-- The Home Page of the Finishing Industry
A website for Serious Education, promoting Aloha,
& the most FUN smiley you can have in metal finishing

topic 4058

Hard anodizing of piston ring grooves



We have some diesel engine pistons for repair.

We have had a chemical analysis performed and it tells us that we have 4032 cast aluminum.

The repair is to the top ring groove and we have repaired this by welding with a suitable filler rod by the TIG welding method.

The customer wants this area hard anodized can you explain if this is correct in doing also how much penetration we would expect.


Mac Horne

McAllister Horne
- Ontario, Canada

Hi, Mac. Hard anodizing can be varied somewhat in thickness, but is usually in the neighborhood of .001" to .002". Anodizing is a conversion process where aluminum is consumed to make the aluminum oxide film. You consume about .001" of aluminum in building .002" of anodizing. So the net dimensional change is about half of the coating thickness.


Ted Mooney, Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

July 10, 2008

I would like you direct you to:
US Patent 6425364 - Two-stroke direct fuel injected marine engine having anodized piston ring grooves, which I found in a single search together with your post.

The Gramm Technik deals with partial hard-anodizing of pistons. The hard anodised surface treatment will leave about 50-100 micrometers thick oxide layer. Their leaflet is pretty informative even for those who will not use that particular technology. The "gammat" process creates 15 um layer in just 60 seconds of anodising and the hardness is 350 HV.

Mario Bee
- Zapadna, Slovakia

This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site

ADD a Q or A to THIS thread START a NEW THREADView This Week's HOT TOPICS

Disclaimer: It's not possible to 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 may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices

©1995-2017     -    Privacy Policy
How Google uses data when you visit this site.