Description
Factory-Direct Seamless Hollow Section Supply — Shandong Xin Jiyuan runs three production lines covering Q195 through ASTM A500 grades with original mill certificates on every heat.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Carbon Steel Seamless Square & Rectangular Hollow Section |
| Product Type | Seamless Square and Rectangular Steel Tube / Hollow Section |
| Steel Grade | Q195, Q215, Q235, Q345, #20, #45, S195, S235, S355JR, A53 Grade A, A53 Grade B, A500 Grade A, A500 Grade B, A500 Grade C, STK400, SS400, ST42.2 |
| Standard | EN10219, EN10210, GB/T 6728, JIS G3466, ASTM A500, ASTM A36, ASTM A53 |
| Section Shape | Square / Rectangular / Round |
| Size Range | Square 20×20mm – 500×500mm; Rectangular 20×40mm – 300×500mm |
| Wall Thickness | 1.2mm – 20mm |
| Length | 3m – 12m (random or fixed) |
| Technique | Hot Rolled / Seamless |
| Surface Treatment | Black / Pre-galvanized (40–80g/m²) / Hot-dip galvanized (200–600g/m²) / Customized |
| Tolerance | ±1% |
| Ends | Plain / Beveled / Threaded |
| Application | Construction, steel structures, solar structures, machinery, shipbuilding, bridges |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Building | Commercial building frames, industrial warehouse columns, housing structural members |
| Renewable Energy | Solar mounting structures, greenhouse frames, photovoltaic support posts |
| Infrastructure | Bridge handrails, airport terminal structures, highway guardrail posts |
| Machinery & Equipment | Machinery manufacturing bases, hydraulic cylinder sleeves, conveyor structures |
| Marine & Heavy Industry | Shipbuilding internal structures, oil storage tank frameworks, pressure vessel supports |
What Wall-Thickness Tolerance Costs on a Seamless Hollow Section Order
A ±1% tolerance on seamless square and rectangular tubes keeps structural calculations valid — anything wider forces engineers to over-order or face rejection at site inspection.
Procurement teams across Southeast Asia and the Middle East regularly encounter shipments where wall thickness drifts beyond declared tolerance, triggering SGS rejections at destination ports. The root cause is often a supplier running hot-rolled seamless tubes without piece-by-piece measurement before loading. When a 100×100×5mm seamless square tube arrives at 4.2mm instead of 5mm, the entire container faces hold or return — costing weeks of delay on time-critical infrastructure projects. [NEED_CITE: EN 10219 cold-formed and EN 10210 hot-finished hollow section dimensional tolerance requirements]
Matching Seamless Hollow Sections to Structural Load Paths
Seamless square and rectangular hollow sections in grades Q235, S355JR, and ASTM A500 Grade C carry uniform stress distribution across all four faces, making them the default choice for moment-resisting frames and compression members in multi-storey buildings. The seamless manufacturing route eliminates the weld seam found in ERW alternatives, which matters when the tube will be bent or punched close to the corner — a common requirement in solar mounting structures and greenhouse frames where connection points cluster near edges. Our production lines hold full-size stock from 20×20mm up to 500×500mm, so project buyers consolidating structural tubes, solar posts, and fence uprights into one container avoid the coordination overhead of splitting orders across three suppliers.
Compliance Requirements Across Engineering Codes
Structural engineers specifying seamless hollow sections for load-bearing frames must verify that the supplied material conforms to the governing code — EN 10210 for European projects, ASTM A500 or A53 for North American work, and JIS G3466 for Japanese-spec infrastructure. Each standard governs chemical composition limits, dimensional tolerance, and mandatory testing protocols differently; mixing certificates across standards on a single project creates customs and inspection exposure. [NEED_CITE: steel grade equivalence mapping between EN 10210, ASTM A500, and JIS G3466] Hot-dip galvanized seamless tubes (200–600g/m² zinc coating) are specified for coastal highway railings and bridge structures where corrosion protection exceeds 25 years, while pre-galvanized (40–80g/m²) suits indoor machinery frames and greenhouse structures with shorter design life. Fixed-length cutting to site-specific dimensions reduces on-site waste and welding time, particularly on large-scale airport terminal and housing projects where hundreds of identical members are needed.
Steel Grade Selection and Seamless Manufacturing Fundamentals
The Q-series (Q195–Q345) follows Chinese GB standards where the number denotes minimum yield strength in MPa; S235JR and S355JR follow European EN standards with JR indicating +20°C Charpy impact energy; ASTM A500 Grades A/B/C and A53 Grades A/B follow American standards with escalating tensile requirements. For structural frames in seismic zones or cold climates, S355JR and Q345 provide higher yield strength than S235JR or Q235, allowing engineers to specify thinner walls while maintaining load capacity — directly reducing per-meter weight and shipping cost. [NEED_CITE: yield strength comparison across Q-series, S-series, and ASTM structural steel grade systems]
The hot-rolled seamless process starts from solid round billets pierced and elongated into hollow form, producing tubes with no longitudinal weld seam. This matters for pressure-containing applications like oil storage tank nozzles and hydraulic cylinder sleeves where weld integrity is a failure point. Wall thickness on our seamless hollow sections ranges from 1.2mm to 20mm, with ±1% tolerance held through in-house three-stage inspection including ultrasonic wall measurement on every piece before bundling. Surface treatment selection follows the corrosion environment: black finish for indoor structural use or further painting, pre-galvanized for moderate humidity, and hot-dip galvanized for direct soil burial or marine splash zones.
Hidden Costs of Unverified Seamless Hollow Section Procurement
Paying a lower unit price on seamless tubes without mill certificate traceability often costs more in rework, customs delays, and structural re-engineering than the savings justify.
