| 摘要 |
PURPOSE:To provide a pipe having thick thickness and small diameter and high quality in the inner peripheral surface and improving guarantee of repeated inner pressure resistance by executing machining following the inner peripheral surface of the pipe to be worked preceding with a pipe drawing work in a process near the finish process repeating a process composed of the pipe drawing work and a heat treatment work to the pipe to be worked. CONSTITUTION:At the time of manufacturing the pipe having the desired inner and outer diameters by repeating the process containing the pipe drawing work and the heat treatment work to the pipes 10A-10J to be worked at plural times after machining the inner part in the initial stage, preceding with the pipe drawing work in the process near the finish process worked to the small diameter, e.g. mandrel having a cutting edge 5 at the one end is relatively pulled to the pipe to be worked and shifted in the pipe to be worked. Further by relatively rotating the pipe to be worked and the mandrel 4, even if there is some eccentricity or uneven thickness in the pipe to be worked, the machining following the inner peripheral surface is executed to perfectly remove the scaling layer at the time of hot-rolling and also even if fine crack, recessed wrinkle, etc., are newly developed at the pipedrawing process before machining, these surface defects can be removed. |
