6106 is a medium-strength, heat-treatable 6xxx extrusion alloy. Its defining property is extrudability: it flows into thin, complex sections that the stronger 6xxx grades will not fill. It carries less magnesium and silicon than 6061, and that leaner chemistry is the point — it can be extruded into thinner walls and more complicated cross-sections than 6061 or 6082 manage, while still running above 6063 in strength. Typical uses are structural: ladders and access towers, railway rolling stock, automotive structures, and above-deck marine fabrications.
Two things trip up first-time specifiers. The first is form: 6106 is not a rolled designation, so a drawing that specifies 6106 plate or sheet to ASTM B209 has no standard product behind it. The second is welding. Because 6106 gets its strength from heat treatment rather than from cold work, an arc weld removes a large part of it locally, and that loss governs how the joint is sized.
What Is 6106 Aluminum?
6106 is an aluminum–magnesium–silicon alloy (with manganese) in the 6000 series, first registered in 1979. Designations you will see on drawings and mill documents:
| Designation system | Valore |
| Associazione Alluminio (AA) | 6106 |
| UNS | A96106 |
| EN numeric / chemical | EN AW-6106 / AlMgSiMn |
| Chinese standard | GB/T 3190 |
| Composition limits for analytical control | 1060-O (Ricotto) |
| Extruded product mechanical values | EN 755-2 |
| Barra, vergella, filo, profilo, tubo estrusi | ASTM B221 |
| Extruded rod, bar, tube, profile (ISO) | ISO 6362-2 |
The alloy description used by most European stockists sums up the design intent better than a datasheet does: an extrusion alloy intended to give the best available combination of mechanical properties, shape complexity, minimum section thickness, and surface quality, while keeping the corrosion resistance, weldability, and formability associated with the 6000 series. Sections that cannot be produced in stronger alloys such as 6082 are routinely produced in 6106.
That position matters more than any single property number. If you picture 6xxx alloys on one axis running from 6063 through 6106 to 6061 and 6082, extrudability falls as you move right and strength rises. 6106 sits deliberately in the middle, and it earns its place when neither end of that line will do.
Composizione chimica
Limits below follow EN 573-3 and the Aluminum Association registration. Everything is weight percent, balance aluminum.
| Elemento | Composizione (%) |
| Silicio (Si) | 0.30 – 0.60 |
| Magnesio (Mg) | 0.40 – 0.80 |
| Manganese (Mn) | 0.05 - 0.20 |
| Ferro (Fe) | 0,35 max |
| Rame (Cu) | 0,25 max |
| Cromo (Cr) | Famiglia |
| Zinco (Zn) | 0,10 max |
| Titanio (Ti) | 0,10 max |
| Altri, ciascuno | 0,05 max |
| Altri, totale | 0,15 max |
Read this against 6061, which runs roughly 0.8–1.2% magnesium, 0.4–0.8% silicon, and adds 0.15–0.4% copper. That difference explains nearly every behavior gap between the two alloys:
- Lower Mg + Si total means less Mg₂Si precipitate available for strengthening, so peak strength is lower — but there is also less dissolved alloying left in the aluminum, which is why electrical conductivity is higher and flow stress during extrusion is lower.
- Very low copper keeps corrosion behavior clean and helps anodizing consistency. It also means 6106 cannot chase strength the way copper-bearing 6xxx alloys can.
- Manganese is deliberately present (0.05–0.20%), unlike most 6xxx grades where it is only an impurity. Mn controls grain structure through recrystallization and improves the toughness and surface finish of the extruded section.
- Tight iron control matters for anodizing. Iron-bearing intermetallics are what show up as streaks and grey speckle in a clear anodized finish.
