World's Greatest Hobby on Tour
24 inches X 48 inches
Although the blast furnace is the most easily-recognized structure in a steel mill, that is not where the steel is made.
The liquid iron produced in the blast furnace can be converted to steel by several processes - one of the most common today is the Basic Oxygen Process.
Large-scale steel production in the late 19th century and early 20th century was made possible by the Bessemer process, which gave way in the mid-20th century to the open-hearth process. Today, both are almost extinct, replaced by electric furnaces and by basic oxygen furnaces.
In the Basic Oxygen Furnace (BOF), pure oxygen (99.6% or better) is blown into the molten metal, burning away any remaining impurities in the iron, and also allowing the incorporation of desired additives into the material. These additives may include chromium, nickel, copper, and other materials, depending on the type of steel being made.
While many older steel-making facilities had open sides to allow cooling air to enter, the modern Basic Oxygen Furnace (BOF) is mostly enclosed, with air blown in and out mechanically, allowing better control over the quality of the air inside and outside the structure. The gases and dust produced inside are drawn away and filtered, with clean air being released outside.
Steel produced in the BOF may be either teemed into ingots, but very often, it is sent directly to a continuous caster, which produces rough shapes to be further formed in the rolling mills.
Diagram showing the general arrangement of this module.
The BOF module under construction.
The BOF Structures mocked-up in foamcore. This helps plan the shape and size of the final structures when they are built.