The following points have to be considered in the modeling process:
Flanges require 2 ports: Left and right flush-mounted
For welding flanges please pay attention to the following:
Port 1 must be positioned flush on the connection side.
Port 0 must be positioned starting from the opposite side with an insertion depth of flange thickness - 0.1 mm (i.e. 0.1 mm above port 1).
Port 0 and 1 have to be in the mainline, port 2 on the pipe junction.
The Y axis has to point in direction of the junction.