Have a look on the fin extrusion process

This example shows the rolling process for the manufacture of rolled or extruded bimetal finned tubes. The inner tube has a diameter of 25 mm with any standard wall thickness. Any pipe material can be used. The rolled aluminum tube creates a seamless and gap-free finning with 57 mm 
fin diameter with a medium fin thickness of 0.4 mm. The fin spacing can be between 7 and 11 fins / inch. The contact and thus the heat exchange of the inner tube and finning is optimal. The finned tubes are manufactured to the length specified by the customer as well as the length of the unfinned or bare tube ends. As an extra you can also order tube supporting rings.

We deliver the finned tubes ready for installation