I-beam steel (I-shaped with tapering flanges) follows regional dimensional standards:
China (GB/T 706):
Ordinary I-beams: Ranged from No. 10 (100×68×4.5mm) to No. 63 (630×176×12.5mm), with Q235/Q355 grades.
Light I-beams: Reduced flange width, e.g., No. 10 (100×64×4.2mm), suitable for light loads.
United States (ASTM A6):
W-shapes (wide flange): W12×50 (12in height, 50lbs/ft weight), A992 grade (yield ≥345 MPa).
S-shapes (standard I-beams): S10×35 (10in×35lbs/ft), A36 grade.
Europe (EN 10279):
IPE (light I-beams): IPE120 (120×64×3.5mm), S235 grade.
IPB (heavy I-beams): IPB250 (250×125×6mm), S355 grade.
Japan (JIS G3192):
SHI (standard I-beams): SHI200 (200×100×7×11mm), SS400 grade for seismic zones.
Key difference: Chinese I-beams feature tapering flanges (1:6 slope) for cost efficiency, while US W-shapes have parallel flanges for heavy loads.