JP2008509282A - Low pressure thermochemical processing machine - Google Patents

Abstract

The present invention provides a low-pressure metal component comprising at least one carburizing temperature setting cell (2), one charcoalization cell (3) and one carbon diffusion cell (4) arranged continuously in series. The present invention relates to a machine for carburizing. The cells (2, 3, 4) have a proportional length (L1, L2, L3) that conforms to the standard shape and duration of processing performed in each cell.
Each cell (2, 3, 4) comprises a processing zone (14) arranged between a supply module (10a) and a discharge module (10b), said supply and discharge module being associated with a corresponding cell ( 2, 3, 4), respectively, to form a thermally insulated cold zone. The machine (1) comprises means for driving and moving parts forward between the cells arranged in the supply (10a) and discharge (10b) modules of the cells (2, 3, 4). Become.
[Selection] Figure 1

Description

Background of the Invention

  The present invention is a machine for thermochemically treating metal parts, comprising at least one heating cell, one charcoal cell for increasing the surface of the part to be treated, and the surface of the part. A carbon diffusion cell for diffusing into the core and at least one curing cell, the cells being arranged in series and in a length adapted to the duration of the treatment performed in each cell And mechanical means for transporting and moving the parts from cell to cell and also comprising insulating means for insulating the cells from each other during different sequential processing steps.

  Numerous thermochemical processing equipment for carburizing and carbonitriding metal parts, especially equipment in the form of cases containing solid cement, equipment in an uncontrolled atmosphere, controlled with constant carbon potential There are devices in the atmosphere, or low pressure devices with a pressure of about 5 mbar to 20 mbar and possibly up to 100 mbar.

The carburizing and carbonitriding processes generally involve carburizing gases formed by hydrocarbons such as methane (CH ₄ ), acetylene (C ₂ H ₂ ) or propane (C ₃ H ₈ ), and optionally nitriding gases such as A partial pressure of ammonia (NH ₄ ) is required. The carburizing operation, that is, the carburizing temperature setting process, the surface carburizing process, and the carbon diffusion process are preferably performed under a nitrogen partial pressure. To prevent any oxidation during the carburizing process and when transported to the curing cell, the parts are not exposed to air at any time.

  In the curing operation following the carburizing process, the parts are cooled rapidly. This operation is carried out in oil or molten salt baths or in various mixtures of stirred high pressure gases such as nitrogen, helium or neutral gases such as carbon dioxide or hydrogen.

  These various operations, ie the various steps of the carburizing process, are generally performed in the same case and the curing is performed in a separate cell.

  European patent EP-A-0 922 778 describes a heat treatment apparatus comprising a plurality of cells specifically designed to heat treat a series of metal parts. These cells are all connected to a central case that is at the same pressure as the processing cell. Parts are transported from cell to cell by transport and handling rails. After carburizing in the corresponding cell, the carburized parts are transported via the central case to the hardening cell, i.e. not in contact with the surrounding air.

  Another device is composed of independent cells connected to each other by a movable cell, the function of which is the function of transporting to a loading and curing cell or curing under pressurized gas simultaneously with the loading and transporting operation. is there.

  Another apparatus comprises a single partitioned cell of the “driven plate” type comprising an input chamber and a cell that is cured under gas.

  In each case of low-pressure carburization at 5 to 20 mbar, each of the carburizing processes, that is, at least the carburizing temperature setting process, the carbon surface increasing process of the part surface, and the carbon diffusion process from the surface of the part to the core are one and the same. It is carried out continuously in the cell or in a single partitioned cell comprising mechanical means for advancing and transporting the parts. In that case, the mechanical means are located in the hot zone.

  Another type of machine is described in US Pat. No. 3,662,996. This machine is a conventional gas carburizing machine performed at atmospheric pressure, one cell for each carburizing process, namely a carburizing heating cell, a carburizing cell for increasing the surface of the part to be processed, and parts A carbon diffusion cell for diffusing carbon from the surface to the core. These cells are continuously arranged in series, the parts move from cell to cell and undergo carburization, and the length of the cells is predetermined according to the processing time required in those cells.

