Abstract: A continuous nitriding treatment furnace includes a nitriding chamber, a heater, a first nitriding zone, and a second nitriding zone lower in atmosphere gas temperature than the first nitriding zone by 25° C. to 150° C., the continuous nitriding treatment furnace being configured such that an atmosphere gas in the first nitriding zone flows into the second nitriding zone and being configured to execute a nitriding treatment that forms an iron nitride compound layer composed of an ? phase or of the ? phase and a ?? phase on a surface of the steel member in the first nitriding zone and precipitates the ?? phase in the iron nitride compound layer in the second nitriding zone.

Abstract: A continuous nitriding treatment furnace includes a nitriding chamber, a heater, a first nitriding zone, and a second nitriding zone lower in atmosphere gas temperature than the first nitriding zone by 25° C. to 150° C., the continuous nitriding treatment furnace being configured such that an atmosphere gas in the first nitriding zone flows into the second nitriding zone and being configured to execute a nitriding treatment that forms an iron nitride compound layer composed of an ? phase or of the ? phase and a ?? phase on a surface of the steel member in the first nitriding zone and precipitates the ?? phase in the iron nitride compound layer in the second nitriding zone.

Abstract: The present invention provides a heat treatment apparatus for carrying out heat treatment for a circular workpiece. The heat treatment apparatus includes a treatment room configured to carry out a predetermined treatment for the workpiece, a transportation mechanism configured to transport the workpiece into the treatment room and out of the treatment room, and a mounting table on which the workpiece transported into the treatment room is mounted. The transportation mechanism is provided with a transportation arm which mounts and transports the workpiece. The transportation arm is provided with at least three transport support pins which support the workpiece when the workpiece is transported, and the mounting table is provided with at least three mounting table support pins which support the workpiece.