Roll-forming of cold-rolled strips of stainless steel or alloys with high nickel content to the required diameter.

TIG welding in inert atmosphere.

Sizing of outside diameter.

Heat-treatment at 1000-1100° (for annealed tube) or nickel-plating (for nickel-plated tube)

Cutting, winding in coils and pressure test (for heat treated tube)

Cutting to length, straightening and sizing of the ends for the other types of tubes.

Heat-treatment or nickel-plating and non-destructive tests are carried out on line without interruption. Destructive mechanical tests to check the resistance of the weld are carried out cyclically out of the line.