CARBON CONTENT

Generally speaking, there are several types of carbon steel plates: Different types depend on the carbon content, manufacturing method, thickness and application.

According to the carbon content, there are generally low-carbon steel plates, medium-carbon steel plates, high-carbon steel plates and ultra-high-carbon steel plates.

Low carbon: Carbon content 0.06% to 0.25%. Also known as low-carbon board.

Medium carbon: Carbon content 0.25% - 0.6%.

High carbon: Carbon content 0.6% - 0.95%.

Ultra-high carbon: Carbon content 0.96% to 2.1%.

It should be noted that as the carbon content increases, the hardness of steel increases, but the final plasticity decreases.

Carbon plates can be classified into thin, medium, thick and extra-thick types according to thickness.

TABLE OF COMMON STRUCTURAL STEEL PLATE GRADES

TABLE OF HIGH-QUALITY STRUCTURAL PLATE GRADES

The uses of hot-rolled coil

Hot-rolled coil is suitable for applications that do not require a perfect surface and precise dimensions. But they have some excellent properties, such as high strength, high toughness and good weldability. Therefore, hot-rolled products are widely used in manufacturing industries such as construction, automotive structures, machinery, boilers, pressure vessels, and steel pipes, including:

Construction: building structures, frames, Bridges, fences, partitions, railway tracks, I-beams, etc.

Pipelines are used for the transportation of oil, natural gas, water, heating networks and sewage pipelines.

Machinery, body and component machinery, automobiles and trucks, tanks, cranes, etc.

The advantages of hot-rolled steel

1. Price: Hot-rolled coil is cheaper than cold-rolled coil.

2. Increase ductility and toughness;

3. Good flexibility. It can be easily used for different purposes. For example, it can be formed into different shapes, such as arcs, arches, large sheets, etc.

4. However, there is a layer of scales on its surface, which is formed at high temperatures.

Hot-rolled steel is rolled at a very high temperature, which is higher than the recrystallization temperature of the steel. Now let's review its production process.

1. Send the billet into the heating furnace;

2. Use a hydraulic scale remover to remove the surface scale.

3. Send it to the roughing mill and cut the end.

4. The thickness and width of the coil are adjusted through the finishing mill to form a smooth surface.

5. After cooling, roll it into a roll.

Hot-rolled coil vs. cold-rolled coil

Rolling is an important metalworking technique for enhancing the strength of steel. The main metal rolling process is to make the steel reach the required thickness and shape. Wanzhi Steel has both hot rolling and cold rolling production lines. The following are some differences for your reference.

The production processes are different

Hot-rolled steel: After heating the raw material, it undergoes rough rolling and fine rolling to become the finished product. It features high production efficiency and large output, making it suitable for large-scale production. However, its dimensional accuracy is relatively low.

Cold-rolled steel: It includes processes such as pickling, cold rolling, annealing, and flattening. The production process is long and the cost is high, but the product precision is high, the surface quality is good, and thin-sized products can be produced.

2. Different processing temperatures

Hot-rolled steel is a rolling process that involves rolling steel at extremely high temperatures exceeding 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. As a result, the hardness of the metal increases, its deformation resistance rises, and the rolling pressure also increases accordingly.

3. Different surfaces

The surface of hot-rolled steel coils has an oxide scale, which is formed at high temperatures.

In contrast, cold-rolled coils have smaller tolerances and smoother surfaces. Therefore, cold-rolled steel is more suitable for applications that require precise dimensions or an attractive appearance.