The steelmaking process transforms iron ore into finished steel products.

Steel—the “backbone” of modern industry—is widely used in construction and machinery, vehicles, and everyday consumer products. But how does the journey from raw iron ore to high-quality steel bars occur? This article will provide a detailed look at the modern steelmaking process, from ore mining to finished products, through advanced techniques and modern technology.

History of steel development

Before learning about the steel production process, let’s look back at the important steps in the history of the steel industry to see the remarkable development of metallurgical technology.

• Early Period: Humans have used steel for thousands of years, mainly to make weapons and tools. The manual steel production method during this period was very simple, based on heating iron ore with charcoal.

• 18th Century: New methods of steelmaking were developed, allowing for larger-scale production of better-quality steel. Notable examples include the cementation method (heating iron bars with charcoal) and Benjamin Huntsman’s smelting well.
• 19th Century: This was a boom time for the steel industry with revolutionary inventions:
  • Bessemer Process (1855): Allowed cheap mass production of steel, ushering in a new era for the steel industry.

  • Siemens-Martin Process: Combines pig iron, scrap steel, and iron ore to produce steel, increasing efficiency and quality.

• 20th century – present: Steel production technology continued to improve with the advent of modern methods:

  • Linz-Donawitz Process (BOS) (1952): Uses oxygen to refine steel, resulting in increased productivity and superior steel quality. BOS allows steel production 12 times faster than the Siemens-Martin open-hearth process.

  • Electric Arc Furnace (EAF): Recycling scrap metal into new steel, contributing to environmental protection and sustainable development.

Steel production process

Today, the modern steelmaking process typically includes the following main steps:

Step 1: Iron Ore Mining

Iron ore is mainly found as oxides such as hematite (Fe₂O₃) or magnetite (Fe₃O₄). Open-pit or underground mines are used to extract the ore. The ore is then crushed to prepare it for further processing.

Step 2: Iron ore reduction

• The ore is mixed with coke and fed into a blast furnace.
• At high temperatures (around 2000°C), the ore is reduced to produce molten pig iron.

Step 3: Refining pig iron into steel

• BOS method: Oxygen is blown into the furnace to remove impurities such as silicon, sulfur, and excess carbon.
• EAF method: Recycling scrap steel by melting it in an electric furnace.

Step 4: Steel casting

The refined liquid steel is transferred to the casting area.

Steel is cast into semi-finished products such as steel billets, steel ingots, steel plates, etc. depending on the intended use.

There are two main casting methods: continuous casting and die casting.

• Continuous Casting: Liquid steel is poured into a continuous casting mould, forming steel billets of unlimited length.
• Die casting: Liquid steel is poured into a mould of a defined shape.

Step 5: Steel processing

Factors affecting steel quality

Steel quality depends on many factors:

• Carbon content: Carbon is the most important element affecting the properties of steel. High carbon content increases the hardness and strength of steel but also reduces ductility.
• Alloying elements: Elements such as nickel, manganese, chromium, and vanadium… are added to steel to improve specific properties such as strength, hardness, corrosion resistance, heat resistance…
• Heat treatment: Heat treatments such as annealing, quenching, and tempering are used to change the microstructure of steel, thereby changing its mechanical properties.
• Process Control: Close control of process parameters throughout the manufacturing process is essential to ensure steel quality and consistency.

Conclude

Steel production is not only a complex technical process but also the foundation for economic and social development. From classical methods to modern technologies such as BOS or EAF, the steel industry is constantly improving to create high-quality products to meet the diverse needs of the market.

Bao Tin Steel Company is proud to provide high-quality steel, ensuring it meets all requirements from construction to industrial production. Please contact us for more details!

References:

• “History of the steel industry (1850–1970).” https://en.wikipedia.org/wiki/History_of_the_steel_industry_(1850%E2%80%931970).
• “Bessemer process.” https://en.wikipedia.org/wiki/Bessemer_process.
• “Benjamin Huntsman.” https://en.wikipedia.org/wiki/Benjamin_Huntsman.
• “Cementation process.” https://en.wikipedia.org/wiki/Cementation_process.

Tiger Steel is a subsidiary of Bao Tin Steel