METHOD TO PRODUCE VARYING CROSS-SECTION PIPES FROM NON-FERROUS METALS OF TITANIUM SUBGROUP AND THEIR ALLOYS Russian patent published in 2014 - IPC B21B17/08 

FIELD: metallurgy.

SUBSTANCE: method involves successive deformation processing of a pipe workpiece with the cross section constant in length. First of all the pipe workpiece is subject to deformation processing into length parts with the length corresponding to the thin-walled section of the ready pipe, with the reduction of the external diameter and wall thickness to the intermediate size. Afterwards the obtained workpiece with variable cross section is thermally treated by the external diameter and wall thickness, then part of the workpiece corresponding to the thick-walled section of the ready pipe is reduced to the intermediate external diameter with or without the decrease of the wall thickness and the intermediate workpiece of mainly constant external diameter and variable wall thickness by length is produced, then final deformation processing is carried out to the size of the ready pipe with the decrease of intermediate size of the external diameter and wall thickness as well as the formation of a transient section, then final thermal processing follows.

EFFECT: minimal difference of the accumulated deformation along the pipe length.

4 cl, 5 dwg, 1 tbl