Scale‐up laws in heated tool butt welding of HDPE and PP

Abstract

In order to achieve high fatigue strengths in heated‐tool butt welds in plastic pipes used in gas and water supply lines, it is essential that optimum welding parameters be selected. In this paper, the different process phases are described by means of dimensionless characteristic parameters that have been obtained by applying similarity principles to heated‐tool butt welding. On the basis of strength studies conducted on welded Joints, it is shown that the best weld quality is attained when the welding parameters are selected such that identical sheaf deformations result in the joint zones of small and large pipes. Laws for scaling data from small‐pipe to large‐pipe welds are then based on the values of these nondimensional numbers.