An Aluminum I-Beam Is Extruded, Not Rolled

Lightweight structural aluminum profiles — I-beam, T and tapered-wall sections — are extruded in 6063-T5/T6 or 6061-T6 and used where a steel section is heavier than the job needs. Wall from 0.8 mm, circumscribed circle to 540 mm, and 500 kg per profile whether or not a new die is cut.

A steel wide-flange beam is hot-rolled and can run 600 mm deep. An aluminum I-beam is pushed through a die in a hydraulic press, so the section is limited by what the press can take and what the die can hold. That is why commercial aluminum I-beams rarely exceed 250 to 300 mm depth, and why the flange is normally uniform in thickness with no taper. These are not defects; they are the geometry that comes with extrusion, and designing around them is what makes aluminum work in a structural frame.

Linkedalu Metal Group Co., Ltd extrudes custom aluminum I-beam and T-profile sections for structural framing, stiffening, machine bases, transport equipment and architectural work where steel is simply heavier than the specification allows. Mill test certificates against GB/T 5237, EN 755-9 or ASTM B221 ship with every order.

Aluminum vs Steel: An Honest Comparison

At an equal cross-section a 6061-T6 aluminum beam reaches first yield at about 70 percent of the steel load (240 MPa against 345 MPa), at about one-third the weight; at equal deflection it carries about a third, because 69 GPa is a third of 200 GPa. Two numbers are routinely missed. Aluminum's elastic modulus is about one-third of steel's, so a same-size aluminum beam deflects roughly three times more under the same load. Its thermal expansion is about twice steel's, so long-span members need movement allowed at the connection rather than only at the surface.

Stiffness: What 69 GPa Costs You, and How to Recover It

Because deflection is rarely fixed by changing alloy, it is fixed by changing geometry or span. Three levers work: go deeper, since moving from a 100 mm to a 150 mm aluminum I-beam multiplies the moment of inertia by about four (158 to 716 cm4 at the reference sections); add internal stiffening ribs in the extrusion, which puts material where stress is highest for little weight penalty; or accept the lower stiffness and reduce the unsupported span with closer supports. A drawing review will tell you which lever the section geometry allows.

Extrusion also lets the cross-section be designed for the load path rather than for a rolling mill, using tapered wall thickness, a hollow tubular web or internal ribs. Those are the design moves that let aluminum win on specific strength. Welding follows the usual aluminum rules: 6061-T6 welds cleanly with TIG or MIG using 4043 or 5356 filler, and the heat-affected zone loses temper, dropping to roughly T4 strength in the weld zone.

Aluminum I-Beam Sizes, Tapered Walls and Tolerances

On presses from 500 MT to 5,000 MT the practical envelope is a depth up to about 300 mm, a flange width up to about 200 mm, web and flange thickness from 2 mm to 25 mm depending on depth, and a weight per meter that normally stays below 16 kg/m. Beyond about 300 mm depth the web cools slowly while the flanges cool fast, and the differential contraction warps the section.

Weights are theoretical and for reference only; the certified figure travels on the mill test certificate. Sections are held to GB/T 5237 high-precision grade. Where a face has to mate, a machined seat or a bolted flange, we machine it after extrusion rather than asking the die to hold it, because a tighter tolerance slows the press, adds inspection and sometimes forces die modification.

T-Profile Variants and Alloy Choice

Four decisions change what a T-profile does. An equal T, where flange width and stem height are similar, is the default for stiffeners, ceiling grids and partition frames because loading across the flange is symmetric. An unequal T, with a flange wider than the stem, suits display frames, architectural reveals and signage holders where the mounting surface needs more contact than the stem needs for stiffness. Sharp corners give a clean architectural line with a modest stress concentration, while radiused corners distribute stress better, extrude more easily and are safer to handle, which is why visible architectural T profiles almost always use radiused corners.

6061-T6, with a minimum tensile of 260 MPa and yield of 240 MPa, is specified for structural T-bars, stiffeners, welded machine frames and transport equipment. 6063-T5, at 160 MPa tensile and 110 MPa yield, is the default for visible architectural T profiles, ceiling grids and reveals because it anodizes bright and uniformly. 6060-T5 serves European specifications with tighter visual standards, 6063, 6061, 6463 and 6082 are the standard set, and 6005A or individual 5xxx and 7xxx grades are produced on request.

A structural T-profile is not a T-slot profile. T-slot extrusions such as 2020, 2040, 4040 and 4080 are a separate product family with slots machined into the flange to accept T-nuts for modular framing. They look similar and do different jobs, so say explicitly that you want a structural T.

Where These Sections Work

Transport equipment is aluminum's home ground: an aluminum 6061-T6 I-beam frame can cut frame weight by 40 to 50 percent against a steel equivalent and convert that saving directly into payload. Machine builders move to aluminum I-beams when the machine has to be repositioned regularly or when corrosion matters, as in food processing and wash-down areas. T-profiles in 6063-T5 sit behind suspended ceiling grids, partition framing and architectural reveals, and a T-profile bonded to the back of a flat panel raises the panel's moment of inertia so a flexible sheet becomes structural. Marine structures such as boat lifts, dock frames and gangways use aluminum because it needs no painting at the waterline.

Fabrication covers cut-to-length, drilling, mitering, welded sub-assemblies and labeling to your call-up list. Lengths come from your cutting list, not a stock length: a 20 ft container takes up to 5.85 m and a 40 ft takes 6.0 m in two lengths. Finishes run from mill finish through anodizing at AA10 or AA15, or powder coating; other systems are quoted on request. Minimum order is 500 kg, whether or not a new die is cut.