Description
Factory-Direct Pre-Galvanized SHS & RHS — Every Q235, Q345, SS400, and A36 square and rectangular tube rolls out of the mill with original heat-number traceability, cutting out trader markups on structural hollow sections.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Pre Galvanized Square & Rectangular Steel Tube |
| Product Type | Galvanized Square / Rectangular Steel Tube (SHS / RHS) |
| Steel Grade | Q235, Q235B, Q345, Q345B, SS400, A36 |
| Standard | GB |
| Section Shape | Square / Rectangular |
| Size Range | Customized outer diameter or side length |
| Wall Thickness | Customized |
| Length | Customized |
| Technique | ERW (Welded) |
| Surface Treatment | Pre-Galvanized / Zinc Coated |
| Application | Concrete reinforcement, concrete construction support, scaffolding, structural frames |
| MOQ | 5 Tons |
| Origin | China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction | Concrete reinforcement cages, formwork support frames, column bracing |
| Steel Fabrication | Scaffolding uprights and ledgers, mezzanine structural frames |
| Infrastructure | Bridge handrail posts, highway sign gantry columns |
Where Grade Confusion Costs You a Full Container Return
Mixing up Q235B with A36 on a drawing spec can land a 25-ton container stuck at customs or rejected on site.
I have seen buyers specify SS400 on their purchase order while the engineer’s calculation sheet calls for A36 — the chemical composition overlaps enough that the mill rolls it without flagging, but the third-party inspector at destination ticks “grade mismatch” and the whole lot gets refused. Galvanized hollow sections make this worse because once the zinc is on, you cannot do a spark test or grind a coupon without destroying the coating. The BS EN Standard Pre Galvanized Square Rectangular Steel Tube Supplier you work with must cross-reference GB, JIS, and ASTM equivalences before the coil is slit, not after the container is sealed. [NEED_CITE: steel grade equivalence between GB, JIS, and ASTM standards for structural hollow sections]
Matching Hollow Sections to Concrete and Scaffolding Loads
Pre-galvanized SHS and RHS in Q235 and Q345 grades sit directly inside concrete formwork and scaffolding systems where compressive load and corrosion resistance matter more than tensile elongation. The zinc coating formed during the pre-galvanizing line protects the tube during the months it sits exposed on a construction site before being encased or painted. For scaffolding uprights, the square profile gives flat bearing surfaces against couplers, reducing slippage compared to round pipe. We cut Q345B rectangular tubes to exact lift lengths so fabricators do have to re-saw on site and re-touch-up the zinc at every cut end.
Structural Codes, Zinc Durability, and Customs Paperwork
Engineering specs for scaffolding and concrete support frames typically reference load tables that assume a minimum wall thickness and a defined yield grade. When the BS EN Standard Pre Galvanized Square Rectangular Steel Tube Supplier ships Q235B against a drawing calling for S235JR, the equivalence is generally accepted, but the customs broker at the destination port still wants to see the mill test certificate state the matching chemistry. Pre-galvanized coating thickness sits lower than hot-dip for the same service life, so engineers specifying marine-adjacent scaffolding need to understand the trade-off before signing off. Third-party inspection by SGS or BV before loading closes the gap between mill paperwork and site acceptance. [NEED_CITE: pre-galvanized versus hot-dip galvanized coating thickness comparison for structural steel]
Reading the Grade List: Q235, Q345, SS400, A36
Q235 and Q235B are Chinese carbon structural grades where the “B” denotes room-temperature impact testing — essential for scaffolding used in colder climates. Q345 and Q345B step up to a higher yield tier, used where column loads push the section closer to its limit. SS400 is the JIS general structural grade commonly called for in Southeast Asian projects, while A36 covers the same territory under ASTM for North American and Middle Eastern tenders. The ERW welding process used for these tubes produces a straight seam that is cold-planed and then galvanized as a complete section, so the zinc layer covers the weld line uniformly. Pre-galvanizing deposits a thinner zinc coat than hot-dip but keeps dimensional tolerance tight — critical when tubes must slide into sleeve connections on scaffolding systems.
