Description
Factory Direct Supply, No Middlemen — XJY Structure operates its own steel mill and fabrication workshop, delivering Q235 and Q345 hot dipped galvanized square and rectangular steel tubes with full material traceability from raw coil to finished section.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 / Q345 Hot Dipped Galvanized Square & Rectangular Steel Tube |
| Product Type | Hot Dipped Galvanized Square and Rectangular Steel Tube |
| Steel Grade | Q195, Q215, Q235, Q345, SS330, SS400, S235JR, S235JO, S235J2, ST52, SGCC, SGCD, SGCH, SPHC, SPCC |
| Standard | ASTM, JIS, GB, DIN, BS |
| Section Shape | Square / Rectangular |
| Wall Thickness | 0.6–28 mm |
| Length | 6 m / 6.4 m / 12 m or customized |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Dipped Galvanized |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Greenhouse structures, Steel structures, Construction frames, Fluid transportation, Machinery parts, Automobile and tractor parts |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Agricultural Construction | Greenhouse skeleton frames, irrigation support columns, shade structure purlins |
| Industrial Building | Warehouse portal frames, mezzanine platforms, crane runway beams |
| Infrastructure & EPC | Solar mounting structures, sound barrier posts, bridge handrail systems |
| Mechanical Engineering | Conveyor frame assemblies, machine base supports, equipment guarding structures |
| Commercial Construction | Building column and beam frames, stairway stringers, canopy supports |
Where Zinc Coating Consistency Determines Project Acceptance
A 60μm hot dipped galvanized coating must read 60μm on every face — including internal weld zones — or the shipment fails third-party inspection at the port.
Overseas buyers sourcing Hot Dipped Galvanized Square and Rectangular Steel Tube Supplier products from China frequently encounter coating thickness variations between outer and inner surfaces. When ERW weld seams receive insufficient zinc penetration, corrosion initiates at the weld line within months of installation in humid or coastal environments. Fragmented procurement — buying raw tubes from one supplier and sending them to a separate galvanizing facility — creates gaps in coating uniformity that no mill certificate can cover. [NEED_CITE: hot dipped galvanizing coating thickness standards for structural hollow sections]
Matching Greenhouse and Structural Frame Engineering Requirements
Hot dipped galvanized square and rectangular steel tubes in Q235 and Q345 grades serve greenhouse skeleton systems where corrosion resistance and dimensional precision carry equal weight. The ±1% tolerance on wall thickness and section dimensions ensures that bolt-hole alignment and connection plate fitting proceed without on-site rework — a critical factor when greenhouse projects span hundreds of connection nodes across thousands of meters of framing. XJY Structure’s vertically integrated production line controls every stage from ERW welding through hot dipped galvanizing, meaning zinc coating thickness remains consistent across all surfaces including internal corners and weld seams.
Structural Code Compliance and Certification Pathways
Engineering specifications for greenhouse and industrial frame structures typically reference EN 10219 for cold-formed welded structural hollow sections or ASTM A500 for cold-formed welded and seamless carbon steel structural tubing. The Q235 grade corresponds broadly to S235JR under EN standards and SS400 under JIS, while Q345 aligns with S355JR — but equivalence is not automatic and must be confirmed through chemical composition and mechanical property documentation. [NEED_CITE: steel grade equivalence tables between GB Q-series and EN S-series] For projects entering the European market, CE marking under EN 10219 requires factory production control certification and declaration of performance. Southeast Asian and Middle Eastern EPC projects increasingly demand SGS or BV third-party inspection reports before shipment, making complete documentation packages — not just the steel itself — a procurement prerequisite.
Understanding ERW Welding and Hot Dipped Galvanizing for Square and Rectangular Sections
ERW (Electric Resistance Welded) forming produces square and rectangular hollow sections by cold-forming flat steel strip into shape and welding the seam through electrical resistance heating. This process delivers tight dimensional tolerance and smooth surface finish suitable for architectural exposure, while remaining cost-effective for high-volume structural applications. Hot dipped galvanizing immerses the formed and welded tube in molten zinc at approximately 450°C, creating a metallurgical bond between zinc and steel that provides sacrificial corrosion protection across all exposed surfaces. The zinc-iron alloy layers formed during this process offer superior adhesion compared to electroplated or spray-coated alternatives, making hot dipped galvanizing the standard specification for outdoor structural applications in agricultural, industrial, and infrastructure environments. Wall thickness tolerance of ±1% ensures that theoretical weight calculations match actual delivered weight — a factor that directly affects structural load calculations and project budgeting.
