Introduction

Steel mills convert raw materials into molten steel at temperatures up to 1700°C. Global steel production reached nearly 1.9 billion tons in 2024, making steel the world’s most widely used metal.

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Raw Material Preparation

Iron Ore Processing

Steel plants treat iron ore based on its size and form. Fine and powdery ore undergoes high-temperature sintering. This process improves strength and permeability. It also prevents blockage and increases reduction efficiency.

Coke Production

Producers heat coking coal above 1000°C in oxygen-free coke ovens. This process removes volatile substances like gas and tar. It leaves behind coke, which contains mostly fixed carbon and minerals.

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Blast Furnace Ironmaking

Charging the Furnace

Operators load iron ore, coke, and fluxes from the top of the blast furnace. They arrange these materials in alternating layers. This structure ensures good airflow and stable reactions.

High-Temperature Reduction

Hot air enters the furnace at 1100–1300°C through the tuyere. The air reacts with coke and generates intense heat. The temperature quickly rises to 1500–1600°C. Carbon dioxide forms and reacts with coke to produce carbon monoxide. This gas reduces iron ore into molten iron. The molten iron collects at the bottom and is tapped when ready.

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Converter Steelmaking

Oxygen Blowing

Workers transfer molten iron into a converter. They add scrap steel and lime. Then they blow high-pressure oxygen onto the surface. Oxygen reacts with impurities and generates heat. The molten steel begins to boil, while slag forms on top.

Slag Removal

Operators remove slag regularly during the process. This step prevents impurities from returning to the steel.

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Secondary Refining

Alloy Adjustment

Technicians refine the molten steel to meet target specifications. They add alloying elements such as manganese, silicon, chromium, and nickel. These additions control the chemical composition and improve performance.

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Continuous Casting

Billet Formation

The plant casts refined molten steel into continuous billets. This step creates semi-finished products for further processing.

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Rolling and Finishing

Reheating and Rolling

Workers reheat billets to the austenite zone. This temperature range provides optimal plasticity. The billets pass through multiple rolling stands. Rollers reduce the cross-section and increase the length.

Cutting and Final Processing

Operators cut off irregular ends after rolling. They then cut the steel to the required length. After cooling, they mark each piece for identification. Finally, the steel is ready for sale or further processing.