APPARATUS AND METHOD FOR MANUFACTURING PIPE WITH GROOVE ON INNER SURFACE

摘要

PROBLEM TO BE SOLVED: To provide an apparatus and a method for manufacturing a pipe with a groove on an inner surface for executing working of a consistent inner surface shape over the entire length of the pipe without any breakage of the pipe even when the pipe is long by reducing a tensile load and achieving the consistent tensile load. SOLUTION: A diameter-reduction working unit 13, an intermediate drawing unit, and a grooving unit are provided along the drawing direction X of a tube stock 11a. The diameter-reduction working unit 13 includes a diameter-reduction die 22, and a floating plug 23 for the diameter of the tube stock 11a together with the diameter-reduction die 22. The diameter reduction ratio RD(%) of the tube stock 11a to be expressed by formula RD=ä(Do-D2)/Do}×100(%) using the outside diameter Do (mm) of the tube stock 11a and the diameter D2(mm) of the diameter-reduction die 22 is set to satisfy RD≤30 at the diameter-reduction working unit 13, and the outside diameter D1(mm) of the floating plug 23 and the diameter D2(mm) of the diameter-reduction die 22 are set to satisfy inequality: D1-D2≥0.1. COPYRIGHT: (C)2010,JPO&INPIT