Method for manufacturing branched metal tubes

摘要

The invention relates to a method for manufacturing a branched and monoblock-structure weld-free metal tube or collector. A flattened-profile tubular blank 51' is preformed by means of a tool, comprising a mandrel rod 55 fastened onto an extrusion mandrel 56, then by arranging the whole between two dies 52, 53 which, by being brought closer together and with the aid of the mandrel rod 55, produce an expanded part in the tubular blank; the intermediate product thus obtained then undergoes a correction operation in order to make it circular once again; the mandrel rod 55 and the mandrel 56 are then removed and final machining operations are performed in order to give the final product the required dimensions. <IMAGE>