Description
Factory-Direct ERW Hollow Sections — Shandong Xin Jiyuan produces Q235 Q345 ERW square rectangular steel tube in-house with full mill test traceability, eliminating middlemen markups on structural procurement.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Q345 ERW Square and Rectangular Steel Tube |
| Product Type | Square and Rectangular Steel Tube / Hollow Section |
| Steel Grade | Q195, Q215, Q235, Q345, S235JR, GR.B-D, STK500 |
| Standard | GB/T 3091-2001, BS 1387-1985, DIN EN 10025, EN 10219, JIS G3444:2004, ASTM A53 SCH40/80/STD, BS EN 10255-2004 |
| Section Shape | Square / Rectangular |
| Size Range | 10mm×10mm – 500mm×500mm |
| Wall Thickness | 0.6mm – 20mm |
| Length | 1m – 12m (customizable) |
| Technique | Hot Rolled / Cold Rolled ERW |
| Surface Treatment | Oiled, Black Painted |
| Tolerance | ±1% |
| Ends | Plain, Beveled, Threaded with couplings or sockets; plastic caps and steel rings available |
| Application | Steel structures, Construction frames, Machinery, Scaffolding, Furniture, Fluid transport |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors & Construction | Building frames, scaffolding systems, industrial platform structures |
| Machinery Manufacturers | Equipment base frames, conveyor support structures, hydraulic cylinder housings |
| Infrastructure Developers | Bridge handrails, industrial walkways, solar mounting structures |
| Steel Fabricators | Welded assemblies, column sections, beam-to-column connections |
Where Wall-Thickness Tolerance Decides Structural Acceptance
A ±1% tolerance on 20mm wall Q345 tube means the difference between passing third-party inspection and scrapping an entire container at Jebel Ali.
EPC project engineers specifying Q235 Q345 ERW square rectangular steel tube for load-bearing frames have been burned by suppliers claiming “standard tolerance” while delivering walls 8% under nominal. The mill cert looks clean, but independent testing at destination reveals yield strength margins eaten away by actual thickness deviation. When EN 10219 cold-formed hollow section requirements demand documented compliance, missing or falsified test reports trigger customs holds that delay crane schedules and burn liquidated damages [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements].
Matching Hollow Section Profiles to Structural Load Paths
Q235 Q345 ERW square rectangular steel tube in 10×10mm to 500×500mm profiles serves distinct engineering functions based on section geometry. Square tubes provide equal moment resistance on both axes for column applications, while rectangular sections optimize bending resistance where depth exceeds width — typical in beam-to-girder connections. The 0.6mm to 20mm wall range covers everything from light furniture frames to heavy machinery bases, with ERW welding ensuring consistent seam integrity across the full length. Our in-house physical and chemical laboratory verifies each heat before release, so the Q345 you spec arrives with documented yield characteristics matching GB/T 1591 requirements.
Engineering Compliance and Certification Pathways
Structural engineers designing to EN 1993-1-1 or AISC 360 require material documentation that traces back to recognized standards. Q235 Q345 ERW square rectangular steel tube produced under EN 10219 carries CE marking for EU market access, while ASTM A53 compliance opens North American procurement channels. The oiled or black painted surface treatment provides short-term corrosion protection during fabrication and transit — for aggressive environments, galvanizing or epoxy coating follows as secondary operations. Wall thickness tolerance of ±1% ensures that calculated section properties (moment of inertia, radius of gyration) hold true during structural analysis, preventing costly redesigns when as-built dimensions deviate from model assumptions [NEED_CITE: steel grade equivalence between GB Q-series and EN S-series standards].
Steel Grade Selection and ERW Process Fundamentals
The Q-series (Q195, Q235, Q345) and S-series (S235JR) represent equivalent yield strength classes across Chinese and European nomenclature — Q235 maps to S235JR at 235 MPa minimum yield, while Q345 aligns with S355JR at 355 MPa. STK500 per JIS G3444 serves Japanese-spec structural applications. ERW (Electric Resistance Welding) forms the tube from hot-rolled or cold-rolled coil, with the longitudinal seam forged under pressure without filler metal — this process delivers tight dimensional tolerance and consistent mechanical properties across the 10×10mm to 500×500mm size range. For wall thicknesses up to 20mm, ERW offers cost efficiency over seamless alternatives while maintaining weld integrity verified through ultrasonic testing. The ±1% tolerance standard ensures that theoretical weight calculations align with actual mass, preventing invoice disputes over negative tolerance exploitation.
Hidden Costs of Non-Compliant Hollow Section Procurement
Sourcing Q235 Q345 ERW square rectangular steel tube from traders without in-house testing capability introduces risks that surface only after containers reach destination ports. Material substitution — receiving Q195 when Q345 was contracted — compromises structural safety margins and triggers rejection during third-party inspection. Missing CE certificates under EN 10219/EN 10210 block EU customs clearance, forcing expensive re-documentation or return shipments. Wall thickness below specified tolerance reduces load capacity, requiring engineering reassessment or member replacement that delays project handover and activates penalty clauses [NEED_CITE: structural steel hollow section compliance requirements for EU construction projects].
