Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
  • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
  • C23C8/20—Carburising
  • C23C8/22—Carburising of ferrous surfaces
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/0062—Heat-treating apparatus with a cooling or quenching zone
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
  • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
  • C23C8/20—Carburising

Definitions

• the invention relates to a machine for the thermochemical treatment of metal parts comprising at least one heating cell, a carbon enrichment cell for the surfaces of the parts to be treated, a carbon diffusion cell, the surface towards the core of the parts, and at least one quenching cell successively arranged one after the other and of length adapted to the duration of the treatment performed in each cell, the machine also comprising mechanical means of transfer and advancement of parts of a cell to the next and isolation means for isolating the cells together during the different successive processing phases.
• thermochemical treatment systems for carburizing and carbonitriding of metal parts, such as box-like systems with a solid cementitious material, uncontrolled atmosphere systems, controlled atmosphere systems with a constant carbon potential, or low pressure systems, of the order of 5mbar to 20mbar, sometimes even up to 100mbar.
• Carburizing and carbonitriding generally require a partial pressure of cementing gas, consisting of a hydrocarbon, for example methane (CH 4 ), acetylene (C 2 H 2 ) or propane (C 3 H 8 ), and optionally a nitriding gas, for example ammonia (NH 3 ).
• a hydrocarbon for example methane (CH 4 ), acetylene (C 2 H 2 ) or propane (C 3 H 8 )
• a nitriding gas for example ammonia (NH 3 ).
• the carburizing operations namely a carburizing treatment treatment, a surface enrichment treatment and a carbon diffusion treatment, are preferably carried out under nitrogen partial pressure. To avoid oxidation during carburizing treatment and during transport to the quenching cell, the parts are not exposed to air at any time.
• the quenching operation which follows the carburizing treatment, consists of rapidly cooling the parts. It is carried out either in a bath of oils or molten salts, or under high pressure gas and stirred, such as nitrogen, helium or various mixtures of neutral gases, such as carbon dioxide or hydrogen.
• Patent EP-A-0922778 in particular, describes a heat treatment plant comprising a plurality of cells for the heat treatment of a set of metal parts.
• the cells are all connected to a central chamber in equipression with the treatment cells.
• the parts are transferred from one cell to another via transport and handling rails. After carburizing in the corresponding cell, the cemented parts are transferred into the quenching cell through the central chamber, so there is no contact with the ambient air.
• Other installations consist of independent cells connected together by a mobile cell, whose function is either the loading and transfer operations to the quenching cell, or the loading, transfer and quenching operations simultaneously. under pressurized gas.
• the phases of the carburization treatment namely at least one carburizing heating phase, a phase of carbon enrichment of the surface of the parts and a diffusion phase carbon, from the surface to the heart of the parts, are successively carried out in the same cell or in the same partitioned cell, comprising mechanical means of advancement and transfer of parts.
• the mechanical means are then located in a hot zone.
• the machine is a conventional gaseous carburizing machine at atmospheric pressure and comprises a cell for each phase of the carburizing treatment, namely a carburizing treatment unit. , a carbon enrichment cell of the surfaces of the parts to be treated and a carbon diffusion cell, from the surface to the heart of the parts.
• the cells are successively arranged one after the other and the pieces pass from one cell to another to receive the cementation treatment, the length of a cell being defined beforehand according to the desired treatment time in the cells.
• this type of machine can only work under certain conditions, especially at high pressures.
• the mechanical means for transferring and advancing the parts are located in the hot zone, where the corresponding treatment takes place, and are not thermally insulated.
• this type of machine is difficult to integrate into existing production lines and the length of each cell is not easily scalable depending on the desired treatment time.
• the object of the invention is to overcome the abovementioned drawbacks and is aimed at the design of a low pressure carburizing or carbonitriding thermochemical processing machine, which is efficient, flexible and can easily be adapted and integrated into lines of mass production of parts.
• the cells for heating, carbon enrichment and carbon diffusion are of standard form and each comprise a treatment zone. in low pressure located between an input module and an output module, the input and output modules each constituting a cold zone, thermally isolated from the treatment zone of the corresponding cell, the mechanical transfer means and the advancement being located in the input and output modules of the cells and the output module of a cell being connected to the input module of the adjacent cell.
