Background:
Rolling mill vibration mechanism is very complex, and people haven't found a satisfactory
vibration control method. Rolling interface is one of the vibration sources of the rolling mill system, and its friction and
lubrication state has a great impact on the vibration of the rolling mill system. It is necessary to establish an accurate
friction model for unsteady lubrication process of roll gap and a nonlinear vibration dynamic model for rolling process. In
addition, it is necessary to obtain more direct and real rolling mill vibration characteristics from the measured vibration
signals, and then study the vibration suppression method and design the vibration suppression device.
Methods:
This paper summarizes the friction lubrication characteristics of rolling interface and its influence on rolling
mill vibration, as well as the dynamic friction model of rolling interface, the tribological model of unsteady lubrication
process of roll gap, the non-linear vibration dynamic model of rolling process, the random and non-stationary dynamic
behavior of rolling mill vibration, etc. At the same time, the research status of rolling mill vibration testing technology and
vibration suppression methods were summarized. Time-frequency analysis of non-stationary vibration signals was
reviewed, such as wavelet transform, Wigner-Ville distribution, empirical mode decomposition, blind source signal
extraction, rolling vibration suppression equipment development.
Results:
The lubrication interface of the roller gap under vibration state presents unsteady dynamic characteristics. The
signals generated by the vibration must be analyzed in time and frequency simultaneously. In the aspect of vibration
suppression of rolling mill, the calculation of inherent characteristics should be carried out in the design of rolling mill to
avoid dynamic defects such as resonance. When designing or upgrading the mill structure, it is necessary to optimize the
structure of the work roll bending and roll shifting system, such as designing and developing the automatic adjustment
mechanism of the gap between the roller bearing seat and the mill stand, adding floating support device to the drum
shaped toothed joint shaft, etc. In terms of rolling technology, rolling vibration can be restrained by improving roll
lubrication, reasonably distributing rolling force of each rolling mill, reducing rolling force of vibration prone rolling mill, increasing entrance temperature, reducing rolling inlet tension, reducing strip outlet temperature and reasonably arranging
roll diameter. The coupling vibration can also be suppressed by optimizing the hydraulic servo system and the frequency
conversion control of the motor.
Conclusion:
Under the vibration state, the lubrication interface of roll gap presents unsteady dynamic characteristics. The
signal generated by vibration must be analyzed by time-frequency distribution. In the aspect of vibration suppression of
rolling mill, the calculation of inherent characteristics should be carried out in the design of rolling mill to avoid dynamic
defects such as resonance. It is necessary to optimize the structure of work roll bending and roll shifting system when
designing or reforming the mill structure. In rolling process, rolling vibration can be restrained by improving roll
lubrication, reasonably distributing rolling force of each rolling mill, increasing billet temperature, reasonably arranging
roll diameter and reducing rolling inlet tension. Through the optimization of the hydraulic servo system and the frequency
conversion control of the motor, the coupling vibration can be suppressed. The paper has important reference significance
for vibration suppression of continuous rolling mill and efficient production of high quality strip products.
Time Frequency Representation Enhancement via Frequency Matching Linear Transform for Bearing Condition Monitoring under Variable Speeds