Steel & Metal Manufacturing
Steel manufacturing methods have evolved dramatically since the processes of the industrial revolution began in the middle 19th century. however modern methods are still based on the Bessemer process which was practiced over 150 years ago. This was a way to introduce oxygen into molten iron in order to reduce the amount of carbon contained within.
Modern-day steel production makes use of both traditional raw materials (iron) and recycled materials to tern them into steel. With this in mind, here are the 6 steps to modern steel production explained.
Steel & Metal Proccess
To create pure steel, the products that go into it- lime, coke and iron ore- must be made into iron. These are all put into a blast furnace and melted down to create what is called molten iron or hot metal. The iron still has many impurities at this point, and they will have to be removed to ensure the metal is not brittle.
There are two main methods for making steel these are Basic Oxygen Steel making (BOS) and Electric Arc Furnaces (EAF). BOS methods for example involve adding scrap (recycled) steel to the molten iron when in the furnace. Oxygen is then forced through the liquid (the Bessemer process) to cut the impurities in the molten metal down to 0.5% - 1.5%.
Alternatively, with the EAF method, recycled steel is fed into an electrical arc furnace along with the molten iron which is then heated to around 1650 degrees Celsius in order to convert it into high grade steel.
Secondary steel making involves treating the molten steel produced from both BOS and EAF routes to adjust the steel composition. This is done by adding or removing certain elements and/or manipulating the temperature and production environment. depending on the types of steel required, the following secondary steel making processes can be used:
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stirring
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ladle furnace
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ladle injection
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degassing
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CAS-OB (Composition Adjustment by Sealed argon bubbling with Oxygen Blowing)
Next, the steel in its molten form is cast into cooling molds. This allows the steel to become hard, and the steel is drawn out of there while it is still hot. Guided rollers are used to pull it out and then the steel is cut into the desired lengths. It may be used for beams, billets, slabs or other items, and when the parts are fully cooled, they are sent elsewhere for primary forging.
Also known as primary forming, the initial shapes of slabs, blooms, and billets are formed into the various shapes usually by hot rolling. Products that are hot rolled are then divided into flat products, long products, seamless tubes, and special products for one last stage of processing.
To create the final shape of the steel there are a number of secondary techniques that can be used, including:
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Coating
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Thermal treating
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Joining
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Pressing
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Drilling
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Machining
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Riveting
