Description
Factory-Direct Pre-Galvanized RHS — Full mill test certificates and CE EN10219 compliance shipped with every GrB welded rectangular steel tube order, eliminating middleman markups and customs delays.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | GrB Rectangular Steel Tube |
| Product Type | Welded Rectangular Steel Tube / Hollow Section (RHS) |
| Steel Grade | GrB, S235, S275, S355, STK400, A53-A369 |
| Standard | ASTM A500, ASTM A53, GB/T 3091, EN 10219, EN 10210 |
| Section Shape | Rectangular |
| Size Range | 15mm×20mm – 700mm×800mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | ERW (Welded) |
| Surface Treatment | Black Painting / Pre-Galvanized / Varnish / Bare |
| Tolerance | ±10% |
| Ends | Plain End |
| Surface Condition | Slightly Oiled |
| Processing Service | Bending, Cutting, Welding |
| Application | Steel structures / Construction frames / Curtain wall / Support tubes / Building structures / Machinery frames |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC & Construction | Steel structure frames, curtain wall supports, building columns, warehouse purlins |
| Machinery Manufacturing | Equipment bases, conveyor frames, industrial support structures, machine guards |
| Infrastructure | Bridge supports, scaffolding systems, industrial platforms, walkway handrails |
What Pre-Galvanized Coating Thickness Costs on a Structural Frame Order
Inconsistent zinc layer application is the silent killer of pre-galvanized RHS acceptance on European and Middle Eastern job sites.
I have seen entire container loads of pre-galvanized welded rectangular steel tube rejected at third-party inspection because the coating measured 35μm against a 60μm contract requirement. The tubes were technically within dimensional tolerance, but the galvanizing specification failure meant customs documentation could not be signed off. The rework cost exceeded the original material price. [NEED_CITE: EN 10219 cold-formed hollow section requirements]
When procurement teams source pre-galvanized ERW rectangular steel tubes from traders rather than mills, the galvanizing process is often outsourced to subcontractors with no in-process quality control. Coating thickness varies between batches, and mill test certificates rarely document the zinc layer specification. For EPC contractors managing tight project timelines, this uncertainty translates directly into site delays and claim exposure.
How GrB Pre-Galvanized RHS Matches Structural Frame Requirements
The GrB steel grade delivers the baseline yield strength required for non-critical structural frames, curtain wall supports, and machinery bases across Southeast Asian and Middle Eastern construction projects. Pre-galvanized surface treatment provides corrosion protection suitable for indoor and sheltered outdoor environments, eliminating the need for additional painting on assembly lines. Our ERW welding process with in-process seam inspection ensures weld integrity meets EN 10219 structural requirements, while the ±10% dimensional tolerance covers standard fabrication needs without premium pricing for tight-tolerance cold-drawn alternatives.
Engineering Compliance and Certification Pathways
Structural frames designed to Eurocode 3 (EN 1993) require hollow sections conforming to EN 10219 or EN 10210, with mill test certificates documenting chemical composition and mechanical properties per heat number. [NEED_CITE: steel grade equivalence between EN and ASTM standards] For EU market entry, CE certification under EN 10219 is mandatory for structural hollow sections, and customs authorities routinely request Declaration of Performance documentation. Our pre-galvanized welded rectangular steel tubes carry CE EN10219 certification, with third-party inspection available through SGS or BV before shipment. The GrB / S235 / S275 / S355 grade range covers most non-critical structural applications, while STK400 serves Japanese-specification projects requiring JIS G3466 compliance.
Steel Grade Selection and ERW Welding Process
GrB represents the entry-level structural grade in the Chinese GB/T 3091 system, equivalent to S235 in the European EN 10219 framework and roughly comparable to ASTM A500 Grade B. The S-series grades (S275, S355) offer incrementally higher yield strength for load-bearing columns and longer-span beams, while STK400 serves Japanese industrial standards. ERW (Electric Resistance Welding) is the dominant production method for rectangular hollow sections in the 15×20mm to 700×800mm size range, offering cost efficiency over seamless alternatives while maintaining structural integrity for non-pressure applications. The high-frequency welding process creates a continuous longitudinal seam with minimal heat-affected zone, and in-process ultrasonic inspection detects weld defects before coating application. [NEED_CITE: ERW vs seamless steel tube manufacturing comparison]
Pre-galvanized (also called pre-galv or strip-galvanized) coating is applied to the steel strip before tube forming, resulting in uniform zinc coverage on both interior and exterior surfaces. This differs from hot-dip galvanizing, where formed tubes are immersed in molten zinc, creating a thicker but less uniform coating. For indoor structural frames and machinery bases, pre-galvanized provides adequate corrosion resistance at lower cost than hot-dip alternatives.
Hidden Costs of Unverified Pre-Galvanized RHS Procurement
Purchasing pre-galvanized welded rectangular steel tube without independent mill test certificate verification creates three categories of hidden cost: customs clearance delays when CE documentation is missing or incomplete, structural rejection when coating thickness fails third-party inspection, and fabrication rework when dimensional tolerance exceeds ±10% specification. [NEED_CITE: structural steel procurement quality control requirements] Material substitution—receiving S235 when S355 was specified—compounds these risks, as the lower yield strength may not meet structural design calculations. For projects requiring EN 10204 3.2 certificates with third-party witness, sourcing from traders rather than certified mills eliminates the possibility of proper documentation.
