Description
Factory-Direct Galvanized SHS/RHS — Q235 square and rectangular tubes hot-rolled and galvanized in-house, shipped with mill test certificates to 50+ countries without broker markups.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Galvanized Square and Rectangular Steel Tube |
| Product Type | Galvanized Square and Rectangular Steel Tube (SHS/RHS) |
| Steel Grade | Q195, Q235, Q345, STK400, STK500, S235, S355 |
| Standard | GB, ASTM, JIS, EN10210, EN10219 |
| Section Shape | Square / Rectangular |
| Size Range | 100×100 mm reference model; full catalog covers 2,800+ specifications |
| Wall Thickness | 1.0–2.0 mm standard; up to 40 mm on custom order |
| Length | 6–12 m |
| Technique | Hot Rolled Based / ERW |
| Surface Treatment | Galvanized, Zinc Coating Z30–Z60 |
| Spangle Type | Zero Spangle / Regular Spangle |
| Hardness | Hard / Mid Hard |
| Tolerance | ±1% |
| Ends | Plain |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Application | Steel structures, construction frames, machinery frames, scaffolding, fencing, container manufacturing, corrugated sheet production, industrial fabrication |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors | Industrial plant frameworks, pipe rack supports, equipment skid bases |
| Construction Companies | High-rise building columns, bridge support piers, scaffolding uprights |
| Machinery Manufacturers | Conveyor frames, automation gantries, agricultural equipment chassis |
| Infrastructure Developers | Highway sound barriers, solar mounting structures, fencing systems |
| Container & Sheet Fabricators | Container corner posts, corrugated roofing purlins, warehouse portal frames |
What Zinc Coating Class Actually Means for a Q235 Frame Order
A Z30 coating survives warehouse storage; a Z60 coating survives a coastal construction site — specifying the wrong one costs more in rework than in upfront material.
Procurement teams often receive quotes labeled simply “galvanized” without a coating class, then discover on site that the zinc layer is too thin for the actual environment. On a Q235 galvanized square and rectangular steel tube order destined for Southeast Asia or the Middle East, salt-laden air accelerates white rust formation within weeks if the coating falls below Z50. We have seen containers arrive with visible staining because the supplier defaulted to the lightest commercial grade. The Galvanized Square and Rectangular Steel Tube Supplier you work with should declare Z30, Z50, or Z60 on the proforma invoice — not just “galvanized.” [NEED_CITE: hot-dip galvanized coating thickness classes and corrosion performance]
Matching Q235 and S235 Grades to Structural Load Paths
Q235 and its European counterpart S235 sit at the entry level of structural carbon steel, offering adequate yield strength for non-primary frames, scaffolding, and light machinery bases. When an engineer specifies S355 for a load-bearing column, substituting Q235 without recalculation creates a hidden safety gap. Our Galvanized Square and Rectangular Steel Tube Supplier catalog holds both grades in square and rectangular sections from 1.0 mm to 40 mm wall, so the correct grade can be pulled from stock rather than re-rolled. For projects spanning multiple standards — GB for domestic Chinese elements, EN for exported modules — equivalence documentation is prepared at the mill stage.
Compliance Pathways Across GB, EN, and JIS Frameworks
A Q235 tube shipped to the EU must carry CE marking under EN 10219 for cold-formed sections or EN 10210 for hot-formed sections; without it, customs holds the container regardless of material quality. Japanese-spec projects require JIS G3466 STK400 or STK500 designation, which maps closely to Q235 and Q345 in chemistry but differs in elongation and impact testing requirements. [NEED_CITE: steel grade equivalence between GB Q-series and EN S-series structural standards] Our in-house physical and chemical laboratory tests every heat for composition, tensile properties, and coating adhesion before release, and third-party inspection by SGS or BV is available for projects demanding independent verification.
How Hot-Rolled Base and ERW Processes Shape the Final Tube
Hot-rolled based production gives Q235 galvanized square and rectangular steel tubes a uniform grain structure suited to welding and bending without cracking at the corners. ERW (Electric Resistance Welded) forming then shapes the flat strip into square or rectangular profiles, with the weld seam undergoing ultrasonic inspection to match the parent metal’s integrity. The galvanizing step follows — typically hot-dip — applying Z30 to Z60 zinc coating depending on the end-use environment. Zero spangle finish is selected for architectural applications where appearance matters; regular spangle is acceptable for industrial framing hidden behind cladding. Wall thickness tolerance of ±1% ensures that theoretical weight calculations match actual delivered weight, preventing budget overruns on tonnage-based contracts.
The Hidden Cost of Unverified Coating Thickness and Negative Tolerance
Ordering galvanized tubes without specifying minimum zinc coating class invites suppliers to deliver the thinnest commercially viable layer — often below Z30 — which fails field corrosion tests within months. Similarly, accepting “standard tolerance” without referencing EN 10219 or ASTM A500 tables allows mills to push wall thickness to the lower limit, reducing actual load capacity below design assumptions. [NEED_CITE: EN 10219 dimensional tolerance requirements for cold-formed hollow sections] Engineering inspectors rejecting material on site means demurrage charges, air-freight replacements, and schedule delays that dwarf the original material savings. A Galvanized Square and Rectangular Steel Tube Supplier who provides EN 10204 3.1 mill certificates with actual measured coating weight eliminates this risk at the source.
