PURPOSE: To make surely uniform the wall thickness at the end of a finish pipe by subjecting the thick-walled part to warm drawing by using a die of which the inside diameter is a target outside diameter and a core tool of which the outside diameter is a target inside diameter.
CONSTITUTION: The front end and rear end of the finish pipe 9 formed by stretch reducing with a stretch reducer are cut by a flying saw. The thick wall parts at the front and rear end of the pipe 9 are subjected to the warm drawing by the die 13 of a drawing machine and the plug 14 as the core tool, by which the pipe 9 having the prescribed length is obtd. The outside diameter of the plug 4 is of the value approximately equal to the target inside diameter of the pipe 9 and the inside diameter of the die 13 is set equal to the target outside diameter of the pipe 9.
IMAE TOSHIO
TAKADA ISAO
