Description
Factory-Direct SHS & RHS Supply — ASTM A500 Gr.B and EN S235/S275/S355 welded square and rectangular tubes rolled from our own steel coil, shipped with full mill test certificates and no trading markup.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500 / A53 Welded Square / Rectangular Steel Tube |
| Product Type | Welded Square / Rectangular Steel Tube / Hollow Section (SHS / RHS) |
| Steel Grade | Gr.B, A53-A369, Gr.B / S235 / S275 / S355 / STK400 |
| Standard | ASTM A500, ASTM A53, GB/T 3091 |
| Section Shape | Rectangular / Square |
| Size Range | 15mm×20mm – 700mm×800mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | ERW (Welded) / Cold Rolled |
| Surface Treatment | Black Painting / Pre-Galvanized / Varnish / Bare |
| Tolerance | ±10% |
| Ends | Plain End |
| Oiled or Non-oiled | Slightly Oiled |
| Application | Steel Structure Pipe, Construction Pipe, Building Pipe, Curtain Wall Pipe, Support Tubes, Fertilizer Tube |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial & Industrial Construction | Building frames, column and beam assemblies, warehouse portal frames |
| Curtain Wall & Façade Engineering | Mullion support tubes, transom framing, cladding sub-structures |
| Infrastructure & Civil Works | Bridge handrails, highway sign gantries, lighting pole bases |
| Industrial Plant & Equipment | Conveyor support structures, platform framing, pipe rack columns |
| Scaffolding & Temporary Works | Shoring towers, access scaffolding uprights, formwork bracing |
What Pre-Galvanized Coating Thickness Really Means for Site Weldability
A 38-micron reading on a 60-micron spec means the entire batch gets rejected at port.
I have watched a Chilean warehouse project lose weeks and tens of thousands in freight insurance claims because a third-party inspector found pre-galvanized RHS coating below the contracted minimum. The paper mill certificate looked perfect; the actual zinc layer did not survive the salt-air transit. When you source a Pre Galvanized Welded Square Rectangular Steel Tube Supplier from overseas, the gap between a clean lab report and a real coating gauge reading is where projects bleed money. Inconsistent zinc thickness also causes weld spatter and porosity on site — the welder burns through the thin spots and the fumes from the thick spots ruin bead quality. [NEED_CITE: pre-galvanized coating thickness tolerance per ASTM A525 and EN 10346]
Matching Section Geometry to Structural Load Paths
Cold rolled ERW welded SHS and RHS sections deliver tight corner radii and consistent flat-to-flat dimensions, which matters when a 700×800 mm RHS has to bolt flush to a base plate or splice into a moment connection. The full 1–30 mm wall range across side lengths from 15×20 mm up to 700×800 mm means a single Pre Galvanized Welded Square Rectangular Steel Tube Supplier can feed both the light-gauge curtain wall mullions and the heavy column sections on the same project, keeping steel grades and surface treatments aligned across drawings. Our vertically integrated mill rolls the coil, welds the tube, runs the galvanizing line, and stamps the heat number — so the coating thickness you approve in the shop drawing is the coating thickness that arrives on the flatrack.
Engineering Code Compliance Across Export Markets
Structural hollow sections shipped to Europe must satisfy EN 10219 dimensional and tolerancing rules, while North American EPCs specify ASTM A500 Grade B or Grade C with AISC-aligned mill documentation. The same 700×800×20 RHS can be certified to both frameworks if the chemistry, tensile results, and impact testing are documented per heat. [NEED_CITE: steel grade equivalence between EN 10025 S-series and ASTM A500 Gr.B] Choosing S235, S275, or S355 for an EU project, or Gr.B for an ASTM job, is not a paperwork exercise — it determines whether the section passes customs inspection and whether the structural engineer signs off on the connection calculations. Plain ends and ±10% tolerance match the downstream cutting and welding sequences typical on EPC job sites, and the slightly oiled surface prevents white rust during container transit without interfering with primer adhesion.
Why Cold Rolled ERW and Pre-Galvanized Matter Together
ERW welding followed by cold rolling produces a square or rectangular section with a smooth external profile and a weld seam that is normalized through the cold-forming pass — this is what gives the corner its dimensional repeatability. When that section then enters a continuous pre-galvanizing line, the zinc bonds to a clean, work-hardened surface rather than a hot-rolled mill scale, which is why pre-galvanized coating adhesion consistently outperforms post-galvanizing on thin-wall tubes. The S235 to S355 grade progression lets engineers step up yield strength without changing the fabrication sequence, and the ASTM Gr.B / A53-A369 equivalents cover the same structural logic for North American specs. Wall thickness tolerance directly affects theoretical weight: a 10 mm RHS ordered at nominal 10 mm but delivered at 9 mm changes the section modulus and the load table the engineer relied on. [NEED_CITE: cold-formed hollow section manufacturing tolerances per EN 10219]
The Hidden Cost of Accepting “Equivalent” Grades Without Paperwork
A container of RHS labeled S355 but arriving with a mill certificate that only references a generic “structural grade” will fail third-party inspection at the port of discharge. The buyer then faces three choices: pay for on-site chemical analysis, return the cargo at freight cost, or accept the material and carry the liability if a structural audit later flags the discrepancy. Missing heat-number traceability, absent coating thickness reports, or tolerance sheets that only show “standard” rather than measured values all create the same problem — the engineer cannot certify the connection, the contractor cannot close the quality file, and the project owner cannot hand over the building. [NEED_CITE: EN 10204 3.1 and 3.2 inspection certificate requirements for structural steel]
Why Buyers Consolidate SHS and RHS Orders With Us
We roll our own hot-rolled coil into welded SHS and RHS, run the pre-galvanizing line in the same facility, and issue the mill test certificate from the same quality system — which means the heat number on the tube matches the chemistry on the certificate and the coating thickness on the gauge. Our catalog covers over 2,800 size and thickness combinations, so a project needing 15×20 mm curtain wall mullions and 700×800 mm portal frame columns sources both from one production line with one quality file. SGS and BV third-party inspections are conducted before the container is sealed, and our loading team plans bundle weight and bracing around the specific length and section so that 12-meter RHS does not shift during ocean transit. Custom cut-to-length and non-standard dimensions are available above the 1-ton MOQ, and every order ships with the full export documentation package the EPC needs to clear customs at the destination port.
