THE MAIN SECTIONS OF WORK:

1 A SURVEY OF RESEARCHES ON RESONANT VIBRATIONS IN THE COLD ROLLING MILLS AND APPROACHES FOR THEIR ELIMINATION

2 DESIGN OF THE STRUCTURE OF THE MATHEMATICAL MODEL OF OSCILLATIONS
2.1 Model of vibration of roll stack system and drive line
2.2 The model of oscillations of friction forces in the deformation zone
2.3 Model of inter-stand tension vibration
2.4 Models of various kinematic disturbances
2.5 Frequency characteristics of the mechanical system of stand and drive line

3 ADAPTATION OF MATHEMATICAL MODEL OF OSCILLATIONS IN THE MILL STANDS ACCORDING TO VIBRATION MEASUREMENTS AT THE CERTAIN POINTS OF EQUIPMENT
3.1 Dependence of natural frequencies on the technological parameters
3.2 The amplitudes of the kinematic frequencies of equipment at various rolling speeds

4 ANALYSIS OF THE METHODS OF DIAGNOSIS OF EQUIPMENT OF ROLLING STANDS AND DRIVE LINES OF MILL
4.1 Bearings of work rolls
4.2 Bearings (MORGOIL) of backup rolls
4.3 Gear couplings of spindles, gearboxes and safety couplings

5 ANALYSIS OF THE KINEMATIC FREQUENCIES OF EQUIPMENT ACCORDING TO VIBRATION MEASUREMENT IN MILL 2030
5.1 Vibration of rolls bearing units
5.2 Vibrations in the drive line gears

6 EXPERIMENTAL STUDY OF VIBRATION IN MILL STANDS AND PROCESS PARAMETERS OF STRIP ROLLING A OF VARIOUS SIZES
6.1 Statistical data processing of the technological parameters during chatter vibration
6.2 Vibration frequency analysis at different points of equipment
6.3 Recommended layout of vibration sensors on the mill 2030

7 DEVELOPMENT OF THE ROLLING TECHNOLOGY ENHANCING SPEED AND REDUCING STRIPS BREAKAGE
7.1 Possible ways to affect the critical dynamic conditions in the mill
7.2 Monitoring the development of a dynamic conditions in the mill
7.3 Reducing the winding reels eccentricity influence of the occurrence of resonant vibrations at the coincidence of the coil and backup rolls diameters
7.4 Diagram of kinematic and natural frequencies of mill equipment

8 TESTING NEW TECHNOLOGICAL SOLUTIONS AND ALGORITHMS
8.1 Vibration threatening ranges of rolling speed
8.2 Effect of specific tension distribution and the width of the strips
8.3 The weakening the connection between stands at the expense of lower levels of tension and the step-down reduction schedule
8.4 Operating the rolling process with a guaranteed value of a positive forward slip in the stands

Example of the vibration sensor installation in the stand

Shift of the maximum vibration spectrum in the 5th stand at the kinematic frequency
range 500-600 Hz, under the speed decreasing

The development of vibration before alarm signal produced by the system

THE MAIN SECTIONS OF WORK:

1 ANALYSIS OF KNOWN STUDIES OF RESONANT VIBRATIONS
1.1 Dynamic models of resonant vibrations and mill control methods
1.2 Influence of periodic defects in the rolls grinding
1.3 Effect of the technical condition of mill equipment
1.4 Monitoring of process parameters and mill speed control
1.5 Passive damping of resonant vibrations
1.6 Active damping of resonant vibrations
1.7 Statement of the objectives of the study of resonant vibrations in the mill 2030

2 RESEARCH OF WORKING ROLLS BEARING VIBRATIONS
2.1 Analysis of defects in the bearings of work rolls
2.2 Calculation of the kinematic frequencies of bearings vibration
2.3 Analysis methods for diagnosis of bearings of work and backup rolls
2.4 The influence of the roll hydraulic bending on bearings vibration
2.5 The influence of rolls profiling on frequency properties of the stands

