Mild steel billets are semi-finished steel products that serve as a crucial raw material for various downstream industries such as construction, automotive, Mild Steel Billets and manufacturing. The production of mild steel billets is a detailed and energy-intensive process that transforms raw materials, mainly steel scrap or direct reduced iron (DRI), into solid rectangular or square bars. This process involves several key stages, including melting, refining, casting, and cooling.
1. Raw Material Preparation
The process begins with the collection and sorting of raw materials. Steel scrap is the most common input, which may include old machinery, used vehicles, demolished structures, and manufacturing off-cuts. In some plants, DRI or pig iron is also used to complement scrap, especially when a specific chemical composition is required. The quality of the input material significantly affects the final billet's properties, so scrap is thoroughly inspected and sorted to remove impurities such as non-ferrous metals, plastics, and dirt.
2. Melting in the Furnace
The sorted scrap is charged into a furnace for melting. Electric Arc Furnaces (EAFs) are widely used in billet production due to their flexibility and lower environmental impact. The scrap is heated using high-voltage electric arcs until it reaches a molten state, usually at temperatures above 1600°C. During this phase, various fluxes are added to facilitate impurity removal, forming a slag layer on top of the molten steel.
3. Refining and Alloying
Once the steel is molten, it undergoes refining to ensure the desired chemical composition and mechanical properties. This may include the removal of excess carbon, sulfur, and phosphorus. Deoxidizing agents such as aluminum or silicon are added to improve steel purity. In some cases, alloying elements like manganese or chromium are introduced to enhance specific characteristics of the final product.
4. Continuous Casting
After refining, the molten steel is transferred to a continuous casting machine. Here, the liquid steel is poured into a water-cooled mold where it begins to solidify. The partially solidified steel is then withdrawn in a continuous strand and further cooled using sprays of water or air. The continuous casting process results in billets with uniform cross-sections—typically square or rectangular—and consistent internal quality.
5. Cutting and Cooling
The long strands emerging from the continuous caster are cut into required lengths using mechanical shears or oxy-fuel torches. These billets are then slowly cooled on cooling beds to prevent internal stresses or cracks. Proper cooling is crucial for maintaining the structural integrity of the billet.
6. Inspection and Storage
The final billets undergo rigorous quality checks including visual inspections, ultrasonic testing, and chemical analysis to ensure they meet industry standards and client specifications. Approved billets are then stored and later transported to rolling mills or other manufacturing units for further processing into finished steel products like bars, rods, and wires.
In conclusion, the production of mild steel billets from scrap is a complex yet efficient process that plays a foundational role in the steel supply chain. Each stage—from raw material selection to final inspection—ensures that the billets produced are reliable, consistent, and ready for use in a wide range of applications.