  However, even though each process step is performed in a different cell, this type of machine can only function under certain conditions, especially under high pressure. Moreover, the mechanical means for advancing and transporting the parts are located in the hot zone where the corresponding processing takes place and are not thermally isolated. Furthermore, this type of machine is difficult to incorporate into an existing production line and the length of each cell cannot be easily adjusted according to the duration of processing required.

Object of the invention

  The object of the present invention is to design an efficient and flexible low-pressure thermochemical carburizing or carbonitriding machine that eliminates the above-mentioned drawbacks and can be easily adapted and incorporated into mass production lines of parts. It is.

  According to the invention, this object is achieved according to the appended claims, in particular the temperature setting, the carbon increase and the carbon diffusion cells have a standard shape, each being arranged between the supply module and the discharge module. Each of the supply and discharge modules forms a cold zone that is thermally isolated from the processing area of the corresponding cell, and mechanical means for transport and movement are provided in the cell. Located in the supply and discharge module, this is achieved by connecting the discharge module of one cell to the supply module of an adjacent cell.

  Other advantages and features will be better understood from the description of particular embodiments of the invention, which will now be described by way of non-limiting example only with reference to the accompanying drawings.

Description of special embodiments

1-6, the thermochemical processing machine is a machine 1 for low pressure carburizing metal parts under vacuum. The machine 1 includes a plurality of processing cells 2 to 5 that are continuously arranged in series. Each cell has a standard shape and length L that corresponds to a particular step of the low pressure carburization process and can be adapted according to the duration of the process required in the cell. The cell manufacturing technique is a cold wall vacuum furnace manufacturing technique that allows operating pressures of 10 ^-1 mbar to 30 mbar.

  The machine 1 also comprises means for moving and transporting parts from cell to cell and closing means designed to insulate the cell from adjacent cells during the various steps of the carburizing process. Parts are transported between cells at a predetermined pressure of about 5 mbar to 20 mbar, ie carburizing pressure. The pump mechanism maintains the three cells at the same pressure, including the transport period.

  In FIG. 1, the machine 1 comprises in particular a carburizing heating cell 2. The purpose of the treatment performed in cell 2 is to raise the temperature of the parts to the required carburizing temperature of about 880 ° C to 1050 ° C. This step is carried out at a carburizing pressure of about 5 mbar to 20 mbar, preferably in the presence of nitrogen. In special cases, the pressure can be increased to 100 mbar.

  The machine 1 includes a carbon increasing cell 3 downstream of the carburizing heating cell 2. The treatment performed in cell 3 is to increase the surface of the part with carbon or carbon and nitrogen to increase the hardness of the part after curing. This carbon augmentation process is preferably performed by injecting nitrogen or other neutral gas at a temperature of about 880 ° C. to 1050 ° C., and is completed by injection of a hardening gas at regular intervals. The pressure in the cell 3 is for example about 5 mbar to 20 mbar, depending on the curing gas used.

  After the augmentation cell 3, the parts are sent to the final carbon diffusion cell 4. The treatment performed in cell 4 diffuses carbon in the thickness direction of the part, from the surface of the part to the core, to the required depth of the hardened surface to the percentage of carbon required on the part surface. That is. This processing step is performed at the same pressure as that of the carburizing heating cell 2 and the carbon increasing cell 3. This temperature is preferably adjusted to 880 ° C. to 1050 ° C. so as to obtain a good rate of carbon penetration into the part and to obtain the optimum temperature of the part before performing the curing operation.

  The processing temperature required inside the carbon diffusion cell 4 is preferably different from the temperature required inside the carburizing heating cell 2 and the carbon increasing cell 3.

  Downstream of cells 2-4, the machine 1 also comprises a curing cell 5 with a pressure-tight door. For example, cell 5 is a curing cell that performs quenching by gas quenching, oil quenching, salt bath quenching, or other methods that can cool the parts at the required rate and obtain the required hardness.

