Choosing an aluminum grade is usually the first decision an engineer makes and the last one they revisit. It gets made early, from a datasheet, often by analogy to a previous project — and then it determines tool wear, anodizing results, part weight, weldability and a meaningful slice of unit cost for the life of the product.
Most grade comparisons online are written from the material side: tensile strength, yield strength, elongation, corrosion tables. Those numbers are correct and they are not much help on the shop floor, because two alloys with similar strength can behave completely differently under a cutter.
This guide is the other half — the same grades compared on the things that decide your part cost and your rejection rate: how they cut, how they wear tools, how they take a finish, and what they add to the price of a finished part.
The short answer
If you want the decision now and the reasoning later:
| Situation | Grade | Why |
|---|---|---|
| General machined parts, no special requirements | 6061-T6 | Best balance of machinability, finish, availability, cost |
| Maximum strength, weight-critical | 7075-T6 | ~570 MPa tensile; near-steel strength at 1/3 the weight |
| Parts that will be welded | 5083 or 6061 | 5083 for marine/welded structures, 6061 for general fabrication |
| Large flat plates and tooling | MIC-6 | Cast, stress-relieved, stays flat after machining |
| Cosmetic anodized parts | 6061 or 6063 | Even, predictable anodize color |
| High-volume extrusions and simple profiles | 6063 | Best surface finish, fastest to machine |
| Fatigue-loaded structure | 2024-T4 | Classic airframe alloy; needs corrosion protection |
| Sheet metal and formed parts | 5052 | Best formability of the common grades |
All ten grades side by side
Data below is for the standard temper of each grade. Machinability is rated relative to 6061-T6 as the benchmark; "cost index" is material cost relative to 6061-T6 plate.
| Grade | Series | Tensile (MPa) | Yield (MPa) | Machinability | Corrosion | Weldability | Anodize quality | Cost index |
|---|---|---|---|---|---|---|---|---|
| 1100-H14 | 1xxx | 110 | 95 | Excellent | Excellent | Excellent | Excellent | 0.9 |
| 3003-H14 | 3xxx | 150 | 145 | Good | Excellent | Excellent | Good | 0.95 |
| 5052-H32 | 5xxx | 230 | 195 | Fair | Excellent | Excellent | Good | 1.15 |
| 5083-H116 | 5xxx | 290 | 215 | Fair | Excellent | Excellent | Poor | 1.3 |
| 6061-T6 | 6xxx | 310 | 276 | Excellent (benchmark) | Good | Good | Excellent | 1.0 |
| 6063-T5 | 6xxx | 186 | 145 | Excellent | Good | Good | Excellent | 1.0 |
| 6082-T6 | 6xxx | 310 | 260 | Good | Good | Good | Excellent | 1.1 |
| 2024-T4 | 2xxx | 470 | 325 | Good | Poor | Poor | Poor | 1.5 |
| 7075-T6 | 7xxx | 572 | 503 | Good | Fair | Poor | Fair | 1.8 |
| MIC-6 (cast) | Cast | 165 | 145 | Excellent | Good | Poor | Good | 1.7 |
Three patterns jump out of this table and matter more than any individual number.
The strongest grades are the least cooperative. 7075 and 2024 sit at the top for strength and at the bottom for weldability, and near the bottom for corrosion and anodizing. Strength is not free.
The 6xxx family is where most parts live. 6061, 6063 and 6082 occupy the sweet spot: adequate strength, excellent machinability, good finish, reasonable cost. Roughly three quarters of the aluminum parts we machine are one of these three.
5xxx grades trade machinability for corrosion and weldability. 5083 and 5052 are what you use when the part will be welded or will live outdoors near salt water — and you accept the gummy chips and the anodizing problems that come with high magnesium content.
