jseyfert3
Contributor
They are. I watched a video on the making of both aluminum and steel scuba tanks a few weeks ago. The steel tanks start out as a disk of steel that is progressively bent into a cylinder in 3 or 4 steps, the aluminum tanks start out as a solid cylindrical blank that is put into a hydraulic press which extrudes the hollow cylindrical tank in a single operation. I always like watching how it's made type videos.Also understand that the equipment used to make Worthington steels (deep draw) are completely different than that used for aluminium (reverse extruded) and are incompatible to each other.
Here's the aluminum tank process (Catalina):
And the steel tank process (Worthington):