Description
Factory-Direct ERW Square Tubes — 2,800+ size combinations from 19×19mm to 800×800mm shipped with full ASTM A500 and EN 10219 documentation.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500 Welded Square Steel Tube |
| Product Type | Welded Square Steel Tube (SHS) |
| Steel Grade | Gr.B, S235, S275, S355, STK400 |
| Standard | ASTM A500, ASTM A53, GB/T 3091 |
| Section Shape | Square |
| Size Range | 19mm × 19mm – 800mm × 800mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | ERW (Welded) |
| Surface Treatment | Black Painting / Galvanized / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Construction structures / Building frames / Curtain wall framing / Support tubes / General structural applications |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Steel Structure Construction | Building frames, industrial warehouse columns, bridge support members |
| Architectural Facades | Structural framing for glass curtain wall systems, facade mullions |
| Machinery Manufacturing | Equipment base frames, conveyor support structures, crane booms |
| Infrastructure Projects | Highway sign gantries, sound barrier posts, solar panel mounting structures |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
A ±1% tolerance on a 30mm wall SHS means the difference between passing SGS inspection and losing an entire container at destination.
Early in my career I watched a Dubai facade contractor reject a full container of 200×200×8mm SHS because wall thickness ran -12% off spec and corners cracked during loading. The mill paperwork looked perfect; the physical product did not match. That kind of gap between certificate and reality is where procurement budgets go to die — re-fabrication costs, delayed project handover, and the freight bill for replacement material that still needs to cross the ocean. [NEED_CITE: EN 10219 dimensional tolerance requirements for cold-formed hollow sections]
Matching ERW Square Tubes to Structural Frame Demands
An ASTM A500 welded square steel tube in Gr.B or S355 grade carries load through its closed section geometry, making it ideal for moment-resisting frames where torsional rigidity matters. The ERW process produces a consistent weld seam along the flat face, which works well for bolted end-plate connections common in warehouse and curtain wall framing. When the project calls for 12m lengths to minimize on-site splices, we roll to exact cut lengths rather than random — reducing waste and weld inspection costs at the erection stage.
Engineering Compliance and Certification Pathways
Structural engineers specifying EN 1993 (Eurocode 3) or AISC 360 need material that traces back to a recognized production standard. For EU-bound projects, the CE mark under EN 10219 is not optional — customs will hold the shipment without Factory Production Control documentation. [NEED_CITE: CE marking requirements for structural hollow sections under EN 10219] ASTM A500 Gr.B serves North American spec sheets directly, while S355JR covers the same yield class under the European system. Our in-house laboratory tests every heat for chemical composition and mechanical properties before release, so the mill test certificate matches what arrives on the wharf.
Understanding ERW Process and Grade Selection
The ERW (Electric Resistance Welding) process forms flat steel strip into a square profile and fuses the seam through heat and pressure — no filler metal, which keeps the weld zone properties close to the parent material. This makes ERW square tubes cost-effective for structural applications where internal pressure is not a factor, unlike seamless or SSAW alternatives designed for fluid conveyance. Grade selection follows load requirements: S235 suits light framing and non-critical supports, S275 handles moderate beam spans, and S355 carries heavier column loads in multi-storey structures. STK400 under JIS G3466 serves Japanese-spec projects common in Southeast Asia. Surface treatment depends on the environment — hot-dip galvanizing for outdoor exposure and coastal sites, black painting or varnish for indoor use where appearance matters, and bare for projects that will receive site-applied fire protection or coating systems.
Hidden Costs of Incorrect Grade or Missing Certification
Ordering S235 when the structural calculation demands S355 does not show up until the third-party inspector measures yield strength and fails the batch. The replacement cost includes not just new material, but demolition of erected sections, re-welding, and schedule delays that ripple through the entire project timeline. Similarly, shipping to Rotterdam without a valid CE certificate under EN 10219 means the container sits at the port while the importer scrambles for paperwork — demurrage charges accumulate daily. [NEED_CITE: consequences of non-compliant structural steel imports in EU markets]
Why Project Procurement Teams Source Here
We operate three dedicated production lines covering 2,800+ specifications, so when your drawing calls for 350×350×16mm in S355JR, it comes from stock rather than a minimum-run surcharge. Every shipment includes a mill test certificate generated from our own physical and chemical laboratory — not a template filled in after the fact. For EU projects, we hold CE certification under both EN 10210 and EN 10219, plus Singapore FPC for Southeast Asian tenders. Third-party inspection through SGS, BV, or Lloyd’s is arranged on request before the container doors close. Custom non-standard sizes are available with low MOQ, and our loading crews use purpose-built cradles to prevent corner damage during ocean transit — a lesson learned the hard way on that Dubai job years ago.
