Description
Factory-Direct Galvanized Tubes — Vertically integrated steel mill and fabrication facility producing Q235 galvanized square and rectangular steel tubes with full heat-number traceability from raw slab to finished bundle.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Galvanized Square and Rectangular Steel Tube |
| Product Type | Square and Rectangular Steel Tube (SHS / RHS) |
| Steel Grade | Q195, Q235, Q345, STK400, STK500, S235, S355 |
| Standard | GB, ASTM, JIS |
| Section Shape | Square / Rectangular |
| Size Range | 100×100 mm (model reference) |
| Wall Thickness | 1.0–2.0 mm |
| Length | 6–12 m |
| Technique | Hot Rolled Based |
| Surface Treatment | Galvanized (Zinc Coating Z30–Z60) |
| Tolerance | ±1% |
| Ends | Plain |
| Spangle Type | Zero Spangle / Regular Spangle |
| Hardness | Hard / Mid Hard |
| Skin Pass | Yes |
| Oiled or Non-oiled | Non-oiled |
| Application | Steel structures / Construction frames / Making pipes / Cutting sheets / Making containers / Making corrugated sheets / Making fences / Making small tools |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial Construction | Building frames, column and beam assemblies, mezzanine platforms |
| Industrial Facilities | Factory warehouse structures, equipment support frames, conveyor gantries |
| Infrastructure | Scaffolding systems, fencing posts, highway signpost foundations |
| Container Manufacturing | Container corner castings, floor frame members, wall purlins |
| Agricultural & Storage | Grain silo frames, corrugated sheet purlins, livestock shelter structures |
What Zinc Coating Weight Decides Before the First Weld
Z30 versus Z60 is not a price line — it is the difference between twelve months of rust spotting and a decade of structural integrity in humid climates.
When overseas buyers source a Galvanized Square and Rectangular Steel Tube from China, the most common failure point is not the steel itself — it is the zinc coating. A shipment arriving with 45 micrometers against an 80-micrometer contract clause means every single piece fails inspection, the entire container gets rejected, and the project schedule collapses. I watched this happen on a West African EPC site. The root cause was always the same: fragmented procurement where the galvanizing subcontractor and the tube mill point fingers at each other, and the buyer holds the loss.
With vertically integrated production, the hot-rolled black tube goes directly into the galvanizing line under one quality system. Coating weight is measured inline, not sampled after the fact. [NEED_CITE: hot-dip galvanized coating thickness measurement per ISO 1461]
How 1.0–2.0 mm Wall Thickness Serves Light-to-Medium Structural Frames
The 1.0–2.0 mm wall range positions this Galvanized Square and Rectangular Steel Tube squarely in the light structural and secondary member category. For primary moment frames in multi-story buildings, engineers typically specify heavier sections — but for purlins, girts, bracing members, scaffolding uprights, and container framing, this wall range delivers adequate load capacity at significantly lower weight per meter. The ±1% tolerance combined with skin-pass treatment ensures flat surfaces that sit flush against connection plates, reducing fit-up gaps during bolting or welding on site. Non-oiled finish means the tubes arrive ready for welding without solvent cleaning, which matters when a fabrication shop is processing hundreds of cuts per shift.
Structural Compliance Across GB, ASTM, and JIS Frameworks
Projects spanning multiple regions require steel grades that cross-reference cleanly between standards. Q235 maps to S235 under EN designation and approximates ASTM A36 in yield behavior, while Q345 aligns with S355 for higher-load applications. [NEED_CITE: steel grade equivalence between GB, EN, and ASTM standards for structural hollow sections] The hot-rolled based technique produces sections with more consistent corner mechanical properties compared to cold-formed alternatives, which matters when connection design assumes uniform yield across the section. For European market shipments, EN 10219 compliance documentation and CE marking become customs-critical — without them, containers sit at port while the buyer scrambles for retroactive certification. [NEED_CITE: EN 10219 cold-formed structural hollow section compliance requirements]
Hot-Rolled Based Technique and Galvanized Surface: Why the Combination Matters
Hot-rolled based tube starts from a hot-rolled coil that is formed and welded into the hollow section, then galvanized. The base metal’s grain structure from hot rolling provides better ductility at the corners of square and rectangular sections compared to cold-formed-only alternatives — the corners do not work-harden to the point of micro-cracking during subsequent bending or drilling. The galvanized zinc coating at Z30 to Z60 provides sacrificial corrosion protection: Z30 suits indoor or sheltered applications where moisture exposure is intermittent, while Z60 is specified for outdoor structures, coastal environments, or agricultural buildings where condensation and humidity are constant. Zero spangle finish delivers a uniform matte appearance preferred in architectural-exposed applications, while regular spangle is acceptable for hidden structural members where appearance is secondary.