  In another embodiment not shown in the figure, the machine 1 can comprise a tempering cell downstream of the curing cell 5. The tempering step is performed at a temperature of about 200 ° C. to 300 ° C., for example.

  Upstream of the carburizing heating cell 2, the machine 1 also comprises a supply chamber 6 designed to accommodate parts that wait until entering the cell 2 (FIG. 1). In this case, before the parts are supplied, the pressure in the chamber 6 becomes equal to the pressure in the carburizing heating cell 2 and the air in the supply chamber 6 is evacuated to ensure that most of the air is discharged. You need to be careful.

  In another embodiment shown in FIG. 2, the machine 1 comprises a gas pump device 7 connected to the augmentation cell 3 by suitable means and designed to remove the gas present in the cells 2, 3 and 4. Become. Only the charcoal cell 3 contains a hardened gas that tends to contaminate the cells 2 and 4. Therefore, it is advantageous for the pump device 7 to generate a gas flow in the direction of the arrow F1 from the carburizing heating cell 2 and the carbon diffusion cell 4 that may be contaminated toward the carbon increasing cell 3.

  The machine 1 also comprises a first independent pump device 8 in the supply chamber 6 and a second independent pump device 9 in the curing cell 5.

  In a general manner, the three cells 2, 3, 4 corresponding to the three essential steps of the low pressure carburizing process are cold wall cells so that they are cold, non-contaminating and not dangerous. The parts to be cured must pass continuously through all of the low pressure carburizing cells 2, 3, 4 arranged in series.

  According to the invention, the cells 2, 3 and 4 of the machine 1 all follow the same general model and have a standard shape adapted to each function (heating, increasing and spreading), the length L being adjustable Thereby, the processing time of each cell can be accurately adjusted to a specific processing speed. By changing this speed, various carburizing depths can be effectively achieved. Thus, the length L of the cell is proportional to the duration of processing performed in this cell.

  Moreover, the temperature can be adapted and the properties to be obtained on the part to be processed can be precisely adjusted.

  3 showing only the carburizing heating cell 2 of the machine 1 shown in FIGS. 1 and 2, the cell 2 comprises a supply module 10a into which the parts to be processed enter and a discharge module 10b into which the parts come out after processing. The supply module 10a and the discharge module 10b have a standard shape and can each accommodate a charge 11 of metal parts.

  Cell 2 has a longitudinal axis 12 directed from supply module 10a to discharge module 10b. The vertical axis 12 corresponds to the direction of the load 11 in the direction of the arrow F2 inside the cell 2.

  Between the supply module 10a and the discharge module 10b, the cell 2 comprises two equal standard intermediate modules 13. The length L1 of the cell 2 can be changed by attaching several intermediate modules 13 between the supply module 10a and the discharge module 10b. For example, for the carbon diffusion cell 4, the greater the number of modules 13, the greater the carburization depth at the same rate of advancement of the charge 11 in the cell 4.

  The standard module 13 of the cell 2 constitutes a low-pressure processing area 14 in which processing suitable for the cell 2 is performed. The processing area 14 is preferably provided with a cold wall by a standard module 13 and is isolated and insulated from the supply module 10 a and the discharge module 10 b, the supply module 10 a and the discharge module 10 b constituting the cold area of the cell 2. To do. The cold zone is thermally insulated, for example by a thermally insulated cooling door 15 located between the supply module 10a and the discharge module 10b and the isolated processing zone 14.

  For example, the door 15 is cooled by a heat exchanger that circulates water at the level of the door 15.

