Description
Factory-Direct Welded SHS — 2,800+ specifications in ready stock for immediate dispatch
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Carbon Steel Welded Square Steel Tube |
| Product Type | Welded Square Hollow Structural Section (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 (Electric Resistance Welded) |
| Surface Treatment | Black Painting / Galvanized / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Processing Service | Bending, Cutting |
| Invoicing | By Theoretical Weight |
| Packing | Below 8 inch in bundles; above 8 inch in bulk; Standard Seaworthy Packing |
| Application | Construction structures / Building frames / Curtain wall supports / Structural tubes / Machinery / Scaffolding |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Building & Construction | Structural columns, roof trusses, floor beam grids, portal frame systems |
| Facade & Curtain Wall | Mullion supports, transom framing, cladding sub-structures |
| Industrial & Machinery | Equipment bases, conveyor frame structures, machine guarding frames |
| Infrastructure & Scaffolding | Scaffolding uprights, cross bracing, temporary works platforms |
What Wall-Thickness Tolerance Costs on an ASTM A500 Welded Square Steel Tube Order
Tolerance drift on welded SHS does not show until the first connection plate fails to sit flush.
When wall thickness runs below the specified tolerance on a structural frame order, the consequences compound silently. Beam-to-column connections designed for a given section modulus lose bearing contact, bolt holes misalign, and field crews waste hours shimming or re-drilling. On projects governed by ASTM A500 compliance, inspectors flag sections that measure outside the ±1% envelope — even if the theoretical weight invoiced appears correct. [NEED_CITE: ASTM A500 dimensional tolerance requirements for cold-formed hollow sections] The real cost is not the missing steel; it is the rework, the delayed handover, and the eroded trust between contractor and supplier.
How This SHS Range Matches Structural Frame and Scaffolding Demands
An ASTM A500 welded square steel tube spanning 19×19mm to 800×800mm covers the full spectrum from light curtain wall mullions to heavy portal frame columns. The ERW welding process produces a consistent longitudinal seam suited to axial compression and bending in building frames, while the ±1% wall thickness tolerance ensures predictable section properties for structural calculation. For scaffolding applications, the 1–30mm wall range allows contractors to select lighter sections for bracing and heavier sections for uprights — all from one supplier holding ready stock across 2,800+ specifications.
Structural Compliance and Surface Protection for Site Conditions
Load-bearing frames designed to EN 1993 or AISC standards require verified section properties that depend directly on wall thickness and dimensional accuracy. [NEED_CITE: EN 10219 cold-formed welded structural hollow sections dimensional and mass tolerances] For outdoor or coastal environments, galvanized surface treatment provides long-term corrosion resistance without field painting, while black painted or varnished finishes suit interior or temporary applications where cost matters more than durability. Steel grade selection — S235 for light structures, S355 for heavily loaded frames — directly determines the member sizes required and therefore the overall tonnage and cost of the project. Third-party inspection by SGS or BV before shipment confirms that the mill test certificates match the physical material loaded. [NEED_CITE: steel grade equivalence between ASTM A500 Gr.B and EN S235/S355]
Welded Process, Steel Grade Selection, and Surface Treatment Trade-Offs
The ERW (Electric Resistance Welded) process forms the square section by cold-rolling a flat strip into shape and welding the seam through electrical resistance heating — producing a clean, consistent joint suitable for structural applications up to moderate wall thicknesses. Steel grades follow distinct international systems: ASTM A500 Gr.B serves North American projects, EN S235/S275/S355 cover European and African markets with incrementally higher yield strength, and JIS STK400 specifies structural use in Asian markets. Surface treatment choice depends on the service environment: hot-dip galvanizing adds a zinc layer for corrosion resistance in outdoor or humid conditions, black painting provides basic protection for indoor use, and bare or varnished finishes suit applications where the tube will be painted on-site or enclosed within a building envelope. Wall thickness tolerance of ±1% ensures that theoretical weight invoicing aligns with actual section properties, preventing disputes over material received versus material specified.
The Hidden Cost of Unverified Tolerance and Missing Certification
Purchasing an ASTM A500 welded square steel tube without verified mill test certificates creates risk that surfaces only at project inspection. Material that fails to meet the specified steel grade chemistry or yield strength will not pass structural engineer approval, forcing replacement at the contractor’s expense. [NEED_CITE: consequences of non-compliant structural steel in building construction] Negative tolerance exceeding the ±1% threshold reduces the actual load-bearing capacity below the design assumption — a safety concern that no amount of cost-saving justifies. Customs clearance delays occur when certificates are missing, incomplete, or do not match the physical shipment, leaving containers stranded at port while demurrage charges accumulate.
