The main differences between hot rolled and cold rolled steel coil plate are:

1. **Manufacturing Process**:
   - Hot Rolled Steel: The steel is heated to a high temperature (around 1200°C) and then passed through large rolling mills to reduce its thickness and shape it into coils.
   - Cold Rolled Steel: The steel is processed at room temperature or slightly above and passed through a series of smaller rolling mills to further reduce its thickness and improve the surface finish.

2. **Thickness and Dimensional Tolerance**:
   - Hot Rolled Steel: Typically has a greater thickness and wider dimensional tolerances compared to cold rolled steel.
   - Cold Rolled Steel: Undergoes more extensive rolling, hot rolled steel coil plate  resulting in a thinner final product with tighter dimensional tolerances.

3. **Surface Finish**:
   - Hot Rolled Steel: Has a rougher, uneven surface finish due to the high-temperature rolling process.
   - Cold Rolled Steel: Undergoes a more controlled rolling process, resulting in a smoother, more uniform surface finish.

4. **Mechanical Properties**:
   - Hot Rolled Steel: Has higher strength and hardness due to the high-temperature processing, but lower ductility.
   - Cold Rolled Steel: Undergoes work hardening during the cold rolling process, which increases its strength and hardness, but also its ductility.

5. **Applications**:
   - Hot Rolled Steel: Commonly used for structural components, heavy-duty equipment, and applications where strength and durability are the primary requirements.
   - Cold Rolled Steel: Suitable for a wider range of applications, including automotive parts, appliances, and other products where a combination of strength, formability, and surface finish is desirable.

In summary, the main differences between hot rolled and cold rolled steel coil plate are the manufacturing process, resulting in differences in thickness, dimensional tolerance, surface finish, and mechanical properties, leading to different applications for each type of steel.