Rolling Mill

Real-time vibration monitoring and diagnostics system is developed and supplied for the 5 stand 4-h tandem cold rolling mill 2030 NLMC. Mechanism of chatter regeneration due to high frequency strip thickness variation and stands synchronization in the tandem rolling mills are considered. Methods for chatter passive damping and active suppression are considered. Work rolls hydraulic bending system influence on bearings vibration and chatter is discussed. The new methods are used for the 3rd octave chatter early diagnostics and model based mill control.

An overview is represented of the telemetry systems, which applied for torsional measurements in the different branches of industry. The advantages and shortcomings shown for different principles of measurement and data transferring from rotating shafts in the rolling mills drive trains. The description is represented of the digital telemetry devices, which designed in Iron and Steel Institute, NAS of Ukraine and embedded monitoring system with the diagnostics function of wear (angular backlashes).

Uncertainty of technology and equipment parameters is particular for the rolling mills dynamics. Contact friction produces a wide band stochastic impacts which cause chatter vibration in the middle and higher natural frequencies range (100-1000 Hz) of the mill. Strip elasto-plastic deformation as a nonlinear spring in the stand depends on random technology parameters (rolls bending, strip tensions, mill speed). The transfer functions were used for principal mode distribution and chatter vibrations control in the cold rolling mills. The second cause of uncertainty is wear (backlashes) which makes drive train an essentially nonlinear system. The backlashes gaps and rolling loads are always uncertain at the beginning of transient process in the hot rolling mills causing dynamic torques scattering in the multibody drive trains. The low frequency (10-20 Hz) torsional vibrations are investigated. The output dynamic load distribution parameters were obtained. Statistical aspects of the mill control and diagnostics are discussed.

The excessive dynamic loads and shock vibration are particular for the hot rolling mills equipment. An attempt to reduce torque amplification factor (TAF) has been done for the roughing stands of a wide strip hot rolling mill. Drive acceleration method was used in order to close the open backlashes gaps before transient process begins. This method is usually implemented for the reversing stands without gearboxes. But for the drive trains which include heavy gearboxes with the big rotating inertias it could be applied effectively partly. The second mode of torsional vibration may significantly change TAF in the different couplings. Therefore torque active control by motor speed regulation should be rearranged. Industry measurements of the torques and vibrations have been carried out to prove drive acceleration method to torsional vibration active control in dependence on drive trains design.

The campaign increase of the rolls in mills reduces remarkably reduce the production costs The premature wear out of the rolls generates a reduction of the campaign leading to replacement and reconditioning. Therefore, it is extremely important to increase the campaign. This roll change need can be reduced enhancing mechanical and tribological properties on the surface by the deposition of chromium thin layers. This study evaluated the campaign of tool steel rolling mill rolls with chrome plating comparing to the results of uncoated cylinders.

Operation of industrial metallurgical plants is associated with significant wear in spindles, gearboxes and bearings where difficult to implement digital diagnostic tools due to harsh operating conditions. Angular and radial gaps produce extremely high dynamic loads and abrupt failures in the multi-stand hot rolling mills. Reliable vibration monitoring is very complicated due to inherent changes of technological regimes, treated material and drive speed. It appears more beneficial to monitor dynamic torques in addition to vibration signals, but this is restricted to the installation of strain gauges. The more acceptable approach is to monitor static torques of electric motors and, having identified multi-body models, to calculate remaining useful life (RUL) of elements. Based on this approach, the new monitoring system is developed for the multi-stand mill with integration into plant automation infrastructure. Parameters adaptation of nonlinear dynamical models is provided and technological loads optimization by the criterion of RUL in rolling stands. System supports a database of maintenance actions and elements failures. Reports are generated on overloading and RUL.

Improved energy efficiency in supply chains can reduce both environmental impact and lifecycle costs, and thus becomes a competitive advantage in the work towards a sustainable global economy. Viewing the supply chain as a system provides the holistic perspective needed to avoid sub-optimal energy use. This article studies measures relating to technology and management that can increase energy efficiency in the supply chains of five aluminium products made in Sweden. Additionally, energy efficiency potentials related to the flows of material, energy, and knowledge between the actors in the supply chains are studied. Empirical data was collected using focus group interviews and one focus group per product was completed. The results show that there are several areas for potential energy efficiency improvement; for example, product design, communication and collaboration, transportation, and reduced material waste. Demands from other actors that can have direct or indirect effects on energy use in the supply chains were identified. Despite the fact that companies can save money through improved energy efficiency, demands from customers and the authorities would provide the additional incentives needed for companies to work harder to improve energy efficiency.

The new theoretical approach is used to determine rolling mills chatter cause. Nonlinear positive feedback in the work rolls and strip contact is described by the second order differential equations. Mathematical model allows to simulate and to predict chatter appearance. Software is designed to identify mathematical relations between the chatter features and the rolling parameters. Model based mill control is discussed.

SUBSTANCE: forming of control signal at moment preceding vibrations transition into sympathetic phase. The moment preceding development of hazardous vibrations is determined from combined or separate occurring of complex of conditions. To them the following can be related: reaching the limit (threshold) values of mean square deviations of maximums of the vibration acceleration signal specter at several stands of the mill, starting from the last stand, and coefficients of correlation of vibration acceleration signals for at minimum in one pair of adjacent stands.
EFFECT: upgraded quality of rolled flats, increased speed of rolling and also reduced rolls wear and stands idle time.

Operation of industrial metallurgical plants is associated with significant wear in spindles, gearboxes and bearings where difficult to implement digital diagnostic tools due to harsh operating conditions. Angular and radial gaps produce extremely high dynamic loads and abrupt failures in the multi-stand hot rolling mills. Reliable vibration monitoring is very complicated due to inherent changes of technological regimes, treated material and drive speed. It appears more beneficial to monitor dynamic torques in addition to vibration signals, but this is restricted to the installation of strain gauges. The more acceptable approach is to monitor static torques of electric motors and, having identified multi-body models, to calculate remaining useful life (RUL) of elements. Based on this approach, the new monitoring system is developed for the multi-stand mill with integration into plant automation infrastructure. Parameters adaptation of nonlinear dynamical models is provided and techn...

Improved energy efficiency in supply chains can reduce both environmental impact and lifecycle costs, and thus becomes a competitive advantage in the work towards a sustainable global economy. Viewing the supply chain as a system provides the holistic perspective needed to avoid sub-optimal energy use. This article studies measures relating to technology and management that can increase energy efficiency in the supply chains of five aluminium products made in Sweden. Additionally, energy efficiency potentials related to the flows of material, energy, and knowledge between the actors in the supply chains are studied. Empirical data was collected using focus group interviews and one focus group per product was completed. The results show that there are several areas for potential energy efficiency improvement; for example, product design, communication and collaboration, transportation, and reduced material waste. Demands from other actors that can have direct or indirect effects on e...

The methods of analysis and calculations outlined for a small brass-slab rolling mill can be applied to other installations. The time and money spent selecting the proper motor size saves extravagance in first cost, maintenance, and power factor correction.