| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent a defect in which a heating wire is partially bent and short-circuited as it is buckled in an electric fusion coupling. SOLUTION: In an electric fusion coupling in which a heating wire 3 is buried in the inner periphery of a coupling main body 1 made of a thermoplastic resin, the volume resistivityρof the heating wire 3 is set in the range of 0.20 to 0.30 (μΩm), and the temperature coefficient of resistanceαis set in the range of 40 to 70×10<-5> (/ deg.C). For instance, the heating wire is made of a copper-silicon alloy containing Si in the range of 3.0 to 4.2%, Mn of 0.2% or less, the residual of impurities and Cu in the weight ratio.</p> |
