Method for manufacturing coated pipes

摘要

The invention concerns a method for manufacturing pipes coated with a peelable protection layer, wherein the core pipe (1) is produced by extruding and calibrating, after which the surface of core pipe (1) is heated before a protecting coating layer (7a) is applied onto the core pipe (1) on passing through a coating die (7), followed by cooling the applied coating layer (7a) before the readily coated pipe (9) is drawn out of the process. The method is characterized in that the degree of adhesion between core pipe (1) and coating layer (7a) is controlled by rapid and effective heating of the surface of the core pipe (1) to a predetermined temperature and by controlling welding time and stretching of the coating layer being applied onto the core pipe (1) by maintaining a controlled vacuum level inside the coating die (7) forcing the coating layer to hit the surface of the core pipe at an angle as steep as possibly, preferably between 45 and 90 degrees, most preferably between 60 and 80 degrees.