Cast iron steel and rolled or forged in bars of proper section, ultrasonic tested.
These bars are selected for heat, for manufacturing by campaign and cut into blocks.
These blocks are re-heated in a furnace and pressed in a way to obtain a solid bottom tube (shell).
The shell obtained is then drawn on a horizontal press, in order to get the final shape of the cylinder bottom.
After having been cut to length, the shell are ultasonic tested.
