The production process of hot-rolled coils involves heating continuously cast slabs or rough-rolled slabs in a furnace to approximately 1250°C, bringing them to a red-hot, plastic state. They are then rolled under high pressure in multiple passes on roughing and finishing mills, ultimately coiled into coils.
Its core characteristics are:
1. High production efficiency and relatively low cost.
2. Typically thicker products, commonly ranging from 3.0mm to over 20mm; thicker products require production as medium-thick plates.
3. Due to the high-temperature rolling, a dark blue oxide scale (iron oxide scale) forms on the surface, resulting in a rough surface (rough texture). Dimensional accuracy and shape control are relatively poor, with thickness tolerances typically within ±10 microns.
4. Mechanical properties include lower strength but good plasticity and ductility; the internal structure is equiaxed crystals.

Cold-rolled coils, on the other hand, use hot-rolled pickled coils as raw material. After the oxide scale is removed in the pickling line, the hot-rolled coils are rolled at room temperature.
Its core characteristics are:
1. Extremely high product precision. Wide thickness range, from 0.3 mm to 3.0 mm or even thinner, with thickness tolerance controllable within ±1 micrometers, and a straight sheet shape.
2. Excellent surface quality. Various exquisite surfaces can be obtained through subsequent processing, such as 2B (bright surface after cold rolling followed by heat treatment, pickling, or similar treatment), BA (bright annealed mirror finish), No.3/4 (ground surface), etc.
3. Changes in mechanical properties. Cold work hardening significantly improves the material's strength, hardness, and fatigue resistance, but reduces plasticity. To restore plasticity, eliminate internal stress, and obtain the required mechanical properties, annealing treatment must be performed after cold rolling, followed by temper rolling (finishing) in the final stage.

Time：15/06/2026 17:41:09

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