Q355B Low Alloy High Strength Hot Rolled H-Beam Steel for Construction Grade Structural Projects
Q355B Hot Rolled H-Beam is a low-alloy high-strength structural steel that complies with Chinese national standard GB/T 1591-2018, replacing the traditional Q345B material. This steel offers superior yield strength, tensile strength, low-temperature impact toughness, and excellent weldability and cold-working properties.
Compared to ordinary carbon steel, Q355B H-beams can reduce cross-sectional area and structural weight by approximately 10%-15% under the same load-bearing conditions, making them ideal load-bearing components for modern large-scale buildings, industrial plants, and bridge projects.
| Parameter | Value / Standard |
|---|---|
| Standard | GB/T 11263-2017 (Dimensions), GB/T 1591-2018 (Material) |
| Material Grade | Q355B (Equivalent to ASTM A572 Gr.50 / EN S355JR) |
| Process | Hot Rolled |
| Yield Strength (ReH) | ≥ 355 MPa (t ≤ 16mm) ≥ 345 MPa (16mm < t ≤ 40mm) |
| Tensile Strength (Rm) | 470 - 630 MPa |
| Elongation | ≥ 21% |
| Impact Energy (0°C) | ≥ 34 J (Longitudinal) |
| Carbon Equivalent (CEV) | ≤ 0.45% (ensures good weldability) |
| Chemical Composition | C ≤ 0.20%, Si ≤ 0.55%, Mn ≤ 1.60%, P ≤ 0.035%, S ≤ 0.035% |
| Model (H x W) | Dimensions (mm) | Web Thk (mm) | Flange Thk (mm) | Weight (kg/m) |
|---|---|---|---|---|
| HW 100x100 | 100 x 100 | 6 | 8 | 17.2 |
| HW 150x150 | 150 x 150 | 7 | 10 | 31.9 |
| HM 194x150 | 194 x 150 | 6 | 9 | 31.2 |
| HM 294x200 | 294 x 200 | 8 | 12 | 57.0 |
| HM 488x300 | 488 x 300 | 11 | 18 | 124.9 |
| HN 400x150 | 400 x 150 | 8 | 13 | 55.8 |
| HN 600x200 | 600 x 200 | 11 | 17 | 106.0 |
| HN 900x300 | 900 x 300 | 16 | 28 | 243.0 |
| Item | Details |
|---|---|
| Pricing Mechanism | Floating - based on Mysteel Q355B H-beam ex-works price (incl. VAT) |
| Reference Price (FOB China Main Port) | 680-850 USD / MT (depends on quantity, size, delivery) |
| MOQ | Standard sizes: 20 MT (mixed allowed) Special rolling: 50 MT |
| Incoterms | EXW (Tianjin/Shanghai/Lecong), FOB, CIF, CFR |
| Lead Time | Stock: 3-5 days Production: 15-25 days |
| Payment Terms | TT (30% deposit + 70% before shipment / BL copy) LC (sight, irrevocable) |
Q355B steel boasts high strength, and H-beams possess excellent mechanical properties (wide flanges, high bending strength, and economical cross-section), making them suitable for:
- Steel structure industrial buildings - bearing dynamic loads from cranes and roof snow loads (e.g., automobile factories, logistics centers)
- High-rise buildings - main columns and beams in steel-concrete composite structures (SRC)
- Bridge engineering - steel box girders for pedestrian bridges, longitudinal/transverse beams for highways
- Heavy machinery foundations - equipment bases, port crane rails, mine support
- Underground engineering - subway excavation support (steel bracing), initial tunnel lining
Load Capacity Priority: If your project spans greater than 8 meters or loads greater than 10 tons/square meter, the higher strength of Q355B can reduce beam height (H), thereby increasing headroom or reducing floor height.
Dynamic Loads: For frequent lifting operations or vibrating equipment, Q355B's superior fatigue resistance and impact toughness (Q355C/D can be used at 0°C or -20°C) ensure long-term safety.
Total Cost: While Q355B is approximately 5-8% more expensive per unit than Q235B, its strength is over 30% higher, resulting in approximately 15% savings in steel weight and reduced welding materials and labor costs, leading to lower overall project costs.
Most Suitable Scenarios: Main load-bearing components requiring large spans, heavy loads, and easy welding/bolting connections. Typical projects: 25-30 meter span steel structure factory buildings, 6-story prefabricated steel structure residential buildings, 20-ton bridge crane beams.
Not Recommended For: Temporary sheds, non-load-bearing decorative frames, and extremely cold regions (below -20°C - upgrade to Q355D recommended).
A: Not exactly. Q355B is the updated grade under GB/T 1591-2018. It has slightly higher yield strength (355 MPa vs 345 MPa) and better impact toughness. For most structural applications, Q355B is the direct and improved replacement for Q345B.
A: Yes. However, you must use welding consumables (electrodes/wire) suitable for low-alloy steel (e.g., E5015 or ER50-6). Preheating is generally not required for thinner sections (<20mm) but is recommended when thickness exceeds 30mm or in low-temperature conditions.
A: We supply black (mill-finish) H-beams as standard. We can also arrange hot-dip galvanizing (ASTM A123) or primer painting (red oxide or epoxy) through our partner facilities - please request a separate quote.
A: Yes. We provide value-added processing including flame cutting, laser cutting, drilling, and end milling. Custom processing lead time: +2-4 days.
A: Indoors in dry conditions: 6-12 months without significant rust. Outdoors: surface rust (oxidation) begins within 2-4 weeks. This is normal for mill-finish steel and does not affect structural performance. Rust can be removed by wire brushing or sandblasting before painting.
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