| 摘要 |
A curved pipe and a manufacturing method thereof are provided to improve durability for bending by installing reinforcing curved recessed parts and projection parts outside. A curved pipe comprises a hollow part inside, reinforcing curved recessed parts(111), projection parts(112). The plural reinforcing curved recessed parts are formed at the outer surface of the pipe, and have the projection parts therebetween. A shape of the curved pipe(100) having the reinforcing curved recessed parts and the projection parts is a triangle or rectangle. The curved pipe including a flat part and a tip part is formed by pressurizing a circular pipe through a pressurizing device having a flat pressurizing roller. The reinforcing curved recessed part is formed by pressurizing the flat part to pass the pipe through the pressurizing device having a curved roller.
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