StructureCalcsHSS6.625X0.280
Round HSS · AISC Shapes Database v15.0 · United States
HSS6.625X0.280 is a round hollow structural section 168.4 mm in outside diameter with a 6.6 mm wall, weighing 28.3 kg/m. The dimensions below are the published AISC Shapes Database v15.0 values; the drawing is generated from them.
Round HSS are structural tubes with identical properties about every axis, tabulated by AISC on the design wall thickness.
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Published dimensions
| Property | Metric | Imperial |
|---|---|---|
| Outside diameter, d | 168.4 mm | 6.63 in |
| Wall thickness, t | 6.6 mm | 0.260 in |
| Mass per metre | 28.3 kg/m | 19.0 lb/ft |
| Area, A | 3,355 mm² | 5.20 in² |
| Second moment, Ix | 10,988,510 mm⁴ | 26.4 in⁴ |
| Second moment, Iy | 10,988,510 mm⁴ | 26.4 in⁴ |
Derived section properties
Integrated analytically from the exact circular tube. For HSS6.625X0.280 the computed area agrees with the published value to better than 0.01% and Ix to 0.07%. Where a value is also published, the published one above is the one to quote.
AISC tabulates hollow-section properties on the design wall (tdes = 0.93 tnom, per AISC 360), while the published mass reflects the nominal wall — which is why mass and area here differ by about 7% by convention, on every AISC hollow section.
| Property | Value |
|---|---|
| Elastic modulus, Sx | 130,602 mm³ |
| Elastic modulus, Sy | 130,602 mm³ |
| Plastic modulus, Zx | 172,879 mm³ |
| Plastic modulus, Zy | 172,879 mm³ |
| Radius of gyration, rx | 57.3 mm |
| Radius of gyration, ry | 57.3 mm |
S is the elastic modulus and Z the plastic modulus, following AISC 360. Australian and British practice reverse the letters.
Neighbouring sizes
Where these numbers come from
Published AISC Shapes Database v15.0 values. How StructureCalcs verifies its numbers · Understanding steel section properties · Query this section over the API