1. Classification by Material
Steel Coil: The most common type of steel coil, classified by material as carbon structural steel coil (such as Q235), low-alloy high-strength steel coil (such as Q355), stainless steel coil (such as 304 and 316), and alloy structural steel coil. Applications include construction, machinery, and chemical industries.
Aluminum Coil: Made from aluminum alloys (such as 1-series, 3-series, and 5-series), it is lightweight, corrosion-resistant, and has excellent thermal conductivity. It is used in aerospace, automotive parts, and decorative materials.
Copper Coil: This includes red copper coil and brass coil. It offers excellent electrical and thermal conductivity and is used in electrical equipment, precision instruments, and pipelines.
Other Metal Coil: Specialty Coil, such as titanium coil (high-temperature and corrosion-resistant, used in aerospace) and zinc coil (as a substrate for anti-corrosion coatings), is used in high-end applications.
2. Classification by Rolling Process
Process Type Production Process Characteristics Performance Characteristics Applications
Hot-rolled Coil: Steel billets are heated to a high temperature (usually above 1000°C) before rolling. This process provides high rolling forces and allows for the production of thicker sheets. These sheets offer high surface roughness, good toughness, medium strength, and low cost. These sheets are used in building structures (such as steel structures and bridges), machinery manufacturing blanks, and pipelines.
Cold-rolled Coil: Hot-rolled coil is rolled at room temperature, resulting in higher precision and the ability to undergo multiple rolling passes for thinning. These sheets offer high surface finish, high dimensional accuracy (small thickness deviation), and increased strength and hardness (strengthened through cold rolling). These sheets are used in automotive panels, appliance housings, precision machinery parts, and decorative materials.
3. Classification by Surface Condition
Pickled Coil: Hot-rolled coil is pickled to remove surface oxide scale, resulting in a smoother surface suitable for direct welding or subsequent cold rolling.
Galvanized Coil: A zinc layer is applied to the coil surface through hot-dip galvanizing or electroplating, resulting in excellent corrosion resistance. These coils are used in building exteriors, appliance housings, and automotive chassis.
Color-coated coil: A colored coating (such as polyester or fluorocarbon coating) applied to the surface of galvanized or cold-rolled coil. It combines decorative and corrosion-resistant properties and is used in building curtain walls, appliance housings, billboards, and other applications.
Uncoated coil: Bare coil without surface treatment, such as hot-rolled black coil (with oxide scale) and cold-rolled bright coil (smooth, uncoated).