80 x 40 mm heavy-wall six-slot aluminium strut profile with four slots on the long faces and two on the short faces. Heavy rectangular beam for bending loads using M8 fasteners.
| Material | Aluminium |
|---|---|
| Alloy Grade | 6063-T5 |
| Temper | T5 |
| Section Size | 80 x 40 mm rectangular, heavy-wall, six slots on all faces |
| Slot | 6 x 10.2 mm groove, 8 mm mouth, 2 per long face + 1 per short face, 40 mm pitch, M8 |
| Length | 6 m stock, cut to drawing to +/-0.5 mm |
| Tolerance | EN 755-9 / GB/T 6892, wall +/-0.15 mm |
| Surface | Mill finish / clear anodised / black anodised |
| MOQ | Made to order; small trial lengths available from stock offcuts |
| Lead Time | Typically 2 to 3 weeks for mill finish, plus 1 week for cutting and drilling, plus a week for anodising |
| Loading Port | Shanghai, Ningbo, Qingdao |
| Supply Ability | Extrusion capacity for heavy-wall rectangular beam profiles, with in-house anodising and machining |
| Payment Terms | T/T 30 per cent deposit, balance against copy of bill of lading; L/C at sight for larger orders |
| Trade Terms | FOB, CIF, CFR, EXW |
| Certifications | Mill certificate to EN 10204 3.1 on request, RoHS and REACH declarations |
Because a rectangular section has a strong axis and a weak axis. The 80 x 40 has a second moment of area about 11 cm4 on the strong axis (bending with the 80 mm dimension as height) and about 3.5 cm4 on the weak axis (bending with the 40 mm dimension as height). The four-slot 40 x 40 has about 5.8 cm4 on both axes. So on the strong axis, the 80 x 40 is about 1.9 times stiffer than the 40 x 40, for only 2.4 times the weight.
The heavy variant has a wall thickness of about 3.5 mm, compared to about 2.0 mm on the standard-wall 80 x 40 six-slot. The weight is 3.60 kg/m versus about 2.86 kg/m for the standard. The second moment of area is about 11 cm4 versus about 9.5 cm4. The heavy variant is for applications where the beam must carry a significant bending load without deflection.
Heavy machine frames, gantry beams, conveyor support rails, workbench tops, and any application where a horizontal beam must span a gap and carry weight. The 80 mm dimension is oriented vertically to use the strong axis for gravity loads.
Six slots in total: two on each 80 mm long face and one on each 40 mm short face. This gives fixing positions on all four sides of the beam, so accessories, brackets and panels can be mounted from any direction.
| Item | Value | Note |
|---|---|---|
| Envelope | 80 x 40 mm rectangular | 2:1 aspect ratio |
| Slots | 6 | 10.2 mm groove, 8 mm mouth |
| Slot layout | 2+2+1+1 | 2 per long face, 1 per short face |
| Slot pitch | 40 mm | centre-to-centre on long faces |
| Centre bore | Phi14 mm typically | for through-bolts or location |
| Wall | approx. 3.5 mm | heavy-wall variant |
| Weight | approx. 3.60 kg/m | vs 2.86 kg/m for standard-wall |
| I strong axis | approx. 11.0 cm4 | bending about the 40 mm width |
| I weak axis | approx. 3.5 cm4 | bending about the 80 mm width |
| Alloy | 6063-T5 | EN AW-6063 |
| Standard | EN 755-9 / GB/T 6892 | wall tolerance +/-0.15 mm |
| Length | 6 m stock | cut to drawing to +/-0.5 mm |
The strong-axis to weak-axis stiffness ratio is about 3.1:1. This means the beam is three times stiffer against bending when the 80 mm dimension is vertical. Orient the section so the strong axis resists the primary load.
A rectangular section has two bending axes. The strong axis is the one where the taller dimension (80 mm) is the height of the beam. The weak axis is where the shorter dimension (40 mm) is the height. The second moment of area is proportional to the cube of the height, so doubling the height from 40 to 80 increases the stiffness by a factor of about 8 for a solid section, and about 3 for an extruded section with slots.
| Orientation | Beam height | I (approx.) | Deflection ratio |
|---|---|---|---|
| Strong axis (80 mm vertical) | 80 mm | 11.0 cm4 | 1.0x |
| Weak axis (40 mm vertical) | 40 mm | 3.5 cm4 | 3.1x more |
| 40 x 40 four-slot (reference) | 40 mm | 5.8 cm4 | 1.9x more |
In practice, this means the beam should be oriented with the 80 mm dimension vertical when it is used as a horizontal span. The deflection under a midspan load is about 3 times less in the strong-axis orientation than in the weak-axis orientation.
