| 摘要 |
PURPOSE:To form a uniform cemented layer of a constant concn. by giving preference to reaction of alloying a treating material on an object to be treated and treatment of diffusing the treating material in the material to be treated in treating the surface by glow discharge. CONSTITUTION:Auxiliary graphite electrodes 20 are provided in places requiring abrasion resistance of an object 2 to be treated to provide cathodes. A furnace body 1 is used as an anode. First, the inside of the furnace body 1 is evacuated to <=10<-1> torr in a vacuum device 9, and gaseous mixeture of metane and hydrogen are introduced. At the carburizing, the gases are kept at about 3 torr, and at the diffusing they are kept at about 4 torr by stopping the introduction of the gaseous methane, thence DC voltage is applied between both electrodes. The carburization time per time is set at about 3min, and the diffusion time per time at about 9min, and the treatment is carried out repeatedly about 5 times. After the carburization, the object is cooled in a furnace, thence it is heated of the surface at about 930 deg.C by high frequency induction heating, and is quenched by spray cooling. Following to this, it is tempered at a low temp. of about 180 deg.C for aobut 1hr. |