The Hidden Cost When Coating Weight Does Not Match the Purchase Order
Ordering galvanized tubes based on price per ton alone invites a specific category of loss. If the actual zinc coating falls below the specified Z30 or Z60 threshold, the tubes will corrode prematurely — but the failure may not surface until months after installation, when rust bleeds through paint systems or connection points degrade. At that stage, replacement costs include not just the material but demolition, re-fabrication, re-shipping, and project delay penalties. [NEED_CITE: consequences of substandard galvanized coating on structural steel service life] Beyond coating, material certification gaps create customs and inspection failures: a mill test certificate that does not match the heat number stamped on the tube, or a certificate referencing a different steel grade than what was ordered, will trigger rejection at the destination port. These are not theoretical risks — they are the most frequent claims I processed during years on the procurement side of international construction projects.
Why XJY Structure Eliminates the Procurement Gaps That Cause These Losses
XJY Structure operates as the dedicated structural steel fabrication division of Shandong Xin Jiyuan Special Steel Tube Co., Ltd, meaning the same facility that produces the raw steel tube also handles galvanizing, fabrication, and quality documentation. There is no handoff between a tube mill and a separate galvanizing subcontractor — coating weight, dimensional tolerance, and surface quality are controlled under one production management system. The company maintains its own steel production facility with three production lines and over 2,800 specifications of raw material in inventory, so orders for Q235 galvanized square and rectangular steel tubes in 1.0–2.0 mm wall thickness can be fulfilled from existing stock or scheduled against confirmed coil supply without waiting for third-party material procurement. Welding procedures are certified to AWS and EN standards, and the quality documentation package includes WPS, PQR, weld maps, dimensional inspection reports, and coating thickness reports — the complete set that international inspectors and customs authorities require.
Documentation & Compliance
- Mill Test Certificate documenting Q235 chemical composition and mechanical properties per GB/T 700, with heat number traceability linked to each bundle
- Galvanized coating thickness report confirming Z30 or Z60 zinc coating weight per ISO 1461 measurement standards
- ISO 9001 quality management system certificate covering the integrated steel production and galvanizing process
- SGS or BV third-party inspection report available upon request, covering dimensional verification, coating weight measurement, and visual surface inspection
- Material traceability records linking each bundle to its production heat number, rolling date, and galvanizing batch
- Complete export documentation set including packing list, bill of lading, and certificate of origin for destination customs clearance
Packaging, Loading & Delivery
- Q235 galvanized square and rectangular steel tubes bundled with steel strips and edge protectors to prevent zinc coating damage from strap abrasion during ocean transit
- Non-oiled, non-oiled galvanized surface protected by interleaving separators between layers to avoid contact staining and surface scratching in 6–12 m lengths
- Container loading optimized for 100×100 mm sections in 6 m and 12 m lengths, maximizing weight utilization within 20-foot and 40-foot standard shipping containers
- Heat number and steel grade markings stenciled on each bundle tag for site-level identification and traceability verification upon arrival
- FOB, CIF, and DDP shipping terms available with professional oversized cargo loading plans and complete export documentation support
Start Your Inquiry With Drawings and Specifications
Share your project drawings in PDF or DWG format along with the required steel grade, wall thickness, coating weight, and quantity. The engineering team responds within 24 hours with a preliminary assessment, detailed quotation covering material, galvanizing, packing, and shipping costs, and a shop drawing timeline. Third-party inspection arrangements and certification documentation requirements are confirmed at the quotation stage, so there are no surprises at the destination port.
Frequently Asked Questions
Q: How does Q235 compare to S235 and ASTM A36 for structural applications?
A: Q235 is the Chinese standard grade under GB/T 700 with a minimum yield strength in the 235 MPa class. It is widely accepted as equivalent to S235 under European EN standards and closely matches ASTM A36 used in North American projects. For projects requiring formal equivalence documentation, the mill test certificate can reference the applicable standard cross-references.
Q: What is the difference between Z30 and Z60 galvanized coating for square and rectangular tubes?
A: Z30 and Z60 refer to the zinc coating weight class, with Z60 providing a thicker zinc layer and longer corrosion resistance in demanding environments. Z30 is suitable for indoor or sheltered structural applications, while Z60 is recommended for outdoor exposure, coastal areas, or agricultural buildings with high humidity.
Q: Can you provide third-party inspection for galvanized tube shipments?
A: Yes, SGS and BV third-party inspections are available upon request. The inspection covers dimensional verification, coating thickness measurement per ISO 1461, visual surface quality assessment, and review of mill test certificates against the production heat numbers.
Q: Do you offer custom cutting, drilling, or fabrication services for these tubes?
A: XJY Structure provides CNC cutting, drilling, welding, and assembly services beyond standard tube supply. Shop drawings are prepared for client approval before fabrication begins, and all fabrication follows certified welding procedures under AWS or EN standards with complete quality documentation.
Q: What quality documentation is included with each shipment?
A: Each shipment includes a mill test certificate with chemical composition and mechanical properties, galvanized coating thickness report, material traceability by heat number, packing list, bill of lading, and certificate of origin. Additional third-party inspection reports and welding procedure documentation are provided when fabrication services are included.
Get Your Quotation With Full Material Traceability
Submit your project specifications, steel grade requirements, and destination port to receive a detailed quotation and mill test certificate sample within 24 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.xjystructure.com
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@xjystructure.com
