculated by the mathematical expression:
providedZΔZk,
where Ckis a constant equal to the speed of deformation in the direction of rolling for each elementary volume ∆ kthe deformation zone, which is determined by the minimum of mathematical expressions:
Sσzdxdy+2(tgα±η)GσndG-σzHSξprovided Z∈∆k,
ξ is small, front selectable number tending to zero, but not zero;
X, Y - coordinates, perpendicular to the direction of rolling;
Z - coordinate coincides with the direction of rolling;
k is the number of elementary volumes (Δ k), which divide the amount of deformation;
∈ is the membership of Z elementary volume ∆ kdeformation zone;
σzH- tension the tension of the metal workpiece at the outlet of the deformation zone when it occurs, MPa;
S - current-sectional area of the workpiece relative to the particle deformation zone ΔZkmm2;
G - side surface of a particle deformation zone ΔZkmm2;
2(tgα±η) is a multiplier that takes into account the friction η according to the Coulomb law on the border of the metal billet - roll, the angle α is the angle of contact of the metal billet with a roller for each elementary volume deformation ΔZk, grad.;
σn- normal stress acting on the side surface of a particle deformation zone ΔZk, MPa;
σzthe stress acting along the direction of the rolling axis Z, in the elementary volume ∆ kthe deformation zone, depending on the configuration of the side surface of the elementary volume ∆ kthe deformation zone, the magnitude of the accumulated therein hydrostatic pressure σ* and index of compressibility of the material, MPa;
fk- term used as an amendment defined velocity (Vz)k particles of a particle deformation zone ΔZkrelative to the speed of movement of particles of the metal billet in neutral cross section of the deformation zone, mm/s;
when this step of determining the velocity for each particle deformation zone ΔZkfor each rolling stand is determined from the interval10<ZBΔZk<300,
where ZBthe length of the deformation zone in the direction of the Z-coordinate, mm



 

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8 cl, 6 dwg

FIELD: process engineering.

SUBSTANCE: invention relates to metallurgy. Proposed regulator 7 comprises force regulator 8 and position regulator 9 inferior to the latter. In operation, rated rolling force F* and actual rolling force F are fed to force regulator 8. The latter is used to define correcting value δs1* for adjusting stroke proceeding from received aforesaid values. Said correcting value δs1* of adjusting stroke differing from δs1*, eccentricity compensation δs2* and actuator adjusting stroke actual value 2 are fed to position regulator 9 The latter defines adjusting parameter δq proceeding from received δs1*, δs2*, s. Parameter adjusting δq is used to vary adjusting stroke of actuator 6.

EFFECT: higher quality of rolled stock.

11 cl, 3 dwg

FIELD: automation of rolling processes.

SUBSTANCE: method comprises steps of measuring disturbance-stimulated strip thickness in front of rolling stand; controlling measurement result until inlet of stand; compensating it in stand by moving screws of screw-down mechanism at predetermined rate for preset time interval; measuring fluctuation of strip thickness relative to predetermined value when strip leaves stand; acting upon movement rate of screws according to disturbance and to fluctuation of strip thickness after multiplying said values and differentiating received product.

EFFECT: enhanced accuracy and reliability of controlling strip thickness.

2 dwg

FIELD: continuous rolling of strip, namely rolling strip having different thickness portions joined through transition wedge-shaped portion.

SUBSTANCE: method is used for rolling metallic strip 1 in rolling mill having at least two rolling stands. Metallic strip 1 has at least two zones 3,4 of different thickness mutually joined through wedge-shaped or approximately wedge-shaped transition portion 2. Rolling rate in rolling stand at rolling wedge-shaped portion 2 is tuned depending upon forward slip of rolling stand and also depending upon temperature of metallic strip 1. Apparatus for rolling includes rolling mill having at least two rolling stands providing tuning of rolling rate at rolling wedge -like or approximately wedge-like transition portion 2 of strip depending upon forward slip of rolling stand and upon temperature of metallic strip 1.

EFFECT: enhanced quality of rolled products.

2 cl, 5 dwg

FIELD: automation of rolled stock production.

SUBSTANCE: at controlling thickness of tube wall in multi-stand continuous stretch-reducing mill, thickness of tube wall is measured behind mill by means of wall thickness measuring devices. Measured values are processed in computing unit. Revolution numbers of drive engines of rolls are controlled by means of units for controlling revolution number. In order to minimize formation of inner multi-arc profile at passing tube, total elongation value is kept constant due to changing revolution number of drive engines of rolls under control of computing unit.

EFFECT: enhanced quality of products.

5 cl, 4 dwg

FIELD: rolled stock production.

SUBSTANCE: method of rolling metallic strip with use of skin pass stand comprises steps of reducing strip by thickness; adjusting speed Vi of strip at inlet of stand and speed Vo of strip at outlet of stand regardless of strip tension; setting relation of Vi/Vo equal to (1 - E*) being relation of desired strip thickness at outlet of stand to strip thickness at inlet of stand, E* - preset value of strip elongation. Apparatus for rolling metallic strip includes skin pass rolling stand for reducing thickness of strip and setters for setting inlet and outlet speed values of strip for adjustment of speeds Vi and Vo regardless of strip tension.

EFFECT: enhanced quality of rolled strip.

8 cl, 3 dwg

FIELD: plastic working of metals.