  In FIG. 3, the supply module 10 a and the discharge module 10 b have a standard shape with a substantially U-shaped cross section, each having an opening connecting to the adjacent module 13, and three pieces closing the end of the cell 2. With walls. In the special embodiment shown in FIG. 3, the supply module 10a comprises a supply orifice 16 located on the wall of the supply module 10a parallel to the longitudinal axis 12 of the cell 2, and the discharge module 10b is a discharge module 10b. The discharge orifice 17 is located on the wall parallel to the longitudinal axis 12 and located on the same side of the cell 2 with respect to the longitudinal axis 12. The part load 11 enters and exits via the same side of the cell 2.

  The supply module 10a and the discharge module 10b, respectively, for example push the load 11 and fix the discharge device 18 designed to remove from the corresponding module 10a, 10b and the load 11 before removal. 1 is provided with a buffer stop device 19 designed as described above. The discharge device 18 and the buffer stop device 19 constitute a mechanical means by which the parts can be moved and transported between the cells and are advantageously located in the cold zone of the cells 2, 3, 4.

  The movement of the charge 11 inside the cell is performed by the charge 11 itself, and each time a new charge 11 is supplied, the charge 11 is pushed forward one by one. Thus, the processing zone 14 does not include any mechanical means for movement or advancement, which means are only arranged in the cold zone constituted by the cell supply module 10a and the discharge module 10b.

  By disposing the moving means at the level of the supply module 10a and the discharge module 10b, that is, the low temperature area of each cell, in particular, the efficiency of the carburizing process is improved, and the characteristics of the parts are more effectively protected between the cells.

  Further, the carbon increase cell 3 includes a neutral gas injection step alternately with the hardening gas injection step, and movement of parts between the cells is advantageously performed simultaneously with the neutral gas injection step. It is therefore necessary to activate different movement and advancement means so that a sufficiently long neutral gas injection period is provided and all charges 11 can be moved along the machine 1 accordingly. Therefore, the hardening gas is confined only in the increase cell 3 and there is no risk of contaminating the other cells 2 and 4.

  In the special embodiment shown in FIGS. 1 and 2, the carburizing heating cell 2 comprises two standard modules 13, the supply orifice 16 and the discharge orifice 17 of the cell 2 being parallel, In contrast, it is located on the same side of cell 2.

  The next increase cell 3 comprises a single standard module 13, whose longitudinal axis 12 is parallel to the longitudinal axis 12 of the preceding cell and is oriented in the same direction. . Accordingly, the supply orifice 16 of the supply module 10a faces the discharge orifice 17 of the discharge module 10b of the preceding cell 2, and the discharge orifice 17 of the discharge module 10b of the cell 3 is It is arranged on the same side as the supply orifice 16 of the supply module 10a.

  Therefore, the carbon diffusion cell 4 also comprises two standard modules 13 and is arranged in parallel with the other two cells, and its longitudinal axis 12 faces the same direction as the carburizing heating cell 2 and carburizing. Aligned with the heating cell 2. Accordingly, the supply orifice 16 and the discharge orifice 17 of the supply module 10a and the discharge module 10b, respectively, are arranged on the same side of the cell 4 with respect to the longitudinal axis 12. The curing cell 5 is connected to the discharge orifice 17 of the cell 4, and the supply chamber 6 is connected to the supply orifice 16 of the cell 2.

  Thus, the arrangement of the machine 1 according to FIGS. 1 and 2 faces each other in a substantially L-shaped shape, and the parts move in the direction of the arrow F2 (FIG. 1) in the cell.

  Furthermore, the supply module 10a and the discharge module 10b of the cells 2, 3, 4 are advantageously arranged so as to form a connection chamber 20 between two adjacent cells. In that case, the chamber 20 of the machine 1 can be provided with a device 21 that insulates the gas and pressure from cell to cell during the treatment process. The chamber 20 can also include a check valve mechanism for controlling the gas flow between the cells.

  For example, the machine 1 comprises a pressure sensitive door 21 arranged between the supply module 10 a of the carburizing heating cell 2 and the supply chamber 6.

