Cold-reduced hard coil is a type of steel coil that has undergone cold rolling. It belongs to the same category as cold-rolled coils, cold-rolled sheets, and cold-rolled strip steel. It is produced through cold rolling of hot-rolled steel coils after pickling to remove oxide scale. Carbon steel, also known as plain carbon steel, has a carbon content ranging from approximately 0.02% to 2%. The primary components of carbon steel cold-reduced hard coil are iron and carbon, where the carbon content determines the hardness and strength of the steel. Variations in carbon content enable different grades and properties of carbon steel cold-reduced hard coils, allowing them to meet diverse industrial requirements.