Q355 square hollow tubes are high-strength, low-alloy structural steel tubes widely used in construction, shipbuilding, cranes, airports, and MRT projects.
Manufactured in both welded and seamless forms, Q355 steel offers excellent weldability, formability, and durability, making it ideal for structural applications that require reliable load-bearing performance.
These tubes can be produced in various shapes, including circular steel pipes, square hollow sections, rectangular hollow sections, and oval tubes, catering to diverse industrial and construction requirements.
Specifications
| Shape | Size Range (mm) | Wall Thickness (T, mm) |
|---|---|---|
| Square | 30×30 – 600×400 | 2 – 25 |
| Rectangular | 60×20 – 600×400 | 2 – 25 |
| Common Sizes | 30×30, 40×40, 50×50, 60×60, 70×70, 75×75, 80×80, 90×90, 100×100, 120×120, 150×150, 200×100, 250×200, 300×200 | 2 – 25 |
Length: Customizable (standard 6–12 m)
Standard Compliance: EN10210, EN10219, JIS G3466, ASTM A500, GB/T3094-2000, GB/T6728-2002
Surface Treatment: As per customer requirements (black painted, galvanized, oiled, etc.)
End Finish: Plain, beveled, threaded, or per request
Chemical Composition & Mechanical Properties (Typical Q355)
Carbon (C): ~0.16%
Manganese (Mn): 0.5 – 1.5%
Silicon (Si): ~0.17 – 0.37%
Phosphorus (P): ≤0.045%
Sulfur (S): ≤0.045%
Mechanical Properties:
Tensile Strength: 490–630 MPa
Yield Strength: ≥355 MPa
Elongation: ≥21%
Applications
Q355 square hollow sections are suitable for high-demand structural and industrial uses, supported by their mechanical and dimensional properties:
Construction: Support frames, scaffolding, bridges, airport structures, MRT infrastructure
Example: A 200×200×8 mm SHS can safely support 12–15 tons in structural applications due to its yield strength ≥355 MPa.
Shipbuilding: Structural frameworks and marine components
Example: 250×250×10 mm tubes withstand torsional and bending stress in marine decks and bulkheads, compliant with ASTM A500 & EN10210.
Cranes & Heavy Machinery: Load-bearing beams, columns, and structural supports
Example: 300×300×12 mm SHS shows tensile strength of 490–630 MPa, making it suitable for crane booms and heavy-duty machinery frames.
General Engineering: Automotive frames, agricultural machinery, mechanical structures
Example: 80×80×5 mm SHS used in farm equipment can handle dynamic loads exceeding 1.5 tons without deformation.
Advantages
High Strength & Durability:
Tensile strength: 490–630 MPa
Yield strength: ≥355 MPa
Elongation: ≥21%
Result: Reliable performance for heavy-load and long-span structures.
Versatile Manufacturing:
Available in welded or seamless, square, rectangular, circular, and oval shapes
Wall thickness range: 2–25 mm, allowing adaptation for light to heavy-duty structures
Standards Compliance:
EN10210, EN10219, ASTM A500, JIS G3466, GB/T 3094-2000, GB/T 6728-2002
Ensures consistent quality, traceability, and safety for international projects
Customizable:
Length: 6–12 m (customized per project)
Surface treatments: Galvanized, painted, or oiled
Enables tailoring to environmental conditions and specific load requirements
Reliable Supplier:
Cangzhou High Booming stocks >20,000 tons of SHS monthly
Delivery lead time: 5–30 days
Full technical support, inspection, and packaging options
