Description
Factory-Direct Galvanized Tubes — Every Q195–Q345 and S235–S355 rectangular steel square pipe rolls off our own ERW lines with in-house galvanizing and lab verification, eliminating trader markups and specification guesswork.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Galvanized Rectangular Steel Square Pipe |
| Product Type | Galvanized Square / Rectangular Steel Tube |
| Steel Grade | Q195, Q215, Q235, Q345, GR.A, GR.B, S235, S355 |
| Standard | ASTM A213, DIN EN 10217-1 |
| Section Shape | Square / Rectangular |
| Size Range | Customized outer dimensions |
| Wall Thickness | 0.8–30 mm |
| Length | 500 mm / 1000 mm / 4000 mm / 5800 mm / 11800 mm (customizable) |
| Technique | Welded (ERW) |
| Surface Treatment | Pre-galvanized / Hot-dipped galvanized / Bare / Oiled |
| Tolerance | ±1% |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Invoicing | By Theoretical Weight |
| MOQ | 10 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors & Construction | Structural frames for warehouses, portal frames, steel posts, building skeletons |
| Infrastructure & Fencing | Highway guardrails, perimeter steel fences, utility poles, signpost foundations |
| Machinery Manufacturers | Equipment base frames, conveyor support structures, machine guards |
| Steel Distributors | Stocking programs for light-to-heavy structural hollow sections |
Where Galvanizing Thickness Decides Whether Your Steel Survives the Job Site
Coating weight is not a line item — it is the difference between a structure that lasts and one that rusts through before warranty expires.
I have watched entire container loads of galvanized rectangular steel square pipe get rejected at a West African port because the zinc layer measured 35μm against a 60μm spec. The air-freight bill for replacements cost more than the original cargo. Humid coastal climates and industrial zones do not forgive thin coatings, and third-party inspectors are measuring with magnetic gauges the moment the container doors open.
Beyond coating inconsistency, buyers face missing mill certificates that stall customs clearance, fragmented sourcing across pipes, plates, and beams that multiplies coordination costs, and negative tolerance stacking that erodes actual structural capacity [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerances].
Matching Wall Thickness and Coating to Structural Exposure
A galvanized rectangular steel square pipe with 0.8–2.0 mm wall thickness and pre-galvanized coating fits indoor conveyor frames and light fencing where handling damage is minimal. Move to 3.0–30 mm sections in hot-dipped galvanized finish, and the same product family carries portal frames, bridge handrails, and coastal warehouse structures where salt spray demands thicker zinc sacrifice. The ±1% tolerance on our ERW lines keeps fit-up predictable when site crews are bolting or welding connections under schedule pressure.
Engineering Compliance Across Markets
Structural frames designed to EN 1993-1-1 or AISC 360 require documented yield strength and dimensional conformity. Our Q345 and S355 grades meet EN 10219 cold-formed structural hollow section requirements, while Q195–Q235 serves non-load-bearing fencing and cladding support [NEED_CITE: steel grade equivalence between EN 10219 and ASTM A500]. CE certification under EN 10210/EN 10219 clears EU customs, and SGS or BV third-party inspection reports satisfy project consultants in the Middle East and Southeast Asia. Custom cut-to-length at 500 mm to 11800 mm reduces on-site welding and secondary fabrication waste.
Reading the Steel Grade and Galvanizing Specification
The Q-series (Q195, Q215, Q235, Q345) follows Chinese GB standards where the number indicates minimum yield strength in MPa — Q235 is the workhorse for general construction, Q345 steps up for heavier structural frames. S235 and S355 are the European EN equivalents, with S355JR delivering higher load capacity for portal frames and crane runways. GR.A and GR.B shipbuilding grades appear when marine environments demand tighter chemistry control.
On the galvanizing side, pre-galvanized (also called sendzimir or continuous hot-dip) coats the strip before tube forming, giving a thinner but uniform layer ideal for indoor or mild outdoor use. Hot-dipped galvanized tubes are formed first, then immersed in a zinc bath, producing a thicker metallurgically bonded coating that resists scratches and coastal corrosion. Choosing between them is a cost-versus-exposure calculation, not a quality judgment.
The Hidden Cost of Buying the Wrong Grade or Missing Certificate
Specify S355 and receive Q235 stamped with a forged certificate, and the structural engineer’s calculations are void. Ship to Rotterdam without EN 10210 CE marking, and the container sits at port while demurrage accumulates. Accept negative tolerance beyond ±1% on a 30 mm wall section, and the theoretical weight invoiced no longer matches the actual load-bearing metal delivered. These are not hypotheticals — they are the daily reality for procurement teams buying from traders who cannot verify chemistry or coating weight [NEED_CITE: consequences of non-conforming steel in structural applications].
