STK 318.5x10.3
STK 318.5x10.3 Structural steel tube
Dimensions
| Parameter | Symbol | Value | Unit | Data |
|---|---|---|---|---|
| Outside diameter | D | 318.5 | mm | U |
| Thickness | t | 10.3 | mm | U |
Section Properties
| Parameter | Symbol | Value | Unit | Data |
|---|---|---|---|---|
| General | ||||
| Mass per metre | mass | 78.29 | kg/m | C |
| Gross area | A | 9,973 | mm² | C |
| About x-axis (major) | ||||
| Second moment of area Ix | Ix | 118.544 | 10⁶ mm⁴ | C |
| Elastic section modulus Zx (min) | Zx | 744.4 | 10³ mm³ | C |
| Plastic section modulus Sx | Sx | 978.7 | 10³ mm³ | C |
| Radius of gyration rx | rx | 109.0 | mm | C |
| About y-axis (minor) | ||||
| Second moment of area Iy | Iy | 118.544 | 10⁶ mm⁴ | C |
| Elastic section modulus Zy (min) | Zy | 744.4 | 10³ mm³ | C |
| Plastic section modulus Sy | Sy | 978.7 | 10³ mm³ | C |
| Radius of gyration ry | ry | 109.0 | mm | C |
| Torsion & warping | ||||
| Torsion constant JExact (2I) | J | 237.088 | 10⁶ mm⁴ | C |
| Surface area | ||||
| External surface area | extArea | 1.001 | m²/m | C |
| Internal surface area | intArea | 0.936 | m²/m | C |
Steel Grades
| Grade | Standard | fy MPa | fu MPa | Note | Data |
|---|---|---|---|---|---|
| STK400 | JIS G 3444 | 235 | 400 | Common grade | U |
Strengths shown for governing thickness t = 10.3 mm. Density 7850 kg/m³, E = 200 000 MPa.
Where to buy
Producers of Hollow sections & pipes – local mills first. Buy direct from the mill for large tonnages, or through a steel distributor / stockist for small quantities and cut lengths.
Local producer
Standards: JIS G 3444
Local producer
Standards: JIS G 3444, JIS G 3466
International producer
Standards: EN 10210, EN 10219
International producer
Standards: GB/T 8162, GB/T 8163
International producer
Standards: ASTM A500, ASTM A1085
International producer
Standards: AS/NZS 1163
Buying checklist
- Specify the section designation, product standard and steel grade exactly (e.g. "STK 318.5x10.3 – JIS G 3444 – STK400").
- Ask for mill test certificates (EN 10204 type 3.1 or equivalent) traceable to the heat number.
- Sections from another standard system are not automatically equivalent – have the engineer approve any substitution.
- Check availability, minimum order quantity, stock lengths, lead time and delivery terms with the mill or distributor.
All producers of this product type →
Listing is informational only – not an endorsement, offer or confirmation of availability. Company details are marked UNVERIFIED until checked.
Source & Verification
- Source publisher
- Pending verification – nominal dimensions entered by the application developer
- Source document
- JIS G 3444 Carbon steel tubes for general structure
- Edition
- —
- Publication year
- —
- Page reference
- —
- Last updated
- 2026-10-12
- Verification status
- Unverified
Typical grade: STK400. Nominal dimensions require verification against JIS G 3444 Carbon steel tubes for general structure and the manufacturer catalogue.