GB standard angle steel, governed by GB/T 706-2016, includes both equal and unequal angle sections. Equal-angle steel (denoted by "L") has symmetric legs, with sizes ranging from 20 mm × 20 mm × 3 mm to 200 mm × 200 mm × 24 mm. For example, the L50×50×5 (50 mm legs, 5 mm thickness) is ideal for light-duty framing in residential projects, while the L200×200×24 is used in heavy industrial structures.
Unequal-angle steel (denoted by "L") features legs of different lengths, such as 25 mm × 16 mm × 3 mm to 200 mm × 125 mm × 18 mm. An example is the L100×63×8 (100 mm × 63 mm legs, 8 mm thickness), suitable for asymmetric load-bearing in mechanical supports. These dimensions align with China's construction standards, enabling compatibility with GB/T 1591 low-alloy high-strength steels for enhanced load capacity.