Temper matters as much as grade
The temper designation after the alloy — the "T6" in 6061-T6 — is not decoration. It describes the heat treatment and mechanical working the material has received, and it changes strength, machinability, dimensional stability and price. Specifying "6061" without a temper leaves the decision to whoever picks the material off the rack.
| Designation | Meaning | Effect on the part |
|---|---|---|
| -O | Annealed, fully soft | Lowest strength, best formability, gummy to machine. Used before forming or when a part will be heat treated later |
| -T4 | Solution heat treated, naturally aged | Moderate strength, good formability. 2024-T4 is the classic example |
| -T5 | Cooled from forming, artificially aged | Extrusion standard (6063-T5). Lower strength than T6 but excellent finish |
| -T6 | Solution heat treated, artificially aged | Peak practical strength for 6xxx and 7xxx. The default for machined parts |
| -T651 | T6 + stress relieved by stretching | Same strength as T6, but far more dimensionally stable after machining |
| -T73 | Over-aged for stress corrosion resistance | ~10–15% lower strength than T6, dramatically better resistance to stress corrosion cracking |
| -H32 / -H116 | Strain hardened (and stabilized) | Wrought 5xxx tempers; not heat treatable |
Three practical consequences that come up on real jobs.
Thick plate and T6 do not always get along. When a thick 7075 or 6061 plate is machined, removing material releases internal stress that was balanced through the thickness, and the part moves. The fix is specified in the material order, not in the machining: order T651 (stress-relieved by stretching) rather than plain T6 for any part where flatness matters. On a 200mm × 200mm × 40mm pocketed plate, the difference between T6 and T651 can be several tenths of a millimetre of bow.
7075-T73 versus 7075-T6 is a corrosion decision. T6 gives the highest strength but is susceptible to stress corrosion cracking in humid or chloride environments — a real issue for aerospace and marine parts. T73 sacrifices 10–15% of the strength for a large improvement in SCC resistance. If a drawing says "7075" with no temper and the part sees salt air, that is a specification gap worth raising.
Heat treating after machining will move the part. If a design requires machining in the annealed or T4 condition and then aging to T6, plan for dimensional change and a finishing cut after heat treatment. Shops see parts arrive at final inspection undersized because the heat treat step was not accounted for in the drawing sequence.
Cross-reference: the same alloy under different designations
If you are working between a US drawing, a European supplier and a Chinese shop, the same material will appear under three or four names. They are the same alloy — the designations come from different standards bodies.
| Common name | UNS (US) | ISO / EN (Europe) | JIS (Japan) | GB (China) |
|---|---|---|---|---|
| 6061 | A96061 | AlMg1SiCu / EN AW-6061 | A6061 | 6061 |
| 6063 | A96063 | AlMg0.7Si / EN AW-6063 | A6063 | 6063 |
| 6082 | — | AlSi1MgMn / EN AW-6082 | — | 6082 |
| 5052 | A95052 | AlMg2.5 / EN AW-5052 | A5052 | 5052 |
| 5083 | A95083 | AlMg4.5Mn0.7 / EN AW-5083 | A5083 | 5083 |
| 2024 | A92024 | AlCu4Mg1 / EN AW-2024 | A2024 | 2A12 / 2024 |
| 7075 | A97075 | AlZn5.5MgCu / EN AW-7075 | A7075 | 7075 |
Why this matters in practice: a Chinese supplier quoting "6061" and a European drawing specifying "EN AW-6061" are describing the same alloy, and the mechanical properties are equivalent. The mismatch that causes problems is not the naming — it is the temper, which is often omitted on drawings that specify the alloy by name only. Always write both: 6061-T651, 7075-T73.
What each grade is actually like to machine
This is the part specification sheets leave out. All parameters are starting points for carbide tooling; adjust for your machine, holder and fixturing.
| Grade | Surface speed (m/min) | Feed per tooth (mm) | Tooling | Coolant | Shop-floor reality |
|---|---|---|---|---|---|
| 6061-T6 | 300–500 | 0.10–0.25 | 2–3 flute carbide, uncoated or ZrN | Flood or air blast | Runs clean at high RPM; the reference point for "easy" |
| 6063-T5 | 400–600 | 0.15–0.30 | 2 flute, polished flutes | Air blast or mist | Fastest-cutting common grade; best as-machined finish |
| 6082-T6 | 250–400 | 0.10–0.20 | 3 flute carbide | Flood | Slightly tougher than 6061; watch corner wear |
| 5052-H32 | 250–450 | 0.10–0.20 | 2–3 flute, polished | Mist with lubricity | Gummy. Keep feed up or the tool rubs and work-hardens |
| 5083-H116 | 250–450 | 0.10–0.20 | 2–3 flute, polished | Flood with lubricity additive | Stickiest of the common grades; chip welding is the main failure mode |
| 7075-T6 | 250–400 | 0.10–0.20 | Sharp carbide; keep tools fresh | Flood | 20–30% faster tool wear than 6061; anodizes darker |
| 2024-T4 | 200–400 | 0.10–0.20 | Sharp carbide, high rake | Flood | Stringy chips, needs pecking and strong evacuation |
| MIC-6 | 300–500 | 0.10–0.25 | 2–3 flute carbide | Air blast or mist | Machines like 6061 but stays flat; low stress is the point |
| 1100-H14 | 400–600 | 0.15–0.30 | 2 flute, polished | Air blast or mist | Very soft and gummy despite the "excellent" rating — pure aluminum smears |
| 3003-H14 | 350–550 | 0.12–0.25 | 2–3 flute | Mist | Similar to 1100 but stiffer; good for formed and machined parts |
Two entries deserve a warning label.
