W-beam steel, whether standard or light, due to its relatively high and narrow cross-sectional dimensions, has significantly different moments of inertia for its two principal axes. Therefore, it can only be directly used in components that bend within the web plane or in components that form truss-like load-bearing structures. It is not suitable for components under axial compression or those with bending perpendicular to the web plane, which greatly limits its application range. W-beams are widely used in construction and other metal structures.

Common I-beams and light I-beams have a relatively high and narrow cross-sectional size, which results in a significant difference in the moment of inertia of the two main axes of the cross-section, limiting their application range greatly. The selection of I-beams should be based on the requirements of the design drawings.

In structural design, the selection of I-beams should be based on their mechanical properties, chemical properties, weldability, and structural dimensions to choose a suitable I-beam for use.