Beech, Burley, Bunn
# 1988 Bath
Production of plastics pipes by conventional extrusion results in 'frozen i n r stress in the pipe wall, termed residual stress. Techniques have been established for assessina the levels of ~, this stress and relating to extrusion coaling conditions by mathematical modelling. However, the effects on long term performance have not been clearly established. ~ ~~ A joint project involving BP Chemicals, Stewarts and Lloyds Plastic; and Wavin Industcial Products was established in 1987 to investigate residual stress in large diameter MDPE water pipe.