Finally, the solidified strand is straightened, cut, and then discharged for intermediate storage or hot charged for finished rolling. To start a cast, the bottom of the mould is sealed by a steel dummy bar. This bar prevents liquid metal from flowing out of the mould and the solidifying shell until a fully solidified strand section is obtained. The liquid poured into the mould is partially' solidified in the mould, producing a strand with a solid outer shell and a liquid core. In this primary cooling area, once the steel shell has a sufficient thickness, the partially solidified strand will be withdrawn out of the mould along with the dummy bar at the casting speed.
Liquid metal continues to pour into the mould to replenish the withdrawn metal at an equal rate.
Once the strand is fully solidified and has passed through the straightener, the dummy bar is disconnected, removed and stored. Tundish The shape of the tundish is typically rectangular. Nozzles are located along its bottom to distribute liquid steel to the mould. The main function of the mould is to establish a solid shell sufficient in strength to support its liquid core upon entry into the secondary spray cooling zone. The inner face of the copper mould is often plated with chromium or nickel to provide a harder working surface, and to avoid copper pickup on the surface of the cast strand, which can otherwise facilitate surface cracks on the product.