C210R vs 7075: Strength or Stability?
Last reviewed 2026-08-24 by Team GCA
If the part carries load, specify 7075. If the part is machined heavily and then has to hold size, specify cast plate. That is the whole answer, and the rest of this page is the evidence for it. The two materials are not close substitutes and the comparison is not a scoreboard where one wins.
What makes the choice hard is that both are sold into the same jobs. A shop building a die set, a mold base or a large fixture will be quoted both, and the datasheets look like 7075 wins on every line that a datasheet reports. The properties that decide it in practice are the ones a strength table does not show.
Where 7075 wins, and it is not close
There is no honest way to soften this. Rolled 7075-T651 is roughly four times the yield strength of the 5083-based G.AL® grades. If your part is structural, that ends the discussion.
G.AL® figures are from the GLEICH datasheets. The 7075-T651 column shows published typical values for the alloy, not GLEICH measurements; specified minima are lower.
| Property | G.AL® C210R / C250 (EN AW-5083, O3) | G.AL® C330R / C330 (EN AW-7021, T79) | Rolled 7075-T651 (typical) |
|---|---|---|---|
| Yield strength Rp0.2 | 16 – 19 ksi | 42 – 49 ksi | approx. 73 ksi |
| Tensile strength Rm | 33 – 42 ksi | 46 – 55 ksi | approx. 83 ksi |
| Elongation A | 10 – 15 % | 2.5 – 4.5 % | approx. 11 % |
| Hardness HBW | 68 – 73 | 110 – 120 | approx. 150 |
| Density | 0.096 lb/in³ | 0.101 lb/in³ | 0.102 lb/in³ |
| Modulus of elasticity | 10.2 × 10³ ksi | 10.2 × 10³ ksi | approx. 10.4 × 10³ ksi |
| Thermal conductivity | 64 – 75 BTU/ft·hr·°F | 72 – 90 BTU/ft·hr·°F | approx. 75 BTU/ft·hr·°F |
| Max service temp, long / short | 356 / 536 °F | 248 / 284 °F | approx. 250 °F long term |
| Weldable | C210R yes, C250 not by hand | No | No |
| Food contact per DIN EN 602 | Yes | No | No |
Note the middle column. G.AL® C330R is EN AW-7021 in T79 temper at 42 to 49 ksi yield. It closes roughly two thirds of the gap to 7075 while keeping the cast plate stability. Where a job genuinely needs more than 5083 can give, C330R is usually the answer rather than a jump all the way to rolled 7075.
One figure in that table deserves more attention than it usually gets: elongation on the 7021 grades is 2.5 to 4.5 %. That is very little plastic reserve. It does not matter in normal service, and it matters a great deal when a plate is dropped on a corner, a clamp is overtightened or a tool crashes. The 5083 grades at 10 to 15 % deform locally and survive; a low-elongation material cracks.
Where cast plate wins: it does not move
Rolled 7075-T651 arrives carrying stress from two sources. The rolling reduction stores stress through the section, and solution heat treatment plus quenching adds more. The T651 designation indicates a stretch-relief operation, which reduces stress but does not remove it.
While the section is intact those stresses balance each other. Rough a pocket into it and they no longer balance, so the plate relaxes into a new shape. GLEICH measured how far, testing deviation from flat over a 10 in. length.
Distortion from flat over a 10 in. length. GLEICH test data - our own measurements, on which we have an obvious interest. Ask us for the test conditions if the absolute numbers matter to your decision.
| Material | Route | Distortion |
|---|---|---|
| G.AL® C250 | Cast, sawn and milled | 0.010 in. |
| G.AL® C330 | Cast, sawn and milled | 0.026 in. |
| EN AW-5083 | Rolled | 0.055 in. |
| EN AW-6061 | Rolled | 0.072 in. |
| EN AW-7075 | Rolled | 0.100 in. |
Rolled 7075 moved 0.100 in. Cast C250 moved 0.010 in. Ten to one, and 7075 is the worst performer of the five materials tested. That is not a coincidence: the same heat treatment that produces its strength is what puts the stress into it.
The cost of that movement is not the material, it is the process built around it. Shops machining 7075 to tolerance use rough-and-rest cycles, an intermediate stress-relief step, or machine oversize and come back for a finishing pass. Every one of those is spindle time, handling and an extra chance to scrap the part on the second setup, after most of the value has already been added.
What it costs on the machine
GLEICH costed the same part out of five materials: a base plate 2.4 x 15.7 x 39.4 in. Figures below are converted to a CAD 125 per hour shop rate with setup at exactly one machine hour, which is how the original German study was built.
| Material | Machine time | Machining | With setup |
|---|---|---|---|
| Rolled 7075 | 3.25 h | CAD 406.25 | CAD 531.25 |
| Rolled 6082 / 6061 | 2.75 h | CAD 343.75 | CAD 468.75 |
| G.AL® C210R / C330R | 1.74 h | CAD 217.50 | CAD 342.50 |
| G.AL® C250 / C330 | 1.22 h | CAD 152.50 | CAD 277.50 |
Against rolled 7075, C210R took 1.74 hours instead of 3.25 - 46 % less machine time, and CAD 189 less per part including setup. C250 took 1.22 hours, 62 % less, and CAD 254 less per part.
The reason C250 beats C210R here is simply that it arrives milled to a tight thickness, so there is no facing operation. C210R is bought deliberately with a finishing surplus by shops that were going to machine both faces regardless, which is why it is the more common purchase despite the longer number in this table.
