DEVICE FOR TREATMENT OF PIPE INTERNAL SURFACE Russian patent published in 1998 - IPC

FIELD: thermochemical treatment in glowing discharge; devices for nitriding of pipe internal surface; may be used in mechanical engineering. SUBSTANCE: device includes pipe 1 which serves as cathode and accommodating insulated electrode 5, anode and power source 13 connected with cathode and anode. Pipe 1 i closed by covers 7 with pipe union 8 for evacuation and pipe union 10 supplying gas into working hollow 11. Pipe 1 is placed in thermostat 12. Power source 13 is connected with its negative pole to pipe 1 and with its positive pole, to electrode 5 through busbar 14. Nitriding process includes heating the pipe and passing nitrogen-containing gas through it. In this case, insulated electrode 5 is placed in pipe and centered. Pipe is sealed, evacuated and glowing discharge is initiated. Internal surface of pipe is subjected to cathodic cleaning. Then pipe is heated to temperature of nitriding and held for 1-12 h. EFFECT: higher efficiency. 1 dwg