Proprietà meccaniche in base al trattamento termico
6106 gains its strength from solution heat treatment followed by aging, so the temper on the line item determines nearly everything about how the part behaves. The values below are typical; the numbers that actually govern acceptance are the minimums in the product standard, and those should be confirmed against the mill test certificate for the specific profile and wall thickness ordered.
| Temperamento | Typical tensile strength (MPa) | Typical yield strength (MPa) | Typical elongation (%) | Utilizzo tipico |
| O (ricotto) | ~110 | ~60 | ~22 | Forming stock before further treatment |
| T4 (solution treated, naturally aged) | ~200 | ~120 | ~16 | Bend or form, then age to T6 |
| T5 (press-quenched, artificially aged) | ~220 | ~165 | ~12 | Cost-sensitive structural extrusions |
| T6 (solution treated, artificially aged) | ~290 | ~220 | 9 – 14 | Standard structural specification |
For profiles up to 10 mm wall thickness, EN 755-2 sets minimum values in the T6 condition of 250 MPa tensile, 200 MPa proof stress, and 6% elongation. Note how much lower those minimums are than the typical figures: that gap is normal, it widens with wall thickness, and it is why design should either use the standard minimum or the MTC value — never a typical figure quoted from a datasheet.
Three practical consequences follow from the table:
T5 is worth pricing before T6. T5 takes its quench from the extrusion press rather than a separate furnace cycle, which removes a process step and usually lowers cost. For many structural sections the strength difference does not change the design, so it is real money left on the table when T6 is specified by habit.
Forming belongs before final aging. Cold work in T6 is possible but limited. Bends that would crack in T6 are straightforward in O or T4, and the part can be aged afterward to reach T6 properties. If your sequence is currently “extrude T6, then bend,” ask whether “form T4, then age” works instead.
Thickness changes the answer. Published minimums are tied to wall thickness for a reason: thicker sections quench more slowly, so less alloying stays in solution and less strengthening precipitate forms later. A heavy-walled 6106 profile will not reach the values a thin-walled one does, and the MTC for the actual section is the only reliable record.
Proprietà fisiche
| Proprietà | Valore |
| Densità | 2,70 g/cm³ |
| Melting range (solidus–liquidus) | ~610 – 660 °C |
| Modulo di elasticità | ~69.5 GPa |
| Coefficiente di dilatazione termica | ~23.4 × 10⁻⁶ /K |
| Conducibilità termica | ~190 W/m·K |
| Electrical conductivity (equal volume) | ~49 % IACS |
| Maximum continuous service temperature | ~160 °C |
| Fatigue strength (T6) | ~88 MPa |
Two of these deserve a note because they are routinely misread.
Thermal expansion does not separate 6106 from 6061. 6106 measures about 23.4 × 10⁻⁶/K and 6061 about 23.6 × 10⁻⁶/K. Any comparison table you see listing “lower thermal expansion” as a 6106 advantage is reporting a rounding difference as if it were a property. If thermal movement governs your joint design, treat these alloys as identical and solve the problem in detail design.
Electrical conductivity is genuinely higher, and it is the lean chemistry showing up in the numbers. At roughly 49% IACS, 6106 runs above 6061 (about 40–43%), which is why it turns up in bus bar, conductor rail, and heat sink work where the mechanical requirement is modest but the electrical one is not. Combined with ~190 W/m·K thermal conductivity, that makes it a reasonable single-spec choice for parts that must carry both current and heat.
The ~160 °C ceiling is a real limit, not a formality. Strength comes from Mg₂Si precipitates, and sustained exposure above roughly that temperature coarsens them permanently. There is no re-aging your way back once a part has been cooked.
Why 6106 Is Classified as an Extrusion Alloy
This is the section most alloy write-ups skip, and it is the one that decides whether 6106 belongs on your drawing at all.
Extrudability is not a single property. It is a bundle of behaviors that together determine what a press can produce: how much pressure the alloy resists as it flows through the die, how fast it can be pushed before the surface tears, whether it fills thin and remote corners, how much the die deflects, and whether the finished surface looks clean enough to ship without masking the defects under paint. Alloy content pushes every one of those in the wrong direction, so a lean chemistry wins by default — and 6106 is lean.
What that buys in practice:
- Thinner minimum walls. A section whose web has to come down to meet a weight target may simply not be fillable in 6061 at production speed, while running comfortably in 6106.
- Higher complexity. Multi-void hollows, deep recesses, and fine detail are all easier. Stockists routinely note that shapes impossible in 6082 are routine in 6106.
- Better surface. Lower flow stress means less die pickup and fewer surface defects, which matters directly when the finish is anodized rather than painted.
- Higher line speed. Depending on the section, 6106 can run faster than 6061, which shows up in unit cost even when the billet price is the same.
The trade is strength, discussed next.
If you want the mechanics of the process itself, including what a mill needs from a drawing before quoting a profile, our custom aluminum extrusion guide covers it separately.
6106 vs 6063 vs 6061 vs 6082
This comparison is where 6106 actually earns or loses a specification, and picking the right comparator matters — comparing only against 6061 makes 6106 look like a weaker version of something, rather than what it is.
Typical T6 values:
| Proprietà | 6106-T6 | 6063-T6 | 6061-T6 | 6082-T6 |
| Resistenza a trazione (MPa) | ~290 | ~240 | ~310 | ~310 |
| Carico di snervamento (MPa) | ~220 | ~215 | ~275 | ~260 |
| Allungamento (%) | ~9 | ~12 | ~12 | ~10 |
| Complex thin-wall extrusion | Molto buona | Eccellente | Buono | Fiera |
| Anodized surface quality | Molto buona | Best | Buono | Fiera |
| Lavorabilità | Buono | Moderato | Buono | Moderato |
| Arc weldability | Molto buona | Molto buona | Molto buona | Buono |
| Typical work | Ladders, towers, rail stock, auto structures | Rifiniture architettoniche, cornici delle finestre | General structural, machined parts | Bridges, cranes, heavy frames |
The reading that matters: 6106-T6 carries roughly 20% more tensile strength than 6063-T6 while staying much closer to it than to 6061 on the extrudability axis. That is the specific reason to specify it — a structural section that still needs to look good anodized, and needs to be more complicated than 6061 will reliably produce.
Where each alternative wins instead:
- 6063 when the part is architectural trim or window framing, the section is simple, the finish is the priority, and loads are low. It extrudes even more easily and finishes better.
- 6061 when strength governs, when the part will be machined heavily, or when you want the widest stock coverage and engineers already know it. See our guida all'alluminio 6061.
- 6082 for heavy structural work — bridges, cranes, vehicle chassis — where its strength-to-toughness balance is the reason it is specified, accepting that complex thin sections are off the table. Compare 6082-T6 before committing to a section.
- 6005 is another thin-wall structural extrusion worth pricing alongside 6106 for structural tube and truss work; its properties and limits differ enough to be worth a look.
Applicazioni
6106 shows up wherever a welded structural assembly needs to be light, extruded rather than machined, and held to tight dimensional repeatability.
Ladders, towers, and masts. The classic application, and named first by nearly every stockist. Extension ladders and scaffold rails benefit from thin-wall hollow sections at high stiffness-per-weight, from clean surface finish on parts users handle, and from weldability. Rung-to-rail joints are welded, so the HAZ allowance below governs the joint design.
Railway rolling stock. Extruded structural sections in body frames, floor supports, and interior framing. The combination of complex multi-void profiles, weldability, and fire and smoke behavior keeps 6xxx alloys dominant here, and 6106’s fill capability supports the integrated sections that replace multiple fabricated parts.
Automotive structures. Crash boxes, bumper beams, subframe components, roof rails, and battery enclosure framing. Thin-wall capability drives mass reduction directly, and the higher conductivity matters where the enclosure is part of a thermal management path.
Marine and offshore. Deck structures, gangways, masts, and superstructure framing. Worth stating plainly, though: good general corrosion resistance is not the same as marine-grade. Continuous seawater immersion or splash-zone service belongs to 5xxx alloys such as 5083-H116 or 5086-H116, which resist sensitization in a way high-magnesium-but-different 6xxx sections do not. Use 6106 above the waterline, not below it.
