Steel

During the last 4,000 years, steel has become so common that we stopped noticing its presence. Thousands of specialized steels are used in health care, infrastructure, mobility, energy and agriculture. Steel is 100% recyclable, and close to 100% is indeed being recycled. We "meet" the same steel every 20 to 30 years.

Steel production is energy and CO2 intensive. Inefficiencies must be eliminated. Highest quality standards have to be applied. Tiniest deviations of one process can cause substantial quality losses downstream. Process automation is extremely high. Huge amounts of relational data, time series data, image and video data as well as audio data are generated 24/7.

Steel is commanding us to blend process expertise with AI and Machine Learning knowhow!

The following example lists processing steps of an integrated flat steelmaker, from iron ore to high quality galvanized sheet. Note that there are many more setups, such as for heavy plate production and long products.

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Sinter Plant (SP): Fine ore and ore lumps are agglomerated in order to form a chargeable burden for the consecutive blast furnace process.

Blast Furnace (BF): Oxygen is removed from oxidic iron ore to create liquid iron. Liquid iron is then transferred to the next process step, the basic oxygen furnace. Within the blast furnace the hot metal has a carbon concentration of 4.5%.

Basic Oxygen Furnace (BOF): The charged hot metal is converted to crude steel by means of oxygen to remove the carbon. Crude steel is tapped into refractory lined ladles for following refining processes.

Electric Arc Furnace (EAF): Scrap metal or direct reduced iron is being molten by the use of electrical energy introduced via electrodes. Crude steel is tapped into refractory lined ladles for following refining processes.

Ladle Furnace (LF): Crude steel is refined and reheated for casting.. Excess oxygen from previous processing steps is fully removed. The steel is trimmed to meet the high quality needs for consecutive process steps.

Vacuum Degasser (VD): Certain steel grades require an additional degassing to meet the highest quality demands for special applications. A Vacuum Degasser sets the whole heat under vacuum to install this high cleanliness.

Continuous Casting Machine (CCM): Liquid steel solidifies to produce steel bars in an endless process. Steel bars, either slabs or billets/blooms are then cut to length at the end of the process.

Hot Strip Mill (HSM): The bars from the casting process are rolled after a reheating, temperature homogenization and surface cleaning to their final dimensions in rolling mills.

Pickling Line (PL): The surface of the product is cleaned from grease and scale formed during the rolling process for perfect input conditions into the cold rolling process.

Tandem Cold Mill (TCM): Hot rolled strips are cold rolled for special applications with a higher surface demand.

Continuous Galvanizing Line (CGL): The surface of the final product is annealed and coated in a Zinc bath for achieving an increased corrosion resistance.
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AIST's steel wheel, explaining numerous production paths

World Steel's infographic on steel production

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