Q355 Steel Specification
Q355 steel, corresponding to the 16Mn grade, is typically produced in a hot-rolled condition-including hot-rolled steel plates, coils, and sheets. It offers a balanced combination of high strength, good toughness, excellent weldability, and reliable forming performance, making it widely used in a broad range of structural applications.
Thanks to its mechanical properties-yield strength ≥355 MPa, tensile strength 470–630 MPa, and impact toughness meeting low-temperature requirements-Q355 is commonly adopted in:
Shipbuilding and marine structures
Railway and vehicle manufacturing
Bridges and long-span structures
Boiler and pressure vessel components
Storage tanks, oil tanks, and steel containers
General welded structural parts
Its strength range is higher than traditional 16Mn, and significantly stronger than S235/S275 structural steels, while remaining equivalent or close to the performance of S355 according to EN standards.
Product Description – Small Diameter Square Tube Q355
Small Diameter Square Tube Q355 is manufactured with high-frequency welding technology and is available with various surface protection options, including pre-galvanized, hot-dipped galvanized, and hang-planting zinc coating.
With comprehensive strength and excellent welding properties, Q355 square tubes serve as reliable materials in both structural and fluid-conveying applications.
Product Range
Size Range: 50×50 mm – 600×600 mm
Zinc Coating: 200–600 g/m² (≈20–83 μm or 0.13–2 oz/ft²)
Technique: Pre-galvanized / Hot-dipped galvanized / Hang-planting galvanization
Available Steel Grades
Q195, Q235A–B, Q345A–E, 20#, 10#, 16Mn, ASTM A36, ASTM A500, etc.
Standards
GB/T 3091-2001, GB/T 13912-2002, BS 1387, ASTM F1083, and other related standards.
Pipe Ends Options
Plain, beveled, threaded, socketed, with holes, or with PVC caps/couplings/clamps-
Customized pipe-end processing is available upon request.
Applications
Suitable for:
Liquid delivery (pumping systems, wells, water, gas)
Construction and scaffolding pipes
Structural frameworks and steel fabrication
Mechanical support systems
Industrial and general-purpose engineering
Package
Bundled packing
Waterproof wrapping (optional)
Customized packaging available
Delivery Time
From stock: 10 days
New production: 15–20 days depending on order quantity
Payment & Price Terms
Payment: T/T or L/C
Price Terms: CIF, CFR, FOB
Loading Port: China
Additional Notes
All tubes are high-frequency welded for superior consistency and structural integrity.
For customers unsure of model selection or specification details, our engineering team can provide professional recommendation based on project requirements.
Choosing GNEE STEEL ensures access to diversified product categories, stable supply, certified quality, and professional service.
