Description
Full-Range Seamless Hollow Sections — 2,800+ specifications from a single certified source.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Seamless Square and Rectangular Hollow Sections |
| Product Type | Seamless Square and Rectangular Steel Tube |
| Steel Grade | Q195, Q215, Q235, Q345, 20#, 45#, S195, S235, S355, A53 Grade A, A53 Grade B, A500 Grade A, A500 Grade B, A500 Grade C, STK400, SS400, ST42.2, S355JR, A36 |
| Standard | EN10219, EN10210, GB/T 6728, JIS G3466, ASTM A500, ASTM A53, ASTM A36 |
| Section Shape | Square, Rectangular, Round |
| Size Range (Square) | 20×20mm – 500×500mm |
| Size Range (Rectangular) | 20×40mm – 300×500mm |
| Wall Thickness | 1.2mm – 20mm |
| Length | 3m – 12m (random) |
| Technique | Hot Rolled / Seamless |
| Surface Treatment | Pre-galvanized (40–80g/m²), Hot-dipped galvanized (200–600g/m²), or per customer requirement |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Steel structures, Construction frames, Solar structure components, Fence posts, Greenhouse frames, Machinery manufacturing, Shipbuilding, Power engineering, Pressure vessels, Bridges, Highway railings |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors | Solar mounting structures, bridge support frames, power engineering frameworks |
| Construction Companies | High-rise building frames, greenhouse structural frames, infrastructure fencing posts |
| Machinery Manufacturers | Equipment load-bearing frames, precision hollow sections for conveyor systems |
| Infrastructure & Civil Engineering | Highway railings, shipbuilding structural members, pressure vessel shells |
Where Wall-Thickness Tolerance Decides Whether a Container Gets Rejected at Site
A ±1% tolerance on a 500×500×20mm Seamless Square and Rectangular Hollow Sections order is the difference between passing structural inspection and scrapping an entire shipment.
I have watched project managers in the Middle East pull out digital calipers on the dock and reject a full container because the wall thickness on a 200×200×10mm section measured 9.3mm instead of the nominal 10mm. When negative tolerance runs unchecked, the theoretical weight calculation collapses — you lose structural load capacity, the mill test certificate no longer matches the physical product, and customs agents flag the shipment for re-inspection. [NEED_CITE: EN 10219 dimensional tolerance requirements for cold-formed hollow sections] Fragmented sourcing makes this worse: when pipes, plates, and beams come from three different suppliers, nobody owns the tolerance chain, and the contractor absorbs every delay.
How Seamless Hollow Sections Match Structural Load Requirements Across Project Types
When an EPC contractor specifies Q345 or S355JR for a solar mounting structure or bridge support frame, the Seamless Square and Rectangular Hollow Sections must deliver consistent yield behavior across every piece in the order. Our hot-rolled seamless process produces walls from 1.2mm to 20mm with ±1% tolerance, meaning a 300×500mm rectangular section ordered for a power engineering framework arrives with uniform load distribution — no weak spots from weld seams. For machinery manufacturers building conveyor frames, the tight tolerance ensures precision fit-up during fabrication, reducing on-site rework.
Engineering Compliance: From EN10210 in Europe to ASTM A500 in North America
Structural hollow sections used in load-bearing applications must comply with regional engineering codes. Seamless Square and Rectangular Hollow Sections produced to EN10210 and EN10219 carry CE marking required for EU customs clearance, while ASTM A500 Grade B and Grade C sections meet North American structural specifications. [NEED_CITE: ASTM A500 cold-formed welding structural tubing requirements] For Southeast Asian infrastructure projects, Singapore FPC certification ensures local regulatory acceptance. The choice between Q235 (Chinese standard), S235JR (European), and A53 Grade B (American) depends on the project’s governing code — and mixing certifications from different suppliers creates documentation gaps that stall approval.
Steel Grade Selection and Seamless Manufacturing: What the Specification Sheet Does Not Say
The jump from Q195 to Q345 or from S235 to S355JR represents a significant increase in yield strength, directly affecting how much load a hollow section can carry before permanent deformation. Seamless manufacturing eliminates the longitudinal weld seam found in ERW tubes, making these Seamless Square and Rectangular Hollow Sections suitable for higher-pressure applications and environments where weld integrity is a concern. [NEED_CITE: comparison of seamless versus welded steel tube manufacturing processes] Surface treatment selection — pre-galvanized at 40–80g/m² for indoor or mild environments versus hot-dipped galvanized at 200–600g/m² for outdoor or corrosive conditions — must match the project’s exposure profile. For sharp-corner rectangular tubes, our proprietary technology achieves tight corner radii that improve connection fit-up in steel frames, a detail that matters when bolted joints must align precisely.
