Steel is one of the most widely used materials on Earth, but few outside the industry understand what it actually takes to produce it. This article explains—in simple, clear terms—how iron ore is transformed into usable steel, covering the process from mine to mill
Where Does Iron Come From?
Steel starts with iron ore, a naturally occurring rock rich in iron oxides. The three main types of iron ore used in steelmaking are:
- Hematite (Fe₂O₃) – Typically 60–70% iron content
- Magnetite (Fe₃O₄) – Often processed into pellets
- Goethite/Limonite – Lower grade, more common in tropical regions
Iron ore is mined in massive open-pit operations in countries like:
- Australia (Pilbara region – Rio Tinto, BHP
- Brazil (Vale’s Carajás mine)
- South Africa
- India, Canada, China
Once mined, the ore is crushed, screened, and upgraded (via magnetic separation, flotation, or pelletising) to increase its iron content and make it suitable for smelting.
Step 1: Reduction – Making Iron from Ore
Iron ore must be chemically reduced to extract metallic iron. This can be done in two main ways:
Blast Furnace (BF) Method
This is the traditional method used for large-scale production.
- Inputs: Iron ore + coke (a carbon-rich fuel made from coal) + limestone
- Blast furnace: Hot air is blasted in to ignite the coke, producing carbon monoxide
- The CO reacts with iron oxide → metallic iron (“hot metal”)
- Limestone removes impurities as slag
- Result: Molten pig iron (~94% Fe, very high carbon)
This iron is not yet usable—too brittle and carbon-heavy for modern applications.
Step 2: Steelmaking – Refining the Iron
The molten pig iron is transferred to a Basic Oxygen Furnace (BOF), where:
- Pure oxygen is blasted in at high speed
- The excess carbon is burned off
- The chemical composition is adjusted with scrap steel and alloying elements
- Result: Liquid steel (~0.2–1.0% carbon)
This process is fast and scalable, making it the dominant route globally—especially in countries like China, India, and Germany
Alternative Route: Electric Arc Furnace (EAF)
The EAF route skips iron ore entirely by using scrap steel or direct reduced iron (DRI) as input.
- Scrap or DRI is charged into the furnace
- High-voltage electricity arcs between electrodes to melt the metal
- The melt is refined, alloyed, and cast
This method uses far less energy (especially if powered by renewables) and produces lower CO₂ emissions, which is why it’s growing in popularity across Europe, the UK, and North America.
Step 3: Casting – Liquid to Solid
Molten steel is then cast into semi-finished shapes, depending on the product route:
- Slabs → For flat products (coils, sheets, plate)
- Billets → For long products (rebar, wire rod, merchant bar)
- Blooms → For large sections and rails
Today, most mills use continuous casting, which cools and solidifies the molten steel into long, rectangular forms on the move—dramatically improving quality and reducing waste.
Step 4: Rolling and Finishing
The semi-finished steel is reheated and passed through rolling mills to create final usable forms:
- Hot Rolling (above 900°C): Used for bulk shaping
- Cold Rolling (room temp): Used to refine thickness, surface finish, and tolerances
Depending on the product, steel is then:
- Pickled (acid cleaned)
- Galvanised (zinc-coated)
- Painted (coil coated for PPGI)
- Cut, slit, decoiled, or bent into ready-to-use stock
The result: a finished steel product ready for use in construction, fabrication, automotive, white goods, energy infrastructure, and more.
Recap: From Rock to Reinforcement
To recap, the journey of steel looks like this:
Iron Ore → Pig Iron → Liquid Steel → Slab/Billet/Bloom → Coil/Bar/Sheet → Final Product
At M7 Metals, we work with mills and suppliers across this entire value chain—from sourcing stock that started in the Pilbara or Carajás, to delivering cut, certified, construction-ready rebar or PPGI to clients across the UK and Europe.
Want to know which process your steel came from? We’ll tell you—and why it matters.