T6 Aluminum vs Powder Coating
T6 Aluminum vs Powder Coating
(OP)
Seeking someone who knows more about T6 aluminum and heat treating than I do.
I recently had a set of racing wheels powder coated. I had no idea that the powder coating would do anything to the T6 annealing process and found out after the fact. Now I am trying to figure out if the wheels are still usable, or if I have ruined them and made them unsafe.
How much strength reduction as a percentage would heating T6 Annealed Aluminum to 390F for 1.5 hours cause? I spoke with the powder coater and they confirmed that was the temp and duration.
I have studied the linked chart below and from what I can tell it appears to be very minimal. Assuming they annealed the wheels to maximum tensile strength at 400F, another 1.5 hours at 400F appears to be a <5% change.
Thanks for any help!!!
Link
I recently had a set of racing wheels powder coated. I had no idea that the powder coating would do anything to the T6 annealing process and found out after the fact. Now I am trying to figure out if the wheels are still usable, or if I have ruined them and made them unsafe.
How much strength reduction as a percentage would heating T6 Annealed Aluminum to 390F for 1.5 hours cause? I spoke with the powder coater and they confirmed that was the temp and duration.
I have studied the linked chart below and from what I can tell it appears to be very minimal. Assuming they annealed the wheels to maximum tensile strength at 400F, another 1.5 hours at 400F appears to be a <5% change.
Thanks for any help!!!
Link





RE: T6 Aluminum vs Powder Coating
Suggest contacting the wheel manufacturer [or vendor] to clarify/resolve Your question.
Reason.
'T6' is an aluminum-alloy temper state. Without knowing the specific aluminum alloy Your wheels are made from [3-digit number for castings; 4-digit number for wrought], the term 'T6 aluminum' is meaningless... and NO ONE... except the manufacturer... can answer Your question.
Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]
RE: T6 Aluminum vs Powder Coating
Just for your reference, here is a paper with some graphs (figs. 12c & 12d on p.16) showing the effect of exposure at 390degF vs time on the RT tensile properties of 6061-T6 aluminum in the context of a painting operation. You can also take a look at MMPDS-01. Figures 3.6.2.2.1(c) & (d) show the effect of exposure at various times/temps on RT mechanical properties of 6061-T6.
RE: T6 Aluminum vs Powder Coating
RE: T6 Aluminum vs Powder Coating
Your use of the term 'racing' leads me to believe you may be talking about a 3-piece wheel with a cast or forged center, which will likely have very different properties than 6061-T6 depending on the specific alloy used.
You are not the first person in the world to powdercoat an aluminum wheel, that I can guarantee.
RE: T6 Aluminum vs Powder Coating
If the wheel were forged, the code would be H, followed by a number, e.g. 5052-H32.
--
JHG
RE: T6 Aluminum vs Powder Coating
LukeG11 hasn't replied/commented on any element of this thread. I personally dislike that behavior.
Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]
RE: T6 Aluminum vs Powder Coating
Per the manufacturer... flow formed monoblock construction, low pressure cast (one piece)
The manufacturer told me the wheels are ruined and to throw them away, literally. Although I respect them, I believe that is more of a legal response to cover their ass and not respective of the actual situation.
I am trying to determine how much degradation they would have seen from the powder coating process. A 5% or less change is not one I would be worried about. I'm trying to determine a rough estimate of the facts behind this and make an educated decision based on that of whether or not to use the wheels.
RE: T6 Aluminum vs Powder Coating
I went through what you did with our 356-T6 castings years ago. I didn't find any published data that said the strength would decrease by more than about 3% (400 Deg F for 1/2 hour).
RE: T6 Aluminum vs Powder Coating
RE: T6 Aluminum vs Powder Coating
I also tend to agree with the manufacturer doing a CYA in tell you to scrap them.
One other thought is that I would run them. Particularly since being on my race car these things will have the opportunity to be inspected after each event. Unlike on a street vehicle where at best the may get looked at during a 5000 mile tire rotation, maybe.
RE: T6 Aluminum vs Powder Coating
RE: T6 Aluminum vs Powder Coating
Did the wheel OEM ever tell you specifically what alloy the wheels were made from?
"Per the manufacturer... flow formed monoblock construction, low pressure cast (one piece)." ... is a very obscure/obtuse reply from the OEM. They still didn't tell You what the wheels were made from.
Was there any apparent warpage or distortion after this baking process [still round/true]?
Perhaps there is an auto racing components forum on another website that this can be discussed...?!
Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]
RE: T6 Aluminum vs Powder Coating
Unless you're traveling back in time and racing at Lime Rock Park when it was still full of potholes and chop. In that case throw them away.