H-beam steel's performance is defined by its mechanical and physical characteristics:
Mechanical Properties:
Yield Strength: Ranges from 235 MPa (Q235 grade) to 690 MPa (ASTM A514), determining the maximum stress before permanent deformation.
Tensile Strength: Typically 1.2–1.5 times the yield strength, ensuring the material resists fracture.
Elongation: ≥15% for structural grades, indicating ductility and ability to deform without breaking.
Impact Toughness: Measured via Charpy tests, crucial for cold climates (e.g., ASTM A572 Grade 50 with ≥27 J at -20°C).
Physical Properties:
Density: ~7,850 kg/m³, similar to other carbon steels.
Thermal Expansion: Coefficient of ~12 × 10⁻⁶/°C, requiring expansion joints in long structures.
Thermal Conductivity: ~50 W/m·K, necessitating fireproofing (e.g., intumescent coatings) to maintain strength above 400°C.
Corrosion Resistance:
Uncoated H-beams in urban areas corrode at ~0.1 mm/year, while galvanized beams reduce this to ~0.01 mm/year.