The warped intermediate portion of {HEAD ~ the pipe material} is fixed to the supporting surface portion of {TAIL ~ the head pipe} by welding 
The warped intermediate portion of { HEAD ~ the pipe material } is fixed to the supporting surface portion of { TAIL ~ the head pipe } by welding
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH