PIPE HAVING INSERTION PORT PROTRUSION PART AND METHOD FOR FORMING THE PROTRUSION PART

摘要

PROBLEM TO BE SOLVED: To facilitate formation of the protrusion part of the outer periphery of the insertion port of a cast iron pipe. SOLUTION: A plurality of protrusions 22 are formed at the outer periphery of the insertion port 11 of a pipe 10. A protrusion part ring 23 having an inner peripheral groove 26 in which the protrusion part 22 is fitted is fitted on externally of the insertion port 11. Further, by welding a plurality of pieces to the outer periphery of the insertion port 11 of the pipe 10, a plurality of the protrusions 22 are formed on the outer periphery of the pipe 10 and a protrusion ring having an inner peripheral groove 26 in which the protrusion 22 is fitted is externally fitted on in the insertion port 11.