A36 A572 grade 50 hot rolled construction structural universal steel H beam

ASTM A36 and A572 grade 50 hot rolled H beam are common profiles for building structures. The former has a yield strength of ≥250MPa, while the latter achieves high-strength performance of ≥345MPa through niobium-vanadium microalloying. The flange thickness can reach 75mm, which is suitable for high-rise building frames and main beams of industrial plants. The carbon equivalent of A572 grade 50 profile is ≤0.45%, and welding requires 150℃ preheating (plate thickness＞40mm). It is 20% lighter than A36 and has 35% higher seismic performance.

Both profiles are hot-rolled. The impact energy of A572 grade 50 at -30℃ is ≥34J, which is significantly better than A36 (≥27J). The allowable deviation of 600×300mm large-section H-shaped steel is ±3mm/m. A36 is mostly used for light steel structures, while A572 grade 50 is more suitable for large-span stadium trusses, with a fatigue life of 2 million cycles (stress amplitude Δσ=120MPa).

The common A36 A572 grade 50 H beam specifications in the market are H400×200×8×12mm. The unit price of A572 grade 50 profile is 15%-20% higher than that of A36, but the overall cost can be reduced by reducing the amount of steel used. The surface can be sandblasted (Sa2.5 grade) or treated with fire retardant paint, and the fire resistance limit is up to 2 hours (coating thickness 1.5mm).