| 摘要 |
PURPOSE:To obtain a steel material having excellent surface hardening quality by supplying materials for forming heat-treating atmosphere separately to respective stages for carburizing and nitriding and changing the heat treating atmosphere in both stages. CONSTITUTION:A material 1 which is to be hardened and is put into a heating chamber 6 of a furnace is heated by a heater 13 which is operated by the command from a furnace control device 7. An A solenoid valve 9 is first opened and a material 21 for forming a carburizing atmosphere is fed via dripping pipe 12 into the chamber 6, by which a carburizing atmosphere is formed. Since there is no nitriding source in this stage, the secure carburizing atmosphere can be measured and carburizing quality is stabilized. The valve 9 is then closed and a B solenoid valve 19 is operated to supply a material 20 for forming a nitriding atmosphere into the chamber 6, by which the steel material 1 is nitrided. The material 1 subjected to the carburizing and nitriding stages is fed to a hardening cell 15. The secure measurement of the carburizing atmosphere is accomplished in the stage of hardening and the carburizing quality is stabilized. |
