First, let's start with their basic concepts. Cold rolling is a process of rolling metal at room temperature, while hot rolling is a process of heating the metal to a certain temperature before rolling it. This temperature difference can make some noticeable differences.

1. Internal structure: Hot-rolled steel plates are rolled at high temperatures, so their crystal structure will be more uniform and the grain size will be larger. In comparison, cold-rolled steel sheets have smaller grain sizes and a tighter structure.
2. Mechanical properties: Due to the different internal structures of hot-rolled steel plates and cold-rolled steel plates, their mechanical properties are also different. Hot-rolled steel plates have lower strength and hardness, while cold-rolled steel plates have higher strength and hardness. This is because the grain size of cold-rolled steel sheets is smaller and the structure is tighter.
3. Surface quality: Hot-rolled steel plates usually have a rougher surface because the metal is more likely to deform and flow when rolled at high temperatures. In comparison, the surface quality of cold-rolled steel plates is better and smoother.
4. Processing performance: Hot-rolled steel plates are easier to deform and flow during processing, so they are suitable for processing processes that require large deformation, such as bending, forming, etc. Due to its high strength and hardness, cold-rolled steel plates are more suitable for occasions that require precise processing, such as cutting, drilling, etc.
5. Production cost: The production cost of a hot-rolled steel plate is usually lower because less energy is required in its production process. The production cost of cold-rolled steel plates is higher because they need to be rolled at room temperature, which consumes a lot of energy.

In general, cold-rolled steel plates and hot-rolled steel plates have their strengths in the field of metal processing. Hot-rolled steel plates are suitable for processing processes that require larger deformations, while cold-rolled steel plates are suitable for occasions that require precise processing. In addition, they also differ in aspects such as production cost, mechanical properties, and surface quality. When choosing between cold-rolled steel plates or hot-rolled steel plates, you need to consider the specific needs and uses.