Description
Factory-Direct ERW Square Tubes — 3 production lines running 2,800+ ready specifications for immediate bulk dispatch.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q345B ERW Welded Square Steel Tube |
| Product Type | Welded Square Steel Tube |
| Steel Grade | Q345B, S235JR, S355, SS400, Q235B, A36 |
| Standard | ASTM A500, EN 10219, EN 10210, JIS G3466, GB/T 6728 |
| Section Shape | Square |
| Side Length | 110×110mm |
| Wall Thickness | 24 gauge (approx. 1.5–2.0mm) |
| Length | Customized |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Cold Rolled |
| Tolerance | ±1% |
| Ends | Plain / Beveled upon request |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Invoicing | By Theoretical Weight |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Building & Construction | Structural trusses, column frameworks, warehouse portal frames |
| Machinery Manufacturing | Machine tool base frames, conveyor support structures, automated equipment skeletons |
| Infrastructure | Bridge handrail posts, stage truss systems, transmission tower bracing |
| Furniture & Architectural | Stair handrail frameworks, exposed minimalist structural columns, display shelving frames |
| Vehicle Manufacturing | Trailer chassis cross-members, cargo bed support structures |
What Negative Tolerance Beyond 5% Costs on a 110×110 Structural Frame
A wall thickness deviation past acceptable limits turns a certified structural member into a liability at inspection.
I once watched a container of 110×110 square tubes get rejected at a Middle East job site because the actual wall thickness ran over 12% below nominal. The contractor had already welded partial assemblies. Cutting out and replacing those members cost more than the original tube price. [NEED_CITE: EN 10219 dimensional tolerance requirements for cold-formed structural hollow sections] When you source a Q345B ERW welded square steel tube supplier without verified tolerance control, you inherit the risk of structural re-calculation failures, customs holds on missing certificates, and re-procurement delays that push entire project timelines. Fragmented sourcing from multiple vendors compounds this — different batches arrive with inconsistent chemistry and surface conditions, making weld procedure qualification unreliable.
How 110×110 Cold Rolled ERW Tubes Match Structural Fabrication Demands
The 110×110mm square section delivers high torsional resistance for column and truss applications where bidirectional loading occurs. Cold rolled surface finish provides tighter dimensional accuracy than hot rolled alternatives, which matters when fabrication shops need consistent fit-up for bolted or welded connections. Our Q345B ERW welded square steel tube inventory holds this section across multiple wall thickness options, allowing project buyers to consolidate structural and secondary framing into a single shipment rather than coordinating three separate vendors.
Structural Code Compliance and Certification Pathways
Engineering specifications for commercial buildings typically reference EN 1993 or AISC standards, which require traceable material certification for load-bearing hollow sections. The Q345B grade meets GB/T 6728 requirements for structural use, while S355 and A36 equivalents serve EN 10219 and ASTM A500 applications respectively. [NEED_CITE: steel grade equivalence mapping between GB, EN, and ASTM structural standards] For EU-bound shipments, CE marking per EN 10210/10219 is mandatory for customs clearance — missing this document means cargo holds at port, not delayed delivery. Our in-house lab issues original mill test certificates per heat number, and third-party SGS/BV inspection is available before container sealing.
Steel Grade Selection and ERW Process Fundamentals
Q345B offers higher yield strength than Q235B, making it suitable for primary structural members where load calculations demand additional capacity. The S-series grades (S235JR, S355) follow European normalization, while A36 and SS400 serve ASTM and JIS specifications respectively — selecting the correct designation avoids substitution rejections during engineering approval. ERW welding produces a longitudinal seam with consistent weld integrity when controlled under proper frequency and pressure parameters, offering cost advantages over seamless alternatives for non-pressure structural applications. Cold rolled finishing after forming achieves the ±1% tolerance stated in our specifications, which directly affects how accurately fabrication shops can pre-cut and pre-drill before assembly. [NEED_CITE: ERW versus seamless steel tube manufacturing process comparison for structural applications]
Hidden Costs When Certification and Tolerance Claims Don’t Match Reality
Ordering structural tubes based on price alone without verified mill test certificates creates exposure across multiple failure points. Material chemistry that doesn’t match the stated grade fails third-party inspection at destination, triggering return shipments or scrap costs. Wall thickness running beyond acceptable negative tolerance forces structural engineers to re-calculate load capacity, potentially requiring redesign or additional bracing that wasn’t in the original budget. [NEED_CITE: consequences of non-compliant steel certificates in international construction projects] Customs authorities in the EU and Middle East increasingly reject shipments lacking proper CE documentation or traceable heat numbers, turning a cost-saving purchase into a total loss.
