Description
Factory-direct hollow sections, no trading middlemen — XJY Structure produces welded square and rectangular tubes from our own steel mill, then fabricates and finishes under one roof, so every S355JR welded square and rectangular hollow section supplier order ships with unbroken heat-number traceability from slab to finished bundle.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235B / S355JR Welded Carbon Steel Square & Rectangular Hollow Section |
| Product Type | Square / Rectangular Steel Tube (Hollow Section) |
| Steel Grade | Q195, Q235, Q355, S235JR, S355JR, A53 Grade A, A53 Grade B, A500 Grade A, A500 Grade B, A500 Grade C, SS400, STK400, ST42.2, S195 |
| Standard | EN 10219, EN 10210, GB/T 6728, JIS G3466, ASTM A500, ASTM A36, ASTM A53 |
| Section Shape | Square / Rectangular |
| Size Range (Square) | 20×20 mm – 500×500 mm |
| Size Range (Rectangular) | 20×40 mm – 300×500 mm |
| Wall Thickness | 1.2 mm – 20 mm |
| Length | 3 m – 12 m (random or cut to size) |
| Technique | Welded (ERW) |
| Surface Treatment | Pre-galvanized (40–80 g/m²) / Hot-dip galvanized (200–600 g/m²) / Black / Oiled |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Steel structures, building frames, solar structure components, fence posts, greenhouse frames, machinery, construction, industrial platforms |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC & General Contractors | Structural frames for warehouses, logistics centers, and industrial plants |
| Renewable Energy | Solar mounting structures and greenhouse frames requiring galvanized corrosion resistance |
| Construction | Scaffolding uprights, fence posts, and architectural columns |
| Machinery & Industrial | Conveyor structures, machinery frames, and industrial platforms |
When Dimensional Tolerance Drives Rework on a Structural Frame Order
A ±1% tolerance on a welded ERW section is not a marketing line — it is the difference between a column that plumbs true and one that forces field cutting.
When a project specifies a S355JR welded square and rectangular hollow section supplier for a 500×500 mm column, even a few millimeters of out-of-tolerance on the outer dimension can cascade into misaligned bolt holes, re-drilled connection plates, and days of schedule slip on site. Buyers sourcing from traders who buy from third-party mills often find that wall thickness drifts into negative tolerance, dimensional reports are backdated, and the mill test certificate cannot be traced back to the heat number on the bundle. [NEED_CITE: EN 10219 cold-formed welded hollow section dimensional tolerance requirements]
Matching Section Geometry to Load Paths in Building Frames
For warehouse and logistics center frames, the S355JR welded square and rectangular hollow section supplier range from 20×20 mm up to 500×500 mm covers everything from purlin bracing to primary portal columns. Rectangular sections such as 300×500 mm are typically specified for beams where bending resistance in one axis dominates, while square sections suit compression members and bracing where equal stiffness in both directions is required. The ERW welding process produces a consistent seam that passes ultrasonic inspection, and the ±1% tolerance keeps connection detailing predictable for bolted and welded joints alike.
Engineering Compliance Across EN, ASTM, and GB Frameworks
Projects tendered by European EPC firms usually call for EN 10219 or EN 10210, which means CE marking and Factory Production Control audit evidence are mandatory at customs. [NEED_CITE: CE marking requirements for structural hollow sections under EN 10210] Middle East and Southeast Asian specs often accept ASTM A500 Grade B or C, while domestic Chinese projects default to GB/T 6728 with Q355 grade. The S355JR welded square and rectangular hollow section supplier catalogue cross-references these standards so that a single mill heat can satisfy multiple certification packages — reducing the number of separate heats a buyer needs to procure and inspect.
Steel Grade Selection: Q-Series, S-Series, and ASTM Equivalency
Q235 and S235JR occupy the same yield strength band and are interchangeable on drawings that do not specify impact toughness at sub-zero temperatures. Once the design moves to S355JR or Q355, the higher yield strength allows thinner wall sections for the same load — which matters on long-span warehouse portals where self-weight is a significant portion of the total load. ASTM A500 Grade B and Grade C step up further for North American projects, with Grade C demanding tighter chemistry and more rigorous tensile testing. The ERW process used here is suited to sections from 1.2 mm thin-wall light framing up to 20 mm heavy structural columns, and the weld seam is normalized during forming to match the parent metal’s mechanical properties.
Surface Treatment: Pre-Galvanized, Hot-Dip, or Black
Pre-galvanized finish at 40–80 g/m² is the default for indoor structural members and greenhouse frames where the environment is dry and the design life is moderate. Hot-dip galvanizing at 200–600 g/m² is specified for outdoor solar mounting structures, fence posts, and coastal industrial platforms where chloride exposure demands decades of corrosion protection. Black or oiled finish is chosen when the section will be blast-cleaned and painted on site, or when it will be further fabricated into welded assemblies where the zinc layer would need to be dressed at every weld.
Hidden Costs of Sourcing Without Traceable Certification
A S355JR welded square and rectangular hollow section supplier order that arrives without EN 10204 3.1 or 3.2 certificates forces the buyer to either reject the shipment or pay for retrospective third-party testing — both of which delay erection. Wall thickness below the specified tolerance means the as-built section modulus is lower than the structural engineer calculated, which can trigger a design review and potential re-supply. [NEED_CITE: consequences of non-compliant hollow sections in structural steel procurement] Customs authorities in the EU and Middle East increasingly request CE documentation at the port of discharge, and missing paperwork means the container sits in bond until the issue is resolved.
