Rectangular & Square Steel Tube (Hollow Structural Section)
Rectangular and square steel tubes, also known as Hollow Structural Sections (HSS), are cold-formed or hot-finished welded tubes with a rectangular or square cross-section, optimized for structural efficiency and aesthetic appeal in framing.
Material
Carbon Steel and High-Strength Low-Alloy Steel. Common grades include ASTM A500 Gr. B/C (most common), ASTM A1085, EN 10219 S235-S460, JIS G3475 STKR400, GB/T 6728 Q235B/Q355B.
Model
RHS (Rectangular Hollow Section), SHS (Square Hollow Section), HSS
Size
Square tubes: from 10×10 mm to 500×500 mm. Rectangular tubes: from 20×10 mm to 600×400 mm and beyond. Wall thickness typically from 1.0 mm to 25 mm.
Thickness
Wall thickness typically ranges from 1.0 mm to 25 mm, depending on the size and manufacturing process.
Standard
ASTM A500, ASTM A1085, EN 10219, JIS G3475, GB/T 6728.
MOQ
10 Metric Tons.
Delivery Time
Standard lead time is 4 to 8 weeks for mill orders; common sizes are frequently available from stock with 2-4 week delivery.
Long Description
Rectangular and square steel tubes are manufactured from steel coil or plate through a process of cold forming into a circular shape, welding the seam (typically via ERW or HFW), and then reshaping the welded tube into final square or rectangular geometries through a series of sizing stands. They can also be produced as hot-finished seamless sections. These Hollow Structural Sections (HSS) provide superior torsional resistance and bending strength in multiple axes compared to open sections like I-beams or channels of similar weight. The closed shape offers a clean, modern appearance and allows for easier connection details. They are extensively used in welded steel frames where their flat surfaces simplify joining and their high strength-to-weight ratio enables lighter, more efficient structures. Available in a wide range of sizes and wall thicknesses, they are supplied in random mill lengths or cut-to-size.
Key Product Highlights
HSS tubes offer an excellent strength-to-weight ratio and high torsional rigidity due to their closed cross-section.
The flat surfaces on all sides (for rectangles and squares) facilitate simple, clean connections to other members.
Available in a wide spectrum of standardized sizes with consistent dimensional tolerances and corner radii.
The hollow interior can be used for routing utilities, as a conduit, or for filling with concrete to enhance load capacity.
Provides a modern, aesthetic appearance suitable for both structural and architectural exposed applications.
Product Advantages
Efficient material use leads to weight savings in structures, reducing material and foundation costs.
Predictable and consistent dimensions ensure ease of design, fabrication, and assembly.
Can be easily cut, mitred, drilled, welded, and cold-formed (within limits) to create complex frameworks.
Available in various material grades and surface conditions (plain, galvanized, painted) to suit environmental conditions.
Widely available from stock in common sizes, supporting fast-track construction and manufacturing projects.
Industry Application
This product is used for building columns and beams, space frames, trusses, handrails, machinery bases and guards, conveyor frames, agricultural equipment, exhibition stands, and retail display systems.
Technical Specifications
| Parameter | Unit | Square Hollow Section (SHS) | Rectangular Hollow Section (RHS) | Hot-Finished Hollow Section | Notes |
|---|---|---|---|---|---|
| Carbon Content (C) | % | ≤ 0.26 (A500 Gr.B) | ≤ 0.26 (A500 Gr.B) | ≤ 0.22 (EN 10210 S355J2H) | Varies by grade; hot-finished often has tighter control. |
| Manganese (Mn) | % | ≤ 1.35 | ≤ 1.35 | ≤ 1.60 | |
| Phosphorus (P) | % | ≤ 0.035 | ≤ 0.035 | ≤ 0.035 | |
| Sulfur (S) | % | ≤ 0.035 | ≤ 0.035 | ≤ 0.035 | |
| Tensile Strength | MPa | ≥ 400 (Gr. B) | ≥ 400 (Gr. B) | 470 – 630 (S355J2H) | Grade dependent. |
| Yield Strength | MPa | ≥ 250 (Gr. B) | ≥ 250 (Gr. B) | ≥ 355 (S355J2H) | Minimum for the specified grade. |
| Elongation | % | ≥ 23 (Gr. B) | ≥ 23 (Gr. B) | ≥ 22 (S355J2H) | |
| Hardness | HRB | ≤ 80 (Typical for Gr.B) | ≤ 80 (Typical for Gr.B) | N/A | Sometimes specified for cold-formed sections. |
| Outside Dimension (H) | mm | 50 x 50 (e.g.) | 100 x 50 (e.g.) | 150 x 150 (e.g.) | Height/Width of the section. |
| Outside Dimension (W) | mm | 50 (Equal to H) | 50 | 150 (Equal to H) | Width of the section. |
| Wall Thickness (t) | mm | 3.0 | 3.0 | 8.0 | Uniform for SHS; RHS may have slightly different wall specs. |
| Length | m | 6 – 12 (Random or Cut) | 6 – 12 (Random or Cut) | 6 – 18 | Standard mill lengths; cut-to-size available. |
| Surface Treatment | – | Bare (mill scale), Galvanized | Bare (mill scale), Galvanized | Bare (mill scale), Blasted | Galvanizing is common for corrosion protection. |
| Coating / Finish | – | None, Hot-Dip Galvanized | None, Hot-Dip Galvanized | None, Primed | Defines final corrosion protection state. |
| Manufacturing Process | – | Cold Formed & Welded (CFW) | Cold Formed & Welded (CFW) | Hot Finished Seamless or Welded | Process affects corner sharpness and tolerances. |
| Standard Example | – | ASTM A500 Gr. B SHS 50x50x3.0 | ASTM A500 Gr. B RHS 100x50x3.0 | EN 10210 S355J2H SHS 150x150x8.0 | Representative specifications and sizes. |
Packaging & Surface Treatment
Tubes are bundled by size and grade, secured with multiple steel straps to prevent distortion. Bundles are typically placed on wooden cradles or pallets for stability. The standard surface condition is as-welded with light mill scale. A very common specification is hot-dip galvanized after fabrication (HSS members are often galvanized as finished pieces). They can also be supplied pre-primed or painted in custom colors for architectural applications.
Aliases Names
HSS (Hollow Structural Section), RHS (Rectangular Hollow Section), SHS (Square Hollow Section), Box Section, Structural Tubing, Square Tube, Rectangular Tube.
