I can't remember if Honda uses any of the forged control arms from Kobelco, but if so, then here is some information regarding their alloy development/usage:
I have a flywheel made, most likely from 6061-XX. The original machining tapered the crank mating face a few thousandths, as if to perform as a belleville washer. After a partial season that section is badley fretted at the face OD, and riddled with lightning bolt cracks commonly associated with stress corrosion cracking SCC. Some of the various 6061 alloys have fairly poor ratings as resistant to SCC. Also 6000 alloys are forbidden in some MIL spex to be part of structural weldment on shipboard. I picture 100 kmiles zooming along a US rustbelt roadway as a more corrosive atmosphere than a few outings in a race car's bellhousing, so would hesitate to use 6061 in a stressed state, like with fitted taper bolts, press fitted bushings, etc.
And yet, 6061-T6 is used for production suspension arms (as well as wheels, powertrain mounts, and other parts). If 6061-T6 is not ductile enough, how do vehicles get by with cast aluminum suspension arms (fracture strain ~ 8 %)? Low ductility means you have to make compromises with section size (and part mass), and you don't get the theoretical best mass reduction.
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
You must get extra special cast aluminium that the rest of us in the auto industry can't get. Damn those bastards at Alcoa and Alcan hiding the good stuff from us.
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
