Sand cast A380-F???

[peterblais1]

Hi guys,

I'm working on an automotive intake manifold which will be sand cast. The original plan was to do 350 and T6 heat treat it. However, I was down at the foundry today discussing the project and just generally trying to see what we can do to save a few bucks, and they suggested pouring it in 380, and skipping any heat treat.

So, I did a brief scan, and on the surface the 380 seems decent. It's pretty similar in strength, the only thing I see is that the elongation is quite a bit lower... The big thing though I see is that it is listed pretty much universally as a die casting alloy.

Does anybody have any input on using this in a sand casting application? The swap would actually cut unit cost 11% or so.

 

[swall]

380 is basically sand cast alloy 319 with higher silicon and has recently come into favor as cylinder head material (Ford, if I recall). So, don't be afraid to try it in sand cast. I would also investigate doing a T6 heat treatment or perhaps a T5--might help with machinability and dimensional stability. Elongation will still be lousy, though.

 

[TVP]

peter,

swall provided a good summary. 380 can be sand cast, and in the as-cast F condition, will have considerably lower strength than when high pressure die cast. Instead of 23 ksi yield/46 ksi tensile, it will be more like 319-F, which is 13 ksi yield/23 ksi tensile. If these mechanical properties are acceptable, then this could be ok. It will likely experience some natural aging over time due to the temperatures in the engine compartment, which will lead to some dimensional change as well.

 

[peterblais1]

TVP -

That's unfortunate, it's properties as die cast sounded really promising, but I couldn't find any info as sand cast... I'm really not too worried about the tensile properties from a failure POV of the entire component, it's much thicker then it needs to be in order to facilitate the sand casting. However, I am worried about it holding a thread, and there are 3 big gaskets involved which need to stay flat enough.

Is there any chance you can point me to where I can find some further information on it's properties as sand cast? I'm on matweb and a few others but all I can find is the -F condition, which doesn't specify how it was cast, so I'm assuming that is die cast.

Worst case, I bet I can get the foundry to pour us a prototype. They actually just called me and it appears this would save us almost 20%, so it may still be worth pursuing.

 

[swall]

Since you are in contact with the foundry, I would ask them if they have tensile data. If they don't, ask them if they can provided cast test bars for testing.

 

[TVP]

Peter,

I agree with swall-- ask the foundry what they have. I do not have any recommendations for resources that will have mechanical properties of sand cast 380 in the as-cast condition.