Description
Factory-Direct Thick-Wall Tube Supply — ASTM A500 seamless square and rectangular hollow sections rolled in-house across three production lines, shipped with original mill test certificates and no broker markup.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500 Seamless Square Steel Tube |
| Product Type | Seamless Square and Rectangular Steel Tube / Hollow Section |
| Steel Grade | ASTM A500, Q195, Q235, Q345, S235JR, S275JR, S355JR, 20#, S20C, S10C, S15C, SS400 |
| Standard | ASTM A500, ASTM A213, DIN EN 10217-1, GB |
| Section Shape | Square / Rectangular |
| Size Range | 15×15 mm – 500×500 mm (Square); 20×30 mm – 800×1200 mm (Rectangular) |
| Wall Thickness | 0.5 mm – 12 mm |
| Length | 5.8 m – 12 m (or as required) |
| Technique | Seamless (Hot Rolled) |
| Surface Treatment | Black / Bright / Galvanized (40–500 g/m²) / Painted |
| Tolerance | ±1% |
| Ends | Plain |
| Processing Service | Welding, Punching, Cutting, Bending |
| Application | Steel structures, machinery, scaffolding, furniture, industrial equipment frames |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Infrastructure & Construction | Building frames, column supports, beam-to-column connections in commercial and industrial structures |
| EPC & Scaffolding | Heavy-duty scaffolding uprights, shore towers, temporary support frameworks on civil engineering sites |
| Machinery Manufacturing | Equipment base frames, conveyor support structures, hydraulic press columns |
| Structural Fabrication | Welded portal frames, mezzanine structures, load-bearing bracing members |
| Furniture & Decorative | Architectural exposed frames, canopy supports, interior structural columns |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
A ±1% tolerance on a 12 mm thick-wall ASTM A500 tube is the line between passing structural inspection and scrapping a container at the port.
When buyers source thick-wall seamless square tubes from fragmented suppliers, wall thickness often drifts beyond the stated tolerance — especially on the inner surface where hot-rolled seamless processes are hardest to control. I have seen entire shipments of ASTM A500 Grade C square tubes held at destination ports because SGS复检 found negative tolerance exceeding the allowable limit, pushing theoretical weight far above actual delivered weight. The buyer paid for 12 mm wall and received 10.8 mm in places. The structural engineer refused to sign off. Three weeks of delay, re-inspection fees, and a partial reorder that arrived after the crane rental window had closed. [NEED_CITE: ASTM A500 dimensional tolerance requirements for structural hollow sections]
Matching Load-Bearing Capacity to Structural Design Codes
An ASTM A500 thick wall seamless square steel tube sized at 200×200×10 mm delivers the section modulus and radius of gyration that structural engineers specify for column and beam applications in both AISC 360 and EN 1993-1-1 frameworks. The seamless hot-rolled process eliminates the weld seam found in ERW alternatives, giving uniform strength around the entire perimeter — critical when the tube is subjected to multi-axial loading in moment-resisting frames. For scaffolding and heavy-duty support structures, the 12 mm maximum wall thickness in our range covers the upper end of load requirements without stepping into heavier welded box sections that cost more per meter and weigh more per lift.
Engineering Compliance Across ASTM, EN, and GB Standards
Structural projects in North America require ASTM A500 Grade B or C compliance with documented chemical composition and mechanical properties; EU projects demand EN 10210 or EN 10219 conformity with CE marking; Middle East and African infrastructure tenders often accept GB/T 6728 or equivalent with mill test certificates traceable to heat numbers. Our ASTM A500 thick wall seamless square steel tube production covers all three standard families, with steel grades spanning Q195–Q345 (GB), S235JR–S355JR (EN), and ASTM A500 Grades A/B/C — allowing buyers to consolidate multi-standard orders into a single shipment. Third-party inspection by SGS or BV is arranged before loading, and every batch ships with original mill test certificates documenting heat number, chemical analysis, and tensile test results. [NEED_CITE: steel grade equivalence mapping between ASTM A500 and EN 10210]
Steel Grade Selection and Hot-Rolled Seamless Process Logic
The ASTM A500 specification covers three grades — A, B, and C — with increasing carbon content and yield strength, where Grade C (minimum 345 MPa yield) is the default for structural columns and heavy load-bearing frames. In the Chinese GB system, Q345 (now redesignated Q355) offers comparable performance to ASTM A500 Grade C, while Q235 maps to Grade B. European S355JR provides similar yield with guaranteed impact toughness at room temperature, making it the preferred choice for dynamic loading applications. The hot-rolled seamless process starts from solid round billets pierced and elongated through a mandrel mill, producing a tube with no longitudinal weld — this matters for thick-wall sections above 8 mm where ERW weld integrity becomes harder to verify ultrasonically. Surface treatment options include black (as-rolled), bright (pickled and oiled), galvanized at 40–500 g/m² zinc coating for outdoor or marine environments, and painted finishes for architectural exposure.
