Cold rolled steel plate, also commonly known as "cold-rolled steel plates" or "box sheets," are single-sheet steel products made from hot-rolled steel coils. These coils are rolled, annealed, and leveled at room temperature, followed by slitting and shearing. They utilize the same production process as cold-rolled coils, differing only in their final product form.

The production process is essentially the same as for cold rolled steel plate, with the core flow as follows: Hot-rolled coil → Pickling (removing iron oxide scale) → Cold rolling → Annealing → Leveling → Finishing (slitting and shearing) → Finished product (cold-rolled flat sheet)

Among these, "annealing" is the key process. It eliminates the "work hardening" caused by cold rolling, softening the steel sheet and making it easier to stamp.

In terms of strength, hardness, elasticity, and hardenability, cold rolled steel plate is higher than 65# steel. It exhibits superheat sensitivity and a tendency for temper brittleness, while water quenching easily leads to cracking. Annealing processability is still available, but cold deformation plasticity is low, and weldability is poor. It is mainly used in the production of highly wear-resistant parts.

Core Performance and Advantages:
Excellent Surface Quality: Due to room temperature rolling, no iron oxide scale forms on the surface, resulting in a high degree of smoothness.
High Dimensional Accuracy: Tolerances for dimensions such as thickness and width are very precisely controlled.
Good Mechanical Properties: After annealing, its strength, plasticity, and toughness are superior to hot-rolled thin steel sheets.
Excellent Machining Performance: Particularly suitable for stamping and cold bending, making it an ideal material for manufacturing automotive and appliance housings.

Difference from "Cold-Rolled Coil": Both are essentially the same; the core difference lies only in the final delivery form:
Cold-rolled coil (coil): Delivered in long coils.

Cold rolled steel plate: These are produced by leveling and shearing cold-rolled coils into individual sheets before delivery.

Cold rolled steel plate are an important form of cold-rolled sheet/coil product. With their excellent surface quality, high dimensional accuracy, and outstanding processing performance, they have become a core basic material in modern manufacturing, especially in the automotive and home appliance industries. Their production, specifications, and performance are all governed by strict national standards (GB/T 708).

Cold Rolled Steel Plate is a common metal product, and its national standards can vary from country to country. The following are some representative Chinese, British, American and Japanese national standards for cold rolled steel plate:

Chinese standard: 

My country's national standard for cold-rolled steel sheets is GB/T 708-2019, which specifies the classification, size, shape, allowable deviation, and technical requirements of cold-rolled steel sheets and strips.

British Standard: 

BS EN 10130:2006. This standard specifies the technical delivery conditions for cold-rolled mild steel flat products intended for cold forming.

American Standard: 

ASTM A1008/A1008M-21. This standard specifies the standard specifications for cold-rolled carbon structural steel plates.

Japanese standard: 

JIS G 3141:2017. This standard specifies the technical delivery conditions for cold-rolled carbon steel sheets and strips.

These standards specify requirements such as chemical composition, mechanical properties, dimensions and allowable deviations of cold rolled steel plate to ensure their quality and performance in specific applications.

The surface quality of the cold rolled steel plate is good and the finish is high. The cold-rolled products have high dimensional accuracy, and the performance and structure of the products can meet some special requirements. The specifications, dimensions and allowable errors of cold rolled steel plate may vary according to different national standards, steel mills and customer requirements. Generally speaking, the specifications and size ranges of cold rolled steel plate are as follows:

Thickness: usually between 0.5mm and 3mm. In some special applications, thinner or thicker gauges may be available.
Width: Generally between 600mm and 2000mm, there are also other special width specifications. Some special applications may require wider or narrower dimensions.
Length: Generally between 2000mm and 6000mm.

Allowable errors depend on specific specifications and national standards. Generally speaking, the allowable error is usually in units of ± a few millimeters or ± percentage, and the specific value will vary according to the size of the specification and the strictness of the requirements.