Steel grades are distinguished by their chemical composition, mechanical properties, and intended applications. In China, carbon structural steels are classified under GB/T 700, with Q195, Q235, and Q355 being the most common grades. The main differences are in yield strength, tensile strength, elongation, and suitable applications.
| Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Elongation (%) | Features | Common Applications (H Beams & Structures) |
|---|---|---|---|---|---|
| Q195 | ≥195 | ≥345 | ≥26 | Low yield strength, high plasticity, easy processing, cost-effective | Light buildings, simple brackets, scaffolding, guardrails, electric poles; suitable for H Beams in low-load frameworks |
| Q235 | ≥235 | ≥375 | ≥24 (Grade A) / ≥22 (Grade B) | Moderate strength, good weldability and cold formability, widely applicable | Construction, bridges, ships, machinery; H Beams for medium-load structural frameworks, columns, beams, and machinery bases |
| Q355 | ≥355 | ≥470 | ≥20 | High strength and toughness, low-temperature impact resistance, stable under harsh conditions | Heavy buildings, large bridges, high-rise structures, high-pressure vessels; H Beams for key load-bearing structures, crane arms, pressure pipes, and heavy machinery |
Selection Suggestions
Q195: Best for general-purpose, low-load structures where cost-effectiveness is important.
Q235: Ideal for medium-load structural parts, balancing strength, weldability, and formability.
Q355: Recommended for critical structures requiring high strength and toughness, ensuring long-term safety and reliability.
H-Beam Application Guidance
| Steel Grade | Typical H-Beam Use | Key Advantages |
|---|---|---|
| Q195 | Light-load frameworks, small factory buildings | Cost-effective, easy to process and fabricate |
| Q235 | Medium-load frameworks, bridges, warehouses | Balanced strength, good weldability, versatile in construction |
| Q355 | Heavy-load frameworks, high-rise buildings, bridges | High tensile strength, durable under dynamic and heavy loads, suitable for long-span or critical structures |