The Hidden Cost of Accepting Negative Tolerance and Missing Mill Certificates
When a supplier delivers Seamless Square and Rectangular Hollow Sections with wall thickness below the specified tolerance, the structural engineer’s load calculations become invalid — the section may pass visual inspection but fail under design load. Missing or incomplete mill test certificates mean the steel grade cannot be verified, triggering customs holds and project compliance failures. [NEED_CITE: structural steel traceability requirements in EN 10204 inspection documents] Replacing rejected material mid-project costs far more than the original order — crane time, labor delays, and rescheduled inspections compound into weeks of lost schedule.
Why Project Procurement Teams Source Seamless Hollow Sections From Our Facility
We operate three dedicated production lines covering over 2,800 specifications of square, rectangular, and round hollow sections — from 20×20mm to 500×500mm in wall thickness up to 20mm. Our in-house physical and chemical laboratory tests every heat before release, and we issue mill test certificates traceable to the original heat number. The 41 patented technologies include proprietary sharp-corner rectangular tube manufacturing that fills specification gaps unavailable elsewhere. We hold CE certification under EN10210 and EN10219, ISO 9001:2015, Singapore FPC, and accept SGS or BV third-party inspection before shipment. Custom non-standard sizes and cut-to-length processing are available with MOQ of 1 Ton. Professional loading plans optimize container utilization for sections up to 12m, and we coordinate FOB, CIF, and DDP logistics to over 50 countries.
Documentation & Compliance
- Mill test certificate documenting Q345 or S355JR chemical composition and mechanical properties per EN10219, traceable to heat number
- CE certificate confirming compliance with EN10210 for seamless hollow sections and EN10219 for welded alternatives, required for EU customs clearance
- ISO 9001:2015 quality management certificate covering the full production process from raw material incoming inspection to final dimensional check
- SGS or BV third-party inspection report available upon request, verifying wall thickness tolerance, surface coating weight, and dimensional accuracy
- Material traceability documentation linking each bundle to its heat number, steel grade, and production date
- Complete customs document package including packing list, bill of lading, and certificate of origin for import clearance in destination country
Packaging, Loading & Delivery
- Seamless Square and Rectangular Hollow Sections bundled with steel strips and edge protectors to prevent surface damage during ocean transit, with galvanized coatings preserved by waterproof wrapping
- Sections sorted by steel grade and dimension with heat number stenciled on each piece for site identification and traceability verification
- Container loading plans optimized for 3m–12m lengths, maximizing weight utilization for heavy-wall sections (up to 20mm) and volume efficiency for thin-wall profiles
- Cut-to-length processing available for specific project requirements, with plain ends deburred and prepared for welding or mechanical connection
- FOB, CIF, and DDP shipping terms coordinated with professional logistics partners, providing real-time tracking from Jinan port to destination site
How to Request a Quotation for Your Seamless Hollow Section Order
Submit your specifications — section dimensions, wall thickness, steel grade, quantity, and destination port — and receive a detailed quotation within 12 hours including unit pricing, applicable certifications, and production lead time. We provide material samples and original mill test certificates for quality confirmation before contract signing. For non-standard dimensions or custom surface treatment requirements, our technical team reviews your drawing and returns a feasibility assessment with pricing.
Frequently Asked Questions
Q: How do Q235, S235JR, and ASTM A53 Grade B compare for structural applications?
A: Q235 (Chinese GB standard), S235JR (European EN standard), and A53 Grade B (American ASTM standard) occupy similar yield strength ranges and are commonly specified for general structural hollow sections. We provide cross-reference documentation showing chemical composition and mechanical property equivalence, and our mill test certificates reference the specific standard your project requires.
Q: Can you provide mill test certificates and arrange third-party inspection before shipment?
A: Every shipment includes an original mill test certificate documenting chemical composition and mechanical properties, traceable to the heat number. We also accept SGS or BV third-party inspection at our facility before loading, with the inspection report included in your documentation package.
Q: What is the MOQ for non-standard sizes and custom lengths?
A: The minimum order quantity is 1 Ton for standard specifications from our 2,800+ available models. For custom non-standard dimensions or cut-to-length processing, we review your requirements and confirm feasibility and minimum quantity based on production setup.
Q: What is the difference between pre-galvanized and hot-dipped galvanized surface treatment?
A: Pre-galvanized coating at 40–80g/m² provides basic corrosion protection suitable for indoor or mild outdoor environments. Hot-dipped galvanized coating at 200–600g/m² offers heavy-duty protection for outdoor exposure, marine environments, or corrosive industrial conditions. We recommend surface treatment based on your project’s environmental exposure and design life.
Q: Do your CE certificates comply with EN10210 and EN10219 for EU import clearance?
A: Yes, our CE certification covers EN10210 for seamless hollow sections and EN10219 for welded hollow sections, meeting the requirements for structural steel products entering the European market. The CE certificate and Declaration of Performance are included in the shipment documentation package.
Get Your Seamless Hollow Section Quotation With Mill Test Certificates
Send your specifications — dimensions, steel grade, quantity, and destination — to receive pricing and certification details within 12 hours.
Company: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxjysteel.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjysteel.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
