Is C-shaped steel a type of thin-walled steel

Yes, C-shaped steel is a type of thin-walled steel, and more specifically, it is a type of cold-formed thin-walled steel.

According to public information, C-shaped steel is a lightweight steel material processed into a C-shaped cross-section through cold bending technology, using hot-rolled or cold-rolled strip steel. One of its core characteristics is its relatively thin wall thickness, which meets the definition of thin-walled steel.

1. Typical characteristics of thin-walled steel
Thin-walled steel is like the "light cavalry" in the construction industry, focusing on lightweight and efficient load-bearing capabilities. This type of steel typically has a wall thickness of no more than 6 millimeters and is produced through cold bending processes, featuring light weight and diverse cross-sectional shapes. Common examples such as Z-shaped purlins and square tubes belong to this family, which excels in handling low to medium load scenarios that require reduced self-weight.
II. The True Identity of C-Beam

C-shaped steel is indeed an important member of the thin-walled steel family. Its iconic C-shaped cross-section is not designed by chance. This structure can significantly reduce material usage while ensuring support strength. In modern architecture, C-shaped steel with a thickness of 2-4 millimeters is most common, perfectly fitting the core characteristics of thin-walled steel. Especially when building steel structure interlayers, its unit weight load-bearing capacity is about 40% higher than traditional steel.

The following are the key evidences supporting this conclusion:
Clear definition: Cold-formed thin-walled steel refers to finished steel products with various cross-sectional shapes that are bent in a cold state using steel plates or strips. Its types explicitly include C-shaped steel, U-shaped steel, Z-shaped steel, etc. As one of the most common types, C-shaped steel is widely used in fields such as building purlins and wall beams.
Thickness standard: According to the Technical Code for Cold-Formed Thin-Wall Steel Structures (GB50018), the thickness of thin-walled steel is usually not more than 6mm. In the specifications of C-shaped steel (such as C220×75×20×2.0), the plate thickness (t) is generally between 0.5mm and 6mm, such as the common thicknesses of 1.5mm, 2.0mm, 2.5mm, etc., which fully meets the thickness range of thin-walled steel.
Process and characteristics: C-shaped steel adopts cold-formed bending process. Compared to hot-rolled steel, it is characterized by thin walls, light self-weight, and excellent sectional performance. With the same sectional area, it can save 30%-50% of steel, which is the typical advantage of thin-walled steel in pursuing lightweight and efficient material utilization.
Industry application: In the construction field, C-shaped steel is commonly used as "light steel joist" for partitions and ceilings. Its dedicated specification typically has a waist thickness of 0.6-1.2mm, further confirming its thin-walled property.
Therefore, whether viewed from the perspective of production process, thickness standards, or industry classification, C-shaped steel falls under the category of typical cold-formed thin-walled steel.