Abstract: A device for heat-treating metallic workpieces in a vacuum has a revolving vacuum furnace with an inlet transfer lock for introducing a batch of workpieces into the revolving vacuum furnace and with an outlet transfer lock for removing the batch of workpieces from the revolving vacuum furnace. The revolving vacuum furnace has also an annular turntable for transporting the batch of workpieces from the inlet transfer lock to the outlet transfer lock. At least one carburization furnace, for carburization treatment of the batch of workpieces, is connected to the revolving vacuum furnace at least at a peripheral location of the revolving vacuum furnace between the inlet transfer lock and the outlet transfer lock in the direction of transportation of the batch of workpieces. The annular turntable transports the batch of workpieces to the at least one carburization furnace.

Abstract: In a method for controlling the electric current density across a workpiece in a furnace during heat treatment in a plasma an auxiliary electrode with a known surface area is introduced into the furnace. A batch of workpieces is then introduced into the furnace. First a plasma of a neutral gas is generated within the furnace. The total current within the furnace and the current within the auxiliary electrode are measured. The surface area of the workpieces is calculated according to the equation ##EQU1## The auxiliary electrode is then switched off and a material-transmitting plasma is generated. The nominal total electric current for controlling a desired nominal current density is then calculated according to the equationI.sub.Gnominal =F.sub.CH .multidot.J.sub.nominal.The total current is measured in the furnace and is set to the nominal current value.

Abstract: An electrically heated vacuum furnace has a plurality of heating elements (13) distributed in an array extending within the furnace. This allows accurate control of the application of radiant heat energy from the elements (13) of the array to articles (10) within the furnace. The elements (13) are preferably disposed spaced apart across the width of the furnace.

Abstract: A furnace for the thermal treatment of charges of iron and steel components. A cylindrical, vertical heating chamber is disposed within a housing. A plurality of vertical heating elements are disposed in the heating chamber. To accelerate the heating-up of a charge that is disposed within the heating chamber, especially in the lower temperature range, the heating elements have a tubular construction and are provided at their bottom end with an outlet opening. Gas conveyed by a fan flows through the heating elements, at which time it is convectively heated, and thereafter passes into the interior of the heating chamber. In the higher temperature range, the heating elements transfer their heat to the charge as radiant heat, with the furnace then operating in a vacuum.

Abstract: An industrial furnace, especially a single chamber vacuum furnace, for thermally treating metal workpieces. The furnace has a heating chamber which is disposed in a furnace housing and receives a charge. The heating chamber can be heated via heating elements, and has at least one closable chamber opening through which is conveyed a cooling gas which can be circulated with the aid of a blower through a heat exchanger. To control the flow of cooling gas arriving through the cooling gas delivery pipe, a distribution device which is moved back and forth during a cooling process is pivotably mounted in the region of the chamber opening which is provided for the entry of the cooling gas. In order to make it possible for the cooling gas to flow uniformly over the surface of the charge, jet nozzles are provided as the distribution means. The cooling gas flows through these jet nozzles prior to striking the charge.

Abstract: A method and device for control of the carbon level of a gas mixture reacting in a heat treatment furnace, which gas mixture arises by means of the introduction of a fuel containing hydrocarbon into the furnace chamber, the reaction products of which are not in a state of water-gas equilibrium and not in a state of methane gas equilibrium and which gas mixture has an excess of methane. The controlled condition is determined by a first measurement device from the portion of the gas component CO which is present in the furnace chamber as a first measured value, and by a second measurement device from the electrical voltage of an oxygen-ion-conducting solid body electrolyte as a second measured value and by a third measurement device from the furnace chamber temperature as the third measured value. A regulating member is controlled as a result to automatically change the quantity flow of the supply to the furnace chamber until correspondence of the measured carbon level with its desired value exists.

Abstract: A conveyor arrangement incorporated in a continuous oven comprises a plurality of support rails, one mounted in each oven chamber, and load-carrying frames suspended from the rails and arranged to move through the chambers. Each chamber has at least one drive pinion assembly comprising two pinions drivingly coupled by a chain drive, and each pinion can mesh with a rack to advance the load-carrying frames through the oven chamber. Each rack is secured to a respective load-carrying frame.

Abstract: A method for gas carburization of workpieces made of steel in a furnace chamber, by which in the initial phase of the treatment more carbon than desired is released or dissolved in the workpiece surface and in the final phase of the treatment is decarburized to the desired edge carbon content by change of the quantity flow of the decarburizing gas. The decarburizing process is performed by exclusive introduction of a hydrogen-free, oxygen-containing decarburization gas in the furnace chamber.

Abstract: A method and apparatus for the control of the carburizing of parts under vacuum in a vacuum furnace, with which as a carbon carrier a hydrocarbon gas is introduced controlled in the furance. As the control quantity a soot mist formation is used in such a manner that the occurrence of the soot mist is determined, that upon the occurrence of the soot mist the hydrocarbon addition is completely or partially interrupted, and that the hydrocarbon addition is again received if the soot mist formation has dampened out.