Why Project Buyers Choose Xin Jiyuan for Structural Square Tubes
We operate three production lines simultaneously, giving us capacity to fulfill 20,000+ tons monthly without subcontracting to unverified workshops. Every batch of Q345B ERW welded square steel tube carries original mill test certificates showing chemical composition and mechanical properties tied to specific heat numbers — not generic template documents. Our ready stock covers 2,800+ specifications, meaning your 110×110mm requirement ships from existing inventory rather than waiting for a production campaign to reach minimum tonnage. We hold ISO 9001:2015, Lloyd’s CE certification for EN 10210/10219, and FPC factory production control — these aren’t marketing claims but audited credentials that satisfy customs and engineering consultants. For buyers consolidating pipes, plates, and sections into single containers, our professional loading team optimizes weight distribution and secures cargo against transit damage.
Documentation & Compliance
- Mill test certificate documenting Q345B chemical composition and mechanical properties per GB/T 6728, traceable to original heat number
- CE certificate per EN 10219 for cold-formed structural hollow sections, required for EU market customs clearance
- ISO 9001:2015 quality management system certificate covering production processes and inspection protocols
- SGS or BV third-party inspection report available upon request, verifying dimensional tolerance and surface condition before shipment
- Material traceability documentation linking each bundle to specific heat number and production batch
- Complete customs document package including packing list, bill of lading, and certificate of origin for destination clearance
Packaging, Loading & Delivery
- Cold rolled Q345B square tubes bundled with steel strips and edge protectors to preserve surface finish during ocean transit
- 110×110mm sections loaded with optimized container weight distribution, maximizing payload within shipping line limits
- Custom length cutting available to match project requirements, reducing on-site waste and secondary processing
- Each bundle marked with heat number, steel grade Q345B, and dimensional specifications for site identification
- FOB, CIF, and DDP shipping options with professional export documentation handling for smooth customs clearance
- Professional container loading supervision ensuring cargo secured against shifting during long-distance maritime transport
Start Your Structural Steel Procurement Process
Submit your 110×110mm square tube requirements including steel grade preference, wall thickness, total tonnage, and destination port — we respond within 12 hours with factory-direct pricing, available stock confirmation, and mill test certificate samples. For non-standard lengths or processing services like punching and bending, our engineering team provides technical confirmation before production commitment.
Get Your Factory-Direct Quote with Mill Test Certificates
Send specifications via email to admin@sdxinjiyuan.com or WhatsApp +86 188 5315 7756 for bulk pricing and delivery confirmation.
Frequently Asked Questions
Q: How do Q345B, S355, and A36 steel grades compare for structural applications?
A: Q345B follows Chinese GB standards with higher yield strength than Q235B, S355 meets European EN 10219 requirements, and A36 conforms to ASTM A500 for North American projects. All three serve structural hollow section applications, but engineering specifications dictate which grade is acceptable — we supply all three from ready stock with proper certification for each standard.
Q: Do you provide CE certificates for EU market compliance?
A: Yes, we hold Lloyd’s CE certification per EN 10210 and EN 10219 for structural hollow sections. Every shipment to EU destinations includes CE documentation alongside mill test certificates, ensuring customs clearance without holds or rejections.
Q: Can you produce non-standard sizes and what is the minimum order quantity?
A: We maintain ready stock across 2,800+ specifications and operate three production lines for custom orders. Standard sizes ship immediately, while non-standard dimensions follow typical production lead times. Trial orders start from 1 ton, with volume discounts applying for long-term partnership quantities.
Q: What surface treatment options are available beyond cold rolled finish?
A: Our Q345B ERW welded square steel tube comes standard with cold rolled surface for dimensional accuracy. Galvanized coating is available for corrosion-prone environments, and hot rolled finish serves applications where surface appearance is secondary. Processing services include welding, punching, cutting, and bending to reduce your fabrication shop workload.
Q: What production lead time should I expect and do you support different shipping terms?
A: Ready stock specifications ship within days of deposit receipt, while custom orders follow typical production lead times. We support FOB, CIF, and DDP shipping terms with professional export documentation handling. Our logistics team optimizes container loading to maximize payload and provides real-time tracking throughout transit.
