SMART MOULD COMPLEX

The SMART MOULD equipment complex is designed to be used in a Slab Continuous Caster and includes several mutually integrated measuring and controlling systems for the Mould. It ensures smooth and trouble free operation of the Strand as well as high quality of final product.

This complex provides for:

  • accurate automatic stabilization of metal level in the Mould;
  • precision measurement of parameters of the Mould movement in three linear coordinate axis and three angles around these axis;
  • precision measurement of interaction forces between the Mould and the Billet and measurement-based monitoring of the casting Powder operation quality as well as amount;
  • measurement of temperature distribution along the Mould walls during casting;
  • generation of sticking alarms.
The complex considerably improves efficiency of the Caster due to safe increase in the casting speed and enhances the product quality due to significant improvement in surface quality. It also gives customer the opportunity to reach most suitable compromise, which provides both increase in productivity and improvement in quality. Due to improved stability of the casting process and additional information made available through this system, Caster downtime and related economic losses are drastically reduced. The SMART MOULD complex makes it possible to monitor current casting conditions better and take in-process corrective action.


01.jpg

The figure shows three-dimensional temperature distribution image in the mould walls at level of the upper thermocouple row. Temperature is plotted on vertical axis, time on horizontal axis. Rectilinear development of temperature distribution along the Mould perimeter is plotted on the third axis. The obtained surface temperature is screened in different colours, depending on the temperature value.

Upper image shows conditions of manual metal level control, lower image reflects automatic conditions of stabilization. In case of manual control of metal level, fluctuations of the Mould wall temperature, caused by metal level instability, can well be seen.

In automatic operation conditions, the Complex provides substantial improvement in accuracy of the Mould metal level maintenance by factor, as compared with manual control, and much more uniform temperature distribution and smoother and lesser temperature fluctuations.

The above results are achieved due to installation of the additional equipment. The Cater Mould is equipped with thermocouples, which provide indirect measurement of temperature distribution on the surface. Sensors measuring the Mould movement in three linear axis and three angles of rotation around these axis as well as sensors of interaction forces between the Mould and the billet are installed on the Mould Oscillation Mechanism. The liquid metal level sensor is installed on the Mould, and controls the flow of metal from the Tundish to the Mould. It is provided with electric drive for automatic metal level stabilization. Electric drive has provision for  manual operation, which is activated after switching-off the automatic level stabilization system. Information on casting process in text and graphs is displayed on the screen of the caster desk. Information required for Caster operator is displayed on the screen of the monitor located at his desk. On the basis of measurements, the complex equipment generates alarms about the shell sticking to the Mould wall, shows remaining time left for vacating the sticking area under the Mould, i.e. remaining time till commencement of emergency situation resulting in a breakout. This allows the Caster operator to take necessary measures and to prevent the breakout.

Current parameters of the Complex operation are saved by the archiving and visualization system in electronic format and can be used later for monitoring of the technological discipline and for improving the technology of the available equipment in use. The System exchanges information with higher-level Control through its devices. 


The Main Technical Parameters of the SMART MOULD complex

Index

Value

Cross section sizes of the standard Mould (mm)

(it is possible to use moulds with other sizes)

(150330)x (5002,400)
Operation principle of the sensor of metal level in the Mould Eddy current
Error of Mould metal level maintenance in steady conditions (mm)  less 1
Dynamic error of metal level maintaining during step-by-step varying of the casting speed from 0.8 to 1 m/min (mm)
3
Duration of transient process caused by step-by-step casting speed varying (s)
more 12
Number of thermocouples installed on copper plates of the Mould Up to 120
Time from shell sticking alarm generation till beginning of break out (s)
nevertheless 40
Precision of system in measuring the linear movements of the moulds (at 1 Hz frequency) (mm) 0,05
Precision of system in measuring the angular movements of the mould (at 1 Hz frequency) (second of arc)
2,5
Precision of system for measuring the withdrawal force (N)
300

Example of detected hanging

02.jpg


Figure shows detected shell sticking to the Mould wall. Each of the presented three-dimensional images reflects temperature distribution at the corresponding level of the mould. Upper image has been obtained at 150 mm distance from the mould copper plate top edge, central image at 300 mm distance, and lower image at 450 mm distance.

Sections with high temperature (red color) being at the Mould depth determined by central and lower thermocouple layers are the striking examples of sticking. Timely warning about this has made it possible to prevent emergency situation. After receiving the signal, necessary measures have been taken, and speed of the slab withdrawal from the Mould has been reduced, and this has led to the Strand cooling (the strand cooling has been shown by the blue colour appearing on image), and to the increased shell thickness03.jpg

Example of archive record showing casting process with non-accurately installed submerged entry nozzle. The casting was begun with the submerged entry nozzle non-accurately installed or having production defects, and this led to the fact that hot metal streams flowing through the nozzle holes heated the mould walls. This, in turn, caused the two red patches (the first, second, and partly third fragments). Then, the nozzle was changed. In this case, casting  speed was reduced, and this led to slab cooling. The cooling was confirmed by arrival of the blue patches. After replacement of the nozzle by the new one, leveling of temperature distribution was observed, and overheated patches disappeared.