W 18X71 vs H-450x200x14x19
W 18X71 is an W section from the American AISC Shapes Database; H-450x200x14x19 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 2392.5 cm³ against 2399 cm³ of plastic modulus, a difference of 0.3%. W 18X71 is the lighter of the two at 105.7 kg/m against 110 kg/m, a saving of 3.9% on steel weight. W 18X71 is deeper, 469.9 mm against 460 mm, which matters where the floor zone is tight.
| Property | W 18X71 W | H-450x200x14x19 MB & MC | Difference |
|---|---|---|---|
| Mass | 105.7 kg/m | 110 kg/m | -3.9% |
| Depth | 469.9 mm | 460 mm | +2.2% |
| Width | 194.1 mm | 205 mm | -5.3% |
| Web thickness | 12.6 mm | 14 mm | -10.0% |
| Flange thickness | 20.6 mm | 19 mm | +8.4% |
| Area | 134.8 cm² | 140 cm² | -3.7% |
| Second moment, major (Iy) | 48,699 cm⁴ | 47,860 cm⁴ | +1.8% |
| Plastic modulus, major (Wpl,y) | 2,392.5 cm³ | 2,399 cm³ | -0.3% |
| Elastic modulus, major (Wel,y) | 2,081.2 cm³ | 2,081 cm³ | same |
| Second moment, minor (Iz) | 2,510 cm⁴ | 2,742 cm⁴ | -8.5% |
| Plastic modulus, minor (Wpl,z) | 404.76 cm³ | 423 cm³ | -4.3% |
| Radius of gyration, minor (iz) | 4.32 cm | 4.43 cm | -2.5% |
| Torsion constant (It) | 145.3 cm⁴ | 152 cm⁴ | -4.4% |
W 18X71 to AISC Shapes Database v16.0; H-450x200x14x19 to Continental Steel. Difference is expressed relative to H-450x200x14x19.
How to choose between them
On stiffness, W 18X71 has the larger second moment of area: 48,699 cm⁴ against 47,860 cm⁴, a difference of 1.8%. 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, W 18X71 is the more efficient section: 22.6 against 21.8 cm³ per kg/m, 3.8% 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.
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 MB & MC to 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 3.9% weight.
In short, H-450x200x14x19 is the stronger section and W 18X71 is the lighter one; where those are the same section, it is the clear choice, and where they are not, decide on whether your design is governed by capacity or by tonnage.