Description
Factory-direct welded square tubes, no trading markup — every ASTM A500 welded square steel tube rolls off our own ERW lines in Jinan, shipped with in-house mill test certificates and third-party inspection available before container sealing.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500 / A53 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 |
| Invoicing | By Theoretical Weight |
| Processing Service | Bending, Cutting |
| Application | Construction Structure, Building, Curtain Wall, Support Tubes, Steel Structure, Fertilizer Equipment |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & EPC | Building frames, column supports, roof trusses for commercial and industrial projects |
| Facade & Curtain Wall | Architectural square tube framing for glass curtain wall systems and exposed structural facades |
| Machinery & Equipment | Conveyor structures, machine base frames, fertilizer equipment support tubes |
| Steel Structure Fabrication | Primary and secondary members cut and welded into portal frames and bracing systems |
What Tolerance Drift Costs When You Stack 800mm Square Tubes on Site
A ±1% tolerance on an 800 × 800 × 30mm ASTM A500 welded square steel tube means the difference between a plumb column and a rework order.
When structural fabricators receive tubes with inconsistent side lengths or wall thickness beyond declared tolerance, bolt holes no longer align, gusset plates sit at angles, and field welding becomes a guessing game. We have seen project timelines slip because a batch of 300 tubes measured 0.8mm over nominal on one face — acceptable on paper under some mill practices, but enough to force re-drilling on a 1,200-ton steel frame. Our ERW lines hold ±1% across the full 19 × 19 to 800 × 800 range, verified by our in-house lab before any ASTM A500 welded square steel tube leaves the warehouse. [NEED_CITE: dimensional tolerance requirements for structural hollow sections in EN 10219 and ASTM A500]
Matching Wall Thickness and Grade to Structural Load Paths
An ASTM A500 welded square steel tube in Gr.B or S355 serves different roles depending on where it sits in the load path. For primary columns carrying axial compression in a multi-storey frame, S355 or STK400 delivers the yield margin that keeps section sizes practical. For secondary bracing or curtain wall mullions where weight matters more than ultimate capacity, Gr.B or S235 in thinner walls (1–6mm) keeps tonnage — and cost — down. Our 2,800+ specification range means you can source both from a single heat-traceable batch, cut to your shop drawings, rather than splitting orders across two suppliers.
Engineering Compliance Across ASTM, EN, and JIS Frameworks
Specifying an ASTM A500 welded square steel tube for a project in the EU, Middle East, or Southeast Asia means navigating overlapping standards. ASTM A500 Gr.B maps roughly to EN S235JR in yield terms, but the chemical composition limits and testing frequency differ — and customs authorities in regulated markets will reject a shipment whose mill test certificate references the wrong standard code. Our CE certification under EN 10210 and EN 10219 covers the same production lines, so an ASTM A500 welded square steel tube ordered for a Singapore FPC-regulated project ships with the correct Declaration of Performance and Factory Production Control documentation. [NEED_CITE: steel grade equivalence between ASTM A500 and EN 10210 standards] Wall thickness up to 30mm on the 800 × 800 section means heavy structural members can be sourced as welded SHS rather than built-up box sections, reducing fabrication labor on site.
ERW Weld Integrity and Surface Treatment Selection
The longitudinal ERW weld in an ASTM A500 welded square steel tube is normalized online, eliminating the as-welded microstructure and bringing the weld zone mechanical properties in line with the parent metal. This matters for bending: a 12m length of 200 × 200 × 10mm S355 SHS bent to a 6m radius will not crack at the weld line if the normalization has been done correctly. For surface treatment, black painted finish suits indoor structural work where appearance is secondary; hot-dip galvanized is specified for outdoor exposure or high-humidity environments like fertilizer plants; bare tubes ship with anti-rust oil for further coating by the fabricator. Each option changes the theoretical weight calculation and the container loading plan.
The Hidden Cost of Unverified Grade and Negative Tolerance
Ordering an ASTM A500 welded square steel tube based on price alone, without requiring a 3.1 or 3.2 mill test certificate, exposes the project to two risks: actual chemistry outside the Gr.B / S355 envelope, and wall thickness consistently at the negative edge of tolerance — or beyond it. The first risk shows up at structural testing; the second shows up when the theoretical weight invoiced does not match the actual delivered weight, and the tonnage shortfall is discovered only after the tubes are welded into the frame. [NEED_CITE: consequences of negative tolerance abuse in structural steel procurement] Third-party inspection by SGS or BV before loading catches both issues at the mill gate, not at destination.
