PIPE OF ORIENTED THERMOPLASTICS POLYMERIC MATERIAL

摘要

A pipe of oriented thermoplastic polymeric material having an integral socket is manufactured by expanding a tubular blank having a portion of greater wall thickness which is positioned in a portion of a female mould defining the socket. The tubular blank is heated by circulation of hot water to a temperature at which deformation will induce orientation of the polymer molecules, and is then expanded radially outwards against the mould by application of internal pressure. In this manner the wall thickness and rigidity of the socket are increased.