It is another object of the present invention to provide a joining method of the type described above, wherein {HEAD ~ the need} for a joining jig which is required in {TAIL ~ use} of a butt welding joint is eliminated to provide an improved joining operatability 
It is another object of the present invention to provide a joining method of the type described above , wherein { HEAD ~ the need } for a joining jig which is required in { TAIL ~ use } of a butt welding joint is eliminated to provide an improved joining operatability
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH