Hollow Section

Specification of Hollow Section

Here are the detailed size charts for Square Steel Pipe (SHS) and Rectangular Steel Pipe (RHS) , organized by standard and unit system.

Square Steel Pipe (SHS) Size Chart
1. Metric Sizes – EN 10210 / EN 10219 (Cold-Formed & Hot-Finished)
Square hollow sections are designated by outside width × wall thickness (e.g., SHS 50×4). Standard sizes range from 20×20 mm to 400×400 mm.

Wall thickness availability: 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 4.0 mm, 5.0 mm, 6.0 mm, 6.3 mm, and above.

2. Imperial Sizes – ASTM A500 (North American Standard)
Imperial square tubes are specified by outside dimensions in inches. ASTM A500 covers sizes up to a maximum perimeter of 88 inches (approx. 22×22 inches for square shapes).

Standard lengths: 20 ft, 24 ft, 40 ft, 48 ft.

Rectangular Steel Pipe (RHS) Size Chart
1. Metric Sizes – EN 10210 / EN 10219 (Cold-Formed & Hot-Finished)
Rectangular hollow sections are designated by width × depth × wall thickness (e.g., RHS 100×50×4). Standard sizes typically range from 40×20 mm to 400×200 mm.

Wall thickness availability: 1.6 mm – 16.0 mm.

2. Imperial Sizes – ASTM A500
Rectangular tubes are specified by outside width × depth in inches.

ASTM & EN Standard

Below are standard technical tables for square and rectangular steel pipes, covering chemical composition and tensile mechanical properties. All data complies with ASTM and EN standards for each steel grade. Chemical composition defines element content ranges to guarantee weldability, formability, and material purity. Tensile data shows standardized strength and elongation values, ensuring reliable mechanical performance, structural integrity, and load-bearing capacity. All technical indicators are traceable and support third-party inspection for industrial high-standard applications.

Chemical Requirements (%) – ASTM A500

Chemical Requirements (%) – EN 10219

Tensile Requirements – ASTM A500 (Shaped Structural Tubing)

Tensile Requirements – EN 10219

Manufacturing Process & Surface Finishing

Our structural hollow sections (HSS, SHS, RHS) are manufactured using advanced technology to ensure precise dimensions, high strength, and excellent surface quality.

1. Manufacturing Process (ERW / HFW)

Uncoiling & Leveling: High-quality steel coils are uncoiled and leveled to ensure a flat surface for forming.

Roll Forming: The steel strip is gradually shaped into a circular tube using precision rollers.

High-Frequency Welding (HFW): The edges are fused together using high-frequency electric resistance welding, creating a strong, continuous seam without filler metal.

Squaring/Shaping: For SHS and RHS, the welded round tube is passed through a series of turks-head rollers to be reshaped into a precise square or rectangular profile.

Sizing & Straightening: The tube is precisely sized to meet ASTM/EN tolerances and straightened to eliminate any bending.

Cutting: Cut to standard lengths (6m, 12m) or custom lengths as required.

(Optional: Seamless SHS/RHS are produced by reshaping hot-rolled seamless round tubes, providing superior structural integrity for heavy-load applications).

2. Surface Finishing Options

We offer various surface treatments to extend the service life of your structural steel:

Black (Bare): Standard mill finish, lightly oiled if required. Suitable for immediate fabrication or indoor use.

Hot-Dip Galvanized (HDG): The finished tube is immersed in molten zinc, providing a thick, sacrificial coating inside and outside. Essential for outdoor, marine, and highly corrosive environments.

Pre-Galvanized: Made from zinc-coated steel coils. The weld seam is usually treated with zinc-rich paint. A cost-effective option for mild outdoor environments (e.g., fencing, light structures).

Painted / Powder Coated: Available with red primer, black paint, or customized colors for architectural aesthetics and additional protection.

Beveled Ends: Ends can be machined with a bevel for easy welding on-site.

Q1: What is the difference between SHS and RHS?
A: SHS (Square Hollow Section) has equal side lengths (e.g., 100×100 mm), offering uniform strength and excellent compressive stability. RHS (Rectangular Hollow Section) has unequal side lengths (e.g., 150×100 mm), providing higher bending stiffness along its major axis. Both are widely used for structural frames, columns, and beams.

Q2: What is the difference between EN 10219 and EN 10210?
A: EN 10219 covers cold-formed welded structural hollow sections, which offer excellent dimensional accuracy and a smooth surface finish (most common). EN 10210 covers hot-finished structural hollow sections, which are preferred for heavier wall thicknesses and applications requiring higher resistance to impact at low temperatures.

Q3: How do you ensure the strength of the longitudinal weld seam?
A: We maintain Strict Quality Control. The tubes are manufactured using high-frequency welding (HFW), ensuring a strong metallurgical bond without filler metal. We perform 100% online Eddy Current Testing (ECT) to detect any weld defects. Additionally, we conduct Flattening Tests on samples to prove the weld seam can withstand severe deformation without cracking.

Q4: When should I choose Hot-Dip Galvanized instead of Pre-Galvanized tubes?
A: Pre-Galvanized tubes are made from zinc-coated coils and are cost-effective for mild outdoor environments (like fencing or greenhouse frames), but the weld seam must be re-protected. Hot-Dip Galvanized (HDG) tubes are dipped in molten zinc after forming, providing a thicker, more uniform coating inside and outside. HDG is essential for heavy outdoor structures, marine environments, and highly corrosive conditions.

Q5: Do you provide custom cutting and drilling?
A: Yes. We offer Integrated Customized Services. We can cut SHS/RHS to your exact specified lengths, drill bolt holes, and apply custom paints (like red primer) directly at our factory. This significantly saves on-site fabrication time and reduces material waste for your project.

Q6: What are your payment terms and lead times?
A: We offer Flexible Payment plans, including L/C (Letter of Credit) and open account. Standard lead times are typically 20–35 days after receipt of the advance payment, depending on the sizes, wall thicknesses, and order volume.