STEEL BILLETS

We have seen in our last post about the manufacturing of “Direct reduced iron i.e. DRI”

Now it’s time to secure overview of manufacturing of steel billets.

Steel billet is basically made from scraps or pig iron. We will consider following process for manufacturing Steel billet.

In order to manufacture the steel billet we normally use steel melting shop unit where basically following equipments for production are utilized

Scrap shredding unit
Scrap melting unit (Electric arc furnace / induction furnace)
Refining Unit (AOD, VD), AOD stands for Argon oxygen de-carburization and VD stands for Vacuum degas aging unit
Continuous casting machine

Scraps are first shredded in shredder machine so that time consumption in furnaces could be minimized. Capacity of shredder machine is normally given in hr/ton and due to shredding scraps the density of scraps will be increased and will provide better yield during the melting process. Except scraps there are some other important raw materials such as various alloying elements such as Ni, Cr, Mo, and Cu, S, P, Al & carbon.

Scraps are usually charged in arc furnace or induction furnace and melted up to temperature of 1600 degree Celsius. Normally we used to try to maintain the compositions of required grade at melting phase but final compositions are maintained in refining phase at Argon Oxygen Decarburizing.

When required addition completed at AOD then liquid hot metal tapped in a ladle from AOD. Liquid hot metal temperature must be around 1550 degree Celsius before going to Continuous casting machine. Liquid hot metal in ladle will be placed at the top of continuous casting machine and casting of liquid metal started.

Liquid metal comes from curved square mould and will be cut as per desired length from auto gas cutting unit or cut to length unit. Steel billet will be transported to cooling bed areas and finally quality inspected and dispatched.

For melting the scraps we normally used arc furnaces or induction furnaces. If we are in the business of stainless steel then we normally prefer induction furnaces as in induction furnaces we can go for higher grade of steel. Arc furnaces are very important for mild steel melting and processing.

After melting the scraps or other raw materials such as pig iron up to a temperature of 1700 degree Celsius, Liquid metal transported to argon oxygen decarburization or in ladle refining furnaces. Required chemical composition will be prepared over there after that liquid metal will be transported to continuous casting machine.

In continuous casting machine liquid metal will be solidified and solid steel in the form of steel billet will be discharged from withdrawal unit of casting machine and after that required length of steel billet will be cut with the help of auto gas cutter. Steel billet will be transported for inspection and then for dispatch.

We may understand the working and manufacturing of steel bloom or billet with the help of following figure as mentioned in following chart. We may see that raw materials for steel making will be more than one such as iron ore, coal, and coke oven and one simple scraps of steel.