Introduction
Cold rolled steel strip is a critical material in various industries such as automotive, construction, électronique, appliances, and hand tools. Its superior surface finish, precise dimensions, and consistent mechanical properties make it ideal for demanding applications. But how is cold rolled steel strip produced from raw hot rolled coils?
In this article, we will walk you through the complete manufacturing process of cold rolled steel strip—from raw material to the finished precision strip—highlighting key technologies such as acid pickling, laminage à froid, coil slitting, et continuous annealing.
1. Raw Material: Hot Rolled Steel Coil
The journey begins with high-quality hot rolled steel coils, which serve as the base material for further processing. To ensure consistency and mechanical integrity, manufacturers like Jiaxiao MTC source coils from ISO-certified steel mills, ensuring strict compliance with international standards.
2. Acid Pickling: Cleaning the Surface
Hot rolled coils typically have a thick layer of mill scale or oxide on the surface, which can impair downstream processing. The acid pickling process removes these surface contaminants through chemical reactions in acid baths, resulting in a clean, reactive surface. This step is crucial to ensure strong adhesion and surface uniformity in the cold rolling phase.
Tip: Keywords like “acid pickling line for steel coils” or “pickled and oiled steel” are commonly searched by engineers evaluating steel preparation methods.
3. Cold Rolling: Reducing Thickness and Enhancing Precision
Once pickled, the steel enters the cold rolling mill, where it is passed between rollers to reduce the thickness to the required level. Unlike hot rolling, this process occurs at room temperature, which increases dimensional accuracy and surface smoothness.
At Jiaxiao MTC, we use 4-high reversing mills to achieve ultra-thin gauges (as low as 0.08 mm) with tight tolerances in thickness, width, and flatness. Cold rolling also improves the material’s mechanical strength through strain hardening.
4. Slitting: Tailoring to Custom Widths
After cold rolling, the steel coils are too wide for many applications. Therefore, they are slit into narrow strips using precision rotary knives in a process called coil slitting. This step ensures the steel strips meet specific width requirements for various industries like band saw blade manufacturing or automotive springs.
Popular search term: “steel coil slitting service” or “narrow width steel strip supplier”.
5. Continuous Annealing: Restoring Ductility
Cold rolling increases strength but also makes the steel hard and brittle. To regain ductility, the strips undergo continuous annealing—a heat treatment process where the material is heated to specific temperatures and then cooled under controlled conditions.
Depending on the application, two annealing methods are commonly used:
- Bright Annealing – Achieves a clean, polished surface without decarburization.
- Spheroidizing Annealing – Enhances cold formability, ideal for springs, clips, and stamping parts.
6. Surface Finishing and Edge Processing
After heat treatment, steel strips can be polished, deburred, or edge-rounded to meet end-use safety and aesthetic requirements. Jiaxiao MTC offers multiple edge types (slit, square, rounded) and surface finishes (bright, polished, colored).
7. Quality Inspection and Packaging
Every strip coil undergoes strict dimensional, hardness, and surface inspections, ensuring conformity with customer specifications. Finally, strips are lightly oiled, wrapped in rust-proof film, and packed in seaworthy containers for global export.
Conclusion
The production of cold rolled steel strip is a sophisticated, multi-step process requiring advanced equipment, metallurgical expertise, and quality assurance. Understanding this workflow—from hot rolled coil to cold rolled, annealed, and slit strip—helps engineers and buyers make informed decisions when selecting suppliers or optimizing designs.
At Jiaxiao MTC, with over 20 years of experience and a capacity of 15,000 tons/year, we specialize in delivering custom steel strip solutions tailored to your industry’s exacting needs.
Want to learn more about cold rolled strip steel or request a quote?
Contact us or explore our product catalog for detailed specifications.
