Aloha, fun & authoritative answers -- no cost, no registration, no passwords, no popups
(as an eBay Partner & Amazon Affiliate we earn from qualifying purchases)

Where the
world gathers for metal finishing
Q&As since 1989

-----

Temperature effects on Anodized Aluminum Parts

Our company current heat shrinks several aluminum parts together and we are thinking about requiring a hard anodized surface on one of these parts. This surface is also a sealing surface for a gland type o-ring detail. My question is that if we hard anodize the part, what is the maximum temperature we can apply to the part for heat shrinking and not see any surface degradation or cracking which could cause a leak?

Brett Blanchard
Engineering - Knoxville, Tennessee
June 19, 2008

June 20, 2008

Look up the coefficient of thermal expansion for your aluminum alloy and for aluminum oxide. BIG difference and the hard anodize will probably crack and possibly delaminate.
If the inserted part is not anodized, look into shrinking it by using liquid nitrogen and rapidly press that part into a warm larger part. Wonderful shrink fit after they reach room temp.
Dry ice and alcohol get quite cold also, but not as much as liquid gasses and probably cost as much in the long run.
Safety measures are mandatory for both.

James Watts
- Navarre, Florida

Sheasby and Pinner say, "fine cracks may be observed at 80-100C - - cracking is caused by the low coefficient of expansion of the anodic film which is approximately 0.2 times that of the metal,"

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

June 20, 2008

(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories: