Theory and technology of sheet rolling: numerical analysis and applications

494 Pages·2019·43.577 MB·English

by  Mazur, Vladimir Leonidovich, Nogovitsyn, O. V

Theory and
Technology
of Sheet
Rolling

Theory and
Technology
of Sheet
Rolling
Numerical Analysis
and Applications
V. L. Mazur
O. V. Nogovitsyn
Translated from Russian by V.E. Riecansky
CRC Press
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Contents v
Contents
Introduction ix
1. One-dimensional model of the deformation zone 1
1.1. The deformation zone in the moving coordinate system 1
1.2. Differential equation of rolling 4
1.3. Numerical solution method 7
1.4. Rolling force 9
1.5. The torque in the roll 11
2. Mathematical model of wide-strip hot rolling
of steel 14
2.1. Modeling the structure of the steel during hot rolling 14
2.1.1. Model of austenizing steel in heating 14
2.1.2. Mathematical model of the austenitic structure upon
deformation under isothermal conditions 17
2.1.3. Features of modelling the parameters of the structure
of austenite under isothermal multiple deformation 22
2.1.4. Formation of the austenite structure in isothermal
conditions 23
2.1.5. Calculation of isothermal decomposition diagrams
of austenite 24
2.1.6. Method of calculation of thermokinetic diagrams
of austenite breakdown 26
2.1.7. Evaluation of the model of mechanical properties 31
2.2. Deformation resistance 35
2.3. Strip temperature 42
3. Control of the formation of the microstructure
and mechanical properties of rolled steel 47
3.1. Modelling of microstructure and mechanical properties
in the rolling mill 50
3.2. Automatic control system of the properties of rolled
steel in ShSGP wide-strip hot rolling mill 58
3.3. Special features of production of hot-rolled
strip plate for continuous cold rolling mills 62
vi Contents
4. Stability and reliability of the hot rolling process 69
4.1. Increasing the reliability of the analysis of the sheet
rolling process 69
4.2. Stability assessment of the quality of sheet
rolled products 73
4.3. Effect of heating conditions of slabs on the stability
rolling technology for sheets and strips 75
4.4. Reliability of hot strip rolling technology 79
4.4.1. Evaluation of the reliability of hot rolling technology 79
4.4.2. Influence of design features of wide-strip mills
on the reliability of the rolling process and the quality
of sheet steel 87
5. Asymmetric strip rolling 98
5.1. Features and possibilities of asymmetric rolling 98
5.2. Calculation of process parameters of the asymmetric
rolling by the method of slip lines 107
5.2.1. Matrix-operator version of the method of slip lines 107
5.2.2. Basic equations of planar plastic flow 107
5.2.3. Relations along the slip lines 111
5.2.4. Formulation of boundary-value problems 113
5.2.5. The matrix–operator method of constructing slip line
fields 116
5.2.6. Construction of the field of slip lines and the
velocity hodograph 127
5.2.7. The matrix equation for the asymmetric process 131
5.2.8. Analysis of the results of calculation 135
5.3. Effects of process asymmetry in cold strip rolling 146
5.4. Influence of asymmetry on the rolling process on the
texture of steel sheet 164
5.5. Using process asymmetry to determine the
friction coefficient in rolling 172
6. Mathematical model of the process of cold rolling of
strips in continuous mills 180
6.1. The model of the stationary process 180
6.1.1. Selection of the method for calculating the deformation
resistance 180
6.1.2. Investigation of the deformation resistance of steel
in the deformation zone 185
Contents vii
6.1.3. Calculation of the friction coefficient in the
deformation zone 191
6.1.4. Calculation of the strip temperature in the line of the
rolling mill 195
6.2. The model of the non-stationary process 198
6.2.1. The equation of the stand–drive–strip dynamic system 198
6.2.2. Mathematical model of contact stresses in
the deformation zone in rolling welded joints 201
6.2.3. Methods for solving the dynamic problem 205
6.2.4. Simulation of the transition process in rolling a
welded joint 207
7. Optimisation of the technological conditions of
continuous cold rolling of strips 210
7.1. Selection of the criterion and optimisation method 210
7.2. Selection of the value of relative reduction in the final
stand of the cold rolling mill 214
7.3. Rolling in knurled rolls 218
7.4. Rolling in ‘cold’ rolls 219
7.5. Special features of the technology of rolling strips
with welded joints 221
7.5.1. Effect of the rolling process parameters on strip tension 224
7.5.2. The effect of the speed’ in acceleration and
deceleration of the rolling mill 234

