connecting spigot method of forming a shell steel pipe for steel-concrete composite pipe

摘要

PROBLEM TO BE SOLVED: To provide a method of forming a steel pipe connection part in which an end of a steel pipe body part is processed to reduce the diameter and thus an insertion part for connection is not required to be welded and is integrally formed with high accuracy.;SOLUTION: The method is for integrally forming, at an end of the steel pipe body part 22, an insertion part 24 for connection having a smaller diameter than that, and pressurizing a base steel pipe 31 having a same diameter with the steel pipe body part 22 from its outer circumference to partially process to reduce the diameter, thereby forming a recessed groove 33 toward the raw material steel pipe circumferential direction, and then cutting the base steel pipe 31 at a position in the recessed groove 33, thereby making the part processed to reduce the diameter as the insertion part 24 for connection.;COPYRIGHT: (C)2012,JPO&INPIT