Why Buyers Specify XJY Structure for Hollow Sections
XJY Structure operates its own steel mill with three production lines and over 2,800 specifications in raw material inventory, which means the S355JR welded square and rectangular hollow section supplier order is rolled, welded, and finished without leaving the facility. Every heat is tested in-house before the section is formed, and the mill test certificate follows the bundle from slab to finished product — there is no gap where a third-party mill’s paperwork has to be trusted on faith. The fabrication workshop sits beside the mill, so if a project needs columns drilled, beams notched, or assemblies welded, the same quality system covers both operations. CE marking to EN 10210 and EN 10219 is maintained under annual Factory Production Control audit, and third-party inspection by SGS, BV, or Lloyd’s can be witnessed before shipment. Professional loading teams plan container stowage for sections up to 12 m, maximizing payload per 40-foot container and minimizing on-site waste through saw-cut-to-size service.
Documentation & Compliance
- Mill Test Certificate documenting S355JR chemical composition and mechanical properties per EN 10219, with heat number traceable from slab to finished tube
- CE certificate covering EN 10210 and EN 10219 hollow sections, supported by Factory Production Control audit records for European market clearance
- ISO 9001 quality management certificate covering incoming material inspection, in-process ERW welding, dimensional checks, and final surface treatment verification
- SGS or BV third-party inspection report available for pre-shipment dimensional audit, coating thickness measurement, and weld seam NDT
- Material traceability sheet linking each bundle’s heat number to the corresponding mill test certificate and production batch
- Full customs documentation package including packing list, bill of lading, and certificate of origin formatted for EU, Middle East, and Southeast Asian ports
Packaging, Loading & Delivery
- Hot-dip galvanized S355JR sections bundled with soft edge protectors and waterproof wrapping to preserve the zinc coating during ocean transit and prevent white rust formation
- Pre-galvanized and black tubes strapped in steel-strip bundles with clear heat-number stenciling on each end, grouped by section size and wall thickness for fast site identification
- Saw-cut-to-size service available for lengths between 3 m and 12 m, reducing on-site cutting waste and allowing tighter container stowage for 20-foot and 40-foot shipments
- Container loading plans prepared for each order, with heavier wall-thickness sections placed at the bottom and lighter sections nested to maximize payload within weight limits
- FOB, CIF, and DDP terms available, with door-to-door logistics coordination to project sites in the Middle East, Southeast Asia, Africa, and Europe
Starting Your S355JR Hollow Section Inquiry
Submit your project drawings in PDF or DWG format along with the specified steel grade, section dimensions, wall thickness, surface treatment, and destination port. XJY Structure responds within 24 hours with a preliminary assessment, detailed quotation covering material, fabrication, coating, packing, and shipping, and a shop drawing timeline for your approval before production begins.
Request a Quotation with Mill Test Certificate
Share your specifications and required standards to receive pricing, EN 10204 3.1 certification, and a production schedule — contact XJY Structure at +86 188 5315 7756 (WhatsApp/WeChat) or admin@xjystructure.com.
Frequently Asked Questions
Q: How do Q235B, S235JR, and A53 Grade B compare — which grade should I specify for my project?
A: Q235B and S235JR are closely matched in yield strength and are generally interchangeable for indoor structural work where sub-zero impact toughness is not required. A53 Grade B is the standard ASTM equivalent used on North American and many Middle East projects. For heavier load-bearing members where thinner walls are preferred, S355JR or Q355 offers higher yield strength, and ASTM A500 Grade C provides the tightest chemistry control for critical applications.
Q: Can you provide EN 10204 3.2 certificates and arrange SGS or BV pre-shipment inspection?
A: Yes. EN 10204 3.1 certificates are issued with every shipment as standard, and 3.2 certificates with third-party witness sign-off can be arranged. SGS, BV, or Lloyd’s inspection for dimensional checks, coating thickness, and weld seam NDT can be scheduled before the container is sealed.
Q: Can you produce non-standard dimensions such as 450×250 mm rectangular sections, and what is the minimum order quantity?
A: The S355JR welded square and rectangular hollow section supplier range covers square sections from 20×20 mm to 500×500 mm and rectangular sections from 20×40 mm to 300×500 mm, with wall thickness from 1.2 mm to 20 mm. The minimum order quantity is 1 Ton, and non-standard dimensions within these bounds can be produced to order.
Q: Should I choose pre-galvanized, hot-dip galvanized, or black finish for my application?
A: Pre-galvanized at 40–80 g/m² suits indoor structural members and greenhouse frames with moderate corrosion exposure. Hot-dip galvanized at 200–600 g/m² is specified for outdoor solar structures, fence posts, and coastal platforms requiring long-term corrosion protection. Black or oiled finish is chosen when the section will be blast-cleaned and painted on site or welded into assemblies where the zinc layer would need dressing.
Q: How are welded square and rectangular tubes packed for container shipment, and what is the maximum length per container?
A: Sections are bundled with steel strips and edge protectors, with hot-dip galvanized tubes additionally wrapped to prevent coating damage. Lengths up to 12 m can be loaded into 40-foot containers, with stowage plans prepared to maximize payload within weight limits. Shorter cut-to-size lengths can be nested to fill remaining space.
