Steel plays a pivotal role for all crucial manufacturing sectors. India witnessed a tremendous growth in steel production and is the second largest producer in the world. Steel is a popular construction material that offers durability and flexibility along with cost effectiveness.
Products like steel coils finds wide usage in most manufacturing processes . It is an iron alloy that contains 0.2-2% carbon by weight. There are other elements like manganese, silicon, chromium, nickel, phosphorus, oxygen, boron, cobalt added to get required properties. In this article we will talk about how is steel produced and explain the steps involved in the making of steel from iron ore.
Archeologists have discovered evidence of earliest steelmaking 4,000 years ago in Turkey. Crucible steels were made consistently as early as the 4th century BC.
What is the steel manufacturing process?
For any process to run optimally, it’s imperative to source quality raw material first. For successful steel production therefore, it’s vital to procure the right raw materials for it.
The process of producing steel begins by melting the primary raw material of steel – iron ore in a furnace. Once the metal has melted, the impurities are removed from the molten matter, followed by addition of carbon and other alloys to make steel. While steel manufacturing methods have evolved drastically since its beginning in the mid-19th century, modern production is still based on the Bessemer process which uses oxygen to lower the carbon content in iron.
Currently, steel production makes use of recycled materials and traditional raw materials like iron ore, coal, and limestone. The production of steel is mainly done through these two processes:
- Basic oxygen steelmaking (BOS) and
- Electric arc furnaces (EAF)
What are the steps in the steel making process?
Listed below are the six steps that are involved in the production of steel.
Step 1 – The iron making process
The manufacturing process of steel begins by combining iron ore, lime, and coke into a blast furnace and melting it to form a mass of molten iron. Molten iron contains around 4% impurities, mainly carbon and that is responsible to turn the metal brittle and it needs to be removed.
Step 2 – Primary steelmaking
As mentioned above, there are two main processes to make steel – Oxygen Steel making (BOS) and Electric Ark Furnaces (EAF). In the BOS method, scraps of recycled steel are added to the molten iron while it is in the furnace. Then, using the Bessemer process, oxygen is forced through the liquid to cut the impurities in the molten metal substantially.
On the other hand, with the EAF method, recycled steel is introduced into an electrical ark furnace along with the molten iron and heated at 1650 degrees celsius. This process converts the mass into high-grade steel.
Step 3 – Secondary steel making
Once the primary steel making process is completed, the newly formed molten steel is readied to convert it to the perfect steel composition. This is done either through temperature manipulation or removal of certain elements. The processes for this include degassing, stirring, ladle injection, or argon bubbling.
Step 4 – Casting
In the casting process, the hot steel is poured into cooled moulds. This causes the metal to cool quickly. Once the steel is cooled, it is then cut into required lengths as per application. Some of the shapes include blooms for sections such as beams, slabs used in plates, and billets for longer products such as pipes.
Step 5 – First forming
Also called the primary forming process, here the initial shapes of slabs, blooms and billets are moulded into different shapes through hot rolling. The hot rolled products are then divided into flat products, long products, seamless tubes etc. for the last stage of processing.
Step 6 – The fabrication and finishing process
As the last step, through various secondary forming techniques including shaping, machining, jointing, and coating, the steel products are given their final shapes and properties.
Challenges in manufacturing process of steel
These are the main steps in the steel manufacturing process. In recent times, there has been lot of efforts from steel companies in India to produce alternate and more sustainable methods that minimise the damage to the environment, as steel production is majorly carbon based. Pulverized Coal Injection is an example where instead of coke, coal of low carbon content is directly injected into the furnace. Another alternate steelmaking process called HIsarna ironmaking is also gaining popularity where the iron ore is processed immediately into hot metal.
Some of the major challenges in the manufacturing of steel include:
- Price volatility of raw materials
- Harsh environment and accidents
- Solid waste management and pollutant emissions
- Shortage of metallurgical coal
- Inferior quality of products
- Power shortage in manufacturing plants
Safety measures in the production of steel
The iron and steel industry is hazardous by nature and every stakeholder needs to follow utmost safety in the working environment to prevent accidents. Some of the important safety measures that needs to followed include:
- Ensure the work is done by qualified personnel
- Have adequate personal protective equipment
- Follow correct storage of steel elements
- Have safe disposal of manufacturing waste
- Identify potential process safety hazards
Properties of steel
- Yield strength
- Tensile strength
Closing thoughts: Steel market in India
The growth of the steel industry in India is promising and the country is currently the world’s second-largest producer of crude steel, with an output of 10.14 million tonnes (MT). India manufactures all four main types of steel namely carbon steels, alloy steels, stainless steels, tool steels with Odisha, Jharkhand and Chhattisgarh being the largest steelmaking states in the country.
The use of steel will continue to grow. Steelmaking will always be a crucial process in the industrialised world – be it for large scale infrastructure or small kitchen utensils. The construction industry finds wide use for steel TMT bars and corrugated steel roofings due to its durability and cost-effectiveness.
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