Al 2017-T4.

[RollingCamel]

We have been looking for aluminum to machine, uprights, hubs and diff mounts, and we found 2 options, 6063 T5 or 2017 T4.

While the 6063 T5 is cheaper it is also less in properties. The 2017 T4 is much more expensive but it is available in Alexandria and in all sizes. The 6063 T5 is on in Cairo which is 4 hours apart and they only have cylinders, so we have to get them wooden boxes for them to pour in.

We'll try to get a better offer on the 2017 T4 but i would like to know what you think of it.

We don't intend any Al welding so the advantage of 6063 isn't that great.

[SNasello]

You should select the material that suits the part you are designing the best. Perhaps some parts you could make out of the cheaper 6063 and others, such as your hubs, you might want to spend some more money and use the 2017 (which appears to have a much higher fatigue strength).

Perhaps you would be better of making some components from steel, if the cost is not justifiable. I have seen some relatively lightweight steel diff-mounts for example.

[The_Man]

Aluminium hubs can be tricky specially if they are on the inner race of the bearings. When we had Aluminium hubs(2024 T6) we had problems with surface fatigue at bearings. After having to use a press to fit the bearing the hub just came off the bearing after 4-5 runs. I could see a thin layer aluminium paste(finely ground aluminium) on the inner race of the bearing which was rather scary. We switched to steel hubs from then on. We used 7075 T6 at a later stage for uprights and that did not seem to come loose or form a paste.

Aside:
I have hear people say(from higher formulas) that you should have uprights and hubs of the same material so that on temperature rise there is no differential thermal expansion, to tighten the bearing or loosen it. However, I do not think this is really relevant in Formula Student as the temperature are not high enough and even if they get high they do not stay there long enough. Maximum effect it might have is to change the rolling resisting, slightly that too.
Anyone think/observe otherwise?

[flavorPacket]

There is not a single F1 car that has the same material upright and hub, so you can throw that theory out the window.

It is not terribly difficult to calculate how your bearing preload will change with temperature due to thermal expansion of your corner. It is absolutely critical to corner stiffness and fuel economy to understand the effect of temperature on your wheel bearing installation.

[Adambomb]

Originally posted by RollingCamel:
The 6063 T5 is on in Cairo which is 4 hours apart and they only have cylinders, so we have to get them wooden boxes for them to pour in.


I may be misunderstanding, but are you using it for casting? Much better off getting a casting alloy for that (one of the 3-digit ones, like 356), and naturally you'd have to heat treat them (and of course heat treating Al isn't as straightforward as steel). So if that's a case (I'm guessing since you can only get 6063 in round), it would sound like you'd be much better off with the 2017. Personally, I'd avoid casting Al uprights anyway, with the wall thickness you want it'd be fairly hard to get a good quality casting. Only material I'd like to cast for uprights is Mg, as it has a much lower viscosity when molten and is more friendly to casting thin cross sections (note many motorcycle engine covers are cast Mg, and are very nice looking, thin castings). However, the chief tech in charge of our casting lab doesn't want anything to do with it due to Mg's flammability. I'd also avoid re-casting round pieces into billet; I've seen enough crappy castings in my time that I wouldn't feel comfortable doing it myself.

There is definitely something to be said for a well-designed upright made from welded sheets of 4130 (box style). From a strict materials standpoint, stiffness/weight is pretty much identical to Al, strength/weight of heat treated 4130 is better than 6061 (about 15% less than 7075), and a box structure can give you plenty of bending stiffness. I remember seeing a bunch of good designs posted here over the years.

[RollingCamel]

We are not going to cast nor weld. We have enough trouble welding the chassis and they won't understand why we need such accuracy and will tire themselves making good fixtures.

We are going to machine them.

[GianVioli]

I used 6061-T6 for this years uprights and I think is the right material is you wanna go for a milled upright. Our Uprights weight less than 630gr each (all four of them) and are pretty stiff and looks better than welded boxes. Also allows you to be more creative and play more with your layout and packaging.

I would look deeper for some material as 6061-T6, would work great. But regarding the two materials you're asking the question is: can you pay for the 2017-T4 without regrets later on?

[DanGrey]

Would you know where to get a Temperature Control Panel? Its for my bro's.. he'll be needing some. I know its like a dead thread but who knows.