THE CONTINUOUS CASTING OF STEELIn the production of ferrous and non-ferrous metals the melt has to be cast into various shapes . This can be done in two ways :
THE CONTINUOUS CASTING OF STEEL
In the production of ferrous and non-ferrous metals the melt has to be cast into various shapes . This can be done in two ways :
- in moulds ;
- by continuous casting (CC) .
In the first case the liquid metal is cast slag-free in casting moulds with a ladle. After the blocks have cooled down they are taken out of the mould, reheated and hot-rolled and cold rolled into delivery conditions . Figure 3 shows this casting technique。
The other method is continuous casting . In 1857 Henry Bessemer designed a continuous casting production method for steel plate . The installation he used is shown in figure 4 . The liquid steel is cast between two rotating rolls . The metal solidifies and leaves the die in the shape of a plate . The quality of the steel plate proved to be not as good as expected, whereas the process couldn't be controlled with the state of technology in those days . Great efforts on behalf of research and development have led to the use of the continuous casting process on a large scale nowadays . Figure 5 shows a schematic diagram of the process . The melt is cast in a bottomless cooled die . The speed of casting is equal to the speed of solidifying . The cast strand is secondarly cooled after it has left the die and if necessary cut into pieces by an automatic moving saw.The cutting cannot be done until the strand is completely solidified .
The choice between CC or casting in moulds depends to a great extent on the scale of production . If a small output of discrete products is wanted, casting in moulds will be preferred . If a large quantity of integral products is required the continuous casting (CC) process will be used .
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Harm of too high temperature: when molten steel out of cooper mold, the billet shell is thin and easy to break out; The accelerated erosion of refractory can ea
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1. The barrier function (mainly completed by the liquid slag layer) isolates the contact between air and molten steel, blocks the secondary oxidation of molten
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In continuous casting, low corrosion resistance often occurs, which directly leads to uneven composition and will eventually affect the smelting quality. In or