Profile Section
320x73x3mm Steel Sigma Profile, Mill Finish
The 320x73x3mm steel Sigma profile is a cold roll-formed section with an indented web: 320 mm web, 73 mm flanges with 16 mm edge lips and 3 mm thickness, 11.75 kg/m. Roll-formed to order in Magnelis S350GD+ZM steel, the web indent stiffens the section for purlins, rafters and columns. This page shows the size in Magnelis strip S350GD+ZM: zinc–aluminium–magnesium coating, ZM310 or ZM350 coating mass, minimum yield 350 MPa.
Made to Order — Roll Formed
This profile is roll-formed to order in your length (1–25 m). The minimum order is 5000 kg per size and material. Add your sizes to a quote request and we confirm lead time and price.
Add to Quote Request
Select length and quantity to add to your quote cart
Minimum order: 36 pieces
Minimum order: 5,000 kg per size
Optional made-to-order requirements — added to this line for our production team.
Applications & Usage
Sigma 320x73x3 is used for solar tracker and fixed-tilt structures, purlins, racking uprights and light steel buildings. Magnelis is often specified for solar mounting structures and agricultural buildings in corrosive environments. Each size is roll-formed to order in lengths from 1 to 25 m. The minimum order is 5000 kg per size and material — add your sizes to a quote request and we confirm lead time and delivered price.
Technical Specifications
| Specification | Value |
|---|---|
| Dimensions | 320mm × 73mm × 3mm |
| Weight per Meter | 11.75 kg/m |
| Weight of a 6 m length | 70.5 kg |
| Weight of a 12 m length | 141 kg |
| Material | Steel |
| Alloy/Grade | S350GD+ZM310 / ZM350 |
| Standard | EN 1090-1 (CE, EXC2); coated strip to EN 10346 |
| Profile Type | Sigma (Σ) |
| Edge Lip (c) | 16 mm |
| Web Indent (A / B / C) | A 70 · B 15 · C 25 mm |
| Developed Width | 500 mm |
| Cross-Section Area | 14.97 cm² |
| Moment of Inertia Iₓ | 2047.5 cm⁴ |
| Section Modulus Wₑₗ,ₓ | 127.97 cm³ |
| Radius of Gyration rₓ | 11.63 cm |
| Moment of Inertia Iᵧ | 63.5 cm⁴ |
| Section Modulus Wₑₗ,ᵧ | 12.85 cm³ |
| Radius of Gyration rᵧ | 2.05 cm |
| Centroid Distance eₓ | 2.36 cm |
| Available Lengths | 6m, 12m |
| Standard Length | 6 m |
| Minimum Order per Size | 5 t |
| Cut-to-Length Range | 1000 – 25000 mm |
Weight and section properties are nominal values from the mill catalogue table. Values marked ≈ are calculated from the section centerline.
Indicative load span (single span, simply supported)
Allowable uniformly-distributed load (kN/m) limited by elastic bending about the strong axis (γ = 1.5 on yield, S350GD+ZM310 / ZM350). Deflection is not checked and usually governs long spans. Indicative only — confirm with a project calculation.
| Span | Max UDL |
|---|---|
| 2 m | ≈ 59.72 kN/m |
| 3 m | ≈ 26.54 kN/m |
| 4 m | ≈ 14.93 kN/m |
| 5 m | ≈ 9.56 kN/m |
| 6 m | ≈ 6.64 kN/m |
Made to Order — Roll Formed
This profile is roll-formed to order in your length (1–25 m). The minimum order is 5000 kg per size and material. Add your sizes to a quote request and we confirm lead time and price.
Cut to exact length
Any length from 1 to 25 m — no offcut waste on site
Material options
Magnelis (zinc–aluminium–magnesium) coated strip S350GD+ZM to EN 10346, coating mass ZM310 or ZM350.
In-line punching
Holes and slots punched to your drawing
Certified production
EN 1090-1 factory production control (CE, up to EXC2); ISO 9001
Similar Sizes
Explore alternative dimensions that might suit your needs
Technical guides
S350GD, S420GD and DX51D+Z: coated steel grades to EN 10346 explained
What S350GD+Z275, S420GD+ZM310 and DX51D+Z mean: minimum yield and tensile strength of EN 10346 structural and forming grades, coating types and masses, and which grades we roll purlins from.
Read the guide →C, Z or Sigma purlins: how to choose the right cold-formed section
How C, C Plus, Z, Sigma and U cold roll-formed sections differ, where each is typically used, the size ranges available, and what to send for a quote.
Read the guide →Purlin coatings: black steel, galvanized Z275, Magnelis (ZM) or Aluzinc?
How the four material options for cold roll-formed purlins compare — grades, coating mass, cut-edge behaviour and typical exposure — and how to specify them.
Read the guide →Purlin sizes and weights: C, Z and Sigma section tables
Complete size tables for cold roll-formed C, C Plus, Z, Sigma, Sigma Plus and U sections: dimensions, weight per metre, area, Ix and Wx from the mill catalogue.
Read the guide →Steel coatings
Galvanized purlins: pre-galvanized Z275 C, Z and Sigma sections
Cold roll-formed C, Z, Sigma and U sections from pre-galvanized S350GD+Z275 and S420GD+Z275 strip: size ranges, lengths up to 25 m, punched holes and how to order.
View coating →Magnelis (ZM) purlins: zinc–aluminium–magnesium coated C, Z and Sigma sections
Cold roll-formed purlins and girts from ZM310 and ZM350 coated strip in S350GD, S420GD and S450GD — for agricultural, coastal and other aggressive environments.
View coating →Aluzinc purlins: aluminium–zinc coated C, Z and Sigma sections
Cold roll-formed C, Z, Sigma and U sections from Aluzinc (AZ) aluminium–zinc coated strip: where it fits, size ranges, lengths up to 25 m and how to order.
View coating →