300×300×9 mm S420MC–S700MC High-Strength Square Hollow Section
300x300x9mm Steel high-strength square tube in S420MC, S500MC, S600MC, S700MC to EN 10219 / EN 10149-2, with an uncoated steel surface suitable for further processing or painting. Nominal weight 80.053 kg/m.
Minimum order
Minimum 10 t per size. If the size is already in the current production cycle, we can accept orders from 5 t. Standard length 6 m; 4–12 m on request. We confirm the minimum, lead time and grade in your quote.
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Minimum order: 10 t per size (from 5 t if the size is in production)
Applications & Usage
This extra heavy-duty industrial Steel high-strength square tube is commonly specified for heavy structural supports, load-bearing frames, and demanding industrial applications. The 9mm wall thickness provides exceptional structural integrity while maintaining workability. The natural mill finish provides a cost-effective solution for applications where aesthetics are secondary. Available in standard lengths of 6m, this profile can be easily cut, drilled, and welded to suit your specific requirements.
Technical Specifications
| Specification | Value |
|---|---|
| Dimensions | 300mm × 300mm × 9mm |
| Weight per Meter | 80.053 kg/m |
| Material | Steel |
| Alloy/Grade | S420MC, S500MC, S600MC, S700MC |
| Standard | EN 10219 / EN 10149-2 |
| Standard Length | 6m |
| Minimum Order per Size | 10 t |
| Cut-to-Length Range | 4000 – 12000 mm |
Section Properties
Nominal values calculated from nominal dimensions to EN 10219-2.
| Property | Value |
|---|---|
| Cross-sectional area(A) | 102 cm² |
| Second moment of area(I) | 14183 cm⁴ |
| Radius of gyration(i) | 11.8 cm |
| Elastic section modulus(Wel) | 946 cm³ |
| Plastic section modulus(Wpl) | 1102 cm³ |
| Torsional inertia constant(It) | 22661 cm⁴ |
| Torsional modulus constant(Ct) | 1434 cm³ |
| Surface area per metre(As) | 1.16 m²/m |
| Length per tonne | 12.5 m |
High-strength grades for this size
Strength and indicative capacity for each grade this size is rolled in, compared with the S355J2H wall that carries the same bending load in the same outer size.
| Grade | Min. yield ReH | Tensile Rm | Bending Wel·ReH | Axial A·ReH | S355J2H equivalent |
|---|---|---|---|---|---|
| S420MC | 420 MPa | 480–620 MPa | 397 kNm | 4283 kN | 12 mm · 104 kg/m (+29%) |
| S500MC | 500 MPa | 550–700 MPa | 473 kNm | 5099 kN | 14 mm · 119 kg/m (+49%) |
| S600MC | 600 MPa | 650–820 MPa | 567 kNm | 6119 kN | Beyond the S355J2H range of this size |
| S700MC | 700 MPa | 750–950 MPa | 662 kNm | 7139 kN | Beyond the S355J2H range of this size |
In S500MC, this section (80.1 kg/m) carries the elastic bending load of a 14 mm S355J2H wall in the same outer size (119 kg/m), which is 49% heavier per metre. In S700MC, this section carries more elastic bending load than any S355J2H wall rolled in the same outer size; matching it in S355 needs a larger section.
Indicative values from nominal dimensions: Wel × ReH and A × ReH, without buckling, cross-section class or partial safety factors. Not a design check.
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