RECESSED STEEL PIPE JOINT, JOINT STEEL PIPE, AND JOINT METHOD OF STEEL PIPE

摘要

PROBLEM TO BE SOLVED: To solve the problem from a viewpoint of economical efficiency that a weight of the whole steel pipe increases when a steel pipe thickness is thickened, due to requiring to thicken the steel pipe thickness of a recessed steel pipe to be joined to a joint steel pipe by threading work to the recessed steel pipe, since there are consecutive recesses on a surface of the recessed steel pipe.SOLUTION: A joint steel pipe 3 and a recessed steel pipe 2 of forming recesses on the steel pipe surface, are joined by friction welding. When using a recessed steel pipe joint 1 formed by joining the joint steel pipe 3 and the recessed steel pipe 2, other steel pipe can be connected without thickening a thickness of the recessed steel pipe 2.