Cold-rolled hard coil is a type of steel coil processed by cold rolling, falling under the same category as cold coils, cold plates, and cold-rolled strip steel. It is produced through cold rolling of hot-rolled steel coils after pickling to remove the oxide scale. Produced from Q235B carbon steel via the cold-rolling process, it not only enhances strength and hardness but also improves surface finish and dimensional accuracy. Q235B carbon steel cold-rolled hard coil exhibits excellent weldability and processability, making it widely used in the manufacturing of structural components, bridges, ships, vehicles, high-pressure vessels, and building structures.