STEEL PIPE CONNECTING STRUCTURE

摘要

PROBLEM TO BE SOLVED: To provide a steel pipe connecting structure capable of connecting steel pipes easily, rapidly, at a low cost and economically.SOLUTION: This invention relates to a steel pipe connecting structure in which there are provided steel pipes 1 having plural rows of row-like salient groups 15 composed of plural salients 11 arranged along an axial direction at an inner circumferential surface 1B and a short cylindrical joint 3 having integrally an outer flange part 5 and inner inserted cylinders 4, 4, the inner inserted cylinders 4, 4 of the joint 3 are inserted into the end portions 2, 2 facing to each other while being adjacent to each other of the steel pipes 1, 1 arranged on the same axial centers, the inner circumferential surface 1B of the steel pipe 1 is formed with a smooth surface-like longitudinal concavity over a full axial length between plural rows of row-like salient groups 15, 15 adjacent to each other in a circumferential direction, row-like salient groups 15, 15 at opposite side by 180° are arranged the salients 11, 11 in the same phase in the axial center direction, and an outer circumferential surface 4A of the inner inserted cylinder 4 is formed with small lock protrusions 9, 9 engaged with the row-like salient groups 15, 15 at opposite side by 180° while being displaced in an axial center direction under a prescribed phase difference and provided with a circumferential position setting swollen part fitted in the longitudinal concavity.