StructureCalcsHSS6.625X0.188
Round HSS · AISC Shapes Database v15.0 · United States
HSS6.625X0.188 is a round hollow structural section 168.4 mm in outside diameter with a 4.4 mm wall, weighing 19.3 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 | 4.4 mm | 0.174 in |
| Mass per metre | 19.3 kg/m | 12.9 lb/ft |
| Area, A | 2,277 mm² | 3.53 in² |
| Second moment, Ix | 7,658,658 mm⁴ | 18.4 in⁴ |
| Second moment, Iy | 7,658,658 mm⁴ | 18.4 in⁴ |
Derived section properties
Integrated analytically from the exact circular tube. For HSS6.625X0.188 the computed area agrees with the published value to 0.02% and Ix to better than 0.01%. 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 | 90,962 mm³ |
| Elastic modulus, Sy | 90,962 mm³ |
| Plastic modulus, Zx | 118,880 mm³ |
| Plastic modulus, Zy | 118,880 mm³ |
| Radius of gyration, rx | 58.0 mm |
| Radius of gyration, ry | 58.0 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