Architecture and building. Structural curtain wall members, structural glazing profiles, and framing that carries real load rather than trim, where the same extrusion must satisfy both deflection limits and an appearance requirement.
Thermal and electrical. Heat sinks, bus bars, conductor rail, and electrical enclosures, drawing on ~190 W/m·K thermal conductivity and ~49% IACS electrical conductivity. Here the mechanical spec usually arrives second and the section is simple.
Welding 6106
106 is rated very good for arc welding. The difficulty is not joining it — it is what the arc does to the temper alongside the weld.
The heat-affected zone loses strength. 6106 takes its strength from Mg₂Si precipitates locked in by heat treatment. A fusion weld reheats the adjacent metal through that same precipitation window without control, over-aging or dissolving what a furnace cycle built, so the zone beside the weld can lose up to half the parent strength. Lower heat input reduces that loss; it does not remove it. AWS D1.2 reflects this by directing designers to T4 or O properties for the heat-affected zone rather than T6 values, so the operating rule for 6106 is the same one used for every heat-treatable 6xxx extrusion: size the joint on reduced values, and confirm the figure with a qualification test where the load case matters.
What helps:
- Move the weld. The soft zone runs roughly 15–25 mm from the weld centerline, so keeping welds clear of peak bending stress is the cheapest fix.
- Oversize locally. One wall size up on a tube usually recovers the whole welded loss for very little weight.
- Fasten instead. A bolted joint keeps full parent T6 strength.
- Weld in T4, then age. Welding before artificial aging recovers appreciably more than welding after it, and a low-temperature cycle on an already-T6 weldment adds almost nothing. We do not run aging in-house, so build it into the schedule.
Filler. ER4043 suits general fabrication; ER5356 where you need more as-welded strength or a closer color match after anodizing. Our guida ai fili per saldatura dell'alluminio covers the selection, and the 6061 welding guide covers procedure control and joint-strength qualification.
Machining, Forming, and Surface Finishing
Lavorazione a macchina. 6106 machines well in T6 with sharp tools and adequate clearance; the softer O and T4 conditions are more prone to built-up edge and smearing, so the “gummy” reputation attaches to those rather than to the T6 condition people actually machine. In general machining ranking, 6061 still performs better, so where a part is mostly chips rather than mostly extrusion, 6061 remains the better ask.
Formatura. Do it before final aging. T4 is the practical forming condition for bending and shaping; T6 tolerates only limited cold work, and attempting tight bends there invites cracking along the outer fiber. Springback is moderate and is better controlled by die design than by alloy substitution. Remember that any heavy local heating during straightening will soften the area in the same way a weld does.
Anodizzazione. One of 6106’s real advantages. Low iron and copper give consistent clear and colored anodic films, and the good as-extruded surface means less mechanical prep before the tank. The practical caution is that a 6106 section welded together will show the weld and its HAZ as a visible band after anodizing unless the filler and procedure are chosen for appearance; our anodizing guide explains why most visible failures start with alloy selection and surface preparation rather than with the anodizing itself.
Corrosion. Good general atmospheric corrosion resistance, typical of the 6000 series, and better than many users expect in industrial atmospheres. It is not immune to intergranular attack in aggressive conditions, and it does not belong in continuous immersion or the splash zone. Powder coating or anodizing extends service life substantially; for marine immersion, move to 5xxx rather than upgrading the finish.
Standards and Procurement Documentation
Getting the paperwork right matters as much as getting the alloy right, because it is what determines whether the section you receive is the one you specified.
Specify the standard and the temper together. “6106-T6” alone leaves too much open. A complete line item names the alloy, temper, product form, governing specification, applicable dimensional tolerance, and wall-thickness class. For extruded product that means ASTM B221 o EN 755-2 (with 1060-O (Ricotto) for composition analysis and GB/T 3190 for Chinese mill supply). Confirm availability before quoting if a drawing calls for 6106 against a rolled plate or sheet specification — a mismatch discovered after award costs far more than a question asked early.