• FIG. 1 schematically represents a view from above of a first embodiment of a thermochemical treatment machine according to the invention.
• FIG. 2 diagrammatically represents a view from above of an alternative embodiment of a thermochemical treatment machine according to FIG. 1.
• FIG. 3 represents a cell of the thermochemical treatment machine according to FIGS. 1 and 2.
• FIGS. 4 to 6 schematically show top views of alternative embodiments of a thermochemical treatment machine according to the invention.
• thermochemical treatment machine is a low-carburizing vacuum processing machine 1 for metal parts.
• the machine 1 comprises a plurality of processing cells 2 to 5, arranged successively one after the other.
• Each cell corresponds to a particular phase of the low-pressure carburizing treatment and has a standard shape and an adaptable length L as a function of the desired treatment time in the cell.
• the cell manufacturing technique is that of vacuum furnaces with walls cold, allowing an operating pressure between 10 '1 mbar and 30mbar.
• the machine 1 also comprises means for advancing and transferring parts from one cell to the next and closure means for isolating a cell from adjacent cells during the different phases of the cementation treatment.
• the transfer of the pieces between the cells is carried out at a predetermined pressure, namely the cementation pressure, of the order of
• the machine 1 comprises in particular a carburizing temperature of cell 2.
• the treatment carried out in the cell 2 is intended to raise the temperature of the parts to the required carburizing temperature, of the order of 88O 0 C to 1050 ° C.
• This phase is carried out at the cementation pressure, of the order of 5mbar to 20mbar, preferably with nitrogen. In special cases, the pressure can reach up to 100mbar.
• the machine 1 Downstream of the carburizing temperature setting cell 2, the machine 1 comprises a cell 3 for enriching carbon.
• the treatment carried out in cell 3 consists in enriching the surface of carbon parts, or in carbon and nitrogen, in order to reinforce, after quenching, the hardness of the parts.
• This enrichment phase is preferably carried out by an injection of nitrogen or of any other neutral gas.
• a temperature of the order of 88O 0 C to 1050 0 C supplemented at regular intervals by an injection of a cementing gas.
• the pressure in the cell 3 is, for example, of the order of 5mbar to 20mbar depending on the cementing gas used.
• the treatment carried out in cell 4 consists in diffusing the carbon in the thickness of the pieces, from the surface to the core of the pieces, according to the desired depth of the cemented surface and the percentage of desired carbon on the surface of the pieces.
• This phase of the treatment is carried out at the same pressure as that of carburizing 2 and carbon enrichment cells 3.
• the temperature is adjusted, preferably between 88O 0 C and 1050 0 C, to allow good speed to penetrate the carbon into the parts and to obtain the optimal temperature of the parts before carrying out the quenching operation.
• the required treatment temperature inside the carbon diffusion cell 4 is preferably different from the required treatment temperature inside the carburization 2 and carbon enrichment 3 cells.
• the machine 1 Downstream of the cells 2 to 4, the machine 1 also comprises a quenching cell 5 equipped with pressure-tight doors.
• the cell 5 is a gas quenching, oil quenching, salt bath quenching cell or any other system for cooling the parts to the required speed to obtain the desired hardness.
• the machine 1 may comprise, downstream of the quenching cell 5, a revenue cell.
• the tempering phase is carried out at a temperature, for example, of the order of 200 ° C. to 300 ° C.
• the machine 1 Upstream of the carburizing temperature setting cell 2, the machine 1 also comprises an inlet lock 6 intended to store the parts waiting for their introduction into the cell 2 (FIG. 1). In this case, take ensure a vacuum purge in the airlock 6, so that the pressure in the airlock 6 is the same as that in the carburizing temperature cell 2, before the introduction of the parts, and that the air is almost completely purged.
• the machine 1 comprises a gas pumping system 7, connected by appropriate means to the carbon enrichment cell 3 and intended to evacuate the gases present in the cells 2, 3 and 4.
• Only the carbon enrichment cell 3 contains cementing gases capable of contaminating the cells 2 and 4.
• the pumping system 7 therefore advantageously generates a circulation of the gases according to the arrows F1, the cells 2 for heating up the cells. carburizing and 4 of carbon diffusion, to the cell 3 for enriching carbon, possibly contaminated.
