What Is Hot Rolled Coil Used For?

Hot-rolled coils are suitable for applications that don’t require a perfect surface and accurate dimensions. But they have some excellent properties, such as high strength, high toughness, good weldability. So hot rolled products are widely used in construction, car structures, machinery, boiler, pressure vessel, steel pipes, and other manufacturing industries, including:

Construction: architectural structures, frameworks, bridges, fences, partitions, railroad tracks, I-beams, etc.

Pipelines for transportation of oil, gas, water, heat supply networks, and sewerage lines;

Machinery, bodies and components machinery, cars and trucks, tanks, cranes, etc.

Advantages of Hot Roll Steel

1. Price: hot rolled coil is cheaper than cold rolled coils;

2. Increased ductility and toughness;

3. Good flexibility. It is easy to work with for different uses. For example, it can be formed into different shapes, such as curved, arched, large sheets, etc.

4. But its surface has a scaly finish, which forms at high temperatures.

What Is Hot Rolled Coil?

Hot rolled steel is roll-pressed at very high temperatures, which is above the re-crystallization temperature of steel. Below let’s review its manufacturing process.

1. Feeding the steel slab into the reheating furnace;
   2. Using hydraulic descaler to remove scale on the surface;
   3. Feeding into the roughing mill and cutting the ends;
   4. Going through the finishing mill to adjust the thickness and width of a coil and to produce a smooth surface;
   5. Cool down and roll up into coils.

Hot Rolled Coil VS Cold Rolled Coil

Rolling is an important metalworking process that improves the strength of steel. The main metal rolling procedure is to give the steel the required thickness and shape. Wanzhi Steel has both hot rolling and cold rolling production lines. Below are some differences for your reference.

1. Different production processes

• Hot-rolled steel: After the billet is heated, it is rough-rolled and fine-rolled into a finished product. It has high production efficiency and large output, and is suitable for large-scale production, but the dimensional accuracy is low.
• Cold-rolled steel: It includes pickling, cold rolling, annealing, leveling and other processes. The production process is long and the cost is high, but the product has high precision and good surface quality, and can produce thin-gauge products.

2. Different Processing Temperatures

• Hot-rolled steel is a mill process that involves rolling the steel at a very high temperature, over 1,700˚F. This temperature is higher than the recrystallization temperature of most steels.
• Cold-rolled steel is processed at room temperature below the recrystallization temperature of the metal. Without heating, the hardness of the metal increases, the deformation resistance increases, and the rolling pressure also increases accordingly.

3. Different Surface

• Hot rolled steel coil has a scaled surface, which is formed at hot temperature.
• In contrast, cold-rolled coils have closer tolerances and a smoother surface. So cold rolled steel is better for applications that require precise sizes or aesthetic appearance.

4. Different application ranges

• Hot-rolled steel: During processing, the metal undergoes complete recrystallization, which can refine the grains, improve the structure, and enhance the mechanical properties. It is often used for structural parts with high mechanical properties requirements.For example, manufacturing automotive beams, bridges and other structural parts, as well as hot-rolled steel plates and steel strips.
• Cold-rolled steel: Due to work hardening, the metal strength and hardness increase, while the toughness and plasticity decrease. The performance can be adjusted through annealing treatment. It is mostly used for thin plates that require high strength and high precision.For example, automotive body panels, electrical housings, precision instrument parts, etc.

5. Different Characteristics

Due to the increased carbon content, cold rolled steel coil is harder and stronger than the HR coil. It has better resistance to tension breaking and deformation.

6. Different Production Costs

Due to its simpler processing method, the cost of the hot-rolled coil is lower than cold rolled steel. The reason is that cold rolled steel making requires additional processing and more time.