The invention concerns a plasma torch comprising an interchangeable cartridge (100) consisting of six components only: an electroplating copper anode nozzle (1); an electroplating cathode support (2); a doped tungsten cathode (3); a plastic cathode diffusing-centring device (4); a plastic assembling device (5); a ceramic insert (6). Said components are assembled by pressing and the assembly of the components form volumes (71, 72, 73) constituting the anode cooling circuit and the plasma forming gas intake conduits (127, 44). The intake and discharge of fluid are provided by a connecting and maintaining structure designed for the easy mounting of the cartridge (100).