Replacement to investment casting alloy A356 T6 1

[bpss]

Hello All,
I have been given a task to change the process of manufacturing of a cast aluminum enclosure from investment casting to die-casting.
1) Can someone pl. suggest me a die-cast alloy with same or better mechanical properties.
2) Will the change in process be feasible without change in the design (existing design meant for investment casting)
Thank-you for your help,
bpss

 

[CoryPad]

Do you have requirements that you must meet? If so, please share them so that we can answer effectively. Also, why must you change processes? Is it for production efficiency? Can you consider gravity die casting, or only high pressure die casting?

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[bpss]

Hi Cory,
The requirements I have to meet are (identical to the investment cast version with alloy A356 T6 per B618):
1) No design changes if possible. Is it achievable?
2) The enclosure is to be rated to take 4x explosion pressure (of 800 psi), i.e. the die cast alloy should have same or better mechanical properties.
The die cast process under consideration is high pressure die cast only. The the change in processing is solely for production efficiency.
Will the change in process be feasible without change in the design (existing design meant for investment casting).
Hope that the above will enable you to comment.
Thx,
bpss

 

[Cierpy]

About Yr. requirement:
"The die cast process under consideration is high pressure die cast only."

So if You like to use HIGH PRESSURE DIE CASTING,
YOU CAN'T GET "same or better mechanical properties then A356 T6" due to simple reason
THAT YOU CAN'T DO heat treatment T6 on an high pressure die casting.

My Proposal is to pass to GRAVITY die casting with the
same alloy and heat treatment.

Best regards
Axel Cierpinsky

 

[TVP]

In order to use a high pressure die casting, you will need to investigate a process that uses a vacuum to reduce the partial pressure within the die. Alcoa and Gibbs Die Casting are two casters with such capability. I recommend visiting their websites. Also, in Europe, Aluminium Rheinfelden has developed alloys to be used in vacuum die casting that can be heat-treated and welded, two things that frequently cannot be done with conventional HPDC parts, due to the porosity entrapped during turbulent filling. Try the following links for more information:

http://www.alurheinfelden.com/alu_1024_default.html

http://www.alcoa.com/car_truck/en/pdf/modena.pdf

http://www.gibbsdc.com/

 

[etch]

Its funny how all the questions come up about this particular alloy.

Okay here goes my two cents/ tuppence worth.

We currently use this ally in both sand casting ( very thin walled castings for aerospace fuel systems) and in gravity die casting (i think the US call it permanent) for producing swingarms for motorbikes.

We can get rouhly similar properties after heat treatment, but the biggest problem we find with this alloy is that in die casting, feeding is a problem, its hard to feed over long distances and nay feeders have to be placed near the area of concern.

Other alloys to consider are A357 similar to a356 or En2726 an aerospace alloy, quit pure with high Mg 0.45 - 0.7%