FORMATION METHOD OF RAISED PORTION AT INSERTION OPENING OF PIPE

摘要

PROBLEM TO BE SOLVED: To provide such a method that an insertion opening ring can be always and easily positioned on a fixed position when installing the insertion opening ring on a perimeter for forming a raised portion at an insertion opening of a pipe and heat deformation does not occur when welding the insertion opening ring on the insertion opening. SOLUTION: A tool 20 is formed so as to engage with a circular body 18 having no-divided part along circumferential direction and having a perimeter groove 19 along circumferential direction. The circular body 18 is fitted in an outside of the insertion opening 9 under closed fit by moving the circular body 18 along a pipe axis direction with the tool 20, and the circular body 18 is positioned in axis direction in respect to the pipe and fixed by contacting the tool 20 with top end face 9b of the insertion opening 9. Since the circular body 18 has not divided part in the circumferential direction, it is possible to prevent the heat deformation from production when welding the circular body 18 on the insertion opening 9.