PIPE FRAME JOINED STRUCTURE AND JOINING METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a sound pipe frame join structure and its joining method high in efficiency and high in yield. SOLUTION: In a frame joined structure consisting of a main tube 2 orthogonal or oblique to a head tube 1, the pipe frame joined structure has the head pipe 1 and a short auxiliary tube 8 which is fitted into the main pipe 1 at a joined part between the head pipe 1 and the main pipe 2 and joined to the head pipe 1. Further, a pipe material is titanium or titanium alloy. In a joining method of the pipe frame structure, after the auxiliary pipe 8 of short length and having an outer diameter smaller than an inner diameter of the main pipe 2 is joined to the head pipe 1 by arc welding from an inner face of the auxiliary pipe, the main tube 2 is externally fitted on the auxiliary pipe 8 and abutting the main pipe 2 on the head pipe 1, resistance welding is conducted.