CONTINUOUS CASTING PROCESS ( A Type of Permanent Mold Casting)

Continuous Casting is used in general for the production of rods, pipes, sheet metal and other articles known as semi-finished products in an uninterrupted process.

The main feature of  the process is the pouring of molten steel through a tower nearly 300m high ; this replaces the casting of ingots, the removal of molds from ingots, the re-heating of ingots, and their primary rolling. To understand what this shortcut means, one has only to go over the principal operations in a conventional plant. 

In a conventional plant, after pig iron has been turned into steel- say, first, in a Bessemer Converter and then in what is known as an open hearth furnace- the white-hot molten steel flows into a huge ladle ; The ladle is carried by a crane and the molten steel is poured from it into a number of molds to form ingots, i.e., pieces of steel of  manageable size for further processing ; the ingots are then carried to a mill for rolling ; They are first re-heated and then put between rollers ; the products emerge in a uniform, elongated shape, chopped off into convenient lengths, for use in the final fabrication of steel products. 

The method of continuous casting dispenses with these separate and somewhat cumbersome stages. Instead of making ingots and then reheating them for rolling , molten steel is poured steadily from the top of a tower into a long mold, cooled by water, and the passage of the steel through the mold is so controlled that the metal emerges from the other end in the shape of  the products of primary rolling mill. 

The main task is to devise a suitable mold that will withstand the heat and fasten the solidifying steel into desired shape , without obstructing its steady flow. The substance used for mold is copper, with an efficient cooling system.

The method has not yet been developed to such an extent as to lead to its universal introduction; questions of economics and quality are still being examined. 

Molten metal is poured into a metal mold which is cooled by water without interruption by appropriate device. Thus, the casting solidifies and is fed still red-hot to a rolling mill or cut into pieces of required length. The pulling plate 1 is used to pull the solid product  in the continuous length.