CHS Circular Hollow Sections: High-Performance Structural Tubing for Modern Infrastructure
Circular Hollow Sections (CHS), a subtype of Hollow Structural Sections (HSS), deliver unmatched torsional strength and uniform load distribution for architectural, industrial, and civil projects. Certified to ASTM A500 (Grade B/C) and ASTM A1085, these seamless or welded tubes achieve 15–30% higher strength-to-weight ratios than I-beams while minimizing material costs. With diameters from 1.05″ to 24″ and wall thicknesses up to 0.75″, CHS is engineered for columns, trusses, and offshore platforms requiring fatigue resistance and aesthetic precision.
Key Technical Specifications & Compliance
Material Properties by Standard:
| Standard | Yield Strength (MPa) | Tensile Strength (MPa) | Tolerance Class |
|---|---|---|---|
| ASTM A500 Gr.B | ≥315 | 400–550 | ±1.5% OD, ±10% WT |
| ASTM A1085 | ≥365 | 455–620 | ±0.75% OD, ±5% WT |
| EN 10210 S355 | ≥355 | 510–680 | ±1.2% OD, ±8% WT |
Dimensional Range:
| Diameter (inches/mm) | Thickness (inches/mm) | Weight (lbs/ft/kg/m) | Moment of Inertia (in⁴/cm⁴) |
|---|---|---|---|
| 1.05″ / 26.7mm | 0.100″ / 2.54mm | 1.02 / 1.52 | 0.017 / 70.7 |
| 2.735″ / 69.5mm | 0.188″ / 4.78mm | 4.40 / 6.55 | 1.842 / 7,668 |
| 6.625″ / 168mm | 0.375″ / 9.53mm | 22.96 / 34.19 | 28.4 / 118,200 |
Certifications: ISO 9001:2015, CE, AWS D1.1 welding compliance, and NACE MR0175 for sour service.
Engineering Advantages Over Competing Profiles
- Superior Torsional Rigidity: Polar moment of inertia (J) values up to 2,500 in⁴ reduce twist by 40–60% vs. square HSS.
- Aerodynamic Performance: Smooth circular shape cuts wind load by 25% in tower and mast designs.
- Corrosion Resistance: Optional 3PE coating (400μm) or hot-dip galvanizing (610 g/m²) for coastal zones.
- Rapid Assembly: 360° weldable surface simplifies joint fabrication (AWS pre-qualified E70 electrodes).
Critical Applications & Project Case Studies
CHS tubing excels in these high-stress environments:
- Architectural: Cantilevered roof systems (6.625″ OD, 0.375″ WT).
- Energy: Wind turbine monopiles (24″ OD, API 5L X65 steel).
- Transportation: Bridge arch ribs (16″ OD, ASTM A1085).
- Mining: Hydraulic roof supports (10.75″ OD, 0.500″ WT).
Project Highlight: In Dubai’s Museum of the Future, 8,500 meters of 12″ CHS (Grade X70) formed the exoskeleton, achieving LEED Gold certification with 18% lighter framing vs. box sections.
Customization & Quality Assurance
Processing Options:
- Ends: Beveled (37.5°), threaded (API 5B), or flanged (ANSI B16.5).
- Coatings: Internal epoxy lining (250μm DFT) for chemical pipelines.
- Lengths: Standard 20’–24’; custom-extruded up to 50’ (15.24m).
Testing Protocols:
- Hydrostatic Testing: 3,000 psi (20.7 MPa) for 10 seconds (API 5L).
- Hardness Testing: 170–240 HBW (Brinell scale).
- Ultrasonic Weld Inspection: Class B per EN 10219-2.
Why Choose Our CHS Tubing?
Our CHS products deliver 50 kN·m/m bending capacity and 0.95–1.05 ovality ratios for precision fit-up. The JIS G3466-compliant mill produces ±0.2mm wall thickness uniformity, while EN 10219 certification ensures EU market compliance.
Request a free CHS load-bearing calculator to optimize structural designs for axial (P/A) and flexural (M/S) stresses. Download our corrosion resistance guide to select coatings based on exposure class (C1–C5).
Packaging: PVC sleeving + wooden crates; 40ft container holds 18–22 tons.
Lead Time: 25–40 days for stock sizes; 60–75 days for coated/extruded orders.
Packing And Delivery