  In another embodiment shown in FIG. 4, the low-pressure carburizing treatment machine 1 comprises three cells 2, 3, 4 arranged in parallel continuously. The vertical axis 12 of the cell 3 is parallel to the vertical axis 12 of the cells 2 and 4 and faces the opposite direction. The supply orifice 16 of the supply module 10a of the cell 3 is arranged to face the discharge module 10b of the cell 2, whereas the discharge orifice 17 of the discharge module 10b of the cell 3 is the vertical axis 12 of the cell 3. Is arranged on the other side and faces the supply module 10a of the cell 4. Due to this particular opposite orientation of the supply orifice 16 and the discharge orifice 17 of the modules 10a and 10b of the cell 3, the machine 1 is arranged in a substantially S-shaped general shape so that the cells 2, 3, 4 are Can face each other. This saves a large space and allows the overall length of the machine to be relatively small.

  Furthermore, the machine 1 comprises a storage area 22 of a load 11 waiting to be supplied to the supply chamber 6 at the beginning of the processing cycle, at the end of the processing cycle downstream of the curing cell 5, for example another It can comprise a storage area 23 for the load 11 waiting to be taken out to the site.

  In another embodiment shown in FIG. 5, the vertical axis 12 of the cells 2 and 3 is oriented in the same direction, and the vertical axis 12 of the cell 4 is opposite to the other two. In this case, cells 3 and 4 are offset from cell 2. Thus, the machine 1 has a larger overall length. This special, substantially U-shaped arrangement makes it possible in particular to incorporate into the machine 1 pumping devices 7, 8 and 9 associated with the cells 3, 6 and 5, respectively.

  The machine 1 can further comprise a management, inspection and / or control device 24 for inspecting and / or controlling the correct operation of the carburizing cycle adjacent to the cell.

  The alternative embodiment of the machine 1 shown in FIG. 6 differs from the alternative embodiment shown in FIG. 5 by the number of standard intermediate modules 13 in the cells 2, 3, 4. These cells actually comprise three, two and three standard modules 13 arranged between the supply module 10a and the discharge module 10b, respectively. This increases the time spent by the parts in the corresponding cell.

  Starting from the layout of the machine 1 shown in FIG. 5, the discharge module 10b of the cell 2 can be removed, another standard module 13 can be added and the discharge module 10b can be installed again. For cells 3 and 4, another standard module 13 is added in the same way. This particular layout illustrates the great flexibility of easily modifying the machine 1 depending on the application and the required processing time.

  Thus, in a general manner, with one and the same low-pressure carburizing machine 1, the lengths L1, L2 and L3 (FIG. 1) of each of the cells 2, 3, 4 are the standard that they comprise. Depending on the number of modules 13, it may be different. Such a machine 1 can be easily adapted to the installation location and can take several different shapes. Thus, the machine 1 is intended for use, installation size, and necessary, especially for the standard supply module 10a, discharge module 10b and standard intermediate module 13 of each cell 2, 3, 4 of the machine 1. Depending on the processing time, a structure that can be completely rearranged is obtained. This saves time and space in particular and increases productivity.

  Moreover, the machine 1 shown in FIGS. 4, 5 and 6 can place the storage areas 22 and 23 close to each other. This makes handling of the load 11 easier and faster.

  In another embodiment not shown in the figure, the machine 1 comprises two curing cells downstream of the cell 4, e.g. one oil curing cell and one gas curing cell, or two gas curing cells. be able to. In this case, the discharge module 10b of the carbon diffusion cell 4 differs from the discharge modules 10b of other cells in that two discharge orifices 17 arranged on each wall are arranged in parallel with the corresponding longitudinal axis 12 of the cell 4. Prepare. In this case, the two curing cells are connected to the same discharge module 10b, and the parts are supplied to the first or second curing cell and then removed after processing.

  In another embodiment not shown in the figure, the machine 1 comprises a part washing cell between the supply chamber 6 and the carburizing heating cell 2 and prepares the part designed to be cured. Can do. For example, the cleaning cell is a cleaning or degreasing machine that operates at atmospheric pressure or optionally in the vapor phase partial pressure.

