Billet or billet is a type of steel ingot with long length and square or circular cross section. If the maximum width of the billet is 15 cm and has a cross section of 230 cm2, the bloom can be considered the same billet that has a width of more than 15 cm and has a larger cross section. This method is common in Iran and is done using natural gas fuel in regenerative furnaces. The output of the direct reduction furnace is sponge iron, which is commonly used as a briquette. Scrap and used iron are poured into special arc furnaces in special baskets, and then sponge briquette iron is added to the kiln with slag materials such as coke, lime, bentonite, and و from above. The charge of the furnace is melted by the heat generated by electric arcs. The chemical composition of the melt is checked again to reach the desired state. After the separation of impurities, the molten steel is taken to the casting unit by means of trays carrying the molten material. The molten material is poured into a container called a tandish, then it is placed in a round copper water mold on a roller and cooled by spraying water. Then, the obtained frozen ingots are cut to the desired lengths. In this way, all kinds of steel ingots can be produced.
After the molten crude steel is obtained using steelmaking in an electric arc furnace (EAF) or converter, the ingotization process is carried out in two ways: continuous casting and manual (single casting). The method of casting and molding of ingots is very important because the solidification of ingots is done at this stage and the microstructure (internal order) of the piece is formed here and the physical and mechanical properties of other products also depend on this stage