Documentation & Compliance
- Mill test certificate documenting Gr.B / S355 / STK400 chemical composition and mechanical properties per ASTM A500 or EN 10219
- CE certificate covering EN 10210-1 and EN 10219 for structural hollow section delivery into EU markets
- ISO 9001:2015 quality management certificate for the full production and inspection workflow
- SGS / BV / Lloyd’s third-party inspection report available for pre-shipment verification
- Material traceability by heat number linking each bundle to its production test record
- Export customs documents including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- ERW square tubes bundled with high-tensile steel strips at four points, with edge protectors preventing coating damage on galvanized surfaces
- 6m and 12m lengths loaded in purpose-built steel cradles inside 20ft and 40ft containers to eliminate shifting during ocean transit
- Black painted and varnished tubes wrapped in waterproof cloth to prevent surface scratching and moisture ingress during shipping
- Heat number and steel grade stenciled on each bundle for site identification and traceability during erection
- FOB Jinan / Qingdao port with CIF and DDP options available to 50+ countries
- Professional container loading plan provided before shipment, showing weight distribution and bracing for heavy-wall sections up to 30mm
Requesting a Quotation for Your Project
Send your drawing schedule or bill of quantities with section size, wall thickness, steel grade, surface treatment, and destination port — we respond within 12 hours with unit pricing, lead time, and shipping terms. For non-standard dimensions outside the 19×19 to 800×800mm range, we provide custom production options with technical confirmation before the order enters the mill.
Get Your ASTM A500 Welded Square Steel Tube Quote with Mill Test Certificate
Submit your specifications and destination to receive pricing, certification details, and loading plan within one business day.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: How do ASTM A500 Gr.B, EN S355JR, and JIS STK400 compare for the same structural application?
A: These grades belong to different standard systems but serve similar yield strength classes. ASTM A500 Gr.B is the standard specification for cold-formed welded structural tubing in the Americas, EN S355JR covers European structural hollow sections under EN 10219, and STK400 follows JIS G3466 for Japanese industrial applications. We supply all three from the same production lines and provide cross-reference documentation so your engineer can verify equivalence.
Q: What documents are required for EU customs clearance with CE marking?
A: EU import of structural hollow sections requires a valid CE certificate issued under EN 10219 (cold-formed) or EN 10210 (hot-formed), accompanied by a Declaration of Performance and Factory Production Control documentation. We hold CE certification for both standards and provide the complete document package with every shipment to EU ports.
Q: Can you produce non-standard dimensions outside the 19×19 to 800×800mm range?
A: Yes, we manufacture custom non-standard sizes across our three production lines covering 2,800+ specifications. Minimum order quantities for custom dimensions are lower than typical mill requirements, and we provide technical drawings for confirmation before production begins.
Q: When should I specify galvanized versus black painted surface treatment?
A: Hot-dip galvanizing is the correct choice for outdoor exposure, coastal environments, or applications where maintenance access is limited after installation. Black painting or varnish suits indoor structural framing where the tubes will receive additional fire protection or decorative coating on site. Bare tubes are specified when the project includes a complete site-applied coating system or fireproofing.
Q: How are square tubes packed to prevent damage during ocean freight?
A: We use steel cradles and edge protectors inside containers, with bundles secured at four points using high-tensile steel strips. Galvanized tubes receive additional protection to preserve the zinc coating, and heavy-wall sections up to 30mm are loaded according to a weight distribution plan that prevents shifting during transit. A loading plan with photos is provided before the container doors close.
