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MIL-C-5541 is "grainy" on heat treated aluminum





Normal non heat treated aluminum when Alodine treated has even finish if all steps are properly performed.
Why are heat treated parts "grainy" and not evenly coated when a MIL-C-5541 conversion coating process is used? T-42 heat treat. material: 2024-0 aluminum 0.63 thick heat treat to T - 42 per QQ-A-250/4, AMS2770 [affil link]H, AMS 2658B

Ron Mewitz
QA Engineer - Itasca Illinois USA
October 5, 2011



This is very common when you heat treat the 2000's, the copper comes out of alloy, into the grain boundaries, when you come through the prep cycle, the copper falls out leaving a pit. There is nothing you can do about this problem.

robert probert
Robert H Probert
Robert H Probert Technical Services
supporting advertiser
Garner, North Carolina
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October 7, 2011



sidebar

In addition to my previous message, 2000's do respond favorably to higher free acid, so try taking you free acid up to 230 gm/L.

robert probert
Robert H Probert
Robert H Probert Technical Services
supporting advertiser
Garner, North Carolina
probertbanner
October 8, 2011



Hey Robert, Mil-C-5541 is a conversion coating spec, not an anodizing spec.

Marc Green
Marc Green
anodizer - Boise, Idaho
October 11, 2011



Yeh, I caught it right after I punched in the button, thanks for clearing my confusion before it confused anyone else.

robert probert
Robert H Probert
Robert H Probert Technical Services
supporting advertiser
Garner, North Carolina
probertbanner
October 12, 2011




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