The continuous casting automation system contains the entire mechanical controls from the molten steel flowing outside the intermediate frequency furnace to the steel billets being casted. The electrical equipments contain all flow-control cabinets, operation tables, boxes and master operation table of all work stations. And the main control methods are shown as follows:
Secondary Cooling Water Control: after the continuous casting billets being pulled out of the crystallizer, the shells are relatively thinner with the molten steel in the middle; therefore they need to be cooled down by spraying water, and this is called the secondary cooling down. The amount of secondary cooling water is generally controlled according to the steel category, billet thickness and casting speed. The core equipment in the secondary cooling water regulating system is the PLC, and it uses the heat conduction equation of the steel billet as the mathematical model and uses the steel billet surface temperature as the feedback signal to control the amount of the secondary cooling water. It could prevent the cracks on the steel billet if the amount of the secondary cooling water is suitable. The secondary cooling water control is the key link in the zero-defect steel billet production.
Casting speed control: the casting speed is determined according to the steel category, temperature and yield of molten steel. The casting speed requires being unchanged in the continuous casting production process, so that the billet could have the stabile heat exchange. There is the speed regulating device on the tension leveler to guarantee the stable casting speed. When the liquid level of the crystallizer exceeds the upper limit and the liquid level regulating system fails to regulate it, the casting speed shall be accelerated to prevent the molten steel from flowing outside; in the same way, when the molten steel in the crystallizer is below the lower limit, the casting speed needs to be reduced to prevent the steel leakage. There are alarms under both circumstances and they will be correspondingly handled.
Optimum cutting length control: cut the continuous casting billet into certain length for rolling. In order to prevent the short billets and increase the yield rate of molten steel, the optimum cutting length can be calculated according to the casting size, molten steel volume casting speed and allowable range of casting billet length. It can be altered in the latter phase of the ingot period so as to make sure the eventual casting length is suitable.