PROCESS FOR PRODUCING ULTRA-THIN METAL TUBE BY COLD ROLLING METHOD

摘要

A process for manufacturing a metal pipe with extremely thin wall by cold rolling with the use of a cold pilger mill, which process comprises, using rolls with tapered groove dies in which the diameter thereof increases or decreases from a roll biting entrance side toward finish exit side and a tapered mandrel in which the diameter thereof increases from the biting entrance side toward the finish exit side, carrying out drawing involving a reduction of wall thickness while expanding the wall thickness center of a pipe material to thereby attain a tremendous wall thickness reduction.