MANUFACTURE OF INTERMEDIATE DRAWN TUBE

摘要

PROBLEM TO BE SOLVED: To easily manufacture a tube having an intermediate drawn part in which difference in diameter is large between both ends. SOLUTION: One end part of a tubular stock 1 is formed larger in diameter than the other end, and the diameterγof the tubular stock 1 is set to be between the diameterαof a contracted tubular part 3 formed on one end and the diameterβof an expanded tubular part 6 formed on the other end. One end of the tubular stock 1 is contracted, and the other end is expanded. An intermediate part of the tubular stock 1 is drawn to the diameter S smaller than the diameterαof one end contracted through spinning.