Patent ID: 6524425
Filing Date: 2003-02-25
Classification: B29C,B29K,B29L

Abstract:
A method of butt-welding crosslinked polyethylene pipes (PE-X pipes) at connecting surfaces, the method which comprises:providing a profiled heating-element welding tool having a heating element with a radially serrated working face for enlarging the connecting surfaces of the polyethylene pipes; spatially melting end faces of the polyethelene pipes with the working face of the heating element at a temperature of above 420Â° C. and below 450Â° C. to thereby form enlarged and serrated pipe end faces with integral melt layers containing a variety of melting state phases including a vapor or gas phase and a thermoelastic phase; joining the end faces to one another under a welding pressure of 0.10 to 0.40 N/mm2 and meshing the serrated pipe end faces into one another, such that a melt phase of the melt layers that is capable of entering into a connection evokes a mixing effect of the melt by turbulent movements at mutually contacting flanks of the serrated pipe end faces, and such that a spatially distributed weld seam is produced with an enlarged binding surface, and maintaining the welding pressure until the joining zone has cooled to ambient temperature.