When a batch of seamless rectangular hollow sections arrives at a Middle East port without CE marking or with mill certificates that do not match heat numbers on the tubes, customs holds the shipment for weeks — during which the project crane sits idle and the steel erector cannot proceed. Material substitution discovered during structural inspection forces engineers to recalculate load paths, often requiring thicker sections that no longer fit the original connection details. [NEED_CITE: consequences of missing mill test certificates on structural steel customs clearance] Negative tolerance abuse — where actual wall thickness falls below the declared minimum — reduces load capacity below design assumptions, creating latent safety risk that only surfaces under extreme loading or during forensic investigation after failure.
Procurement Confidence from a Jinan-Based Seamless Tube Manufacturer
Shandong Xin Jiyuan operates three simultaneous production lines with monthly capacity exceeding 20,000 tons, pricing direct from the mill without trading company margins — volume discount tiers activate for repeat buyers committing to annual offtake. Every heat carries an original mill test certificate documenting chemical composition and mechanical properties, with SGS or BV third-party inspection available at our facility before container sealing. Our inventory spans 2,800+ specifications in seamless square, rectangular, and round sections, meaning a project buyer sourcing structural columns, solar posts, and machinery frames consolidates into one shipment with unified documentation. Custom non-standard sizes and fixed-length cutting run on 15–25 day lead times with flexible MOQ starting from 1 ton for trial orders. Professional export handling covers container loading optimization — critical when shipping 12-meter seamless tubes alongside shorter sections to maximize payload — and complete customs documentation including certificate of origin and packing lists matched to destination port requirements.
Documentation & Compliance
- Mill test certificate documenting Q235B or S355JR chemical composition and yield strength per EN 10210 or ASTM A500, issued per heat number
- CE certificate covering EN 10210 hot-finished seamless hollow sections and EN 10219 cold-formed sections for European Union customs clearance
- ISO 9001:2015 quality management certificate covering the full production and inspection process at Jinan facility
- SGS or BV third-party inspection report verifying wall thickness, dimensional tolerance, and surface coating weight before shipment
- Material traceability sheet linking each bundle to its heat number, chemical analysis, and mechanical test results
- Export customs package including commercial invoice, packing list, bill of lading, and certificate of origin formatted to destination country requirements
Packaging, Loading & Delivery
- Seamless square and rectangular tubes bundled with high-tensile steel strips at four points, with wooden or rubber edge protectors preventing surface damage on hot-dip galvanized coatings during ocean transit
- Pre-galvanized and black finish tubes wrapped in waterproof cloth at bundle ends to prevent corner moisture ingress during container shipping
- Container loading plans optimized for 12-meter fixed-length seamless tubes mixed with shorter cut-to-size sections, maximizing payload within 20ft and 40ft high-cube limits
- Cut-to-length service available for 3m–12m seamless hollow sections, with each piece marked by heat number and steel grade for site identification
- FOB Jinan/Qingdao, CIF destination port, or DDP door-to-door logistics arranged with forwarders experienced in heavy steel cargo documentation
Starting Your Seamless Hollow Section Inquiry
Submit your specification sheet covering section dimensions, wall thickness, steel grade, total tonnage, and destination port — our team responds within 12 hours with factory-direct pricing, mill certificate confirmation, and container loading plan. For non-standard sizes or custom surface treatment requirements, share your drawing and we return a feasibility assessment with lead time within one working day.
Request Factory-Direct Pricing and Mill Certificates
Send your seamless square and rectangular hollow section specifications to admin@sdxinjiyuan.com or reach our export team on WhatsApp at +86 188 5315 7756 for bulk pricing with original mill test certificates and third-party inspection options.
Frequently Asked Questions
Q: How do Q235, S235JR, and ASTM A53 Grade B compare for structural use?
A: These grades represent Chinese GB, European EN, and American ASTM standards respectively, with broadly comparable yield strength ranges suitable for general structural frames. We supply all three from stock and can provide cross-reference documentation showing chemical composition and mechanical property alignment for your engineer’s approval.
Q: Can I get SGS inspection before shipment on seamless hollow sections?
A: Yes, SGS or BV third-party inspection is available on request at our Jinan facility. The inspector verifies wall thickness, dimensional tolerance, surface coating weight, and reviews mill test certificates against the physical heat number markings on each bundle before container sealing.
Q: What is the minimum order quantity for custom non-standard sizes?
A: Our flexible MOQ starts from 1 ton, supporting trial orders for new projects or small-batch custom sizes. Standard specifications in Q195–Q345 and S235–S355JR grades hold ready stock for immediate dispatch, while custom non-standard dimensions run on typical production lead times of 15–25 days.
Q: How do you prevent galvanized coating damage during shipping?
A: Hot-dip galvanized seamless tubes are bundled with rubber edge protectors at contact points and wrapped in waterproof cloth at bundle ends. Container loading plans separate galvanized bundles from black finish tubes to prevent zinc coating abrasion during ocean transit vibration.
Q: Do you handle export customs documentation for African and South American ports?
A: Yes, our export team prepares complete documentation packages including certificate of origin, packing list, commercial invoice, and bill of lading formatted to destination country requirements. We have shipped seamless hollow sections to 50+ countries and coordinate with forwarders experienced in heavy steel cargo clearance at major ports across Africa, South America, and Southeast Asia.
Secure Your Seamless Hollow Section Supply with Verified Mill Certificates
Email your project specifications to admin@sdxinjiyuan.com or WhatsApp +86 188 5315 7756 to receive factory-direct pricing, original mill test certificates, and a container loading plan within 12 hours.
