Abstract: A vacuum heat-treatment apparatus for heat-treating a workpiece in a treating cell includes a hermetic chamber disposed at the center. A plurality of treating cells are disposed along the periphery of the hermetic chamber, and a workpiece transfer mechanism is disposed inside the hermetic chamber and transfers the workpiece from one of the treating cells to the hermetic chamber and from the hermetic chamber to one of the treating cells.

Abstract: A vacuum heat-treatment apparatus for heat-treating a workpiece in a treating cell includes a hermetic chamber disposed at the center. A plurality of treating cells are disposed along the periphery of the hermetic chamber, and a workpiece transfer mechanism is disposed inside the hermetic chamber and transfers the workpiece from one of the treating cells to the hermetic chamber and from the hermetic chamber to one of the treating cells.

Abstract: In order to keep down soot production and to enable every part of the workpiece, including deep concavities to be uniformly carburized by vacuum carburizing, and to enable decreases in the quantities of gas and heat employed, carburizing treatment is performed in the heating chamber 2 of a vacuum carburizing furnace 1 with workpieces M being heated while acetylene gas is supplied from a carburizing gas source C inside the heating chamber 2, and the inside of the heating chamber 2 being evacuated by a vacuum evacuation source V to give a vacuum of .ltoreq.1 kPa.