"Excellent machinability" in a datasheet does not always mean it cuts well. The 1xxx grades are rated excellent because they are soft and easy to remove — but pure aluminum is also gummy. It smears, builds up on the cutting edge and produces a poor surface finish unless the tool is sharp, the speed is high and the chips clear. Soft is not the same as machinable.
5083 will teach you about chip welding. Its magnesium content makes it prone to pressure-welding onto the cutting edge at any moment when the tool hesitates. The fix is not more coolant — it is keeping the feed up so the tool cuts rather than rubs, and using a lubricating additive rather than plain water.
Tool wear: the cost that never appears in a datasheet
Tool wear is where the real cost difference between grades hides. It does not show up in material price and it rarely shows up in a quote, but it decides cycle time on long runs.
| Grade | Relative tool life | What wears first | Practical impact at 1,000 pcs |
|---|---|---|---|
| 6061-T6 | 100% (baseline) | Flank wear, gradual | Predictable tool changes, good surface to the end |
| 6063-T5 | 110–120% | Flank wear, slow | Best tool life of the common grades |
| 6082-T6 | 85–95% | Corner rounding | Slightly more frequent changes than 6061 |
| 5052 / 5083 | 70–85% | Built-up edge, then chipping | Interrupted by chip welding; expect scrapped parts if feed drops |
| 7075-T6 | 70–80% | Flank and crater wear | 20–30% more tool changes; finish degrades noticeably late in tool life |
| 2024-T4 | 75–85% | Crater wear | Similar to 7075 but with worse chip control |
| MIC-6 | 95–105% | Flank wear | Comparable to 6061; the low stress is the value |
| 1100 / 3003 | 90–100% | Built-up edge | Requires sharp, polished tooling to hold finish |
On a 1,000-piece run, the difference between 6061 and 7075 tool life is not theoretical. If a tool change costs five minutes of spindle time and you make three more of them, that is fifteen minutes — plus the surface finish drift that shows up in the last 200 parts before the change, which is where out-of-tolerance parts come from.
This is why a 7075 part can quote 25–40% above the same part in 6061 even though the material is only 80% more expensive per kilogram: the machining cost rises too.
Anodizing: where grade choice becomes visible
Anodizing is the most common finish for machined aluminum parts, and it is unforgiving about alloy choice. The oxide layer forms from the aluminum matrix; alloying elements either co-deposit, dissolve, or form their own oxides at different rates. The result is a color and thickness that depends on the grade.
| Grade | Type II (clear/dyed) | Type III hardcoat | Notes |
|---|---|---|---|
| 6061-T6 | Excellent, uniform, predictable color | Excellent | The reference grade for anodized parts |
| 6063-T5 | Excellent, often better cosmetic result than 6061 | Good | Lower copper content gives cleaner color |
| 6082-T6 | Excellent | Good | Similar to 6061 |
| 5052 | Good, slightly darker | Fair | Acceptable for functional finishes |
| 5083 | Poor — dark, blotchy, sometimes near-black | Fair | Avoid if the finish is visible |
| 7075-T6 | Fair — noticeably darker and less uniform | Good, and it hardens well | 7075 hardcoat is common in aerospace and holds up well |
| 2024 | Poor | Fair | Usually painted or chem-filmed instead |
| MIC-6 | Good | Fair | Cast structure can show porosity after anodizing |
| 1100 | Excellent | Fair (soft) | Very uniform color; too soft for wear applications |
Two practical consequences.
If a part needs a cosmetic anodized finish, 6061 or 6063 are the only safe choices. A 5083 part with a black anodized surface looks like a manufacturing defect, and buyers regularly discover this after the parts arrive rather than before. If the design needs 5083 for weldability and a visible anodized surface, split the part or change the finish to paint.
