Products Description
S355 square and rectangular hollow sections (SHS / RHS) are high-strength structural steel tubes with a minimum specified yield strength of 355 MPa. They are supplied in two principal conditions: hot-finished to EN 10210 and cold-formed to EN 10219. The grade designation "S355" indicates structural steel with 355 MPa minimum yield strength at room temperature; the suffix and delivery condition determine impact toughness, temperature performance, and manufacturing route. These sections are widely used where a high strength-to-weight ratio, clean lines, and closed-section torsional efficiency are required.
1. Governing Standards:
| Standard | Manufacturing Route | Common S355 Designations | Key Characteristics |
| EN 10210-1 / -2 | Hot-finished (hot-formed) | S355J2H, S355NH, S355NLH | Thicker walls and larger dimensions; fully killed fine-grain steel; suited to heavier structural duty |
| EN 10219-1 / -2 | Cold-formed (cold-formed from hot-rolled coil) | S355J2H | Tight dimensional control; broad size range; cost-effective for general structural and mechanical applications |
2. Commonly Exported Size Ranges:
Square Hollow Sections (SHS)
| Parameter | Typical Export Range |
| Side length | 20 × 20 mm to 400 × 400 mm (EN 10210); up to 500 × 500 mm or 600 × 600 mm on request depending on mill capability |
| Wall thickness | 1.6 mm to 25 mm (EN 10210 / EN 10219); heavier walls up to 40–60 mm available on selected sizes |
| Standard length | 6 m / 12 m; 5.8 m also common for container optimization; custom lengths 6–14 m negotiable |
Rectangular Hollow Sections (RHS)
| Parameter | Typical Export Range |
| Outer dimensions | 50 × 25 mm to 600 × 300 mm (EN 10219); up to 1500 × 1150 mm on heavy mill capability. |
| Wall thickness | 1.6 mm to 19 mm (standard cold-formed range); thicker walls available in hot-finished EN 10210 |
| Standard length | 6 m / 12 m; cut-to-length service available |
Dimensional tolerances (EN 10210-2 / EN 10219-2): outside dimensions typically ±1% with a minimum of ±0.5 mm; wall thickness commonly ±10% (some hot-finished tables permit −10% / +8% on mass); straightness generally 0.15–0.2% of total length, max. 3 mm per metre; twist limits apply by standard.
3. Surface Finish Options:
S355 SHS/RHS are supplied in the condition agreed at order. The standard mill finish is black, bare (uncoated), with a light residual scale or oil film typical of the forming route. Value-added finishes are available:
- Bare / black - default structural finish; suitable for fabrication followed by site-applied protective coating.
- Oiled - temporary corrosion protection for storage and sea freight; compatible with most fabrication processes.
- Hot-dip galvanized - zinc coating to EN ISO 1461 for external or exposed service; coating thickness typically ≥ 70–85 μm depending on section thickness and specification.
- Pre-galvanized / zinc-coated - for lighter-duty or architectural applications where a thinner metallic coating is acceptable.
- Primed / painted - shop primer or full paint system can be applied on request for identifiable project requirements.
- Powder-coated - available for visible architectural or equipment applications.
Customers requiring weathering-grade or low-temperature performance should specify S355NH / S355NLH or offshore grades rather than relying on surface treatment alone.
4. Packing & Shipping:
Export packing is designed for seaworthy, container-friendly, and mechanically unloaded delivery. Standard practice includes:
- Steel-strap bundled bundles, often hexagonal or rectangular, with nylon lifting slings or steel bands; bundle weights commonly up to 2,000 kg, though larger bundles can be arranged.
- End protection: plastic plugs or caps in both ends to prevent moisture ingress and mechanical damage during handling.
- Weather protection: waterproof paper, PVC sleeve, or shrink-wrap for higher-humidity destinations or long sea voyages.
- Tagging: two tags per bundle showing heat number, size, grade, and standard; shipping marks and mill test certificates (MTC) accompany each shipment.
- Shipment mode: container shipment (20 ft / 40 ft) for shorter or mixed-size orders, or bulk vessel for large tonnages and long lengths; mixed sizes and mixed wall thicknesses can be loaded subject to minimum order quantities per size.
