W 18X65 vs H-450x200x11x19
W 18X65 is an W section from the American AISC Shapes Database; H-450x200x11x19 is the closest equivalent in the European (Continental) range. H-450x200x11x19 carries more bending: 2240 cm³ of plastic modulus against 2179.5 cm³, 2.7% more. W 18X65 is the lighter of the two at 96.7 kg/m against 98.9 kg/m, a saving of 2.2% on steel weight. Both are about 464 mm deep, so either fits the same construction zone.
| Property | W 18X65 W | H-450x200x11x19 MB & MC | Difference |
|---|---|---|---|
| Mass | 96.7 kg/m | 98.9 kg/m | -2.2% |
| Depth | 467.4 mm | 460 mm | +1.6% |
| Width | 192.8 mm | 202 mm | -4.6% |
| Web thickness | 11.4 mm | 11 mm | +3.6% |
| Flange thickness | 19 mm | 19 mm | same |
| Area | 123.2 cm² | 126 cm² | -2.2% |
| Second moment, major (Iy) | 44,537 cm⁴ | 45,430 cm⁴ | -2.0% |
| Plastic modulus, major (Wpl,y) | 2,179.5 cm³ | 2,240 cm³ | -2.7% |
| Elastic modulus, major (Wel,y) | 1,917.3 cm³ | 1,975 cm³ | -2.9% |
| Second moment, minor (Iz) | 2,281 cm⁴ | 2,619 cm⁴ | -12.9% |
| Plastic modulus, minor (Wpl,z) | 368.71 cm³ | 403 cm³ | -8.5% |
| Radius of gyration, minor (iz) | 4.29 cm | 4.56 cm | -5.9% |
| Torsion constant (It) | 113.6 cm⁴ | 126 cm⁴ | -9.8% |
W 18X65 to AISC Shapes Database v16.0; H-450x200x11x19 to Continental Steel. Difference is expressed relative to H-450x200x11x19.
How to choose between them
On stiffness, H-450x200x11x19 has the larger second moment of area: 45,430 cm⁴ against 44,537 cm⁴, a difference of 2.0%. 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, the two are equally efficient (22.5 against 22.6 cm³ per kg/m), so on a pure steel-tonnage basis there is nothing to choose between them. The decision comes down to availability, connection detailing and what the rest of the frame uses.
The two diverge much more about the minor axis: H-450x200x11x19 has 403 cm³ of minor-axis plastic modulus against 368.71 cm³, 8.5% 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 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 2.2% weight.
In short, H-450x200x11x19 is the stronger section and W 18X65 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.