FIELD: plastic metal working, namely making branches of tubes. SUBSTANCE: apparatus for flanging tube wall includes stoppers for fixing tube, inductor for heating zone of flanging, punch. Punch includes stem and mandrel joined with it. Mandrel includes set of links having successively increased diameter and mutually joined by means of flexible rope. The last is made of steel with low permeability, for example of stainless steel. Flexible rope in intervals between links and also between stem and first link is protected by builtup casing made of metal with low permeability, for example of copper not disturbing rope flexibility. EFFECT: enlarged manufacturing possibilities due to flanging elongated bent tube in any place and providing necessary height of flange by one operation. 3 cl, 1 dwg
