The section size of billet should be determined according to the need of rolling and the compression ratio during rolling.

The capacity of the furnace and the capacity of the casting machine should also be considered.
It is generally equipped with large section and multi - flow continuous casting machine for large steelmaking furnaces.
The rolling compression is preferable 6 ~ 10.
For stainless steel and heat resistant steel, take a minimum of 8; for high speed steel and tool steel, take a minimum of 10; for carbon steel and low alloy steel, take 6.