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Etching aluminum to reveal heat effected areas of weld regions.

Let me start off by saying that this is a new process that I am developing. For the most part everything I've done to this point I've been able to find info on by doing internet searches - and actually found quite a bit of info on this site as well.

What I am trying to do is determine a way to etch aluminum to be able to see the heat effected area of a weld zone. The aluminum starts in strip from, then is formed into a tube, then welded. After being welded the tube goes through multiple draw dies. I'm then going to take the tube and mount a cross section of the tube in an acrylic mold, polish, then etch it to bring out the heat effected zone. For stainless steel I know to use an acid etchant which darkens different phases exposing the area. However, I can't find anything on aluminum. Anyone have any ideas?

Zach Henderson
Process Engineer - Duncan, South Carolina
June 19, 2008

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ASM has a wonderful book, the last of a series, on microsections. It is expensive, but well worth it for the pictures and comments.
As far as the etch, The two primary manufacturers of mounting and polishing equipment have a free or cheap book on etchants and other information. I had one from Leco that was great.

James Watts
- Navarre, Florida
June 20, 2008