Alum. 6061 vs 7075
Alum. 6061 vs 7075
(OP)
We are currently manufacturing a part out of 6061. The part is very similar to a roller lifter for an automotive engine in shape, and how it must perform. The part is being stressed in compression and also slightly side loaded. There is also lash in the assembly to make up for heat. The part runs in gravety fed oil. It is also hard anodized with a teflon type coating over top of the anodize. We have not had any significant failers, but the customer is asking us to use 7075 instead. Would there be any drawbacks to using the 7075 material such as possibly being more brittle. My concern is the two ears that hold the roller bearing could fatigue and snap off.





RE: Alum. 6061 vs 7075
RE: Alum. 6061 vs 7075
RE: Alum. 6061 vs 7075
RE: Alum. 6061 vs 7075
RE: Alum. 6061 vs 7075
RE: Alum. 6061 vs 7075
what is the customers rationale for wanting 7075?
I would make analysis of both materials, I would sort of throw it back onto their lap.
and ask for a letter or email to remove your self as not responsible if a problem should arise.
HTH
mfgenggear
RE: Alum. 6061 vs 7075
The part is in service for about 9hrs a year. I would say it should run for about 2-3 years before needing possible replacement. The part is returned by a spring with any where from 150-1000 ft lbs. It is making 243 cycles up and down in about 13 seconds. A total of 9750 cycles over the course of a year. So there is sort of a pounding going on.
So will the compression, then non compression of the part cause stress cracking quicker than the current 6061 material vs 7075. The 7075 I believe will resist the mushrooming effect, but will it have a greater chance of stress chacking?
RE: Alum. 6061 vs 7075
I uploaded the material data sheets for each material & compared the physical properties.
the 7075 was more impressive. however I would go the expert material engineers.
as stated above do an actual test.
I am an amature material engineer, i am not an expert. but these are my thoughts
I do see there is 1.5 x difference in hardness, the elongation is basicly the same. fracture toughness is equal.
if the customer wants the better wear & structural I would give it to them.
HTH
Mfgenggear