Annealing Aluminum casting A380 1

[rolan91602]

Hi. I am thinking to replace an extruded aluminum cover with a cast aluminum part (A380). The assembly process requires swaging and I am afraid that the hardness of the casting may lead to fracture and premature tool wear when swaging. I am thinking that annealing would improve ductility. Does someone know where I may find a specific recipe for A380? Is this an "all-or-nothing" process? In other words, can I get a half annealed part?(I would like to retain some strength)
Thanks

 

[MikeHalloran]

Talk to a founder.

The first thing you will find out is that, for a lot of 'technical reasons' that will not be revealed, even|especially to a technical person such as yourself, you can't get a casting in any alloy other than A356.

You might be able to have it delivered in -0 temper instead of the usual/ mandatory for 'technical reasons' -T6. You probably won't like how dead soft the -0 temper is.





Mike Halloran
Pembroke Pines, FL, USA

 

[swall]

Annealing will not help. It is not feasible to anneal die castings, as the elevated temperature will cause the normal gasses entrained in the metal to cause bubbles and blisters. The big problem with swaging 380 is the low ductility to begin with. This is due to the high silicon content of the alloy.

 

[TVP]

Mike is correct that with most casting processes (sand, permanent mold/low pressure, investment) your alloy choice is essentially A356. In this case, A380 is an alloy cast exclusively by high pressure die casting, and as swall pointed out, is not suitable for heat treating. I will add the caveat that there are some vacuum die casting processes that may allow for post-casting heat treat, but even with this, you are back to the case where the yield strength will be quite low (probably ~ 100 MPa).

 

[rolan91602]

Thank you Mike, Swall and TVP. My porcess will be die casting, so I think the founder will be using A380. I have talked to my founder and he recommended a recipe of 280 to 300 C for 3 hours. After, the material has been annealed, do you know if it will work-harden over time?

Thanks again.