In 2017, global crude steel production reached 1.6 billion tonnes, a testament that steel still has a wide range of applications over a broad industry range. And why not? It is strong and you can mould it to suit a myriad of applications.
From steel bars and stainless steel medical equipment to steel beam products, steel has shaped the world we live in today.
History of Steelmaking
History tells us that early mankind has discovered how to fashion steel from rocks and was able to produce steel of various types. From Rome to India and China, and with varying applications, steel and steelmaking have slowly shaped the way we live in this world.
Many years later, towards the modern era, early European steelmakers started smelting iron ore into pig iron via a blast furnace. They had done this using fire and charcoal as a source of heat.
Modern Steel Process
With the developments in the steel manufacturing process, the production of steel has become relatively cheaper. Furthermore, the energy spent in production and carbon dioxide emissions is significantly lower than what was recorded five decades ago.
Manufacturing steel starts from the blasting of iron-ore rich rock. Once collected, the rock is ground and the ore is harvested using strong magnets. The collected iron-ore grains are formed into marble-sized pellets.
Blast Furnace Method
Next is the forming and cleaning of impurities from coal to create a purer form of carbon called coke. This mixture—iron ore and coal—is then put in a blast furnace and heated to form molten iron (sometimes called pig iron, a raw type of iron) from which steel is manufactured.
During this process, the client may request for a specification on their order. Based on their needs, certain minerals or compounds may be added to meet their demand.
Electronic Arc Furnaces (EAF)
If an alloy is to be added, EAF processes are used. The beauty of EAF is that it only uses scrap steel from recycled products. What happens is that scrap metal is put into an EAF. Then the lid is sealed shut. The lid contains electrodes, which are charged with a strong electric current to generate heat, and this is lowered into the furnace. The process melts the scrap metal.
To achieve a specific steel composition, other minerals and elements are added. Then oxygen is also introduced into the mix to purify the steel. To remove further impurities, lime and fluorspar are added, which the impurities adhere to and form slag. This stays on top of the liquid steel, which is discarded.
The most common EAF steel product is stainless steel. To achieve this, chromium and nickel are added to give it the ability to resist corrosion. Steel products from EAF manufacturing are widely used in engineering, armour-plating and aerospace technology.
From bridges to railroads, subways, factories, oil pipelines, medical tools, automobiles, ships, skyscrapers, knives, and military vehicles, you can find steel almost everywhere. Steel is used in so many things that people tend to take it for granted. With a combination of nature’s gift and science, we have shaped steel to serve our varied needs.