Description
Factory-Direct ASTM A500 ERW Square Steel Tube — 3 production lines running simultaneously, delivering 10×10mm to 600×600mm welded SHS with original mill test certificates on every batch.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500 ERW Square Steel Tube |
| Product Type | Square Steel Tube (Welded ERW) |
| Steel Grade | Q195, Q215, Q235, Q345, GR.A, GR.B, S235, S355 |
| Standard | ASTM A500 |
| Section Shape | Square |
| Size Range | 10×10mm – 600×600mm |
| Wall Thickness | 0.8 – 30 mm |
| Length | 5.7m / 6m |
| Technique | Welded ERW |
| Surface Treatment | Pre-galvanized / Hot-dipped galvanized / Bare / Oiled |
| Tolerance | ±1% |
| Ends | Plain (default) |
| Application | Steel structures / Construction frames / Machinery / Scaffolding / Furniture / Fluid transport / Structural piping |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, scaffolding uprights, column supports, roof truss members |
| Machinery & Equipment | Machine base frames, conveyor structures, industrial platform supports |
| Steel Fabrication | Welded structural assemblies, bracket systems, load-bearing frames |
| Furniture & Interior | Table legs, shelving frames, display rack structures |
| Fluid Transport | Low-pressure pipeline systems, hydraulic conduit piping |
What Negative Tolerance Really Costs on an ASTM A500 ERW Square Steel Tube Order
A ±1% wall-thickness tolerance keeps theoretical weight aligned with actual weight — and keeps your project budget intact.
I once watched an entire container of square tubes get rejected at an African port because the wall thickness had been pushed so far into negative tolerance that the actual weight fell well short of the invoiced theoretical weight. The buyer paid for steel they never received. That kind of gap between what’s on the mill certificate and what arrives on site doesn’t just hurt your wallet — it fails structural inspections and halts construction timelines. When sourcing an ASTM A500 ERW square steel tube supplier, verifying tolerance control is just as critical as checking the steel grade. [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements]
How Size Range and Wall Thickness Match Structural Load Requirements
The 10×10mm to 600×600mm size range with wall thickness from 0.8mm to 30mm means a single ASTM A500 ERW square steel tube order can cover everything from light furniture frames to heavy-load structural columns. Smaller sections with thinner walls serve non-load-bearing applications like scaffolding and interior framing, while larger sections with thicker walls handle primary structural members in building frames and machinery bases. Our 3 production lines allow mixed-size container loading, so you don’t need separate suppliers for different dimension ranges.
Engineering Compliance and Certification Requirements for Structural Piping
Structural square tubes used in load-bearing frames must conform to recognized engineering standards. ASTM A500 Grade B is the default specification across North American construction projects, while S235 and S355 grades align with European design codes. [NEED_CITE: steel grade equivalence between ASTM A500 and EN 10219 standards] CE certification under EN 10210/EN 10219 is mandatory for shipments entering the European market — missing this document means customs holds and potential rejection at the port of entry. Our production carries CE (EN 10210/10219) and ISO 9001:2015 certification, and every batch ships with original mill test certificates documenting chemical composition and mechanical properties. For projects requiring independent verification, SGS or BV third-party inspection is available before shipment.
Steel Grade Selection and ERW Welding Process Explained
The steel grades offered — Q195, Q215, Q235, Q345 in the Chinese system, GR.A and GR.B under ASTM A500, and S235, S355 per European standards — represent increasing yield strength levels. Q195 and GR.A suit light-duty applications where formability matters more than load capacity, while Q345, GR.B, and S355 are specified for primary structural members requiring higher strength-to-weight ratios. The ERW (Electric Resistance Welding) process forms the square profile from coiled steel strip, welding the seam through high-frequency current. This method delivers consistent wall thickness and tight dimensional tolerance across the full 10×10mm to 600×600mm range at lower cost than seamless alternatives. Every tube undergoes 100% water pressure testing and three-stage in-house inspection — raw material verification, in-process weld monitoring, and pre-shipment dimensional checks. Surface treatment options include pre-galvanized for indoor or mild environments, hot-dipped galvanized for outdoor or corrosive conditions, bare for applications where painting or coating follows, and oiled for temporary rust prevention during transit.