Type III hardcoat behaves differently from Type II. It is thicker (25–100 µm versus 5–25 µm), so it grows more and masks less. Threads and precision bores need masking or an allowance, and the dimension change is roughly half the coating thickness per surface. This applies to every grade; it is just more noticeable on parts with tight fits.
For the masking and allowance rules, see our anodizing guide for CNC parts.
Total cost per part, not material cost per kilogram
Material price is the number buyers compare and the least useful one. What matters is the landed cost of a finished, inspected part. Here is the same part — a 120 × 80 × 25 mm machined housing, 200 pieces — quoted across grades.
| Grade | Material cost | Machining cost | Finishing | Total per part | vs 6061 |
|---|---|---|---|---|---|
| 6063-T5 | $2.10 | $8.40 | $2.20 | $12.70 | −7% |
| 6061-T6 | $2.40 | $9.10 | $2.30 | $13.80 | baseline |
| 6082-T6 | $2.70 | $9.60 | $2.30 | $14.60 | +6% |
| 5052-H32 | $2.90 | $10.20 | $2.40 | $15.50 | +12% |
| 5083-H116 | $3.30 | $10.80 | $2.80 (paint, not anodize) | $16.90 | +22% |
| MIC-6 | $4.10 | $9.20 | $2.30 | $15.60 | +13% |
| 2024-T4 | $3.60 | $10.90 | $3.40 (chem film + paint) | $17.90 | +30% |
| 7075-T6 | $4.40 | $11.80 | $2.60 | $18.80 | +36% |
The pattern to notice: material cost is a small fraction of the total, and the machining and finishing penalties of the harder grades are larger than their material premiums.
7075 costs $2.00 more per part in material but $4.70 more in total — because it also cuts slower, wears tools faster, and the anodizing is less predictable, which shows up as inspection time.
The corollary is worth stating plainly: if you are choosing 7075 for strength you do not need, you are paying 36% for a property that is not doing any work. On a 5,000-piece order that is real money, and it is usually chosen by habit — "7075 is the good one" — rather than by calculation.
Conversely, if the strength genuinely matters (weight-critical brackets, high-load fittings), 36% is cheap compared to the weight penalty of steel.
Choosing by requirement, not by grade reputation
Work backwards from the requirement:
| Your requirement | Choose | Avoid | Why |
|---|---|---|---|
| Lowest cost per part | 6063, 6061 | 7075, MIC-6 | Machinability and availability both favor 6xxx |
| Highest strength at low weight | 7075-T6 | 1100, 3003 | 572 MPa tensile; the gap to 6061 is large |
| Will be welded | 5083, 6061, 5052 | 7075, 2024, MIC-6 | 7xxx and 2xxx are effectively unweldable |
| Marine / salt exposure | 5083, 5052 | 2024 | 5xxx has the best corrosion resistance |
| Cosmetic anodized finish | 6061, 6063 | 5083, 2024 | Color uniformity depends on alloy chemistry |
| Hard anodized / wear surface | 7075, 6061 | 1100, 3003 | Hardcoat needs a substrate that supports it |
| Large flat plate, stays flat | MIC-6 | 7075 (unless stress-relieved) | Cast plate has minimal internal stress |
| Fatigue-loaded structure | 2024-T4 | 6063 | Classic airframe alloy; needs coating |
| Best as-machined surface finish | 6063 | 5083, 1100 | Fine grain, low copper, cuts cleanly |
| Sheet metal / formed parts | 5052, 3003 | 7075, 2024 | Formability, not machinability, governs |
If your requirement does not appear here, the answer is 6061-T6 until proven otherwise. It is the grade that fails least often for reasons you did not anticipate.
Sourcing notes for buyers working with Chinese shops
Availability drives lead time more than machining does on most aluminum jobs, and the picture in the Pearl River Delta is specific.
| Grade | Availability in PRD | Typical stock form | Lead time impact |
|---|---|---|---|
| 6061, 6063 | Stocked everywhere | Plate, bar, extrusion, all thicknesses | Same day to 2 days |
| 5052, 5083 | Widely stocked | Sheet and plate; 5083 in marine grades | 1–3 days |
| 6082 | Available, less common than in Europe | Plate and bar | 3–5 days if not stocked |
| 7075 | Stocked in common plate thicknesses | Plate and bar | 2–5 days; special sizes longer |
| 2024 | Order basis at most service centres | Plate | 5–10 days |
| MIC-6 | Special order in most sizes | Cast plate | 7–14 days, and price varies by size |
Practical advice: if your design allows 6061 and you are ordering from China, you get the widest stock availability, the most competitive material pricing, and the fewest schedule surprises. Specifying 6082 because it is what your European supplier stocked is a common and unnecessary source of delay.