  In another embodiment, not shown in the figure, the machine 1 may comprise a convection preheating cell of parts upstream of the carburizing heating cell 2. For example, the preheating cell is a convection preheating furnace designed to heat the part to a temperature of, for example, about 300 ° C. to 500 ° C. before the part is supplied to the carburizing heating cell 2. Convection preheating ensures that the heating is homogeneous, in particular the parts are oxidized and the surface is fully activated. This step is carried out in air at atmospheric pressure, preferably with a small amount of nitrogen added. The preheating cell also saves time because the residence time of the parts in the carburizing heating cell 2 is shortened after the parts are preheated. After the preheating step is completed, the preheating cell is evacuated and then the part is moved to the inside of the next cell.

  When using a convection preheating cell, it is necessary to arrange the pressure-tight door 21 between the supply module 10a of the carburizing heating cell 2 and the preheating cell.

  Thus, in any of the above embodiments of the machine 1, the processing machine 1 has the following advantages. The machine 1 is cold on the outside and non-contaminating because of the cold walls of the processing zone 14 in the cells 2, 3 and 4. Since the cells 2, 3, 4 have a standard shape and can be adapted in length by the intermediate module 13 and the standard supply module 10a and discharge module 10b, these can be used with any existing machining equipment and It can be installed in any mass production parts manufacturing facility. Therefore, productivity is greatly improved. Depending on the flexibility of installation, the cells to be used as desired, in particular the washing, preheating and tempering cells, may or may not be inserted according to the production sequence, or a heat treatment can be performed.

  Furthermore, the mechanical means for moving the parts to the cell are located only in the cold area of the cell, i.e. in the supply module 10a and the discharge module 10b. This improves the efficiency of the low pressure carburizing process.

  The present invention is not limited to the various embodiments described above. In particular, the part to be processed can be formed by a series of parts arranged on a support. The cell can have any suitable shape. The moving and closing means can be formed by any suitable means, as long as it can ensure sealing and predetermined pressure characteristics between two adjacent cells. The curing gas can be propane or any other hydrocarbon that can be related to the temperature of the augmentation cell 3 for surface treatment of the parts.

  The moving means located in the cold zone of the cell can be formed by any other moving mechanism and a completely different buffer stop mechanism. If the movement between two adjacent cells takes place at a predetermined pressure, the machine 1 adjusts the pressure inside the chamber 20 during the process, and if necessary during the movement process. Additional means (not shown) for controlling can be included.

  When installing a tempering cell, the machine is then equipped with additional moving means (not shown in the figure) designed to move the part to other finishing machines (shot peening, modification), for example. Can be.

  The cells 2 to 4 can include a heating device, a gas injection circuit, and a pump connector (not shown) for a vacuum pump.

In another embodiment not shown in the figure, the carbonitriding process can be performed in cells 3 and 4. In that case, the thermochemical processing machine 1 is a vacuum carbonitriding machine having a diffusion cell 4 for injecting a nitriding gas. For example, nitrogen enrichment is performed by introducing a gas such as ammonia (NH ₃ ) into the surface augmentation cell 3 and the diffusion cell 4 at a rate determined according to the required result. .

  The machine operation is the same as before, and the parts to be processed are passed continuously through each processing cell. These cells also have the same structure and are completely re-applied depending on the workplace, application and required processing time in the cell by means of the supply module, the discharge module and the standard intermediate modules located between these modules. Form a machine that can be deployed.

1 is a top view schematically showing a first embodiment of a thermochemical processing machine of the present invention. FIG. FIG. 2 is a top view schematically showing another embodiment of the thermochemical processing machine according to FIG. 1. Fig. 3 shows a cell of a thermochemical processing machine according to Figs. FIG. 3 is a top view schematically illustrating another embodiment of the thermochemical processing machine of the present invention. FIG. 3 is a top view schematically illustrating another embodiment of the thermochemical processing machine of the present invention. FIG. 3 is a top view schematically illustrating another embodiment of the thermochemical processing machine of the present invention.

