This paper presents the tensile strength and Shore D hardness behavior of electrofusion-welded and artificially aged polyethylene (PE) pipes of the PE100 SDR11 classification with a nominal diameter of 125 mm and a wall thickness of 11.40 mm. For the study, 12 samples were taken from the body of a PE100 SDR11 pipe (9 of which were obtained from the fusion-welded joint). Subsequently, the 12 samples were divided into 3 groups of 4 pieces (1 unwelded sample and 3 welded samples). Following the Arrhenius method, the samples of the 2 groups (group II and group III) were artificially aged, those belonging to group II were aged 10 for years and those belonging to group III were aged for 20 years. Subsequently, all 12 samples were tested for tensile strength and Shore D hardness. The 10-year aging of the welded samples increased the tensile strength by 12.31% and the 20-year artificial aging increased the tensile strength by 18.44%. For the unwelded samples, artificial aging for 10 years increased the tensile strength by 11.12%, whereas aging for 20 years increased the tensile strength by 12.63%. Artificial aging of the PE100 SDR 11 pipes does not have a significant influence on the Shore D hardness, which was found within the high range of hardnesses. The results show that the PE100 SDR pipes welded by electrofusion can be used for 20 years with safety.