Why Project Procurement Teams Consolidate with Us
Our three dedicated production lines cover square, rectangular, and round sections in over 2,800 specifications — meaning a single purchase order for Q235 galvanized SHS, S355 RHS, and matching steel plates ships from one yard with unified documentation. The proprietary sharp-corner rectangular tube technology, backed by 41 patents, delivers tight-radius corners that improve connection fit-up and architectural appearance without secondary machining. Every shipment carries CE certification under EN 10210/10219 for EU compliance, ISO 9001:2015 quality system coverage, and mill test certificates traceable by heat number. Non-standard sizes and custom lengths beyond the 6–12 m range are produced to drawing, with MOQ flexibility for project-specific quantities rather than mill-run minimums. Professional loading plans optimize container utilization for long-length tubes, reducing freight cost per ton on FOB, CIF, and DDP shipments to 50+ countries.
Documentation & Compliance
- Mill test certificate documenting Q235 chemical composition and yield strength per GB/T 6728, with actual zinc coating weight measured by magnetic thickness gauge
- CE certificate under EN 10219 for cold-formed galvanized rectangular hollow sections, required for EU customs clearance and project handover
- ISO 9001:2015 quality management certificate covering the full production chain from raw coil incoming inspection to final galvanizing
- SGS or BV third-party inspection report available per shipment, verifying dimensional tolerance, coating adhesion, and surface quality
- Heat number traceability linking each bundle to its original steelmaking charge, composition report, and mechanical test results
- Customs document package including packing list, bill of lading, and certificate of origin formatted for the destination port
Packaging, Loading & Delivery
- Q235 galvanized square and rectangular steel tubes bundled with high-tensile steel strips and edge protectors to preserve the zinc coating from abrasion during ocean transit
- Zero spangle finish tubes wrapped in waterproof paper and plastic film to prevent white rust formation from condensation inside closed containers
- 6 m and 12 m lengths loaded with optimized stowage plans maximizing 20ft and 40ft container payload, reducing per-ton freight cost for project volumes
- Custom cut-to-length service available for 1.0–40 mm wall thickness tubes, with cut ends deburred and re-galvanized to maintain corrosion protection
- Each bundle tagged with heat number, steel grade Q235, section dimensions, and length for site identification and inspection traceability
- FOB, CIF, and DDP shipping terms supported with door-to-door logistics coordination to ports across EU, North America, India, Southeast Asia, and the Middle East
Starting Your Q235 Galvanized Tube Procurement
Send your specification sheet — section dimensions, wall thickness, steel grade, zinc coating class, quantity, and destination port — and receive a detailed quotation within 12 hours including unit price, production lead time, payment terms, and applicable certification scope. For non-standard sizes or sharp-corner rectangular tubes outside the catalog range, share your drawing and our engineering team returns a feasibility assessment with tooling requirements. Confirm mill test certificate format, third-party inspection scope, and loading plan before production begins to align documentation with your project’s compliance requirements.
Frequently Asked Questions
Q: What is the steel grade equivalence between Q235, S235, and ASTM A36?
A: Q235 (GB), S235 (EN), and A36 (ASTM) are broadly equivalent in yield strength range and carbon content for structural applications, but differ in elongation, impact testing temperature, and chemical composition limits. Our mill test certificates specify the actual grade produced and can provide equivalence statements for project approval when the design standard differs from the supply standard.
Q: Can you produce non-standard sizes outside the 100×100 mm reference model?
A: Yes, our catalog covers 2,800+ specifications in square and rectangular sections with wall thickness from 1.0 mm to 40 mm. Custom non-standard dimensions are produced to drawing with MOQ flexibility based on project quantity rather than mill-run minimums.
Q: What zinc coating thickness options are available for galvanized tubes?
A: We offer Z30, Z50, and Z60 zinc coating classes depending on the corrosion environment. Z30 suits indoor or dry applications, Z50 covers general outdoor exposure, and Z60 is specified for coastal or industrial atmospheres with high salt or chemical exposure.
Q: Do your galvanized tubes carry CE certification for EU market entry?
A: Yes, our galvanized square and rectangular steel tubes are CE certified under EN 10210 for hot-formed sections and EN 10219 for cold-formed sections, with full documentation including Declaration of Performance and factory production control certificates for EU customs and project compliance.
Q: How do you optimize container loading for 6–12 m long tubes?
A: Our logistics team prepares stowage plans maximizing payload for 20ft and 40ft containers based on your specific lengths and section dimensions. Nested loading for nested rectangular sections and bundled stacking for square tubes reduce freight cost per ton on FOB, CIF, and DDP shipments.
Get Your Q235 Galvanized SHS/RHS Quotation with Mill Test Certificates
Submit your section dimensions, wall thickness, steel grade, quantity, and destination port to receive pricing, certification scope, and production lead time within 12 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxjysteel.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjysteel.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
