Drawn tubing manufacturing process and apparatus therefor

摘要

Herein disclosed is a process of manufacturing drawn tubing, in which steps of applying a lubricant to the surface of a bottomed blank fitted on a mandrel, pushing out the mandrel to draw the blank through a die, and pulling in the drawn blank together with the mandrel out of the die are repeated in the recited order. The drawn blank is turned a predetermined angle, e.g., 180 degrees on the axis thereof during each of the repeating steps i.e., during or after the pulling step. As a result, the lubricant can be applied to another portion of the blank surface at a second or subsequent applying step so that the working conditions which might otherwise become different to cause the drawn blank to have a locally irregular or offset thickness can be made uniform in the circumferential direction of the blank. Also disclosed for practicing the process is a drawn tubing manufacturing press of horizontal type, in which turning means is provided for turning the mandrel the predetermined angle on the axis thereof relative to the mandrel holder thereby to turn the drawn blank the same angle.