Description
Factory-direct pricing, no middlemen — every Q235 galvanized SHS/RHS rolls off our Jinan production lines with original mill certificates attached.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Galvanized Square / Rectangular Steel Tube |
| Product Type | Galvanized Square / Rectangular Steel Tube (SHS / RHS) |
| Steel Grade | Q195, Q215, Q235, Q345, 10#, 20#, 45#, 16Mn, A53 (A/B), St37, St42, St35.4, St52.4, ASTM Grade B/C/D/50 |
| Standard | BS EN, GB, AISI, ASTM, DIN, JIS, ISO 9001, API, CE, BSI, RoHS, SNI, BIS, SASO, PVOC, SONCAP, SABS, SIRM, TISI, KS |
| Section Shape | Square / Rectangular |
| Size Range | 10mm – 1000mm |
| Wall Thickness | 0.6mm – 28mm |
| Length | 1m – 12m (or customized) |
| Technique | Hot Rolled / Cold Rolled / ERW |
| Surface Treatment | Galvanized (Zinc Coating 30–275g/m²), Bare, Oiled, Color Painted, 3PE |
| Ends | Plain, Beveled, Threaded with Couplings/Sockets |
| Application | General engineering structures, fences, construction frames, machinery, scaffolding, furniture, automotive, bridges, ships, boilers, pressure vessels |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, perimeter fencing, scaffolding uprights, bridge support bracing |
| Machinery & Industrial Equipment | Conveyor structures, machine base frames, equipment enclosures, hydraulic support columns |
| Engineering Projects | Pressure vessel jackets, boiler structural supports, ship deck framing, solar panel mounting structures |
| Furniture & Automotive | Warehouse racking systems, vehicle chassis cross-members, display stand frames |
What Wall-Thickness Tolerance Costs on a Galvanized Square Rectangular Steel Tube Order
Negative tolerance beyond acceptable limits means you pay for steel you never receive.
When buyers receive galvanized SHS/RHS with wall thickness running 10–12% below nominal, the weight shortfall compounds across container loads. A 40ft container packed with 10×10mm tubes at 0.6mm wall might carry 18 tons on paper but deliver 15.8 tons on the scale. The zinc coating — applied to the outer surface — cannot compensate for structural section loss. Project engineers signing off on load calculations based on catalog weights face rework when actual section modulus falls short. Customs inspectors in markets requiring SONCAP or SASO certification measure wall thickness on arrival; tubes failing tolerance bands get held at port, triggering demurrage and reshipment costs. [NEED_CITE: EN 10219 dimensional tolerance requirements for cold-formed structural hollow sections]
Matching Galvanized SHS/RHS to Structural Frame and Scaffolding Loads
Galvanized square rectangular steel tube in Q235 grade serves load-bearing frames where corrosion resistance and weldability matter simultaneously. The 30–275g/m² zinc coating range lets specifiers match coating weight to environment severity — indoor racking needs minimal protection, while coastal scaffolding or bridge bracing demands heavier galvanizing to resist salt-laden moisture. ERW-welded Q235 tubes in 50×100mm rectangular profile provide flat bearing surfaces for bolted gusset connections, reducing the need for machined adapter plates. Our production lines run three shifts across square, rectangular, and round sections, so a single order combining 40×40mm fence posts, 100×100mm column sections, and 200×100mm beam members ships in one consolidated container with unified mill documentation.
