Method for forming a socket on a pipe of biaxially oriented polyvinyl chloride

摘要

A method for forming a socket on a pipe of biaxially oriented polyvinyl chloride is claimed comprising : a) placing a support in an end section of the pipe; b) heating the pipe in the region of the end section; c) deforming the pipe to produce a socket in the region of the heated end section, the heated end section being supported internally while the socket is being formed; d) cooling the pipe in the region of the end section, the end section being supported internally during the cooling operation and e) removing the support from the pipe for the purpose of heating the internally supported end section of the pipe. The end section first being heated until the end section has reached, substantially homogeneously, the glass transition temperature of polyvinyl chloride and then being further heated until the end section has reached, substantially homogeneously, a temperature near, preferably just above, the orientation temperature of polyvinyl chloride.