关键词: 聚乙烯, 热熔对接焊, 焊接卷边, 拉伸性能, 应力集中, 管道

Abstract: Tensile tests were carried out to investigate the failure mode, tensile strength, and tensile process of polyethylene (PE) pipe samples with different weld bead situations. It was found that, the failure mode of samples with weld beads was crack propagation because of the stress concentration around the notch tip between weld beads and pipe, and a phenomenon of brittle fracture was observed after large deformation in tensile process of samples without beads. The tensile strength and break elongation of samples without weld beads were much higher than that with weld beads, and the difference would be no less than 27 % and 100 % respectively with a tensile rate of 10 mm/min. It demonstrated that the removal of both butt fusion weld beads could improve its tensile properties notably, but it would be improved slightly when just one of them was removed.

Key words: polyethylene, butt fusion welding, weld bead, tensile property, stress concentration, pipe