Documentation & Compliance
- Mill test certificate documenting Gr.B / S235 / S275 / S355 chemical composition and mechanical properties per heat number, formatted to EN 10204 3.1
- CE marking and Declaration of Performance for EN 10210 / EN 10219 hollow sections where EU customs or end-client specification requires it
- ISO 9001 quality management certificate covering the integrated rolling, welding, and galvanizing process
- SGS or BV third-party inspection report covering dimensional check, coating thickness measurement, and visual weld seam examination before shipment
- Material traceability sheet linking each bundle to its heat number, coil position, and galvanizing batch
- Full customs document set: commercial invoice, packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Pre-galvanized SHS and RHS bundled with steel strips and edge protectors to prevent zinc coating abrasion during handling and ocean transit
- Bare and black-painted tubes lightly oiled and strapped in hexagonal or rectangular bundles sized to match the 5.8 m, 6 m, or 12 m standard length
- Container loading plan optimized by section weight and length: small 15×20 mm to 100×100 mm SHS loaded in 20-foot containers, large 500×500 mm and 700×800 mm RHS shipped break-bulk or on flat racks
- Cut-to-length service available for random or fixed lengths above the 1-ton MOQ, with each piece tagged by heat number and steel grade
- Bundle identification tags showing steel grade (Gr.B / S355 / etc.), section size, wall thickness, heat number, and purchase order reference
- FOB, CIF, and DDP terms supported with door-to-door tracking and full export documentation provided at contract signing
How to Move From Drawing to Mill Certificate in One Step
Send your project drawing list with section sizes, wall thicknesses, steel grade, surface treatment preference, and destination port — we return a detailed quotation covering material, fabrication, coating, packing, and freight within 24 hours, together with the mill test certificate template and third-party inspection schedule your engineer needs to approve before the first coil is slit.
Frequently Asked Questions
Q: How do ASTM A500 Gr.B and EN S235/S275/S355 compare for the same structural application?
A: Both grade families cover carbon-manganese structural steel, but the chemistry limits, tensile requirements, and impact testing temperatures differ. We supply Gr.B for ASTM-specified projects and S235, S275, or S355 for EN-specified projects, each with full mill test certificates showing the actual chemistry and mechanical results per heat.
Q: What is the difference between pre-galvanized and hot-dip galvanized welded tubes?
A: Pre-galvanized tubes are coated from coil in a continuous line before forming, giving a uniform zinc layer suited to indoor and moderate outdoor environments. Hot-dip galvanized tubes are coated after fabrication, providing thicker zinc at the corners and weld seams for aggressive outdoor or marine exposure. We supply pre-galvanized welded SHS and RHS as standard and can arrange hot-dip post-galvanizing for project-specific requirements.
Q: Can you supply non-standard sizes or cut-to-length pieces?
A: Yes. Beyond the standard 5.8 m, 6 m, 11.8 m, and 12 m lengths, we offer cut-to-length service for fixed dimensions. The MOQ for standard sizes is 1 ton; custom or non-standard dimensions are quoted per order based on the rolling and cutting setup required.
Q: How is material traceability maintained from raw coil to finished tube?
A: Every coil is assigned a heat number at the steel mill. That number is carried through the slitting, ERW welding, cold rolling, and galvanizing stages, and appears on the bundle tag and the mill test certificate. Third-party inspectors can trace any bundle back to its original coil chemistry and mechanical test results.
Q: What loading method is used for large RHS sections like 700×800 mm?
A: Sections above approximately 300 mm side length and 12 m length are loaded break-bulk or on flat racks rather than in standard containers. We prepare a loading and lashing plan with photos before the vessel is sealed, and provide the plan as part of the shipping documentation package.
Get Your Quotation With Full Mill Documentation
Submit your section sizes, steel grade, surface treatment, and destination port to receive a detailed quotation and sample mill test certificate within 24 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.xjystructure.com
Tel: +86 531 8573 6315
Mobile / WhatsApp / WeChat: +86 188 5315 7756
Email: admin@xjystructure.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
