The economic development of a country is determined by its steel production and consumption. The growing Indian steel sector is driven by the domestic availability of iron ore and cost-effective labour. This sector has been a major contributor to India’s manufacturing output. India’s finished steel consumption is anticipated to increase to 230 MT by 2030-31 from 133.596 MT in FY22 (Source: IBEF).
Metal rolling is a process to change the shape of metals with the use of a series of rollers to improve its uniformity as well as its mechanical properties. There are two types of rolled steel – hot rolled steel and cold rolled steel with each having distinct characteristics to make them suitable for different applications.
In this article we talk about what is hot rolled steel coils, differences between hot and cold rolled steel coil, and the benefits of hot rolled steel coils.
What is hot rolled steel coil?
Hot rolled steel refers to steel that has been roll-pressed at very high temperatures, usually above 1700° F which is above the re-crystallisation temperature for most steels. This makes the steel easier to form thus helping in products that are easier to work with as it exhibits greater formability and workability.
The hot rolling process involves heating and compressing a large, rectangular slab of metal called billet. It is then made to pass through a series of rotating rulers to achieve the desired dimensions. Finally, the rolled steel is wound into coiled rolls and left to cool.
It may be noted that steel shrinks slightly as it cools. As the rolled steel is cooled after processing, there is less control over its final shape. This makes hot rolled steel coil less suitable for precision applications and is often used where specific dimensions aren’t crucial. The hot rolled steel coil finds application mostly in railroad tracks and construction projects.
Hot rolled steel is identified by the following characteristics:
- A scaled surface due to cooling from extreme temperatures
- Rounded edges and corners due to shrinkage
- Minor distortions as opposed to perfectly squared angles
What are the main differences between hot and cold rolled steel coil?
We have defined how rolled steel coil in the previous section. Let us understand what cold-rolled steel is to understand the difference between the two.
Cold rolled steel coil is a low-carbon hot-rolled steel that has been rolled at room temperature, below its recrystallization temperature. Thus, this steel has a better-quality surface finish, precise tolerances, and straightness than hot rolled. Given below are the three main differences between hot and cold rolled steel coils.
- Hot rolled stainless steel has imperfect edges with distortions unlike cold rolled steel
- Hot rolled steel coils are less time-consuming and cheaper than cold-rolled stainless steel
- Cold rolled stainless steel is stronger than hot rolled stainless steel
What are the common hot-rolled steel grades?
Hot-rolled steel is available in many grades or standards set. Some of the most used hot rolled steel grades are:
- A36: One of the most popular hot-rolled steel grades, this grade is weldable and machine washable along with excellent mechanical properties.
- C1010 and C1018: These hot-rolled steel coils are more formable, machinable, and weldable than alloy and high-carbon steels. The main difference between the two lies in its carbon content.
- A1011: Widely used in automobile bodies, this grade of steel is mostly used in metal fabrication and making of structural applications.
- C1026: This AISI-designated steel has highly similar mechanical and chemical properties to A36 and a lower carbon content. It is widely used in furniture, automotive components, and structures.
It may be mentioned that one of the most versatile stainless steel is 304 hot rolled steel coil that is widely used in the production of equipment. Noted for properties like corrosion resistance and mouldability it is most used for food production equipment, general chemical equipment, nuclear energy, etc.
Uses of hot rolled steel coils:
- Agricultural equipment
- Automobile parts
- Construction materials
- Railroad equipment
What are the benefits of hot rolled steel?
Hot rolled steel coils is heated to high temperature to make the steel malleable. It offers several manufacturing advantages. Some of the benefits of hot rolled steel are described below:
- Cost: Hot rolled steel tends to be less expensive than cold rolled steel as less processing is involved. The hot rolled steel coil price in India is between ₹61 – ₹74 per kg approximately.
- Ease of working: The processed material of hot rolled steel coil is easy to form and shape.
- Minimal internal stress: The hot rolling process is cooled gradually, allowing the material to normalise its structure, and become free of internal stresses.
- Time: Because of its ease of manipulation hot rolled steel can be converted into products faster.
While there are several benefits of hot rolled steel coils, there are a few drawbacks too. This type of steel is weaker than cold rolled steel as the high temperature weakens the metal before it cools back down. Hot rolled steel is also rougher to the touch.
Also Read on:
Aluminium Coil, Hot rolled steel coil, Colour coated steel coil, Stainless steel coil.
To sum up: How to procure hot rolled steel coil for your business?
To conclude, hot rolled steel coil has better mechanical properties than cold rolling. While it lacks the surface finish and dimensional uniformity of cold rolled steel, it has improved tensile strength, yield strength, ductility, and toughness.
If you’re looking at sourcing hot rolled steel coils, you can reach out to service providers like nexProcure who will help you resolve the challenges involved in procurement and help you to obtain raw materials at competitive prices.