Engineering Compliance and Certification Requirements for Galvanized Hollow Sections
Structural engineers designing to EN 1993-1-1 or AISC 360 require hollow sections that conform to recognized dimensional and material standards. Galvanized SHS/RHS produced to EN 10219 (cold-formed welded) or EN 10210 (hot-finished welded) carry CE marking for European project acceptance, while ASTM A500 Grade B/C tubes satisfy North American structural codes. Q235 steel — the Chinese GB/T 700 equivalent of S235JR — provides minimum 235 MPa yield strength suitable for general construction frames, while Q345 (equivalent to S355JR) steps up for heavier bridge or industrial loads. Zinc coating thickness must meet ISO 1461 or ASTM A123 minimums for the intended corrosion category; 275g/m² coating provides roughly 20 microns of zinc per side, sufficient for C3–C4 atmospheric corrosion environments. Third-party inspection by SGS or BV verifies coating adhesion, thickness uniformity, and base metal chemistry before shipment, preventing compliance failures at destination port. [NEED_CITE: ISO 1461 hot-dip galvanized coatings on fabricated iron and steel articles]
Steel Grade Selection and Manufacturing Process for Galvanized Square Tubes
Q235 remains the dominant grade for galvanized square rectangular steel tube in general construction because it balances formability, weldability, and cost. The Q-series (Q195, Q215, Q235, Q345) follows Chinese GB/T 700 designation where the number indicates minimum yield strength in MPa; Q195 suits light-duty furniture frames, Q235 handles structural bracing, and Q345 carries heavier industrial loads. For international projects, ASTM A53 Grade B or St37 provide equivalent mechanical properties under different standard systems — the chemical composition and tensile requirements align closely, though testing protocols and certification formats differ. ERW (Electric Resistance Welded) production dominates the 10–400mm size range because it offers tight dimensional tolerance, consistent weld seam quality, and lower cost than seamless alternatives. Hot-rolled tubes in thicker walls (above 6mm) provide better corner radii for heavy structural connections, while cold-rolled tubes deliver sharper corners and smoother surfaces for architectural applications. Galvanizing occurs after forming — either by batch hot-dip galvanizing of finished tubes or continuous galvanizing of strip before forming — with coating weight selected based on service environment rather than structural requirement. Wall thickness tolerance under EN 10219 allows ±10% of nominal for walls below 3mm, but tighter tolerance agreements are available for projects where section modulus calculations leave minimal safety margin.
Hidden Costs of Incorrect Galvanized SHS/RHS Procurement
Material substitution and certification gaps create expenses long after delivery.
When a buyer accepts Q235 tubes labeled as Q345 without verifying mill test certificates, the lower yield strength may pass visual inspection but fail structural load testing — forcing frame replacement after erection. Missing CE documentation for European projects triggers customs holds; resubmitting paperwork or arranging retroactive inspection costs more than the original tubes. Zinc coating below specified thickness accelerates corrosion in humid or coastal environments, leading to premature rust-through and maintenance calls within two years of installation. Negative wall thickness tolerance compounds across hundreds of tons: the buyer pays for nominal weight but receives less steel, reducing load capacity and potentially violating design safety factors. [NEED_CITE: steel grade equivalence tables between GB, EN, and ASTM standards]
Why Project Buyers Source Galvanized Square Rectangular Steel Tube From Our Jinan Facility
We operate three production lines running simultaneously in Jinan, producing galvanized SHS/RHS from 10mm to 1000mm side length with walls from 0.6mm to 28mm — no order gets turned away for being too small or too unusual. Every batch leaves the mill with original test certificates showing chemical composition and mechanical properties; we do not issue generic certificates copied across multiple heats. Our in-house lab conducts three-stage inspection (incoming strip, post-weld, post-galvanizing) before any tube ships, and we welcome SGS or BV third-party inspection at our facility at no coordination fee to the buyer. Factory-direct pricing means no trading company markup; volume buyers locking annual contracts receive tiered discounts reviewed every six months. Custom lengths from 1m to 12m cut to your bill of materials reduce on-site welding and waste; threaded ends with couplings ship ready for mechanical connection. We handle export documentation including certificate of origin, packing lists, and bills of lading optimized for destination-country customs requirements — SONCAP for Nigeria, SASO for Saudi Arabia, PVOC for Kenya — so containers clear port without document-related delays.