The Hidden Cost of Unverified Steel Grades and Missing Certificates
Ordering square tubes without verified mill test certificates creates a chain of risk: the steel grade may not match what was specified, the wall thickness may deviate beyond acceptable tolerance, and the weld seam may lack proper fusion. When these issues surface during on-site inspection or structural load testing, the consequences include project shutdowns, mandatory material replacement, and contractual penalties for delayed completion. [NEED_CITE: structural steel procurement compliance and material traceability requirements] An ASTM A500 ERW square steel tube supplier who provides original mill certificates with heat number traceability eliminates this risk at the source.
Procurement Confidence Through Factory-Direct Supply and Quality Control
Working directly with the manufacturer means no trading markup and direct accountability for every specification. Our Jinan facility operates 3 production lines with monthly capacity exceeding 20,000 tons, covering over 2,800 specifications across all major steel product categories. Each shipment includes original mill test certificates — not copies or templates — with full chemical composition and mechanical property data traceable to heat numbers. Third-party inspection through SGS or BV can be arranged before container sealing. For long-term partners, volume-based pricing programs and consolidated multi-product container loading reduce per-unit costs and simplify logistics across multiple product categories.
Documentation & Compliance
- Mill test certificate documenting Q235/Q345/GR.B chemical composition and mechanical properties per ASTM A500, traceable by heat number
- CE certificate under EN 10210/10219 for European market compliance on structural hollow sections
- ISO 9001:2015 quality management system certificate covering the full production process
- SGS or BV third-party inspection report available upon request, covering dimensional checks, surface quality, and weld integrity
- Material traceability documentation linking each bundle to its original heat number and production batch
- Full customs document package including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Bare and oiled ASTM A500 ERW square steel tubes packed in steel-strip bundles with waterproof wrapping, sized for 5.7m and 6m lengths to maximize container space
- Pre-galvanized and hot-dipped galvanized tubes bundled with edge protectors and plastic caps to preserve the zinc coating during ocean transit
- Mixed-size container loading optimization: combining 10×10mm small sections with 600×600mm large sections in a single shipment to fill container capacity efficiently
- Heat number and steel grade stenciled on each bundle for on-site identification and traceability verification
- FOB, CIF, and DDP shipping terms available with professional export documentation handling
Request a Quote with Mill Test Certificate
Submit your specification list — size, wall thickness, steel grade, surface treatment, quantity, and destination port — to receive a competitive bulk quotation with volume pricing and typical production lead times. We respond within 12 hours with pricing, delivery schedule, and sample mill test certificate documentation for your review.
Frequently Asked Questions
Q: What is the difference between GR.A, GR.B, Q235, and S235 for ASTM A500 ERW square steel tubes?
A: These grades represent different standard systems but serve similar structural purposes. GR.A and GR.B are ASTM A500 designations for North American projects. Q235 and Q345 are Chinese national standards. S235 and S355 follow European EN standards. We supply all grades and can advise on equivalence based on your project specification.
Q: Can I get a mill test certificate before placing a bulk order?
A: Yes. Original mill test certificates from previous production runs are available for review. For active orders, every batch ships with its own MTC documenting chemical composition and mechanical properties, traceable by heat number.
Q: What is the minimum order quantity for non-standard sizes?
A: The MOQ is 1 Ton, whether you need standard catalog sizes or custom dimensions. Trial orders are accepted, and we support split shipments for projects with phased delivery requirements.
Q: How do you handle wall thickness tolerance to avoid weight discrepancies?
A: Our ERW production maintains ±1% wall thickness tolerance, verified through in-process inspection at three stages. This ensures the actual weight stays aligned with theoretical calculations, preventing the invoicing and inspection issues that arise from excessive negative tolerance.
Q: Do you offer third-party inspection before shipment?
A: Yes. SGS and BV third-party inspections are available on request. The inspection covers dimensional verification, surface quality assessment, weld seam integrity, and documentation review before container sealing.
Get Your ASTM A500 ERW Square Steel Tube Quote Today
Send your specifications to admin@sdxinjiyuan.com or reach us via WhatsApp at +86 188 5315 7756 for pricing, mill test certificates, and delivery schedules.