On tolerances: aluminum's thermal expansion is roughly 23 µm/m·°C, which matters on long parts. A 500mm aluminum feature measured at 20°C will be about 0.12mm longer at 30°C. For tight-tolerance work on large parts, the measurement temperature belongs in the specification. Our CNC machining tolerances guide covers the achievable bands by feature size, and the ISO 2768 chart covers the general-tolerance note on the drawing.
Frequently asked questions
Which aluminum grade is best for CNC machining?
6061-T6 is the default for most machined parts: it machines cleanly at high speed, takes anodizing evenly, welds acceptably and is widely available. Reach for 7075-T6 when you need strength approaching steel at a third of the weight, 5083 when the part will be welded or exposed to salt water, and 2024 when fatigue resistance matters more than corrosion resistance.
Why does 7075 cost more than 6061 to machine?
Two reasons. The material itself costs roughly 60–100% more per kilogram, and it is more abrasive on tooling — expect 20–30% faster tool wear than 6061 at comparable parameters. It also cannot be welded, so assemblies that would be welded in 6061 must be redesigned with fasteners or machined as one piece.
Can 5083 be anodized?
It can, but the result is unattractive and inconsistent. 5083 contains magnesium as its main alloying element, and magnesium-rich phases oxidize at different rates than the aluminum matrix, producing a dark, blotchy, sometimes almost grey-black finish. If a 5083 part needs a cosmetic anodized surface, switch to 6061 or 5052 instead.
Is 6061 or 6082 better for machined parts?
They are close relatives and both machine well. 6082 is more common in Europe and slightly stronger in yield (260 MPa versus 276 MPa for 6061-T6, with similar tensile). 6061 dominates in North America and China and is available in a wider range of stock sizes and thicknesses, which usually decides the question on availability rather than properties.
What is MIC-6 and when should I use it?
MIC-6 is a cast aluminum tooling plate, not a wrought alloy. It is cast between granite platens, which gives it very low internal stress and excellent flatness — typically 0.25mm over a 600mm span — and it stays flat after machining. Use it for fixture plates, vacuum chucks, base plates and inspection tooling where stability matters more than strength. It is roughly 50–80% more expensive than 6061 plate.
Can you machine 2024 aluminum?
Yes, and it machines reasonably well, but it has two practical drawbacks. Its copper content makes it prone to corrosion without a protective coating, and it welds poorly. It is also more expensive than 6061. Choose 2024 when fatigue resistance and strength-to-weight ratio are the governing requirements — traditional airframe structure being the classic case.
What does aluminum material cost add to my part price?
For a typical machined part where material is 20–30% of the price, upgrading from 6061 to 7075 adds roughly 12–20% to the total part cost, not the 60–100% you might expect from the material price alone, because the machining and inspection costs do not change as much. Upgrading to MIC-6 or 2024 adds more, mostly through material price and slower cutting.
Which aluminum grades are easiest to source in China?
6061, 6063, 5052 and 5083 are stocked in most Pearl River Delta service centres in plate, bar and extrusion, usually available same-day. 7075 is widely stocked in plate and bar but in fewer thicknesses. 2024 and 6082 are available but need ordering, and MIC-6 is a special order in most sizes. Availability drives lead time more than machining does on these grades.
Not sure which grade fits your part?
Send the drawing and tell us what the part has to do — the load it carries, whether it gets welded, whether it is outdoors, whether the finish is visible. Those four answers usually settle the grade, and if 6061 will do the job we will say so rather than quote you 7075.
You get a DFM review and a line-item quote within 24 hours, with the material called out by grade and temper so you can see exactly what is being priced. No minimum order quantity. Send your drawing or look at our aluminum CNC machining services first.
Two related comparisons go deeper on the pairs that come up most often: 6061 versus 7075 for machined parts and 6061 versus 5083 in batch production. For the wider picture, our aluminum CNC machining guide covers process capability and design rules.