Hard Cold Rolled Coil, also known as Full Hard Cold Rolled Coil, is a high-strength steel product made by continuously cold rolling Hot Rolled Pickled Coil (HRPC) at room temperature without annealing.
It provides excellent dimensional precision, smooth surface quality, and superior flatness, making it a vital material in automotive, construction, appliance, and coating industries.
For product details and technical parameters, visit:
👉 Hard Cold Rolled Coil | Zhongtang Metal
📐 1. Size Range and Dimensional Parameters
The dimensional specifications of Hard Cold Rolled Coil are determined by thickness, width, and inner diameter, according to national and international standards such as Q/BQB 401–94, ASTM A1008, EN 10130, and JIS G3141.
🔹 Thickness Range
Hard Cold Rolled Coils are available in a wide range of thicknesses, typically from 0.18 mm to 2.5 mm, depending on application requirements.
-
For thickness 0.30–0.80 mm:
The allowable thickness deviation follows Q/BQB 401–94 PT.B (Advanced Precision) standard. -
For thickness 0.18–0.30 mm:
The allowable thickness deviation is ±10% of the nominal thickness.
These tight tolerances ensure uniform thickness and stable forming performance during stamping, drawing, and coating processes.
🔹 Width Range
The standard width for cold-rolled hard coils typically ranges from 600 mm to 1500 mm, depending on rolling mill capacity and customer requirements.
Custom widths up to 1850 mm can be supplied for special industrial applications.
🔹 Inner Diameter (ID)
The standard inner diameters are:
-
508 mm (20 inches) — international standard
-
420 mm — customized for specific coil handling systems
These inner diameters are compatible with common decoiling and slitting machines, ensuring seamless processing.
🔹 Coil Weight
The typical coil weight is not more than 15.1 tons,
and can be supplied by actual weight or theoretical weight depending on customer requirements.
Heavier coils can be produced on request, subject to handling equipment limitations.
⚙️ 2. Dimensional Accuracy and Surface Quality
Hard Cold Rolled Coils are produced under strict rolling control, resulting in:
-
High dimensional accuracy (tighter gauge tolerance than hot-rolled steel)
-
Excellent flatness with minimal waviness
-
High surface smoothness and brightness
-
Clean, scale-free surface ideal for painting, coating, and plating
Cold rolling produces a clean and bright steel surface with a mirror-like finish, free from oxidation and scaling, making it ideal for visible or decorative applications.
🧮 3. Mechanical and Processing Properties
| Property | Typical Range / Description |
|---|---|
| Thickness | 0.18 – 2.5 mm |
| Width | 600 – 1500 mm |
| Inner Diameter | 420 mm / 508 mm |
| Coil Weight | ≤15.1 tons |
| Hardness (HV) | 180 – 240 |
| Tensile Strength (MPa) | 350 – 600 |
| Yield Ratio | High (Full Hard) |
| Surface Finish | Bright / Matte |
| Precision Grade | Q/BQB 401–94 PT.B |
Because the material is not annealed, it retains high internal stress and hardness.
This gives the coil excellent stiffness, formability under high pressure, and precision cutting characteristics.
🧰 4. Typical Applications
Due to its superior flatness and hardness, Hard Cold Rolled Coil is widely used in:
-
Automotive components (chassis, reinforcement panels, seat frames)
-
Home appliance casings (refrigerators, washing machines, air conditioners)
-
Construction materials (roof panels, doors, light structures)
-
Metal furniture and cabinets
-
Pipe manufacturing and galvanized substrate production
-
Umbrella ribs and stationery items (using 0.2–0.5 mm thin hard coils)
It also serves as the base material for galvanizing and tin-plating, forming galvanized steel coils and tinplate products.
📘 5. Applicable Standards and References
Hard Cold Rolled Coil is manufactured in compliance with several international and national standards to ensure consistency, safety, and quality performance:
| Country | Standard | Description |
|---|---|---|
| China | Q/BQB 401–94 | Precision tolerance for cold-rolled coil (advanced grade) |
| China | GB/T 708–1988 | Dimensions, shape, and tolerances for cold-rolled sheet |
| USA | ASTM A1008/A1008M–21 | Specification for cold-rolled carbon steel sheets |
| UK / EU | BS EN 10130:2006 | Cold-rolled low-carbon steel for cold forming |
| Japan | JIS G3141:2017 | Cold-reduced carbon steel sheet and strip |
These standards define thickness deviation, mechanical properties, surface finish, and dimensional tolerance, ensuring Hard Cold Rolled Coils meet global application requirements.
🏁 6. Summary
Hard Cold Rolled Coil provides high precision, flatness, and surface brightness with strict dimensional tolerances.
Its standard inner diameters (420 mm / 508 mm) and coil weight (≤15.1 tons) make it suitable for automated production lines.
The material’s mechanical stability, hardness, and excellent surface finish ensure outstanding performance in high-end industrial applications.
👉 Learn more about product dimensions and technical specifications here:
Zhongtang Metal – Hard Cold Rolled Coil
