| 摘要 |
The present invention is able to improve productivity and quality stability when producing a cladding pipe. Moreover, the present invention provides a manufacturing method of the cladding pipe, comprising: a preparation step of concentrically arranging a pipe and a space forming pipe of which an external diameter is smaller than an inner diameter of the pipe; and a welding step of performing welding to charge a space portion in the space portion between the pipe and the space forming pipe. |
