| 摘要 |
The present invention relates to a corrugated steel pipe in which spiral corrugations (20) are formed along a pipe body (1), and an inner surface (11) of the pipe body (1) is smooth with no corrugation, thereby improving strength of the pipe and enabling fluid to flow stably along the pipe during use. The inner surface (11) of the pipe body (1) of the corrugated steel pipe of the present invention having corrugations (20) has a spiral recess (30) formed integrally with the inner surface (11). The cross sectional surface of each of the corrugations (20) is shaped as a square C formed by a pair of right triangular corrugations (21) which tightly face each other. Flat support portions (22) which are integrally connected to the corrugations (21) are formed at both ends of an inlet of the recess (30). Each of the flat support portions (22) is formed on the same plane with the inner surface (11) of the pipe body (1). The flat support portions (22) tightly support both ends of the inlet of the recess (30) so as to close the inlet of the recess (30) such that the recess (30) is maintained at a tightly sealed state. Thus, the corrugations (20) have structurally superior strength, and overall strength of the steel pipe is significantly improved. |
