J. Vienne, Ph. Vanspeybroeck
Fracture - RCP # 2004 Milan
Since the official introduction of the S4 test in several ISO and CEN standards, different test institutes have achieved experience in the RCP behaviour of polyethylene gas and water pipes. In most cases the S4 test is limited for smaller pipes up to a diameter 250 mm. This paper resumes the results recently obtained by Becetel, on different PE 100 resins, especially on pipes with diameters from 160 mm up to 900 mm. The influence of the extrusion parameters (cooling rate, extrusion speed) are examined and reported. Several techniques have been used in this study to characterise the extrusion conditions (crystallinity, the melt behaviour, the OIT, the internal stresses, etc.,) These results permit to improve the intrinsic quality of large polyethylene pipes in conjunction with an improved RCP behaviour.