Risk of machining alu die castings

Question

Risk of machining alu die castings

Casa250 (Mechanical)

(OP)

21 Jul 21 08:04

Hi all,
among our working colleagues I often hear that sealing areas on alu die castings should not be machined as this could expose potential casting imperfections thus leading to leakage. It would be better to keep the raw casting surfaces for that matter.
Is that a justified concern?
Thanks!

3DDave (Aerospace) · Answer 1 · 2021-07-21 16:05:17

Yes. There can be hidden porosity. However, die castinga are cheap, so throw the ones that leak away or back into the melt.

arunmrao (Materials) · Answer 2 · 2021-07-21 18:11:55

I agree with 3DDave's recommendation.

Die castings are pressure tight and it is wrong to say that under surface porosity is commonly observed .

SwinnyGG (Mechanical) · Answer 3 · 2021-07-21 18:51:25

Quote (arunmrao)
Die castings are pressure tight and it is wrong to say that under surface porosity is commonly observed .

That's a bold statement.

Better would be 'castings are pressure tight, and discovering porosity during machining is rare, when the castings are well designed and casting process is well controlled'

Much depends on the quality of material and the consistency with which it is processed.

arunmrao (Materials) · Answer 4 · 2021-07-21 19:20:31

SwinnyGG
Thanks for your observation. I was only trying to debunk the myth of the OP.

I am an every day sand caster.( ferrous castings).

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Risk of machining alu die castings