Why Procurement Teams Consolidate Here
Our three dedicated ERW lines produce over 2,800 specifications of square and rectangular tubes under one roof, meaning your Q235 pre-galvanized fencing posts and Q345 hot-dipped structural beams ship in the same container from the same mill test batch. The in-house physical and chemical laboratory tests every heat before galvanizing, and we hold 41 patents including proprietary sharp-corner rectangular tube technology that gives tighter corner radii for cleaner welded connections. CE, ISO 9001:2015, Singapore FPC, and SGS/BV verification are standard documentation, not upsells. We have exported to over 50 countries with professional loading plans that maximize container payload for 11800 mm lengths and coordinate DDP delivery to inland project sites.
Documentation & Compliance
- Mill Test Certificate (EN 10204 3.1) documenting Q235B or S355JR chemical composition, yield strength, and tensile properties per heat number
- CE Certificate of Conformity under EN 10210/EN 10219 for EU market customs clearance and structural compliance
- ISO 9001:2015 quality management certificate covering the full ERW welding and galvanizing process
- SGS or BV third-party inspection report verifying zinc coating thickness, dimensional tolerance, and surface quality before shipment
- Material traceability sheet linking each bundle to heat number, galvanizing bath record, and mill test report
- Full customs document package: commercial invoice, packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Galvanized rectangular steel square pipe bundled with high-tensile steel strips and edge protectors to prevent zinc coating abrasion during ocean transit
- Hot-dipped galvanized surfaces wrapped in waterproof paper or shrink film at cut ends to block moisture ingress at exposed steel
- Container loading plans optimized for 5800 mm and 11800 mm lengths to maximize 20ft and 40ft OT payload, reducing per-ton freight cost
- Cut-to-length service at 500 mm to 4000 mm for fencing and machinery frames, shipped on pallets or in bulk bundles per client preference
- Each bundle tagged with heat number, steel grade (Q195/Q235/S355), wall thickness, and length for site identification and traceability
- FOB Jinan/Qingdao, CIF destination port, or DDP door-to-door delivery with real-time container tracking
Start Your Procurement With Verified Numbers
Send your specification sheet — steel grade, outer dimensions, wall thickness, length, galvanizing type, and destination port — and receive a detailed quotation with unit price, mill test certificate preview, and production lead time within 12 hours. Non-standard sizes and custom cut-to-length requests are reviewed by our technical team for feasibility and tooling requirements before contract signing. Confirm your certification needs (CE, SGS, BV) and we include the corresponding inspection and documentation cost transparently in the proforma invoice.
Frequently Asked Questions
Q: What is the difference between pre-galvanized and hot-dip galvanized steel tubes?
A: Pre-galvanized tubes are coated before forming, giving a thinner uniform zinc layer suitable for indoor or mild environments. Hot-dipped galvanized tubes are formed first, then immersed in molten zinc, producing a thicker metallurgically bonded coating that resists coastal corrosion and mechanical damage.
Q: Can you provide custom non-standard sizes and what is the MOQ?
A: Yes, we produce customized outer dimensions and lengths from 500 mm to 11800 mm beyond standard catalogs. The minimum order quantity is 10 tons per specification, and non-standard tooling requirements are confirmed before contract signing.
Q: How do you ensure galvanizing coating thickness meets project specifications?
A: Every batch is tested in our in-house laboratory using magnetic thickness gauges before shipment. We provide coating weight records in the mill test certificate, and third-party inspection by SGS or BV is available for independent verification.
Q: Which certifications do you provide for EU and North American customs clearance?
A: We supply CE certification under EN 10210/EN 10219 for EU markets, ISO 9001:2015 quality certificates, and mill test certificates conforming to EN 10204 3.1. SGS or BV third-party inspection reports are available for project-specific compliance requirements.
Q: What is the typical production lead time and do you offer DDP shipping?
A: Standard specifications ship within typical production lead times after deposit confirmation. We offer FOB, CIF, and DDP shipping terms with professional container loading plans and real-time tracking to over 50 countries.
Get Your Galvanized Rectangular Steel Square Pipe Quote Today
Submit your steel grade, dimensions, wall thickness, and destination port to receive a factory-direct quotation with mill test certificate preview 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
