[TowerTalk] Subject: Wind survival + load ratings... vs,

[jimlux]

On 11/1/17 9:47 PM, Kurt Andress wrote:


> no success. After a few years of effort, and constant search & 
> inquiries, I learned that many EU antenna builders do not have ready 
> access to high strength alloy tubes, like we do here. They can get ~40 
> ksi equivalent tubes in the small tube sizes (maybe up to around 1" 
> diameters), but not in the larger ones.....the larger tubes are rolled 
> and welded, with visible seams, not drawn, with a yield strength of 
> about 1/2 of what we can get here with 6063-T832 drawn tubing. I heard 
> some of the tubes were made in Turkey..... So, plug 23,200 psi yield 
> into those analyses and see what it does. In the UK, they can get real 
> 6061 alloy tubes, but they are 1/16th wall and don't telescope, so they 
> have to grind tubes to get them to fit together.

This is fascinating..  I wonder why it is - clearly, high strength 
alloys are available for some applications (building spacecraft and 
aircraft), but I guess it's not like here where there's a wide range of 
metal tubing suppliers.

Or is it because the big aluminum producers are in the US, and that's 
just where the industry developed.  After all, the Hall process for 
refining aluminum from bauxite started here. And WW 2 led to a huge ramp 
up in aluminum production for airplanes.