METHOD OF FABRICATING MOVABLE MANDRELS OF CONTINUOUS TUBE-ROLLING MILL Russian patent published in 2009 - IPC B21B25/00 

FIELD: metallurgy.

SUBSTANCE: invention refers to method of fabricating movable mandrels of continuous tube-rolling mills. The method consists in work piece shaping, turning, and heating in a furnace with successive rolling in duo-rolling meal and cooling with water. While fabricating the mandrel a work-piece of length is used, which is heated in the furnace before shaping to 750-820°C; also shaping is carried out in 3 (three) passes in the duo-rolling mill with swaging 0.5-0.6 mm. After shaping turning is performed and forming of a lead-in chamfer and a head for extraction on a turning lathe; further there is performed heating in the furnace to the temperature of 800-850°C and repeated rolling on the duo-rolling mill in five passes; also in both cases rolling is executed with simultaneous cooling with water of 18-30°C temperature, which facilitates fabrication of finished mandrel with length.

EFFECT: reduced metal consumption and labour intensiveness at fabrication of mandrels due to usage of work piece (mandrel semi-product) of less length.