The furnace interior structure optimized by fluid analysis flows agitating wind along the furnace wall without resistance, so superior temperature distributing performance can be obtained. In addition, the synergy of smaller surface area and high-performance thermal insulating materials reduces heat dissipation and improved the operation environment and energy saving. The hybrid heating system combining gas heating and electrical heating creates many advantages. In the heating zone, the heat storage type burner saves energy, and in the carburization and diffusion zone, the radiant tube heater enables highly accurate temperature control. In the temperature falling and soaking zone, single-end burners are used and air from the blower is flown into the tube so the tube can be used for cooling and the temperature falling time can be reduced. With the use of the optional RFQ® (relative flow quenching), you can expect higher hardenability, less quenching distortion, less hardness dispersion and other quality improvements.