Why Fabricators and EPCs Source ASTM A500 Welded Square Steel Tube From Our Jinan Mill
We run three dedicated ERW lines producing the full 19 × 19 to 800 × 800 range in wall thickness up to 30mm — no trading company sits between your order and our production schedule. Every ASTM A500 welded square steel tube is tested in our own physical and chemical laboratory; the mill test certificate is generated from actual heat data, not copied from a template. For projects requiring CE marking, our EN 10210/10219 certification and Singapore FPC approval are in place; for buyers who want independent verification, we arrange SGS or BV inspection at no extra coordination cost. Custom lengths, cutting, and bending are done in-house, so a 6m random-length order and a 11.8m fixed-length order ship from the same facility. Professional container loading with custom chocking and strapping — learned from the bent-corner losses I mentioned earlier — means the 800 × 800 × 30mm heavy sections arrive straight, not kinked.
Documentation & Compliance
- Mill test certificate documenting Gr.B / S355 / STK400 chemical composition and mechanical properties per ASTM A500 or EN 10219, traceable by heat number
- CE certificate of conformity under EN 10210 / EN 10219 for shipments entering EU and FPC-regulated markets
- ISO 9001:2015 quality management system certificate covering the full ERW welded square tube production process
- SGS or BV third-party inspection report available on request, covering dimensional check, visual weld inspection, and witness testing
- Material traceability label on each bundle showing heat number, steel grade, size, and length for site identification
- Full customs documentation set: packing list, bill of lading, certificate of origin, and commercial invoice aligned with ASTM A500 / A53 designation
Packaging, Loading & Delivery
- ASTM A500 welded square steel tubes in Gr.B and S355 bundled with high-tensile steel strips, separated by timber dunnage to prevent surface scoring during ocean transit
- Galvanized SHS sections packed with edge protectors and waterproof wrapping to preserve the zinc coating against condensation inside the container
- Heavy-wall tubes (20–30mm) in 800 × 800mm section loaded with custom-fitted steel chocks and ratchet straps to eliminate corner bending — the same lesson from my first Middle East rejection
- Random-length and fixed-length orders (5.8m / 6m / 11.8m / 12m) optimized for 20ft and 40ft open-top or standard containers to maximize payload per shipment
- Each bundle marked with heat number, steel grade (Gr.B / S355 / STK400), section size, and length for immediate site identification
- Shipment terms available FOB, CIF, or DDP with full container tracking until destination port or project site
Ready to Lock in Grade, Size, and Delivery for Your Next Frame Order
Send your section schedule — size, wall thickness, steel grade, length, surface treatment, and destination port — and we return a detailed quotation with unit price, MOQ confirmation, production lead time, and the applicable mill test certificate format within 12 hours. For non-standard sizes outside the 19 × 19 to 800 × 800 range, we confirm feasibility and tooling requirements before you commit.
Request Your ASTM A500 Welded Square Steel Tube Quotation
Submit your specification list and destination to receive pricing, mill test certificate samples, and loading plan within 12 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Tel: +86 531 8573 6315
Mobile / WhatsApp / WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
Website: www.sdxjypipe.com
Frequently Asked Questions
Q: Can I order ASTM A500 Gr.B and EN S355JR square tubes from the same production batch?
A: Yes. Our ERW lines produce both ASTM A500 (Gr.B, Gr.C) and EN 10219 (S235, S275, S355JR/J2) grades on the same equipment. Each heat is tested separately, and the mill test certificate clearly states which standard the chemistry and mechanical results conform to, so you can mix grades in one container without documentation confusion.
Q: What mill test certificate format do you provide with an ASTM A500 welded square steel tube order?
A: We issue EN 10204 3.1 certificates as standard, showing heat number, chemical composition (C, Mn, Si, P, S, and any alloying elements), yield strength, tensile strength, and elongation. For projects requiring third-party witnessed testing, we arrange EN 10204 3.2 certificates through SGS or BV at the time of production.
Q: Do you supply non-standard sizes outside the 19 × 19 to 800 × 800mm range?
A: Standard stock covers 19 × 19 to 800 × 800mm in wall thickness 1–30mm. For non-standard side lengths or wall thicknesses, we review the drawing and confirm whether the section can be produced on existing tooling or requires a dedicated die. MOQ for custom sections is confirmed per order.
Q: How do you choose between black painted, galvanized, and bare finish for an ASTM A500 welded square steel tube?
A: Black painted suits indoor structural applications where further coating is not planned. Hot-dip galvanized is specified for outdoor exposure, coastal environments, or chemical plant structures where corrosion resistance is critical. Bare tubes ship with anti-rust oil and are intended for fabricators who will apply their own coating system after cutting and welding.
Q: Can you arrange third-party inspection before shipment of the ASTM A500 welded square steel tube?
A: Yes. SGS and BV inspection can be arranged at our facility before container loading. The inspection covers dimensional verification, visual weld quality, surface treatment thickness (for galvanized), and witness of mechanical testing if required. The inspection report is issued directly to the buyer.