8. Stability of the technology of cold rolling of strips 241
8.1. Indicators of the instability of the cold rolling process 241
8.2. Calculation of instability parameters of the process 246
8.3. Dynamic loads is drive lines and vibrations in the
stands of continuous cold rolling mills 251
9. Features of the rolling method of production of
sheet steel 263
9.1. A mathematical model of the stress–strain state of
coils of cold rolled strips 263
9.2. Numerical evaluation of the conditions for contact of
strip turns in a roll 282
9.3. Welding of strip loops in rolls during metal annealing 285
9.4. Experimental studies of stresses in strip rolls 291
9.5. Effect of process parameters on the winder stress–strain
state rolls 299
viii Contents
9.6. Selecting tension modes when winding strips rolls
of cold-rolled strips 317
9.7. Stress–strain and temperature condition of hot-rolled
strips 350
9.8. Rational technology of cooling and storage of
hot-rolled strips 366
10. Skin pass rolling of sheet steel 379
10.1. Theoretical basis of skin pass rolling 379
10.2. Kinematic and power parameters of the skin pass
rolling process 383
10.3. Features of technology of skin pass rolling thin strips 399
10.4. Effect of skin pass rolling conditions on the properties
of steel 406
10.5. Skin pass rolling of hot-rolled steel 410
10.6. Relationships governing the formation of metal surface
microrelief 416
11. Energy saving when rolling strips 432
11.1. Saving energy in wide-strip hot-rolling mills 432
11.2. Reduction of energy consumption in the production
of cold rolled steel sheet and tin plate 434
11.3. Thermal insulation and heat saving in rolling mills 443
12. Preventing defects in thin sheet steel 447
12.1. Defect morphology. External features of kinking 448
12.2. Defect formation. Causes and mechanism of kinking 450
12.3. Welding of adjacent turns during the annealing of
cold-rolled steel coils 455
12.4. Effect of coiling technology of cold rolled steel
and of unwinding of strip rolls on the formation of
kinking defects 464
References 470
Index 476
Introduction ix
Introduction
Technical progress is an integral part of the objective process of
the development of society and its productive forces. In metallurgy,
technical progress is aimed at solving urgent problems of improving
the quality and competitiveness, expanding the range of products,
developing new types of products, saving metal, fuel, water, thermal
and electric energy, and reducing production waste. Each of these
tasks is a complex of complicated problems and unresolved issues.
With a view to resolving them, fundamental and applied research
is constantly carried out, offering real recommendations in the
form of technical and technological solutions, the correct use of
which promises additional tangible benefits and the elimination of
negative effects. The development of a number of industries is largely
dependent on the production of rolled steel from ferrous metals.
The development of technology for obtaining various types of
sheet steel, the construction of rolling equipment, systems and means
of automation of the production process are subject to a single goal
- to ensure the required service properties and production volumes.
The technology of sheet rolling production is a set of knowledge
about the methods and means of processing steel from the initial
billet to obtaining sheets and strips of specified sizes, surface
quality, structure and mechanical properties. The creation of
effective technology is always scientific research, which ends with
the acquisition of new knowledge. Here there are: the formulation of
the problem, the analysis of the initial information, the formulation
of the working hypotheses, their theoretical elaboration, organization,
planning, performing the experiments, analyzing and summarizing the
results, checking the correctness of the accepted hypotheses on the
basis of the data obtained, justifying the conclusions, the revealed
regularities and forecasts.
The creation of new and improvement of existing technologies
at present can not be confined to various semi-empirical approaches
based only on production experience, but should be based on a