Scudrunners

Are you a metallurgist or just an engineer.

Anyways, I found this interesting about aluminum alloys at a plant that recycles aluminum as well:

"At this level of sophistication, you have to make sure you don’t mix one aluminum alloy with another aluminum alloy or you risk weakening the finished product. Therefore, Constellium is striving to keep turnings and offcuts well sorted during their entire recycling journey. Constellium even enforces these efforts at the customers’ machining facilities"

I'm just enough of an engineer to know that metallurgy can really mess me up!

All of my grandfather, father and me worked at Alcan in Kingston, Ontario.

When I worked there as a student engineer in the early 80's I met this really
old guy, just about to retire, who had been there forever, and had known my
grandfather, who flew biplanes in WWI and died in 1942. He must have been
a very young man, working at Alcan in the early 1940's.

I know a few AL alloys, is all. 6061 has gotta be painted. 2024Tx is the good
stuff with the cladding. The "x" is how hard it is already work-hardened. There
are a couple alloys in the 10xx range that are super-soft and are used for fairings
and such.

Copper is fucking magical. It, not gold is what you want to alloy with. Never
understood why gold was valuable. Maybe for electrical contacts that don't
corrode is all.

I've done a couple of metalurgy courses in my schooling. In a nutshell the chemistry is what defines any alloy. That and the heat treatment will control the strength of the final product. Here's an example, 6061 chemestry

Aluminum 95.85 - 98.56%
Magnesium 0.8 - 1.2%
Silicon 0.4 - 0.8%
Iron 0.0 - 0.7%
Copper 0.15 - 0.4%
Cromium 0.04 - 0.35%
Zinc 0.0 - 0.25%
Titanium 0.0 - 0.25%
Manganese 0.0 - 0.15%
Remainder 0.05 - 0.15%

While any batch is liquid the mill will pull a sample and do mass spectrometry on it to ensure all the alloying elements are within the required limits. If not they have to add materials to bring them into range. They could for example add a catalyst that precipitates one element out or they could add pure aluminum to bring one element under max adding other elements to bring them to minumums. It's just simpler to start with 6061 scraps to finish up with 6061. 2024 has between 3.8 and 4.9% copper, so having that in the feed stock will contaminate a 6061 batch very badly.

Gerry