The six slots are distributed across all four faces of the beam. The two 80 mm long faces each carry two slots, and the two 40 mm short faces each carry one slot. This gives fixing positions on every side of the profile.
| Face | Slots | Typical use |
|---|---|---|
| Top (80 mm) | 2 slots | accessory brackets, panel mounting |
| Bottom (80 mm) | 2 slots | support brackets, feet, levelling |
| Front (40 mm) | 1 slot | cable chain, sensors, pneumatic line |
| Back (40 mm) | 1 slot | return cable, secondary mounting |
All slots use the same 10.2 mm groove and 8 mm mouth as the standard 40 series, so M8 slot nuts, T-bolts, cover strips, hinges and all standard 40 series accessories fit every slot.
If you need a square section with equal stiffness on both axes, use the 40 x 40 four-slot. If you need an even stiffer beam, consider the 80 x 120 ten-slot. The 80 x 40 six-slot heavy is the mid-range choice for bending loads.
For a simply supported beam with a uniformly distributed load, the midspan deflection is proportional to the load, the span cubed, and the inverse of the second moment of area. With I = 11 cm4 on the strong axis, the deflection of a 1 metre span under a 100 N load is about 0.08 mm. For a 2 metre span under the same load, it is about 0.6 mm.
| Span (mm) | Load (N) | Deflection strong axis (mm) | Deflection weak axis (mm) |
|---|---|---|---|
| 500 | 100 | 0.01 | 0.04 |
| 1000 | 100 | 0.08 | 0.25 |
| 1500 | 100 | 0.27 | 0.84 |
| 2000 | 100 | 0.63 | 1.96 |
These are elastic deflection estimates for a simply supported beam. Real frames have fixed or partially fixed ends, which reduces deflection by a factor of about 3 to 5. Use these numbers for comparison between sections, not for final design.
| What goes wrong | Why it happens | Design it out by |
|---|---|---|
| Beam is installed in weak-axis orientation | the installer oriented 40 mm vertical by mistake | mark the strong axis on the drawing and on the bar at cut |
| Excessive deflection under load | the span is too long for the section stiffness | add an intermediate support or use the 80 x 120 section |
| Slot nuts slip under high load | the 8 mm mouth is too narrow for the load | use double slot nuts or a heavier T-bolt with spring clip |
| Profile twists under asymmetric load | the load is off-centre and the rectangular section has low torsional stiffness | add a second beam or a cross-brace to form a closed frame |
| Heavy-wall cost is not justified | the application does not need the extra 0.74 kg/m | use the standard-wall 80 x 40 six-slot at 2.86 kg/m |
Heavy machine frames, gantry beams, conveyor support rails, workbench tops, and any application where a horizontal beam must span a gap and carry weight with minimal deflection.
The heavy variant has 3.5 mm wall vs 2.0 mm, weighs 3.60 vs 2.86 kg/m, and has I of 11.0 vs 9.5 cm4. Use the heavy for bending loads, the standard for general framing.
The strong axis uses the 80 mm dimension as beam height, giving I about 11 cm4. The weak axis uses 40 mm, giving I about 3.5 cm4. The stiffness ratio is about 3.1:1.
Yes. All six slots use the 10.2 mm groove and 8 mm mouth, so M8 slot nuts, T-bolts and all 40 series accessories fit every slot.
Approximately 3.60 kg/m for the heavy variant, versus 2.86 kg/m for the standard-wall.
Yes. Clear, black, champagne and bronze at 10 to 15 micron. Recommended for exposed surfaces in machine frames.
For a 100 N point load with deflection under 1 mm, the strong-axis span can be up to about 1.5 m. Add intermediate supports for longer spans or heavier loads.
Send those eight items and the quotation comes back with the extrusion price, the machining charge, the finish surcharge and the lead time broken out separately. Browse the full aluminium profile catalogue and the 40 series aluminium profiles range for related sections.
Send the section, the orientation, the wall thickness and the finish. We quote extrusion, machining and anodising as separate lines.
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