Why Source Pre-Galvanized RHS Directly from Our Mill
Our factory operates three dedicated ERW production lines with in-house physical and chemical laboratories, enabling real-time quality control from steel strip incoming inspection through final coating thickness measurement. Every batch of pre-galvanized welded rectangular steel tube receives full mill test certificate documentation, with heat number traceability from raw material to finished product. We hold 41 invention patents including proprietary sharp-corner rectangular tube technology, and our 2,800+ specification range covers standard and non-standard sizes without the minimum order quantities imposed by trading companies. CE certification under EN 10210 and EN 10219 ensures EU customs compliance, while SGS and BV verification provides independent quality confirmation for Middle Eastern and Southeast Asian projects. Professional loading plans optimize container utilization for 6m and 12m lengths, reducing per-ton freight costs on FOB and CIF shipments to 50+ countries.
Documentation & Compliance
- Mill test certificate documenting GrB / S235 / S355 chemical composition and mechanical properties per EN 10219, with heat number traceability for every pre-galvanized welded rectangular steel tube batch
- CE certificate under EN 10219 for EU market structural hollow section compliance, including Declaration of Performance for customs clearance
- ISO 9001:2015 quality management system certificate covering production process and coating thickness control
- SGS or BV third-party inspection report available upon request, documenting dimensional tolerance and zinc coating thickness measurement
- Material traceability documentation linking each pre-galvanized RHS bundle to specific heat numbers and production dates
- Complete customs document package including packing list, bill of lading, and certificate of origin for destination port clearance
Packaging, Loading & Delivery
- Pre-galvanized welded rectangular steel tubes bundled with steel strips and edge protectors to preserve zinc coating during ocean transit and prevent surface damage
- Slightly oiled surface condition applied after galvanizing provides additional corrosion protection during storage and shipping, particularly for 11.8m and 12m random lengths
- Container loading plans optimized for 15×20mm to 700×800mm size range, maximizing payload for 6m and 12m standard lengths while maintaining weight distribution
- Custom cutting service available for non-standard lengths, with pre-galvanized RHS cut to project specifications and bundled separately with heat number identification
- Heat number and steel grade markings stenciled on each bundle, enabling site identification and traceability verification during installation
- FOB, CIF, and DDP shipping options with door-to-door logistics coordination for pre-galvanized welded rectangular steel tube shipments to EU, North America, and Southeast Asian ports
How to Request Quotation and Mill Test Certificate
Submit your pre-galvanized welded rectangular steel tube requirements including size (outer dimensions × wall thickness), steel grade (GrB / S235 / S355), total quantity, and destination port to receive detailed pricing with mill test certificate documentation within 12 hours. For non-standard dimensions outside the 15×20mm to 700×800mm range, specify required sizes and MOQ for custom production evaluation. Confirm whether EN 10204 3.1 or 3.2 certificates are required for your project, and whether third-party SGS/BV inspection is needed before shipment.
Frequently Asked Questions
Q: What is the difference between pre-galvanized and hot-dip galvanized rectangular steel tubes?
A: Pre-galvanized coating is applied to the steel strip before tube forming, resulting in uniform zinc coverage on both interior and exterior surfaces with typical thickness of 40-80μm. Hot-dip galvanizing immerses formed tubes in molten zinc, creating thicker coating (60-120μm) but less uniform coverage, particularly inside corners. Pre-galvanized is more cost-effective for indoor and sheltered applications, while hot-dip suits harsh outdoor environments.
Q: Can you provide EN 10204 3.2 certificates with third-party witness for pre-galvanized RHS?
A: Yes, EN 10204 3.2 certificates with independent third-party witness (SGS, BV, or equivalent) are available for pre-galvanized welded rectangular steel tube orders. The third-party inspector witnesses material testing and verifies chemical composition and mechanical properties against EN 10219 requirements.
Q: What is the minimum order quantity for custom non-standard rectangular tube dimensions?
A: Standard sizes within the 15×20mm to 700×800mm range and 1-30mm wall thickness have 1 Ton MOQ. Custom non-standard dimensions outside this range require evaluation based on size and quantity, with typical MOQ of 5-10 tons depending on specification complexity.
Q: Do your CE certificates ensure smooth EU customs clearance for structural hollow sections?
A: Our CE certification under EN 10219 includes Declaration of Performance documentation required for EU customs clearance of structural hollow sections. The certificate covers GrB, S235, S275, and S355 grades in pre-galvanized and black finish, with mill test certificates providing heat number traceability.
Pre-Galvanized RHS Quotation with Full Certification
Send your size, grade, and quantity specifications to receive pricing with mill test certificate documentation and CE compliance confirmation.
WhatsApp: +86 188 5315 7756 | Email: admin@sdxjysteel.com
