| 摘要 |
PURPOSE: To form a pipe of which the strength between socket type joints and a pipe main body is equal to that of the pipe main body, by a method wherein a socket end having a cut-in part is made in one end of the pipe, while an insertion end having a projecting part inside is made in the other end of the pipe, and materials for sockets are used for forming the end parts of the pipe. CONSTITUTION: End part rings 5 and 6 are put on the opposite ends 3 and 4 of a drum and fixed to the drum 1. The drum being started, a protective layer is spread and, after the protective layer is dried, a reinforcing layer 8 on the side of an outer wall surface is spread. The end part rings 5 and 6 are removed and first and second rings 10 and 11 for forming are fitted to the ends of the drum. The rings 10 and 11 for forming have such annular projecting parts 12 and 13 as to bound an annular space 15, and a material of a core layer 16 is introduced into the annular space 15. When the core layer 16 is spread and the surface is dried, the rings 10 and 11 for forming are replaced by third and fourth rings 20 and 21 for forming and materials 24 and 25 for sockets are introduced into annular spaces 22 and 23. The composition of the materials for sockets corresponds to that of the reinforcing layer 8 and, therefore, excellent joining can be obtained.
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