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Galvanized Square Tube
Steel Sections

Galvanized Square & Rectangular Steel Tube

Galvanized square hollow sections (SHS) and rectangular hollow sections (RHS) for building frames, warehouses, solar mounting, gates, fencing and furniture. Supplied pre-galvanized or hot-dip galvanized, to EN 10219, ASTM A500 or GB/T 6728.

ProductGalvanized square & rectangular steel tube (SHS / RHS)
Size range15×15 – 400×400 mm; rectangular 20×40 – 200×400 mm
Wall thickness0.8 – 20 mm
StandardsGB/T 6728, EN 10219, ASTM A500, JIS G3466
Steel gradeQ195, Q235B, Q345B, S235JRH, S355J2H, A500 Gr.B / Gr.C
CoatingPre-galvanized Z80–Z275, or hot-dip galvanized
Length5.8 m, 6 m, 12 m or to order
ProcessingCutting, punching, drilling, bending, welding
Tolerance±1% or to the chosen standard
CertificatesMill test certificate EN 10204 3.1; SNI support on request
Loading portTianjin / Qingdao
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Where square and rectangular tube is used

For the same weight, a hollow section is stiffer than an angle or channel, and its flat faces make welding, bolting and cladding easy. Our galvanized SHS/RHS goes mainly into:

  • Light steel structures: warehouse columns and purlins, carports, mezzanines and prefabricated houses.
  • Solar PV mounting: ground-mount frames and carport structures, where a long corrosion life matters.
  • Gates, fencing and balustrades: 20×20 to 60×60 mm sections in 1.0–2.0 mm wall.
  • Furniture, shelving and racking: thin-wall pre-galvanized tube, 0.8–1.5 mm.
  • Agriculture: greenhouse frames, livestock pens and trailer chassis.

Pre-galvanized or hot-dip galvanized?

Pre-galvanized tube is formed from zinc-coated coil (typically Z80–Z275). It is economical and has a clean, uniform finish, and it is the standard choice for sections up to about 100×100 mm and 2.5 mm wall. The cut ends and the internal weld are not coated.

Hot-dip galvanized tube is galvanized after forming, so it is fully covered inside and out, with a much heavier coating. Specify it for structures that are outdoors near the coast, in fertiliser or chemical plants, or wherever the design life is 20 years or more.

Popular sizes

Section (mm)Common wall (mm)Typical use
20×20, 25×25, 30×300.8 – 2.0Furniture, fencing, handrails
40×40, 50×50, 40×601.2 – 3.0Gates, frames, solar rails
60×60, 50×100, 80×802.0 – 4.0Purlins, light columns
100×100, 100×150, 150×1503.0 – 8.0Columns, trusses
200×200 – 400×4006.0 – 20Heavy structural members

Grades and standards

  • GB/T 6728 / GB/T 3094: Q195, Q235B, Q345B (Q355B) – the most economical option for general construction.
  • EN 10219: S235JRH, S275J0H, S355J2H – cold-formed structural hollow sections for CE-marked projects.
  • ASTM A500: Grade B and Grade C – for projects designed to US codes, common in the Gulf and the Philippines.
  • JIS G3466: STKR400 / STKR490.

Corner radius, straightness and twist are controlled to the chosen standard. Mill test certificates (EN 10204 3.1) come with every shipment.

Packing and loading

Tubes are packed in square bundles of 1–3 tons and tied with steel strips. Small sections can be wrapped in woven plastic to protect the zinc surface during sea freight. Lengths of 5.8–6 m load into 20ft containers; 12 m lengths go in 40ft containers. We ship from Tianjin and Qingdao to West and East Africa, the Gulf and Southeast Asia.

Frequently asked questions

What is the difference between SHS and RHS?

SHS is a square hollow section with equal sides, such as 50×50 mm. RHS is a rectangular hollow section, such as 50×100 mm. Both are produced on the same ERW lines and come in the same grades.

Can you cut the tube to our length and punch holes?

Yes. We cut to length and punch or drill holes to your drawing before galvanizing. This is common for solar mounting and prefabricated building kits.

What minimum wall thickness do you recommend for outdoor structures?

For load-bearing outdoor frames we usually recommend at least 2.0 mm wall, and hot-dip galvanizing near the coast. Thin-wall pre-galvanized tube is better kept for indoor or sheltered use.

Do you supply black (non-galvanized) square tube as well?

Yes. Black and pre-oiled square tube in the same sizes is available, and usually costs less than galvanized tube.

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