For Balmukund concast ltd, the art of steel making is a magnificent observation. And for over a decade, we have been honing our skills to become the perfect steelartisan. Today our modern manufacturing plant at Bihta has helped us carve a reputation for our company and is as solid as the steel we make.
Balmukund has been producing TMT Saria using the latest TURBOQUENCH TECHNOLOGY. It is well equipped for the production of one lakh tonnes of TMT bar per annum. The plant has the facility of a modern 100 feet oil/gas fired furnace with all automatic controls. The mill uses latest technology for online production and quality control and has thirteen stands suitable for rolling 8, 10, 12, 16, 20, 25, 28, 32 mm sections of FE415 andFE500 grades of mild steel. It has a Flying Sheer to enable the product to be cut to desired sizes. It has automaticallycontrolled water sprinkler quenching system which leads to the quenching and tempering of the required thickness of the shell of the rolled product. The product is normalized on the cooling bed to produce steel of desired specifications. The whole system is fully computerized.
Raw materials such as Sponge Iron/DRI, Billets/ingots, used in predetermined properties are chemically and physically graded. The chemical structure is thoroughly analysed using in-house high qulity testing apparatus. If the raw materials meet the desired specifications then they are safely stored in the Raw Material Yard.
Selected raw material sample is added to lab furnace for melting in a core-less induction furnace. The furnace is composed of a refractory container capable of holding the molten bath, which is surrounded by water-cooled helical coil connected to a source of alternating current. After melting, the furnace is tilted to remove the slag and other impurities that come to the surface of molten metal. To refine the molten metal, Micro Alloying elements are added, and if necessary, de-surfacing and de-phosphorising are done to remove all gasses present. Throughout the process, samples are constantly analysed to ensure accurate and desired chemical composition.
The molten metal tapped to the tundish undergoes a Gas Purging process to retain thermal homogeneity, and to remove excessive non-metallic inclusions.
After purging, the material is taken from tundish to moulds. Liquid steel is poured into moulds to replenish the withdrawn steel at an equal rate, which depends on the cross-section, and the grade and quality of the steel being produced.
The solidified strand undergoes a re-heating process, where billets/ingots are re-heated upto the crystallization temperature. The fuel used for this process is Producer Gas, which is achieved by gasification of solid fuels like coal or biomass in the Gasifier. Re-heating using Producer Gas is very eco-friendly and ensures uniform temperature of billets/ingots. The billets/ingots then are, pushed into re-heating furnace at temperatures controlled at 1150°C to 1180°C.
Once the billets/ingots reach the desired rolling temperature, they are brought out from the furnace and made to first pass through the Roughing Stand, where the process of gradual size reduction of billets begins. The size is further reduced in the Intermediate and Finishing Mills, till their desired size is obtained. Roller Bearings fitted on the Roll Neck prevents unnecessary deformation of the bar. The Lop Scanner in the flow of the bar helps tensionless rolling, ensuring perfect round shape of the bar. This process of gradually reducing the billet/ingot size is paramount to ensure finer grain structure.
At this stage, another round of testing is done, and if accepted, the bars are fed to a Quenching Box at a very high speed. Here, rapid and controlled water quenching is performed to drastically reduce the surface temperature from 950°C to 300°C.
During the quenching process, only the outer portion of the bar (case) gets quenched, while the inner part (core) remains hot. So it is passed on to the Cooling Bed, where the core that is still hot, transfers the heat to the case outside, thereby tempering it. Due to this self-tempering, the martensitic case becomes Tempered Martensite, with more strength and corrosion resistance properties.
Once the bars are cooled, they are straightened and cut into desired lengths by means of cold shear. They are again inspected for chemical and physical properties, and then stored in the Finished Goods Yard and after complete conformation to the customer requirements, they are dispatched to exact site schedules.