Documentation & Compliance
- Mill test certificate documenting Q235 chemical composition (C, Si, Mn, P, S content) and mechanical properties (yield strength, tensile strength, elongation) per GB/T 700 standard
- CE certificate confirming EN 10210 or EN 10219 compliance for hot-finished or cold-formed galvanized hollow sections entering European markets
- ISO 9001:2015 quality management certificate covering production processes from raw material receipt through final galvanizing inspection
- SGS or BV third-party inspection report verifying zinc coating thickness (30–275g/m²), coating adhesion, and dimensional tolerance before container loading
- Material traceability documentation linking each tube bundle to specific heat number, strip coil origin, and galvanizing batch for project audit requirements
- Complete customs document package including commercial invoice, packing list, bill of lading, and certificate of origin formatted for destination-country clearance procedures
Packaging, Loading & Delivery
- Galvanized tubes bundled with steel strips and edge protectors to preserve zinc coating integrity during ocean transit and prevent corner damage from bundle-to-bundle contact
- Surface protection options including oiled coating or plastic end caps for tubes requiring extended storage before installation in humid climates
- Container loading optimization combining multiple size ranges — 20×20mm small sections nested inside 100×100mm larger tubes — to maximize payload per 20ft or 40ft container
- Custom length cutting from 1m to 12m per project bill of materials, reducing on-site cutting waste and welding time for construction crews
- Heat number and steel grade marking stenciled on each bundle tag with corresponding mill test certificate cross-reference for site verification
- FOB, CIF, or DDP shipping terms available with professional export team coordinating port clearance, vessel booking, and door-to-door delivery for project sites
How to Request Quotation and Mill Test Certificates for Your Galvanized SHS/RHS Project
Submit your specification list including outer dimensions, wall thickness, steel grade (Q235, Q345, A53, or other), total quantity, and destination port — we return a detailed quotation with volume pricing, production lead time, and available mill test certificate samples within 12 hours. Non-standard sizes outside the 10–1000mm range or custom zinc coating weights beyond 275g/m² receive engineering review for feasibility and pricing. Confirm required certifications (CE, ISO, SGS inspection) and customs documentation needs so we prepare the complete paperwork package before production begins.
Request Your Galvanized Square Rectangular Steel Tube Quotation Today
Send specifications via email or WhatsApp to receive factory-direct pricing and original mill test certificates within 12 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxinjiyuan.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxinjiyuan.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: What steel grades are available for galvanized square and rectangular tubes?
A: We produce galvanized SHS/RHS in Q195, Q215, Q235, Q345, 10#, 20#, 45#, 16Mn for Chinese standard projects, plus A53 Grade A/B, St37, St42, St35.4, St52.4, and ASTM Grade B/C/D/50 for international specifications. Q235 serves general construction frames, Q345 handles heavier structural loads, and ASTM A53 meets North American piping and structural requirements.
Q: How can I verify zinc coating quality and material traceability?
A: Every shipment includes original mill test certificates documenting base metal chemical composition and mechanical properties by heat number. Zinc coating thickness (30–275g/m²) is measured via magnetic gauge or gravimetric method per ISO 1461, and we welcome SGS or BV third-party inspection at our facility before container loading to verify coating adhesion, thickness uniformity, and dimensional compliance.
Q: Can I order non-standard sizes with low minimum order quantity?
A: Yes, we produce galvanized square and rectangular tubes from 10mm to 1000mm side length with wall thickness 0.6mm to 28mm in custom lengths from 1m to 12m. The minimum order quantity is 1 ton, allowing trial orders for new projects or small-quantity requirements for maintenance and repair work.
Q: What surface treatment options are available besides hot-dip galvanizing?
A: In addition to galvanized coating (30–275g/m² zinc), we supply bare black tubes, oiled tubes for temporary rust prevention, color-painted tubes for architectural applications, and 3PE coated tubes for underground or high-corrosion environments. Surface treatment selection depends on service environment, installation method, and project specification requirements.
Q: How do you handle export documentation and customs compliance for different countries?
A: Our export team prepares complete documentation packages including mill test certificates, CE certificates for European markets, packing lists, bills of lading, and certificates of origin. We format documents to meet specific country requirements — SONCAP for Nigeria, SASO for Saudi Arabia, PVOC for Kenya, SABS for South Africa — and coordinate with inspection agencies to ensure customs clearance without document-related delays.
