Frequently Asked
Questions

Square and rectangular hollow sections give flat faces for bolted or welded connections, simpler cladding attachment and better bending resistance about one axis. Round pipe wins where torsion, fluid flow or uniform buckling behaviour dominates.

Typical rule: facade & frame → SHS/RHS · truss chords & piling → CHS

Welded (ERW) tube is formed from strip and is the most economical route for structural work. Seamless tube is produced without a weld line for high-pressure or heavy-duty mechanical use. Hot-dip galvanized tube adds a zinc layer, typically 60-275 g/m², for outdoor corrosion protection.

Yes. Alongside tube we supply H-beam and I-beam from 100×100 to 900×300 mm, hot-rolled U channel, cold-formed C purlins and equal or unequal angle bar from 25×25×3 to 200×200×24 mm -- so a single container can combine tube and profiles.

Sharp-corner rectangular tube is the preferred choice. The true 90° edge lets glazing gaskets and panels seat flush against the steel face, removing the shadow gap that a radiused corner creates and improving the sightline of the finished facade.

Tolerances follow the ordered standard -- EN 10219, ASTM A500 or GB/T 6728 as applicable. Typical outside dimension tolerance is ±1% (minimum ±0.5 mm), thickness ±10%, straightness ≤ 2 mm per metre and squareness of sides 90° ± 1°.

Yes. Light-gauge tube from 1.2 mm is produced for furniture, greenhouse and light frame markets. Send the required section plus the intended load or standard and we will confirm feasibility and the nearest stock equivalent.

Standard mill lengths are 6 m and 12 m. Fixed lengths between 1 m and 18 m are cut to order, and cut-to-length within a bundle is available at no extra tooling cost for most sections.

Q195 through Q690 and T700, carbon grades 20# and 45#, ASTM A500 Gr.A/B/C/D, EN 10219 and 10210 S235JR to S355J2, JIS G3466 STKR400/490, AS1163 C350/C350L0, plus stainless and alloy grades on request.

Q355B is broadly comparable to S355JR under EN 10219 and to A500 Gr.C for structural tube. Chemistry and impact requirements differ slightly, so we always certify to the standard you name on the purchase order rather than to an equivalence table alone.

GB

Q235B / Q355B

EN

S235JR / S355JR-J2

ASTM

A500 Gr.B / Gr.C

Yes. We participated in drafting China's cold-formed steel industry standards in 2018 and are a recognised national high-tech enterprise, which is one reason our sections are accepted by state-owned enterprises and listed contractors.

Material is retained at the extreme corners of the section instead of being rounded away, which raises the section modulus per kilogram. In practice designers gain a stiffer member at the same weight, or the same capacity at reduced weight.

• +Flush panel & glass seating
• +Higher section modulus per kg
• +Cleaner weld preparation

Glass curtain-wall mullions and transoms, exposed architectural steelwork, high-end steel structures, decorative frames and precision machinery frames where two members must meet without a visible radius gap.

No. The corner is formed, not machined, so the wall thickness and grain structure remain continuous. Weld preparation is in fact simpler because the mating faces are flat to the very edge, and hot-dip galvanizing or powder coating behaves as on any cold-formed section.

Stock items load within 7 to 10 days of deposit. Made-to-order sections normally take 15 to 25 days depending on grade, thickness and surface treatment. We confirm a firm loading date with the proforma invoice.

Stock

7 - 10 days

Made to order

15 - 25 days

Terms

FOB · CFR · CIF

Yes. We provide cut-to-length, end deburring, customer marking or printing, anti-rust oiling, plastic end caps, steel strapping and bundle labelling. Container loading is carried out by a trained export team to prevent transit damage.

Section type and dimensions, wall thickness, steel grade or governing standard, length, surface finish, quantity per size and destination port. With that list we return a quotation within 12 hours and flag any specification we can improve on.