Claims (15)

A machine (1) for thermochemically processing metal parts, comprising at least one heating cell (2) and one carbonization cell (3) for increasing the surface of the part to be treated; The cell comprises one carbon diffusion cell (4) for diffusing from the surface of the component to the core, and at least one curing cell (5). Having a length (L) adapted to the duration of the processing to be carried out, the machine being transported and moved from one cell to the next, in different continuous processing steps Insulating means for insulating the cells from each other,
The heating cell (2), the carbon augmentation cell (3), and the carbon diffusion cell (4) have standard shapes, each between a supply module (10a) and a discharge module (10b). A low-pressure treatment zone (14) arranged, wherein the supply module (10a) and the discharge module (10b) are thermally removed from the treatment zone (14) of the corresponding cell (2, 3, 4). Mechanical means (18, 19) for forming and transporting and moving insulated cold zones, respectively, in the supply module (10a) and discharge module (10b) of the cell (2, 3, 4). A machine that is arranged and wherein the discharge module (10b) of a cell is connected to the supply module (10a) of an adjacent cell.   At least the supply module (10a) and the discharge module (10b) of the heating cell (2) and the carbon increase cell (3) and the supply module (10a) of the carbon diffusion cell (4) are standard. The machine of claim 1, having a shape.   The vertical axis (12) of each cell (2, 3, 4) is directed from the supply module (10a) to the corresponding discharge module (10b), and each supply module (10a) and discharge module (10b) Comprising at least one orifice of the module (10a, 10b) located on a wall parallel to the axis (12), respectively a supply orifice (16) and a discharge orifice (17). The machine according to 1 or 2.   The machine according to claim 3, wherein the longitudinal axis (12) of at least two consecutive cells (2, 3, 4) is parallel to the same direction and / or to the opposite direction.   Each cell (2, 3, 4) is adapted so that the length (L) of the cell (2, 3, 4) matches the duration of the processing cycle performed in the cell (2, 3, 4). 5. The machine according to any one of claims 1 to 4, wherein the processing area (14) of a) consists of a corresponding number of standard modules (13) of equal length.   A gas pump connected to the charcoal cell (3) and arranged to generate a gas flow (F1) from the heating cell (2) and the carbon diffusion cell (4) to the charcoal cell (3) A machine according to any one of the preceding claims, comprising a transport means (7).   The charcoal cell (3) comprises means for alternately injecting a hardening gas with a neutral gas, and means for transporting and moving the parts while injecting the neutral gas (18, 19) The machine according to any one of the preceding claims, wherein is activated and transports the parts.   The insulating means (15) of each processing cell (2, 3, 4) is arranged in a cold area in the corresponding supply module (10a) and discharge module (10b), and the processing area (14) is supplied to the supply area. The machine according to any one of the preceding claims, wherein it is thermally insulated from the module (10a) and the discharge module (10b).   9. Machine according to claim 8, wherein the insulating means is a thermally insulated and cooled door (15).   The treatment zone (14) of the carbon diffusion cell (4) of the heating cell (2), the carbon augmentation cell (3), is composed of a standard module (13) with a cold wall, A machine according to any one of the preceding claims.   The temperature in the treatment zone (14) of the carbon diffusion cell (4) is different from the temperature in the treatment zone (14) of the heating cell (2) and the charcoal cell (3). The machine according to any one of 10.   The supply module (10a) of the heating cell (2) is connected upstream of an additional processing cell, the supply module (10a) comprising a pressure sensitive door (21). A machine according to claim 1.   The machine according to claim 12, wherein the additional processing cell arranged upstream of the heating cell (2) is a convection preheating cell.   A machine according to any one of the preceding claims, comprising a tempering cell downstream of the curing cell (5).   15. Machine according to any one of the preceding claims, comprising means for cleaning the part upstream of the heating cell (2).

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