The use of tensile tests to determine the optimum conditions for butt welding polyethylene pipes of different melt flow index

The butt fusion welding of four different grades of polyethylene pipe has been studied and the feasibility of producing good welds between pipes of different melt flow index has been examined. Weld quality has been assessed on the basis of tensile tests and microstructural studies. The factors influencing the microstructure are discussed; in particular, the flow of molten polymer within the welds.