W 12X50 vs HE 320 AA
W 12X50 is an W section from the American AISC Shapes Database; HE 320 AA is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 1178.2 cm³ against 1200 cm³ of plastic modulus, a difference of 1.8%. They weigh essentially the same, 74.4 kg/m and 74.2 kg/m. W 12X50 is deeper, 309.9 mm against 301 mm, which matters where the floor zone is tight.
| Property | W 12X50 W | HE 320 AA HE | Difference |
|---|---|---|---|
| Mass | 74.4 kg/m | 74.2 kg/m | +0.3% |
| Depth | 309.9 mm | 301 mm | +3.0% |
| Width | 205.2 mm | 300 mm | -31.6% |
| Web thickness | 9.4 mm | 8 mm | +17.5% |
| Flange thickness | 16.3 mm | 11 mm | +48.2% |
| Area | 94.2 cm² | 94.6 cm² | -0.4% |
| Second moment, major (Iy) | 16,275 cm⁴ | 16,400 cm⁴ | -0.8% |
| Plastic modulus, major (Wpl,y) | 1,178.2 cm³ | 1,200 cm³ | -1.8% |
| Elastic modulus, major (Wel,y) | 1,052 cm³ | 1,090 cm³ | -3.5% |
| Second moment, minor (Iz) | 2,343 cm⁴ | 4,960 cm⁴ | -52.8% |
| Plastic modulus, minor (Wpl,z) | 349.04 cm³ | 506 cm³ | -31.0% |
| Radius of gyration, minor (iz) | 4.98 cm | 7.24 cm | -31.2% |
| Torsion constant (It) | 71.18 cm⁴ | 53.6 cm⁴ | +32.8% |
W 12X50 to AISC Shapes Database v16.0; HE 320 AA to EN 10365 · Continental Steel. Difference is expressed relative to HE 320 AA.
How to choose between them
On stiffness, HE 320 AA has the larger second moment of area: 16,400 cm⁴ against 16,275 cm⁴, a difference of 0.8%. This matters more often than the strength comparison, because on normal floor spans deflection rather than bending capacity sets the beam size - so if the two are close on modulus but apart on inertia, the stiffer one is usually the better answer even when it is not the stronger one.
Measured as bending capacity per kilogram of steel, HE 320 AA is the more efficient section: 16.2 against 15.8 cm³ per kg/m, 2.1% better. Over a floor of repeated beams that difference is real tonnage, though it is often outweighed by whichever section the fabricator can actually source.
The two diverge much more about the minor axis: HE 320 AA has 506 cm³ of minor-axis plastic modulus against 349.04 cm³, 31.0% more. If the member sees any minor-axis bending, or if it is unrestrained over a long length and lateral-torsional buckling governs, that gap decides the comparison even though the major-axis numbers looked equivalent.
These come from different catalogues, so treat the swap as a design change rather than a like-for-like substitution. W sections are specified to AISC Shapes Database v16.0 and HE to EN 10365 · Continental Steel; the steel grades, tolerances and available lengths differ, connection details and bolt gauges are set out differently, and the two are rarely both stocked in the same market. Check availability before changing a section on a drawing to save a marginal amount of weight.
In short, these two are genuine equivalents. Pick whichever your supplier stocks and the rest of the frame already uses.