PROCESS OF STEEL MAKING

The first step is to convert sponge iron and steel scrap into rerollable quality billet size ingots by the process of melting down the scrap in the medium frequency induction furnace. ;Elements like Ferro Manganese and Ferro Silicon are added in various forms to achieve a desired composition, reduce the level of impurities and cast in permanent moulds. In this process the heat is generated by inducing a current directly in the charge and generating the required heat. The impurities in the metal are removed by means of slag. The medium frequency induction furnace offers the advantage of providing very high temperature with quick heat availability under fine regulation and control.

The absence of oxidising heat source permits metals of selected high alloyed scrap without much loss of different elements. Induction Furnace allows close control of any desired metal characteristics and permits treatment of metal under various conditions as desired. This close control makes induction furnace versatile and offers great flexibility in terms of product, simplicity of operation, higher yield, fewer rejection and uniform product quality.

A suitable composition of different types of scrap and sponge iron is charged into the crucible and melted. Ferro Manganese, Ferro Silicon and other alloying agents are also included along with the scrap charged in the crucible. After complete melt down, samples of molten metal are taken for chemical analysis.

When desired quality of molten metal is achieved, the power is shut off and the furnace is tilted forward and molten metal flows into pit side ladle to be poured into moulds of ingots. Sufficient time is allowed for solidification and cooling after which the ingots are taken out of moulds.

The process of manufacture of CTD bars, wire rods and strip/flats is similar. Ingots are first checked for physical properties like piping, blow hole, saliva and any other surface defect and also the chemical composition i.e. percentage of carbon etc., because wire rods can be manufactured from ingots which have very low carbon percentage. These ingots are then taken to the pusher platform and with the help of pusher the ingots are pushed into an oil fired furnace in which a conveyor is fitted to facilitate movement of ingots inside the furnace from inlet to outlet. Inside the furnace, the ingots are heated at a temperature of 1100 °C to 1170 °C as per grade requirement and end use of the wire rod. The red hot ingots coming from the outlet of the furnace after remaining in the furnace for approx 125 minutes are then automatically lifted from the furnace and fed into the roughing mill for rolling after which it goes to the intermediate mill and then first and second finishing mill after which the tor steel/wire rod of required size varying from 8 mm to 25 mm is obtained. The wire rod/Tor steel is then sent to the coiler from where the wire rod/Tor steel is obtained in the form of coils. It is then sent to decoiler for cutting it in required length. After that the final inspection is done for size, surface defects, tensile strength and other defects.

Saboo Group of Industries

505-506, Sahyog Building,58-Nehru Place

New Delhi -110019, INDIA