3 STUDY OF THE ROLLS AND STRIP DEFECTS INFLUENCE ON VIBRATION
3.1 Analysis of the rolls eccentricity and the roundness influence
3.2 Analysis of the rolls surface defects influence
3.3 Analysis of strips surface periodic defects (chatter marks)

4 STUDY OF OSCILLATIONS IN THE DRIVE LINES OF STANDS
4.1 Analysis of the rolls diameters relations in stands
4.2 Analysis of the drive lines wear effect on the level of vibration
4.3 Development and testing of a new method of diagnostics of the drive lines

5 STUDY OF REGENERATION OF RESONANT VIBRATION
5.1 Analysis of the effects of vibration on the strip periodic defects
5.2 Analysis of the damping properties of the strip in the deformation zone

6 ANALYSIS OF MILL CONTROL SYSTEM IMPACTS
6.1 Effects of the system of work rolls drives loads balancing
6.2 Impacts under the rolls eccentricity compensation

7 DEVELOPMENT OF TECHNICAL SOLUTIONS FOR VIBRATIONS SUPPRESSING
7.1 Methods of diagnostics of strips periodic defects
7.2 The introduction of methods of early detection of resonant vibration
7.3 Design of passive vibration damping device
7.4 Development of devices of active vibration damping

Marks of periodical wear in the bearings of the rolls

Changing with rolling speed the RMS level of vibration
for different sets of work rolls and chocks

Time diagrams and the spectral vibration composition in the presence of defects
in the bearings of work rolls

Time diagrams and the spectral vibration composition in the presence of defects
in the bearings of backup rolls

Chatter defects on the strip of the 2nd group of surface quiality:

Defects in the backup roll in stand 5 (step 50-60 mm)

Signals of rolling load and vibrations at the moment of mill resonant vibration

THE MAIN SECTIONS OF WORK:

1 STATISTICAL ANALYSIS OF RESULTS OF MILL SPEED AUTOMATIC CONTROL BY THE VIBRATION CONTROL SYSTEM
1.1 Modernization of VCS and vibration analysis of the upper drive line of 2nd stand

2 DETERMINE THE RELATIONSHIP OF MILL VIBRATION PARAMETERS WITH HIGH-FREQUENCY LONGITUDINAL THICKNESS VARIATION OF STRIPS
2.1 The implementation of function for determining of high-frequency strip thickness variation

3 DEVELOPMENT AND TESTING OF NEW TECHNOLOGY AND MODES OF THIN STRIPS HIGH-SPEED ROLLING
3.1 Influence of damping properties and stiffness of the strips material
3.2 Effect of reduction schedule in the stands
3.3 Effect of tension forces between the stands
3.4 Effect of the profile of rolled strips
3.5 Effect of coolant concentration

4 DEVELOPMENT OF VIBRATION DAMPING DEVICES OF ROLLS UNITS
4.1 Modeling of external impacts in the mill 2030
4.2 Assessment of required levels of damping in the stands
4.3 Selecting the material for damping devices
4.4 Development of the drawings and definition of places for the damping devices mounting
4.5 Assessment of the effectiveness of vibration damping devices
4.6 Methods of damping recommended for testing on the mill 2030

5 DIAGNOSIS OF PERIODIC DEFECTS IN GRINDING ROLLS
5.1 Measurements of vibration and process parameters in rolls grinding
5.2 Diagnosis of hidden periodic defects on the rolls surface

Installation and testing of damping devices in the stand

Measuring the parameters of grinding and vibration in the roll grinding machine

Below shown the places of two vibration sensors (accelerometers) installation on the support of grinding wheel spindle.
The list of parameters to be measured:

• feed rate of carriage;
• drive current of wheel;
• wheel rotation speed;
• vibration on the wheel support in a vertical direction;
• vibration on the wheel support in the horizontal direction;
• roll rotation speed (measured by pulse speed sensor).

Diagnosis of the hidden periodic defects on the backup rolls