# Measurement and Model-Based Control of Solidification in Continuous Casting of Steel Billets
## 3 Results
### Operator Information and Advisory System  
The API of the model kernel developed by BFI is used by a model shell developed by ESF for communication between the ESF automation system and the DynSolidCC model. There is a permanent exchange between model, database and Programmable Logic Control (PLC). An extended visualisation and user interface has been developed and installed at ESF billet caster with focus on simplification and user-friendliness for the operator. With this user interface, the operator can select specific data to be displayed or evaluated. Figure 3 shows a screenshot of the extended HMI integrated within the production mask. The user interface shows for a selected distance from the meniscus in the mould a coloured cross-section of the strand produced by the currently casted batch (\"Produktnummer\", cf., Figure 3, left side). It distinguishes within a 17 \(\times\) 17 field different temperature  
Figure 23: Evolution of actual and target casting speed, spray water flow and crater end position without (**top**) and with (**bottom**) application of target casting parameters for target crater end of 20 m at ESF billet caster. ranges depending on the temperatures calculated by the model. Inside the cross-section, the shell thickness is visualised by a black line. It is also displayed numerically (\"Schalendicke\") in millimetres together with the crater end position (\"Sumpfspitze\") in metres for the target and the calculated actual state. Point 8 of the example in Figure 3 is at 0.86 m below the meniscus, i.e., at the exit point of the mould. This point was deliberately chosen because there the shell must be stable enough to withstand the ferrostatic pressure. A sufficiently thick strand shell prevents breakouts. The user has the option to view and evaluate the temperature and solidification state at other positions by using a slider (cf., Figure 3, centre left). If the slider is moved, the model results for the selected position are transferred to the HMI. Additionally, a top view of the caster and the strand is displayed. Here, the casting parameters along the strand related to the primary cooling in the mould and the secondary cooling in the spray water zones 1-4 are shown to the user (cf., Figure 3, centre right). The huge amount of data calculated by the model and the high number of measured parameters cannot be processed in their entirety by the operator. Therefore, a traffic light system has been integrated into the HMI which compares defined collected and calculated data of a strand with specified limit values (cf., Figure 3, right side). If a parameter deviates from the specification, the traffic light switches its colour from green (regular range) to yellow (critical range) or red (dangerous range). Thereby, the operator can localise the cause of irregular casting conditions and intervene, if necessary. Such an intervention may result in a shutdown of the irregularly running strand in order to prevent a possible breakout event. The most important and influencing parameters analysed and visualised by the traffic light system comprise:  
* Temperature in tundish (\"Verteilertemperatur\");
* Temperature of mould water inlet (\"Kokillenwasser-EinlassTemp.\");
* Temperature difference between mould water outlet and inlet (\"Kokillenwasser-Temp.-Diff.\");
* Flow rate of mould water (\"Kokillenwasserdurchfluss\");
* Pressure of spray water zones 1-4 (\"Spritzwasserdurch\");
* Crater end position calculated by DynSolidCC model (\"Position Sumpsfspitze\");
* Shell thickness at mould exit calculated by DynSolidCC model (\"Schalendicke... \"). Finally, the output of recommendations calculated by the dynamic cooling control function based on the DynSolidCC model are also visualised in the HMI (cf., Figure 3, right side, \"Modelempfehlung\"). These recommendations help the operator to properly adjust the spray water flow rates and casting speed (by using another submerged entry nozzle) in order to achieve a given target value for the crater end position.