Abstract: A continuous vacuum carburizing furnace of the invention includes: a heating chamber for heating a workpiece under a atmospheric pressure; a first conditioning chamber in which the pressure is reduced from the atmospheric pressure after the receipt of the workpiece from the heating chamber; a carburizing/diffusing chamber receiving plural workpieces from the first conditioning chamber and conducting plural cycles of carburizing and diffusing processes under the reduced pressure; a second conditioning chamber in which the reduced pressure is returned to the atmospheric pressure after the receipt of the workpiece treated in the carburizing/diffusing chamber; and a cooling chamber for cooling the workpiece introduced from the second conditioning chamber under the atmospheric pressure, the furnace further comprising a door member disposed between a respective adjoining pair of the above chambers, the door member opened/closed only when the workpiece is transported from one chamber to another.

Abstract: A continuous vacuum carburizing furnace of the invention includes: a heating chamber for heating a workpiece under a atmospheric pressure; a first conditioning chamber in which the pressure is reduced from the atmospheric pressure after the receipt of the workpiece from the heating chamber; a carburizing/diffusing chamber receiving plural workpieces from the first conditioning chamber and conducting plural cycles of carburizing and diffusing processes under the reduced pressure; a second conditioning chamber in which the reduced pressure is returned to the atmospheric pressure after the receipt of the workpiece treated in the carburizing/diffusing chamber; and a cooling chamber for cooling the workpiece introduced from the second conditioning chamber under the atmospheric pressure, the furnace further comprising a door member disposed between a respective adjoining pair of the above chambers, the door member opened/closed only when the workpiece is transported from one chamber to another.

Abstract: A steel workpiece maintained at a specified quenching temperature is rapidly cooled to a temperature just above the martensite transformation start point (Ms point) by being immersed in a high-temperature quenching oil. Thereafter, the steel workpiece is taken out of the high-temperature quenching oil so as to be soaked by the heat possessed by the steel workpiece and subsequently cooled by being immersed in the high-temperature quenching oil. Through these processes, a temperature difference between steel workpieces or the portions of a steel workpiece in the martensite transformation stage is reduced, and a cooling speed in a high-temperature region (not lower than about 550° C.) is made to be a slow speed sufficient for restraining a thermal distortion, by which the quenching distortion and quenching variation can be reduced.

Abstract: A steel workpiece maintained at a specified quenching temperature is rapidly cooled to a temperature just above the martensite transformation start point (Ms point) by being immersed in a high-temperature quenching oil. Thereafter, the steel workpiece is taken out of the high-temperature quenching oil so as to be soaked by the heat possessed by the steel workpiece and subsequently cooled by being immersed in the high-temperature quenching oil. Through these processes, a temperature difference between steel workpieces or the portions of a steel workpiece in the martensite transformation stage is reduced, and a cooling speed in a high-temperature region (not lower than about 550° C.) is made to be a slow speed sufficient for restraining a thermal distortion, by which the quenching distortion and quenching variation can be reduced.

Abstract: A method and apparatus for fabricating a plasma display panel with increased efficiency and productivity is provided. A glass panel assembly P1 constructed from two glass plates W1, W2, which are joined together by a jig 10 with a sealant S applied along a periphery of one or the other of the opposing surfaces of the two glass plates W1, W2, is supported on an evacuating cart 20 in such a manner as to be positioned inside a furnace 1. The exhaust pipe Pa provided in any one of the glass plates W1, W2 is connected switchably between an evacuating system 25 and a discharge gas supply system 26. After evacuating the interior of the glass panel P2, a discharge gas is filled into the glass panel P2 and finally the exhaust pipe Pa is sealed and cut.

Abstract: A method of gas carburizing and hardening a steel article and a continuous furnace therefor. The method includes the steps of carburizing the article in a carburizing atmosphere at atmospheric pressure, heating the article in a vacuum for a predetermined period of time, and hardening the article.

Abstract: A method of gas carburizing and hardening a steel article and a continuous furnace therefor. The method includes the steps of carburizing the article in a carburizing atmosphere at atmospheric pressure, heating the article in a vacuum for a predetermined period of time, and hardening the article.

Abstract: A continuous heat treating furnace for heat treating a ferrous metal work in a protective atmosphere, including a furnace separated into a charge chamber and a heat treating chamber by a partition door and provided with a transport device for transporting the work. A first heating device, a recirculating fan and a gas purge device are provided in the charge chamber, while a second heating device is provided in the heat treating chamber supplied with the protective atmosphere, whereby the work is preheated through convectional heat transfer in the charge chamber simultaneously with high-temperature purging of the charge chamber and then, is heat treated under the protective atmosphere in the heat treating chamber.

Abstract: A continuous heat-treating furnace comprises, a housing structure having an entrance and an exit defined at its opposite ends, respectively, and also having defined therein a preheating zone adjacent the entrance, a cooling zone adjacent the exit and a high temperature zone intermediate between the preheating and cooling zones, a recirculating duct fluid-connecting a portion of the housing structure in register with the preheating zone to another portion of the housing structure in register with the cooling zone, and a blower for forcibly drawing gas inside the preheating zone and directing it into the cooling zone through the recirculating duct.