Procurement Confidence from Factory-Direct Supply
Every ASTM A500 welded square steel tube shipped from our Jinan facility comes directly from our own ERW production lines — no trading markup, no intermediary handling. Our in-house metallurgical laboratory tests every heat number for chemical composition and mechanical properties, issuing original mill test certificates that accompany each batch. With 2,800+ specifications held in ready stock, urgent orders and split shipments can be fulfilled without waiting for production scheduling. We hold ISO 9001:2015, Lloyd’s CE (EN 10210/EN 10219), and FPC certifications, and welcome SGS or BV third-party inspection before loading. Our professional export team handles container loading optimization — consolidating mixed-size shipments to minimize freight cost per ton — and prepares complete customs documentation for smooth clearance at destination ports.
Documentation & Compliance
- Mill test certificate documenting Gr.B, S235, S275, S355, or STK400 chemical composition and mechanical properties per ASTM A500 or EN 10219
- CE certificate (EN 10210 / EN 10219) for European market structural hollow section compliance
- ISO 9001:2015 quality management system certificate covering ERW welded square tube production
- SGS or BV third-party inspection report available on request, covering dimensional check, visual inspection, and witness testing
- Full material traceability by heat number from coil input through finished welded square tube
- Export customs documents: packing list, bill of lading, certificate of origin, commercial invoice
Packaging, Loading & Delivery
- Small-section welded square tubes (below 8 inch) packed in steel strip bundles; large sections (above 8 inch) loaded in bulk with dunnage separation to prevent surface damage during transit
- Galvanized SHS bundled with edge protectors and wrapped to preserve the zinc coating against moisture and abrasion during ocean freight
- Container loading optimized by our export team: mixed-size shipments of 19×19mm through 800×800mm sections nested to maximize payload per 20ft or 40ft container
- Random length or cut-to-order 5.8m / 6m / 11.8m / 12m lengths available, with cutting and bending processing services completed before packing
- Each bundle marked with heat number, steel grade (S355, Gr.B, etc.), size, and length for site identification and traceability
- FOB, CIF, and DDP terms available with professional documentation handling for customs clearance at destination
Ready to Specify Your ASTM A500 Welded Square Steel Tube Requirement
Submit your section size, wall thickness, steel grade, quantity, and destination port — our team responds within 12 hours with factory-direct pricing, available stock confirmation, and mill test certificate samples. For non-standard sizes or custom lengths, we provide production scheduling and lead time confirmation before you commit.
Request Your Factory-Direct SHS Quote with Mill Test Certificate
Send your specification list to admin@sdxinjiyuan.com or contact us via WhatsApp at +86 188 5315 7756 for pricing, stock availability, and certification documentation.
Frequently Asked Questions
Q: What is the difference between ASTM A500 Gr.B and EN S355 for welded square steel tube?
A: ASTM A500 Gr.B is the standard specification for cold-formed welded structural tubing in North American markets, while EN S355 (per EN 10219) is the European equivalent with higher yield strength. Both grades are available in our welded square tube range, and we provide mill test certificates confirming compliance with the specified standard.
Q: Can third-party inspection be arranged before shipment?
A: Yes. SGS and BV third-party inspections are available on request, covering dimensional verification, visual weld inspection, and witness testing. Inspection reports are issued before container loading and accompany the shipment documentation.
Q: What is the minimum order quantity for custom non-standard sizes?
A: Our standard MOQ is 5 tons. For non-standard sizes outside our 19×19mm to 800×800mm ready stock range, production lead times apply — contact us with your specification for scheduling confirmation.
Q: How are welded square tubes invoiced — by theoretical weight or actual weight?
A: All welded square tubes are invoiced by theoretical weight based on the specified dimensions and wall thickness, calculated per the standard formula for square hollow sections. The ±1% tolerance ensures alignment between theoretical and actual weight.
Q: What surface treatment options are available for outdoor applications?
A: Hot-dip galvanized surface treatment provides long-term corrosion resistance for outdoor, coastal, or high-humidity environments. Black painted and varnished finishes are available for indoor or temporary applications where cost optimization is the priority.