The Hidden Price of Wrong Tolerance and Missing Paperwork
Buying on price per ton alone ignores what happens when wall thickness runs below the ordered nominal value. A 3 mm specified wall arriving at 2.6 mm actual passes through the galvanizing line looking identical, but the load capacity drops and the engineer’s calculation no longer holds. At the project stage, this means failed compression tests, torn-down scaffolding, and re-ordering with a two-month lead time penalty. Missing heat numbers on the mill test certificate turn a routine delivery into a customs hold, because the importer cannot prove the steel matches the declared grade. [NEED_CITE: negative tolerance practices in welded steel tube trade and structural safety implications]
Why Buyers Return to XJY Plate for Hollow Sections
We run the plate and coil division inside a larger tube mill, so the Q235 and Q345 hollow sections you order come from the same rolling schedule as the plate — no broker layer adding margin and blurring traceability. Every bundle carries the original mill test certificate with heat number, chemistry, and tensile results, and we can arrange SGS or BV inspection at the mill before loading. Custom side lengths and wall thicknesses are cut on our leveling and blanking lines, so a 5-ton scaffold order arrives in exact lift lengths rather than random 6-meter sticks that the fabricator has to re-cut. Flatbed and open-top container loading is handled in-house, with the same crew that learned the hard way after an early Dubai shipment arrived with crushed corners and peeling zinc. ISO 9001:2015 certification and CE marking documentation travel with every container.
Documentation & Compliance
- Mill test certificate listing Q235B / Q345B chemical composition and mechanical properties per GB standard, with heat number traceability
- CE certificate covering structural hollow sections for European market customs clearance
- ISO 9001:2015 quality management certificate for the plate and coil division
- SGS or BV third-party inspection report available before shipment upon request
- Full material traceability linking each bundle to its original heat number and rolling record
- Export documents including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Pre-galvanized SHS and RHS bundled with steel strips and edge protectors to prevent zinc coating abrasion during ocean transit
- Bundles stacked with timber dunnage inside containers to keep the galvanized surface off the floor and avoid moisture pooling
- Custom-length tubes loaded on flatbed or open-top containers, with side-length optimization to maximize 20ft and 40ft payload without overweight penalties
- Heat number and steel grade stenciled on each bundle tag for site identification and inspection matching
- FOB, CIF, and DDP terms available, with break-bulk option for project volumes exceeding container capacity
Getting a Firm Offer on Hollow Sections
Send the side length, wall thickness, length, steel grade, and tonnage together with the destination port, and the quotation comes back within 12 hours with material cost, processing fees, and shipping terms separated. If the drawing calls for a grade not listed in GB, we cross-reference to the nearest JIS or ASTM equivalent and confirm before rolling. Mill test certificates and third-party inspection reports are locked into the contract, not offered as an afterthought.
Frequently Asked Questions
Q: Can Q235B be used in place of S235JR or A36 on a structural drawing?
A: Q235B, S235JR, and A36 are broadly equivalent in yield strength and chemistry for general structural use, and most engineers accept the substitution. The BS EN Standard Pre Galvanized Square Rectangular Steel Tube Supplier should confirm the match in writing and reflect it on the mill test certificate so customs and site inspectors accept the material without dispute.
Q: What is the difference between pre-galvanized and hot-dip galvanized tubes?
A: Pre-galvanizing coats the strip before the tube is formed and welded, giving a uniform but thinner zinc layer suited to indoor and moderate outdoor environments. Hot-dip galvanizing coats the finished tube in a zinc bath, producing a thicker coat for harsher corrosion conditions. The choice depends on the service environment specified by the engineer.
Q: What is the minimum order quantity for custom-size square and rectangular tubes?
A: The MOQ is 5 tons per order. Side length, wall thickness, and length can be customized to project drawings within the 5-ton batch, and cut-to-length processing is included.
Q: How do you verify material quality before shipment?
A: Every order is backed by an original mill test certificate showing heat number, chemical composition, and mechanical properties. SGS or BV third-party inspection can be arranged at the mill before loading for buyers who require independent verification.
Q: What happens if the wall thickness arrives below the ordered value?
A: We control thickness to the ordered nominal value and declare the tolerance on the contract. If a third-party inspection at destination finds deviation beyond the agreed tolerance, the claim is handled under the contract terms, with the mill test certificate and inspection report as the basis for resolution.
Start Your Pre-Galvanized Hollow Section Order
Send your side length, wall thickness, grade, and tonnage to receive a detailed quotation with mill test certificate preview within 12 hours.
XJY Plate — Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Tel: +86 531 8573 6315
Mobile / WhatsApp / WeChat: +86 188 5315 7756
Email: admin@xjyplate.com
Website: www.xjyplate.com