Documents worth requesting:
| Documento | Che cosa offre |
| Mill test certificate (MTC) | Heat-specific composition and actual mechanical values for the supplied lot |
| EN 10204 3.1 certificate | Mill-independent statement that values were verified against the order |
| SGS chemical or mechanical report | Third-party verification where the project requires it |
| SGS dimensional inspection | Verification of critical profile dimensions against the drawing |
The distinction to hold onto: the figures in this article are typical values for orientation. The numbers that bind are the standard minimums and the MTC values for the specific lot. When those disagree, the MTC wins.
Also worth confirming before placing an order: the wall thickness class, since it drives the minimum mechanical values; the temper route, T5 versus T6, since it changes both cost and properties; and whether the drawing intends any post-extrusion aging after forming or welding, since that step belongs in the schedule rather than discovered mid-fabrication.
When to Choose 6106 — and When Not To
Choose 6106 when:
- The section is the constraint, not the alloy number — thin walls, multiple voids, tight tolerances, or details that 6061 will not fill reliably at production speed.
- You need more strength than 6063 and better finish than 6061, particularly where the same extrusion is structural and visible.
- The part will be welded and moderately loaded, with room to place joints away from peak stress or to oversize locally. Every 6xxx behaves this way; plan for it.
- Weight per metre is being driven down through wall thickness rather than through alloy substitution.
- The part also conducts — bus bar, heat sink, conductor rail — where roughly 49% IACS is an advantage 6061 cannot match.
Cercare altrove quando:
- Peak strength governs the design. Step up to 6061-T6 or 6082-T6.
- A welded joint must retain full T6 strength. No 6xxx alloy does this. Either redesign so the weld is not the governing location, or consider whether a non-heat-treatable 5xxx grade suits the load case better.
- The service is continuous seawater immersion or splash zone. Move to 5083-H116 or 5086-H116.
- The part is decorative architectural trim with low load. 6063 extrudes more easily and anodizes better, and it costs less. See our guida all'estrusione del 6063.
- Service runs continuously above roughly 160 °C. Precipitation coarsening is permanent.
Conclusione
6106 is a 6xxx extrusion alloy that trades peak strength for how far it can be pushed through a die — roughly 20% stronger than 6063-T6 while still filling thin-wall and multi-void sections that 6061 cannot produce reliably. Two specification traps drive most failures with it: ordering it against a rolled plate or sheet standard instead of ASTM B221 or EN 755-2, and sizing welded joints on T6 parent values when fusion welding removes up to half the local strength.
Forniamo 6106 as profile, bar, tube, and wire in O, T4, T5, and T6, quoted to ASTM B221 or EN 755-2 with the wall-thickness class stated, and we handle CNC machining, welding, laser cutting, and anodizing in-house. Post-weld aging is a separate mill step we do not run ourselves, so build it into the schedule, and every order carries an MTC.
Send us the drawing, the standard, and the temper route, and we will confirm available wall thicknesses, tolerances, and documentation before you commit.
Domande frequenti
How does 6106 pricing compare with 6063 and 6061?
The grade matters less than how the part is bought. 6106 is a narrower designation with less mill stock than 6063, so form, temper and order quantity move the number more than the alloy choice does. Send the section, temper and annual volume, and we will quote the actual lot rather than a list price.
What is the minimum order quantity for 6106?
Stocked profiles ship from standard pack quantities. Anything outside the stocked range is a low-MOQ custom run, so the practical minimum depends on the form, the temper and whether a heat is available. Tell us the specification and quantity and we will confirm what ships from stock and what has to be produced.
What lead time should I expect for 6106 extrusions?
Plan on roughly 10–60 days, depending on whether the profile is stocked. Stocked sections ship in days; a new die adds design, fabrication and trial time before the first extruded length. Confirm the section against your build schedule early, because the die is on the critical path.