The Hidden Cost of Unverified Coating and Missing Documentation
Procuring Hot Dipped Galvanized Square and Rectangular Steel Tube Supplier products without verified mill test certificates creates downstream risk at multiple project stages. Coating thickness below specification triggers rejection during third-party inspection, forcing re-production and air freight replacement that eliminates profit margins entirely. Material grade substitution — receiving Q195 when Q235 was specified — passes visual inspection but fails structural load testing during engineering acceptance, requiring complete frame disassembly and replacement. [NEED_CITE: consequences of non-compliant steel materials in structural engineering projects] Missing heat number traceability prevents material certification verification, blocking customs clearance in markets requiring EN 10204 3.1 or 3.2 certification documents.
Integrated Production Capability and Quality Assurance
XJY Structure operates its own steel production facility with three production lines covering over 2,800 specifications of raw material, eliminating the supply gap between material supplier and fabricator. This vertical integration means every Hot Dipped Galvanized Square and Rectangular Steel Tube ships with complete quality documentation including WPS welding procedures, PQR records, dimensional inspection reports, and coating thickness measurements — all traceable to specific heat numbers. The in-house理化 laboratory issues mill test certificates documenting chemical composition and mechanical properties per ASTM, JIS, GB, DIN, and BS standards. Certified welding procedures and qualified welders hold AWS and EN certifications, while ISO 9001 quality management systems govern production from coil slitting through final galvanizing and packing. Professional oversized cargo loading and export documentation experience spans projects across the European Union, Middle East, Southeast Asia, and Africa.
Documentation & Compliance
- Mill test certificate documenting Q235 and Q345 chemical composition and mechanical properties per GB/T 6728 and EN 10219 standards, traceable to heat number
- CE certificate confirming compliance with EN 10219 cold-formed welded structural hollow sections for European market projects
- ISO 9001 quality management system certificate covering the full production chain from raw material procurement through hot dipped galvanizing
- SGS or BV third-party inspection report verifying zinc coating thickness, dimensional tolerance, and surface quality before shipment
- Material traceability documentation linking each bundle to specific heat numbers, welding records, and galvanizing batch logs
- Complete customs export documentation including packing list, bill of lading, and certificate of origin for destination country clearance
Packaging, Loading & Delivery
- Hot dipped galvanized square and rectangular tubes bundled with steel strips and edge protectors to preserve zinc coating integrity during ocean transit
- Plain end tubes packed in seaworthy bundles with waterproof wrapping for 6 m, 6.4 m, and 12 m standard lengths or customized cut lengths
- Container loading optimization using nested packing configurations for square and rectangular sections to maximize 20ft and 40ft container utilization
- Heat number and steel grade markings stenciled on each bundle for site identification and material traceability verification
- FOB, CIF, and DDP shipping terms available with professional oversized cargo loading plans for heavy wall thickness sections up to 28 mm
- Door-to-door logistics coordination covering inland transport, port handling, and ocean freight to destination ports across Southeast Asia, Middle East, and Africa
Initiating Your Procurement Inquiry
Submit project drawings in PDF or DWG format along with steel grade requirements, section dimensions, wall thickness specifications, and target quantity to receive a detailed quotation within 24 hours. The quotation includes material costs, fabrication charges, hot dipped galvanizing treatment, packing specifications, and shipping estimates — with shop drawing timelines and production schedules confirmed upon drawing approval. Request mill test certificate samples, third-party inspection arrangements, and custom length cutting options during the initial inquiry stage to align documentation with your project’s engineering and customs requirements.
Frequently Asked Questions
Q: What is the difference between Q235 and Q345 grades for hot dipped galvanized square and rectangular steel tubes?
A: Q235 and Q345 are Chinese standard steel grades where Q represents yield strength and the number indicates minimum yield value in MPa. Q345 offers higher yield strength than Q235, making it suitable for structural applications requiring greater load-bearing capacity. Both grades are available in hot dipped galvanized finish for corrosion protection in outdoor and humid environments.
Q: Can you provide third-party inspection reports for coating thickness verification?
A: Yes, SGS, BV, and TÜV third-party inspection services are available before shipment to verify zinc coating thickness, dimensional accuracy, and surface quality. Inspection reports document coating measurements on all surfaces including internal weld zones, providing independent verification for project acceptance and customs clearance requirements.
Q: What documentation is provided with each shipment of galvanized steel tubes?
A: Each shipment includes mill test certificates documenting chemical composition and mechanical properties, dimensional inspection reports, coating thickness measurement records, welding procedure specifications, and complete export documentation including packing lists, bills of lading, and certificates of origin. All documents are traceable to specific heat numbers for material verification.
Q: Do you offer custom length cutting and end preparation services?
A: Standard lengths include 6 m, 6.4 m, and 12 m, with customized cut lengths available upon request. Plain ends are standard, and additional end preparation services can be discussed during the quotation stage based on your project’s connection requirements and assembly specifications.
Request Your Quotation with Full Material Certification
Send your project specifications including steel grade, section dimensions, wall thickness, quantity, and destination port to receive a comprehensive quotation with mill test certificate samples and production timeline.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.xjystructure.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@xjystructure.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
