1. Production process

- Hot-rolled steel plate:

Rolling is performed above the recrystallization temperature of the metal (usually >900°C). The material is in a high temperature softening state and can be easily processed into different shapes.

The steel billet is directly rolled continuously without intermediate annealing.

- Cold-rolled steel plate:

The hot-rolled steel plate is further rolled at room temperature (usually below the recrystallization temperature).

The oxide layer needs to be removed by pickling, and annealing may be required after rolling to restore plasticity.

2. Appearance and surface quality

- Hot-rolled steel plate:

The surface of the hot-rolled steel plate may have an oxide layer. Because metal is easily oxidized at high temperature, the surface is relatively rough, with iron oxide scale (needs pickling), and the edge may be curved (needs trimming).

- Cold-rolled steel plate:

Cold rolling is at room temperature, the surface should be smoother, the size is more accurate, there is no oxide layer, the size is accurate, the edge is neat, and it can be directly used for spraying or electroplating. However, cold rolling may require annealing to restore plasticity, otherwise the material may be too hard and brittle.

3. Application fields

- Hot-rolled steel plates are relatively thick and can be used in areas with low surface requirements such as building structures (steel beams, bridges), pipelines, truck frames, etc.

- Cold-rolled steel plates are thinner and have good surface quality. They can be used for car bodies, home appliance shells (such as refrigerators, washing machines), precision instruments, and other parts that require high surface quality or complex forming.

4. Mechanical properties

- The steel plate after hot rolling has low strength and good ductility, which is suitable for stamping.

- Cold rolling has high strength and hardness (due to work hardening), but the brittleness increases, and annealing is required to improve plasticity. However, if annealing is performed after cold rolling, the performance can be adjusted.

If you need a material with good formability, you may choose hot rolling, and if you need high strength, you may choose cold rolling.

5. Production cost

- Hot rolling may require fewer steps because it does not require annealing, the process is simple, the energy consumption is low, and the cost is low.

- Cold rolling has a complex process (pickling, annealing, etc.), the cost is high, but the added value is higher

6. The difference between dimensional accuracy and thickness range.

- Hot-rolled steel plates are thicker (usually >1.2mm), common in thick plates (such as more than 3mm), and have larger tolerances.

- Cold-rolled steel plates are thinner (can be as low as 0.1mm or less), have high dimensional accuracy, and are suitable for precision machining.

7.In terms of surface treatment

Hot-rolled steel plates may need pickling to remove the oxide layer, while cold-rolled steel plates can be used directly or electroplated. This may also affect the application selection. For example, automotive panels require a good surface, so cold rolling is used.