Procurement Confidence Through Vertical Integration
Shandong Xin Jiyuan operates three dedicated production lines covering over 2,800 square and rectangular tube specifications, eliminating the coordination gaps that plague fragmented sourcing. Our in-house physical and chemical laboratory conducts incoming raw material verification, in-process weld inspection, and final dimensional checks — every shipment carries original mill test certificates documenting chemical composition and mechanical properties per heat number. The proprietary sharp-corner rectangular tube technology, backed by 41 invention patents, delivers 90-degree internal radii that maximize connection surface area for bolted or welded joints. CE certification under EN 10219/EN 10210, ISO 9001:2015 registration, and third-party verification through SGS and BV provide customs-ready documentation for 50+ export destinations. Custom non-standard sizes,定尺 cutting to 12m maximum, and professional container loading optimization reduce waste and freight costs per ton delivered.
Documentation & Compliance
- Mill test certificate documenting Q235/Q345 chemical composition (C, Mn, Si, P, S) and mechanical properties (yield strength, tensile strength, elongation) per GB/T 1591 or EN 10219
- CE certificate confirming EN 10219/EN 10210 compliance for structural hollow sections exported to EU member states
- ISO 9001:2015 quality management system certificate covering design, production, and inspection of welded steel tubes
- SGS or BV third-party inspection report verifying dimensional tolerance, surface quality, and weld integrity before shipment
- Material traceability documentation linking each tube bundle to heat number, production date, and test results
- Customs documentation package including packing list, bill of lading, and certificate of origin for destination port clearance
Packaging, Loading & Delivery
- Q235 Q345 ERW square rectangular steel tube bundled with high-tensile steel strips at maximum 1.5m intervals, with edge protectors preventing coating damage during transit
- Oiled surface treatment applied uniformly to prevent rust formation during ocean shipment, with black painted options available for extended storage protection
- Container loading plans optimized for 10×10mm to 500×500mm profiles, maximizing payload per 20ft or 40ft container while maintaining weight distribution for crane handling
- Custom length cutting from 1m to 12m per project requirements, with plastic end caps installed to prevent moisture ingress and debris accumulation
- Heat number and steel grade stenciled on each tube bundle, with color-coded banding distinguishing Q235 from Q345 shipments
- FOB, CIF, and DDP logistics options with real-time tracking, coordinating port arrival with project installation schedules
Initiating Your Hollow Section Procurement
Submit your Q235 Q345 ERW square rectangular steel tube requirements — including section dimensions, wall thickness, total tonnage, steel grade preference, and destination port — to receive detailed pricing with mill test certificate confirmation within 12 hours. For non-standard sizes outside the 10×10mm to 500×500mm range or custom lengths exceeding 12m, our engineering team provides feasibility assessment and production scheduling. Certification requirements for EU CE marking or third-party SGS/BV inspection are confirmed at quotation stage, ensuring customs-ready documentation accompanies every shipment.
Frequently Asked Questions
Q: How do Q235 and Q345 steel grades correspond to European EN standards?
A: Q235 meets S235JR requirements under EN 10025 with 235 MPa minimum yield strength, while Q345 aligns with S355JR at 355 MPa yield. Both grades are producible under EN 10219 for CE-certified hollow sections exported to EU markets.
Q: Can you produce non-standard square or rectangular sizes outside your catalog range?
A: Yes, our three production lines cover over 2,800 specifications including custom non-standard dimensions. Minimum order quantities apply for specialized profiles, with feasibility confirmed during quotation based on your technical drawings.
Q: What certifications do you provide for EU customs clearance and project compliance?
A: We supply CE certificates under EN 10219/EN 10210 for structural hollow sections, ISO 9001:2015 quality system certification, and original mill test certificates. Third-party inspection through SGS or BV is available upon request before shipment.
Q: How do you handle loading optimization for heavy steel tube shipments?
A: Our logistics team develops container loading plans maximizing payload per 20ft or 40ft container while ensuring safe weight distribution. Professional lashing and bundling prevent transit damage, with FOB/CIF/DDP options coordinating port arrival to your project schedule.
Q: What is the difference between theoretical weight and actual weight invoicing?
A: Theoretical weight calculates mass based on nominal dimensions and standard density (7.85 g/cm³ for carbon steel), while actual weight reflects measured mass after production. Our ±1% tolerance standard ensures minimal deviation between theoretical and actual weight, with invoicing terms confirmed in your proforma invoice.
Request Your Q235 Q345 ERW Square Rectangular Steel Tube Quotation
Email your specifications to admin@sdxjysteel.com or contact via WhatsApp at +86 188 5315 7756 to receive pricing, mill test certificate samples, and delivery scheduling within 12 hours.