Read this as machining economics, not as the price of the job. It covers machine time and setup only. Material is not included, and cast plate costs more per pound than rolled 7075 does not - 7075 is itself an expensive alloy, which makes this comparison unusually favourable to us. Ask us for both plate prices and do the arithmetic on your own part rather than taking either table on trust.
The properties that quietly decide it
Three differences rarely appear in a side-by-side quote and each of them has ended a material choice on its own.
Welding
7075 is not weldable by conventional methods. Neither are the G.AL® 7021 grades. If any part of the assembly is welded, the choice narrows immediately to C210R or rolled 5083. This catches people out on fixture sub-assemblies, where the main plate is machined but a bracket is welded on.
Food contact and medical
The 5083-based grades are approved for food contact under DIN EN 602. 7075 is not, and neither is the 7021 family. For packaging tooling, food processing equipment or anything that has to survive a hygiene audit, that is a hard gate rather than a preference.
Temperature
C210R and C250 are rated to 356 °F in long-term service and 536 °F short term. That is comfortably above what most tooling sees. 7075 begins to over-age and lose strength permanently at sustained temperatures around 250 °F, which is a real constraint on anything running a cure cycle or a heated tool.
How to choose
| If the part... | Specify | Because |
|---|---|---|
| Carries structural load, strength governs | Rolled 7075-T651 | Roughly four times the yield of 5083. Nothing in the cast range matches it. |
| Is machined heavily and must hold tolerance | G.AL® C210R or C250 | Ten times less distortion, and 46 to 62 % less machine time. |
| Needs strength and stability together | G.AL® C330R or C330 | 42 – 49 ksi yield with cast plate stability. The usual middle ground. |
| Includes a welded joint anywhere | G.AL® C210R or rolled 5083 | 7075 and the 7021 grades are not weldable. |
| Contacts food or pharma product | G.AL® C210R or C250 | Approved under DIN EN 602. 7075 is not. |
| Runs hot in sustained service | G.AL® C210R or C250 | Rated to 356 °F long term. 7075 over-ages around 250 °F. |
| Is bent, formed or a pressure vessel | Rolled plate, not cast | Hard exclusion for cast plate regardless of measured properties. |
The pattern is that 7075 is a structural material that shops also use for tooling, and cast plate is a tooling material that is not pretending to be structural. Most disappointment with either one comes from using it for the other job.
Frequently asked questions
Is 7075 stronger than G.AL® cast plate?
Yes, substantially. Rolled 7075-T651 has a typical yield strength around 73 ksi against 16 to 19 ksi for the 5083-based G.AL® grades, roughly four times. G.AL® C330R in EN AW-7021 closes about two thirds of that gap at 42 to 49 ksi. If the part is structural and strength governs, 7075 is the correct choice and no cast plate substitutes for it.
How much does 7075 move during machining?
In GLEICH testing over a 10 in. length, rolled 7075 deviated 0.100 in. from flat, the worst of the five materials tested. Cast G.AL® C250 deviated 0.010 in., a ratio of ten to one. The same heat treatment that gives 7075 its strength is what stores the residual stress that releases when you machine into it.
Can I weld 7075?
Not by conventional methods. 7075 is generally regarded as unweldable for structural purposes, and the G.AL® 7021 grades C330R and C330 are not weldable either. If any part of the assembly is welded, specify G.AL® C210R or rolled 5083.
Which is cheaper to machine, 7075 or cast plate?
Cast plate, by a wide margin. In a GLEICH cost study on a 2.4 x 15.7 x 39.4 in. base plate, rolled 7075 took 3.25 machine hours against 1.74 for C210R and 1.22 for C250. At a CAD 125 per hour shop rate including one hour of setup, that is CAD 189 less per part for C210R and CAD 254 less for C250. Material cost is not included in those figures.
What temperature can 7075 tooling see?
Roughly 250 °F in sustained service before over-ageing begins to permanently reduce strength. G.AL® C210R and C250 are rated to 356 °F long term and 536 °F short term, which makes the 5083 grades the ones to specify for heated tooling or anything running a cure cycle. The G.AL® 7021 grades are the most limited at 248 °F long term.
Is 7075 approved for food contact?
No. Neither 7075 nor the EN AW-7021 G.AL® grades are approved for food contact under DIN EN 602. The 5083-based grades, G.AL® C210R and C250, are. For packaging tooling or food processing equipment that requirement usually decides the material on its own.
What should I use instead of 7075 for a mold base?
G.AL® C210R for most mold bases, or C250 where the plate goes on the machine as supplied. Both are EN AW-5083 in O3 temper with very low residual stress. Where the tool needs more strength than 5083 offers, G.AL® C330R in EN AW-7021 at 42 to 49 ksi yield is the usual step up and keeps the dimensional stability that rolled 7075 does not have.
Availability in Canada
Stocked in Oldcastle, Ontario
G.AL® plate is stocked in Oldcastle, Ontario, roughly ten minutes from the Windsor-Detroit border. Standard formats ship the same or next business day to most of Southwestern Ontario, and across Canada on a freight quote.
Pickup is available Mon–Fri, 8:00 AM – 4:30 PM ET at 2555 North Talbot Road, Oldcastle, ON N0R 1L0, Canada. Every delivery includes the EN 10204 3.1 inspection certificate for that specific lot at no charge.
Off-cuts and remnant pieces are listed with exact dimensions and prices in the G.AL® Shop.
Your Aluminum Experts in Canada
Our Canadian team understands mold making. Tell us your application and we will recommend the right G.AL® grade, thickness, and format - and get you a quote fast.