SUBSTANCE: method comprises steps of calculating current value of coil diameter at coiling-uncoiling process according to relation of revolution numbers of mill rolls and coiler; according to calculated value setting revolution number of motor of coiler and its electromagnetic parameters; at coiling counting turns of strip in coil simultaneously with calculation of current value of coil diameter; for each turn of coil storing diameter of coil calculated at such time moment; at next uncoiling of coil, counting turns in reverse direction; using stored value of coil diameter of respective turn for setting revolution number of coiler motor and its electromagnetic parameters.

EFFECT: enhanced accuracy of controlling tension of strip due to elimination of influence of reduction change in stand upon calculation accuracy of coil diameter at uncoiling strip.

FIELD: rolling.

SUBSTANCE: invention can be used in automation of hot and cold rolling mills. Method provides determination of parameters of elastic deformation of stand: modulus of rigidity of stand, correction factor for transfer from absolute roll-to-roll clearance of stand to relative position in respect to roll pass design point, efforts on stand elastic deformation line corresponding to beginning of linear section and use of obtained parameters for refined determination of parameters of adjustment (rearrangement) of stand. Method of determination of parameters of stand elastic deformation line is combined with process of stand designing and it is implemented at step or continuous loading of stand rolls by roll compression force created by hydraulic pressure devices from minimum stand off-loading force to designing force. Proposed method improves accuracy of adjustment (rearrangement) of rolling stand by roll-to-roll clearance, decreases breaking of strips and increases yield of good strips by decreasing rejection of metal caused grow-back defect, reduces consumption of metal and work and support rolls owing to exclusion of additionally changing and re-grinding of rolls in case of strip break in stand.

EFFECT: increased yield of strips.

3 cl, 4 tbl, 2 ex, 4 dwg

FIELD: rolling; sheet rolling processes.

SUBSTANCE: proposed method is based on measuring distribution of relative elongations of band longitudinal sections of strips detected by measuring device. According to invention, longitudinal band sections of strip chosen by measuring device adjoin each other without gaps and overlaps covering entire width of strip and strip tension is measured additionally. Relative overspeeding of metal in direction of strip movement in band longitudinal sections of strip singled out by measuring device relative to metal speed in one of band longitudinal sections of strip singled out by measuring device at minimum speed of metal are calculated using mathematical dependence. Relative overspeeds of metal in direction of strip movement in band longitudinal sections of strip singled out by measuring device, as compared with minimum speed of metal in one of band longitudinal sections of strip singled out using measuring device can be used to adjust profile of roll gap for producing strip of high planeness.

EFFECT: improved planeness of rolled strips owing to increased accuracy of measurement of nonuniformity of metal flow in process of rolling.

FIELD: processes for making rolled products such as simple and shaped sections, possibly in continuous rolling mills.

SUBSTANCE: method comprises steps of measuring (at rolling process) size of rolled strip along its length and detecting revolution number of rolls in stands; correcting preset inter-roll gaps and revolution numbers of rolls in stands; simulating parameters of rolling next strip on base of previous data of rolling mode of section; rolling next strip and simultaneously measuring its size and revolution number of rolls in stands; after finally setting inter-roll gaps and roll revolution numbers, evaluating specific consumption of electric energy in stand groups for reducing metal; according to set optimization algorithm, selecting optimal speed mode with minimum specific electric energy consumption.

EFFECT: minimized specific electric energy consumption, possibility for correcting sped mode at temperature fluctuation and at change of physical and mechanical properties of pieces to be rolled next from initial values.

3 dwg

FIELD: cold rolling in six-roll stand.

SUBSTANCE: in six-roll stand having pair of rolling rolls, pair of intermediate rolls and pair of backup rolls at least intermediate and rolling rolls engage with apparatuses for axial shifting. Barrel of each intermediate roll has length increased by shifting stroke and ground zone (x) near band edge at one side. According to invention upper intermediate roll is shifted in axial direction towards side As of drive unit and lower intermediate roll is shifted towards control side BS or vice versa. Said shifting is realized relative to neutral position (Szw = 0 mm) of mean portion (y-y) of stand symmetrically by the same value in direction of their axis (x-x). Shifting position is set in different portions along width of band by means of piecewise characteristics on base of different positions of beginning of ground zone relative to band edge. Configurations of ground zone of roll barrels are normalized by means of mathematical relations.

EFFECT: enhanced accuracy of rolled product geometry.

3 cl, 4 dwg

FIELD: procedures for working coiled rolled strip after rolling it, namely loop-free aggregates for slitting rolled strips, particularly systems for controlling drive unit of circle shears of aggregate.

SUBSTANCE: method for controlling circle shears drive unit of aggregate for slitting coiled rolled strip including coiler, circle shears and uncoiler comprises steps of setting speed and torque moment of circle shears motor depending upon parameters of strip; at guiding strip to coiler (while cutting lead end of strip coil in front of coiler before tensioning it by means of coiler) measuring and storing moment of circle shears motor; after guiding strip to coiler and creating tension of strip by means of drive units of coiler and uncoiler setting revolution number of shears motor more than set speed of strip and setting moment of motor equal to value stored at guiding strip; at next process of cutting strip measuring real moment of circle shears motor and if it is less than of set moment value, lowering set value till measured real value. At cutting process also values of strip tension at side of coiler and uncoiler are measured for calculating their difference and storing its value at beginning of strip cutting with working speed. At each decrease of set moment value of motor depending upon measured real moment in case when said difference exceeds its stored value, increasing set moment of shears motor but no more than real moment value.

EFFECT: improved accuracy for setting moment of circle shears motor, enhanced quality of shearing rolled product.

2 cl

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