Description
Factory-Direct ERW Square Tubes — Every batch of ASTM A500 welded square steel tube ships with original mill test certificates and CE/ISO documentation, eliminating middleman markups on bulk structural orders.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500 Welded Square Steel Tube |
| Product Type | Welded Square Steel Tube |
| 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 structure / Building frames / Curtain wall / Support tubes / Structural pipe |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial Construction | Building frames, column supports, mezzanine structures |
| Façade Engineering | Curtain wall mullions, cladding support tubes |
| Industrial Infrastructure | Equipment support structures, conveyor frame bases, warehouse racking uprights |
| Civil Engineering | Bridge handrail posts, sound barrier frames, utility pole bases |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
A ±1% tolerance on an ASTM A500 welded square steel tube is the difference between passing third-party inspection and losing an entire container at port.
I have seen procurement teams order welded square tubes only to discover that wall thickness drifts beyond acceptable limits during production. When negative tolerance pushes actual measurements below the minimum specified in ASTM A500, the material fails structural load calculations regardless of what the paperwork says. [NEED_CITE: ASTM A500 dimensional tolerance requirements for cold-formed welded structural tubing] Engineers then face a choice: reject the shipment and delay the project by weeks, or accept material that may not perform under design loads. Fragmented sourcing makes this worse — buying pipes from one supplier and beams from another means no single party takes responsibility for dimensional consistency across the full material package.
Matching ERW Square Tubes to Structural Frame Requirements
An ASTM A500 welded square steel tube in S355 or Gr.B grade fits directly into building frame designs where square geometry simplifies bolted and welded connections at beam-column joints. The flat bearing surfaces of square sections allow direct contact with gusset plates and base plates without additional machining, reducing fabrication time on site. For curtain wall systems, the consistent ±1% tolerance across 19×19mm to 800×800mm profiles ensures that mullion alignment stays within architectural specifications even across long runs. Our dedicated ERW lines produce these sections with controlled weld penetration, and every batch goes through three-stage in-house inspection before release.
Structural Code Compliance and Surface Protection Strategy
Load-bearing frames designed under EN 1993 or AISC 360 require documented proof that steel grades meet minimum yield criteria — this is where original mill test certificates become non-negotiable for customs and engineering sign-off. [NEED_CITE: EN 10219 cold-formed welded hollow section compliance for structural applications] In coastal or industrial environments, specifying galvanized surface treatment on ASTM A500 welded square steel tube extends service life without adding ongoing maintenance costs. For interior or temporary structures, black painted or bare finishes reduce unit cost while still meeting short-term project requirements. Steel grade selection directly affects load capacity: S355 delivers higher yield strength than S235 in identical cross-sections, allowing lighter sections to carry the same design loads.
Understanding ERW Welding and Multi-Grade Coverage
The ERW (Electric Resistance Welding) process forms square tubes by rolling steel strip into shape and fusing the seam through electrical resistance heat — this produces a continuous weld line with consistent mechanical properties along the full length. ASTM A500 Gr.B and EN 10210 S355 represent different standardization systems but serve overlapping structural applications; Gr.B aligns with North American construction codes while S235/S275/S355 follow European metric grading where the number indicates minimum yield strength in MPa. [NEED_CITE: steel grade equivalence between ASTM A500 and EN 10210 standards] STK400 covers Japanese industrial applications, and GB/T 3091 serves domestic Chinese projects — our production lines cover all five grades without minimum order penalties for switching between them. Wall thickness from 1mm to 30mm spans light-gauge framing to heavy structural columns, and the ±1% tolerance applies uniformly across this range. Surface treatment choice — galvanized for corrosion resistance, black painting for general protection, varnish for temporary storage, or bare for further processing — should align with the installation environment and project timeline.
Hidden Costs of Sourcing Without Verified Certification
Choosing the lowest quoted price on an ASTM A500 welded square steel tube often means accepting material with unverified chemistry and undocumented wall thickness. When customs authorities at the destination port request mill test certificates that do not exist or show mismatched heat numbers, the entire container sits in bonded storage accumulating daily charges. [NEED_CITE: import documentation requirements for structural steel products] On site, if third-party inspectors discover that actual wall thickness falls below the specified minimum due to excessive negative tolerance, the engineering team must either redesign the structure around weaker material or replace every affected piece — both options cost far more than paying for verified supply from the start. Missing CE certification blocks entry into European markets entirely, regardless of physical material quality.
Direct Factory Supply with Full Documentation Control
As a manufacturer operating three dedicated production lines with monthly capacity exceeding 20,000 tons, we control every stage from raw material intake to final container loading — there are no trading intermediaries adding cost or obscuring material origin. Our in-house laboratory performs chemical composition analysis and mechanical testing on every heat, producing original mill test certificates that travel with each shipment. The factory holds ISO 9001:2015 and CE (EN 10210/10219) certifications, and we arrange SGS or BV third-party inspection at the buyer’s request before dispatch. With over 2,800 specifications in ready stock covering square tubes from 19×19mm to 800×800mm, urgent project requirements can be met without waiting for production scheduling. Our export team handles complete documentation packages including packing lists, bills of lading, and certificates of origin, and optimizes container loading plans to maximize weight utilization for heavy-wall sections.
Documentation & Compliance
- Mill test certificate documenting Gr.B / S355 chemical composition and mechanical properties per ASTM A500 or EN 10219, traceable to heat number
- CE certificate confirming compliance with EN 10210 (seamless) and EN 10219 (welded) hollow section standards for European market access
- ISO 9001:2015 quality management certificate covering full production and inspection processes
- SGS or BV third-party inspection report available upon request, verifying dimensions, surface quality, and mechanical properties before shipment
- Material traceability by heat number linking each bundle to its original mill test certificate and production batch
- Complete customs documentation package including packing list, bill of lading, and certificate of origin for destination-country clearance
Packaging, Loading & Delivery
- ERW welded square tubes bundled with steel strips and edge protectors, sized to match 5.8m / 6m / 12m lengths for secure ocean transit
- Galvanized ASTM A500 welded square steel tube surfaces protected with plastic wrapping to prevent zinc coating damage during handling and shipping
- Container loading plans optimized for square tube geometry, maximizing weight per 20ft or 40ft container based on wall thickness and side length
- Random or fixed cut lengths available to match project requirements, reducing on-site cutting waste for construction frame applications
- Each bundle marked with heat number, steel grade (Gr.B / S355 / etc.), dimensions, and purchase order reference for site identification
- FOB / CIF / DDP shipping terms supported with professional export documentation and real-time shipment tracking
Requesting a Quote for Your Structural Tube Requirements
Submit your specifications including side length, wall thickness, steel grade, total quantity, and destination port to receive a detailed quotation with volume pricing and production lead time. We provide mill test certificates and third-party inspection options before shipment, and our export team confirms container loading plans and documentation requirements for your destination country.
Start Your ASTM A500 Welded Square Steel Tube Order
Send your specifications and quantity to receive factory-direct pricing with original mill test certificates within 12 hours.
Company: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxinjiyuan.com
