Positioner material of construction - Die Cast Aluminium

[johnthebest]

Hello everyone

In our project specification we have set the MOC for the control valve to be Die Cast Aluminium. However the vendor is suggesting "Anodized Aluminium - Low copper content (< 0.4 %)"" in-place of ""Die Cast Aluminium"

what are your thoughts

 

[danw2]

For decades I've handled various instruments with spec sheets touting "low copper content aluminum housing".

No one has EVER been able to tell me why low copper is a benefit for anything. I suspect that it has to do with the casting ability of the aluminum alloy, but again, no one has ever claimed to know.

With regard to anodizing, you should look into whatever coating it is that makes the housing corrosion resistant to meet a NEMA 4X rating. I think epoxy coating is commonly used, but I'm not a manufacturer.

I eagerly await an answer to the low copper content question.