Hidden Costs of Sourcing Without Verified Mill Certificates
Purchasing an ASTM A500 thick wall seamless square steel tube without original mill test certificates means the buyer cannot prove material grade to the project owner or the structural engineer. If the tube fails visual inspection or ultrasonic testing at the construction site, the entire batch must be removed and replaced — at the buyer’s cost. Customs authorities in the EU, GCC, and parts of Africa routinely hold steel imports lacking CE documentation or traceable heat numbers, charging demurrage per container per day. [NEED_CITE: customs documentation requirements for structural steel imports in EU and GCC markets] Negative tolerance abuse — where the supplier invoices on theoretical weight but delivers wall thickness below the minimum allowed — transfers cost directly to the buyer while reducing the structural capacity of the member below what the engineer calculated.
Why Project Buyers Source This ASTM A500 Thick Wall Seamless Square Steel Tube From Us
Our Jinan facility operates three simultaneous production lines with monthly capacity exceeding 20,000 tons, covering over 2,800 specifications in square, rectangular, and round hollow sections — meaning your 200×200×10 ASTM A500 Grade C order ships from ready stock rather than entering a production queue. Every tube leaves our in-house laboratory with a mill test certificate tied to its heat number; we do not outsource testing to third-party labs and then guess at the results. For buyers consolidating pipes, plates, and section steel into multi-product containers, we handle the loading plan to maximize weight per TEU and minimize freight cost per ton delivered. ISO 9001:2015 and Lloyd’s CE certification under EN 10210/10219 are maintained across the product range, and SGS or BV inspection is scheduled at the buyer’s request before container sealing. Flexible MOQ from 1 ton trial orders to full-container bulk shipments means new buyers can verify quality before committing to annual volume contracts with tiered pricing.
Documentation & Compliance
- Mill test certificate documenting ASTM A500 Grade B/C chemical composition, yield strength, and tensile properties per heat number
- CE certificate under EN 10210/EN 10219 for structural hollow sections exported to EU and GCC markets
- ISO 9001:2015 quality management certificate covering the full production and inspection process
- SGS or BV third-party inspection report available on request, covering dimensional checks, surface quality, and witness testing
- Full material traceability from billet heat number through final bundle identification
- Customs documentation package including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Thick-wall seamless square tubes bundled with high-tensile steel strips at intervals matching the 5.8 m–12 m length range, with edge protectors to prevent bundle damage during crane handling
- Galvanized ASTM A500 tubes wrapped with waterproof paper and plastic film to preserve the zinc coating during ocean transit and port storage
- Container loading plans optimized for 20-foot and 40-foot heavy-test containers, maximizing payload within road weight limits at destination
- Custom cut-to-length service available for 12 mm wall thickness tubes ordered in non-standard lengths, reducing on-site cutting waste
- Each bundle labeled with heat number, steel grade (e.g., ASTM A500 Grade C), section size, and wall thickness for site identification
- FOB, CIF, and DDP shipping terms available with professional export documentation handling
Starting Your ASTM A500 Thick Wall Seamless Square Steel Tube Inquiry
Send your specification sheet — section size, wall thickness, steel grade, total tonnage, and destination port — and receive a competitive bulk quotation within twelve hours, complete with mill test certificate samples and container loading estimates. For non-standard sizes outside the 15×15 mm to 500×500 mm range or custom surface treatment requirements, our technical team provides a feasibility assessment and production timeline.
Request Your ASTM A500 Thick Wall Seamless Square Steel Tube Quotation
Submit your specifications via email or WhatsApp to receive factory-direct pricing, mill test certificate samples, and container loading plans within 12 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Email: admin@sdxinjiyuan.com
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Tel: +86 531 8573 6315
Frequently Asked Questions
Q: What is the difference between ASTM A500 Grade B and Grade C for seamless square tubes?
A: ASTM A500 Grade C has higher carbon content and a minimum yield strength of 345 MPa compared to Grade B at 290 MPa, making Grade C the preferred choice for structural columns and heavy load-bearing applications where higher strength-to-weight ratio is required.
Q: Can I order ASTM A500 seamless square tubes in non-standard sizes outside your listed range?
A: Yes, custom sizes outside the standard 15×15 mm to 500×500 mm square range or 20×30 mm to 800×1200 mm rectangular range are available for bulk orders, with typical production lead times of 15–25 days depending on specification complexity.
Q: What documentation is included with each shipment of ASTM A500 thick wall seamless square steel tubes?
A: Every batch ships with original mill test certificates documenting chemical composition and mechanical properties per heat number, and we arrange SGS or BV third-party inspection on request for independent verification before container loading.
Q: How does theoretical weight invoicing work for thick-wall seamless square tubes?
A: Invoicing is calculated by theoretical weight based on the ordered section size and wall thickness; our production maintains ±1% tolerance on wall thickness to ensure delivered actual weight aligns closely with invoiced theoretical weight, avoiding the negative tolerance disputes common in the market.
Q: Do you provide galvanized surface treatment for ASTM A500 seamless square tubes?
A: Yes, galvanized surface treatment is available with zinc coating ranging from 40 g/m² to 500 g/m², suitable for outdoor structural applications, marine environments, and projects requiring extended corrosion resistance without field painting.
