2024 for high temperature service, best temper? (motorcycle power valve) 1

[triumph406]

Hi,

I've been asked to make some replacement power valves for a 2-stroke motorcycle. I had the material analysed, and it's 2024. I forgot to ask for a hardness test to see if the temper could be determined.

I don't know what the max temperature is that the part will see (it's on the edge of the entry into the exhaust port)

Most of the failures are due to the elongation of a slot in one of the parts that allows the part to enter the port and hit the piston. I'm changing the way it's made that should eliminate the elongation of the slot (i'm not the first to do this btw) I don't think the temper had any effect on the elongation of the slot, it was a design problem with some assembled fasteners coming loose and elongating the slot.

I can get locally T3/T351/T4/T851. Of these tempers, is there one temper that might be obviously better to use? The part will be anodized. I'm not sure that SCC is a concern as the part will be covered in oil while installed in the engine.

Thanks in advance for any help that can be provided!

 

[CoryPad]

I think T851 would be best. The other three will overage upon exposure to elevated temperature. T851 has artificial aging at ~ 190 [°]C, so the mechanical properties should be more stable.

 

[triumph406]

CoryPad,
Thanks for the reply, I will order T851.