Loading photos, packing lists, and pre-shipment inspection records can be provided for buyer verification.
| Property | Requirement |
| Minimum yield strength, ReH | 355 MPa for T ≤ 16 mm (some tables apply 345 MPa for 16 < T ≤ 40 mm |
| Tensile strength, Rm | 470–630 MPa (hot-finished EN 10210); 510–680 MPa (cold-formed EN 10219) |
| Elongation, A | 20% minimum (transverse); 22% minimum (longitudinal) on 5.65√S₀ gauge length; reduced by 2% for sections with high B/T ratio |
| Impact strength | 27 J minimum at −20 °C (S355J2H); higher-toughness variants (S355NLH) available for lower temperatures |
| Element | Max |
| C | 0.22 |
| Si | 0.55 |
| Mn | 1.6 |
| P | 0.03 |
| S | 0.03 |
| CEV | 0.45 (depending on product thickness and standard edition) |
Applications
S355 SHS/RHS are selected where high strength, torsional stiffness, and closed-section efficiency matter. Established application areas include:
- Building frames and columns - high-rise and mid-rise steel structures, portal frames, mezzanines, and long-span roofs.
- Bridges and infrastructure - bridge girders, truss members, highway sign gantries, and temporary works.
- Offshore and marine structures - platform topsides, walkways, support frames, and low-temperature modules where S355NH / S355NLH or EN 10225 grades are specified.
- Heavy machinery and equipment frames - crane booms, mining frames, conveyor gantries, and pressure-bearing supports.
- Renewable energy - wind turbine towers, nacelle frames, and solar mounting structures.
- Architectural and visible steelwork - exposed columns, canopies, and feature frames where galvanized or painted finishes are used.
- General fabrication - pallets, racking, guards, and transport equipment requiring a reliable structural grade with good weldability.
FAQ
Q1: What is the difference between EN 10210 and EN 10219 for S355 hollow sections?
EN 10210 covers hot-finished hollow sections, produced by forming at elevated temperature; it generally permits thicker walls and larger dimensions, and the hot route can offer more uniform through-thickness properties on heavy sections. EN 10219 covers cold-formed hollow sections from hot-rolled coil; it offers tighter dimensional control and a very broad size range at lower cost for general structural work. Both standards include S355J2H, so the choice depends on size, wall thickness, toughness requirements, and project specification.
Q2: What does "S355J2H" mean, and how does it differ from S355JR?
S355 = structural steel with 355 MPa minimum yield. J2 = Charpy impact tested at −20 °C with 27 J minimum. H = hollow section. S355JR is a flat/product grade to EN 10025-2 with +20 °C impact testing and is not a hollow-section delivery designation; for hollow sections, the appropriate designations are S355J2H, S355J0H, S355NH, or S355NLH depending on the standard and impact requirement.
Q3: Can you supply lengths other than 6 m or 12 m?
Yes. 5.8 m, 6 m, and 12 m are the most container-efficient and commonly exported lengths. Custom cut-to-length from 6 m to 14 m is generally available, subject to mill rolling schedule and minimum quantity per size. Fixed-length tolerances and bundle configurations should be confirmed at order.
Q4: Is S355 SHS/RHS weldable?
Yes. S355J2H is a low-carbon, fine-grain structural steel with a controlled CEV (typically ≤ 0.45), making it suitable for manual metal arc, MIG/MAG, and submerged arc welding under normal structural fabrication procedures. For thick sections or high-restraint joints, preheat and interpass controls should follow the fabricator's WPS/PQR in accordance with EN 1090-2 or the governing code.
Q5: What surface treatment is recommended for outdoor or corrosive environments?
For external structural steelwork, hot-dip galvanizing to EN ISO 1461 is the default recommendation, often combined with a primer or topcoat for extended durability. For offshore/coastal or chemical environments, a duplex system (galvanizing + paint) or a high-performance paint system may be required. S355NH / S355NLH base material is preferred for weathering or low-temperature service because the steel chemistry is controlled for toughness, not because the surface treatment alone provides corrosion resistance.
Q6: What documentation is provided with an export shipment?
Standard export documentation includes: mill test certificate to EN 10204 3.1, packing list, commercial invoice, bill of lading, and CE Declaration of Performance where applicable. Third-party inspection reports (SGS, BV, TÜV, etc.), loading photos, and non-destructive testing reports can be added at order stage.
Q7: What is the minimum order quantity?
MOQ varies by size and mill. A common export MOQ is 25 tonnes per size for mixed-size container loading; smaller trial orders may be possible for standard stock sizes. Mixed wall thicknesses within a size family are generally acceptable subject to the same tonnage basis.
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Phone Number(WhatsApp/Wechat)
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