• the machine 1 may also comprise a first independent pump 8 system for the entry lock chamber 6 and a second independent system 9 for pumping the quenching cell 5.
• the three cells 2, 3, 4, corresponding to the three essential phases of a low pressure carburizing treatment are cold-walled, so as to be cold, non-polluting and non-hazardous.
• the parts intended to be case hardened pass necessarily and successively, in order, by all the cells 2, 3, 4 of the low pressure carburizing treatment arranged one after the other.
• the cells 2, 3, 4 of the machine 1 are all conformed according to the same general model, of standard form, adapted to each function (heating, enrichment and diffusion), and of length L modulable, this which makes it possible to precisely adjust the processing time of each cell for a given rate.
• the change of pace makes it possible, in particular, to reach different carburizing depths.
• the length L of a cell is therefore proportional to the duration of the treatment carried out in this cell.
• temperatures can be adapted to allow a precise adjustment of the characteristics to be obtained on the parts to be treated.
• the cell 2 comprises an input module 10a, through which the parts to be treated enter, and an output module. 10b, through which the parts come out after treatment.
• the input 10a and output 10b modules are standard in shape and can each contain a load 11 of metal parts.
• the cell 2 has a longitudinal axis 12, oriented from the input module 10a to the output module 10b.
• the longitudinal axis 12 corresponds to the direction of movement, according to the arrows F2, of the charges 11 inside the cell 2.
• the cell 2 comprises two identical standard intermediate modules 13 of the same length.
• the establishment of several intermediate modules 13 between the input modules 10a and output 10b makes it possible to vary the length L1 of the cell 2.
• the standard modules 13 of the cell 2 constitute a treatment zone 14 at low pressure, inside which the treatment specific to the cell 2 is carried out.
• the treatment zone 14, constituted preferably by standard modules 13 with walls cold, is confined and isolated from the input modules 10a and 10b, which then constitute cold zones of the cell 2.
• the cold zones are thermally isolated from the treatment zone 14, for example by means of thermally insulated and cooled doors 15 disposed between the input 10a and output 10b modules and the confined treatment zone 14.
• the cooling of a door 15 is effected by means of a heat exchanger, generating a circulation of water at the level of the door 15.
• the input and output modules 10a and 10b are of standard shape, with a substantially U-shaped section, and each have an opening in connection with the adjacent module 13 and three walls closing the end of the cell 2.
• the input module 10a comprises an input orifice 16, situated on a wall of the input module 10a parallel to the longitudinal axis 12 of the cell 2
• the output module 10b has an outlet port 17, located on a wall of the output module 10b parallel to the longitudinal axis 12 and located on the same side of the cell 2 relative to the longitudinal axis 12.
• the loads 11 coins enter and exit on the same side of cell 2.
• the input 10a and output 10b modules each comprise, for example, an ejection system 18, designed to push and evacuate the load 11 of the corresponding module 10a, 10b and an abutment system 19, intended to block the load 11. before evacuation.
• the evacuation system 18 and the stop system 19 constitute mechanical means for advancing and transferring the parts between the cells and are advantageously located in the cold zones of the cells 2, 3, 4.
• the movement of the charges 11 inside the cells is carried out by the charges 11 themselves, which push each other when introducing a new charge 11.
• the treatment zone 14 thus comprises no means mechanical transfer or advancement, which are only arranged in the cold zones formed by the input modules 10a and 10b output cells.
• the carbon enrichment cell 3 comprises alternating neutral gas injection phases with cementing gas injection phases
• the transfer of the parts between the cells is advantageously carried out simultaneously with the injection phases of the neutral gases. It is therefore necessary to provide a neutral gas injection slot sufficiently long and to actuate accordingly the various means of transfer and advancement, in order to be able to transfer all the charges 11 along the machine 1.
• the cementing gases are thus confined only in the carbon enrichment cell 3 and are not likely to contaminate the other cells 2 and 4.
• the carburizing temperature setting cell 2 comprises two modules 13, the inlet orifice 16 and the outlet orifice 17 of the cell 2 are parallel and located on the same side of the cell 2 with respect to the longitudinal axis 12.
• the following cell 3 of carbon enrichment which comprises a single standard module 13, is arranged such that its longitudinal axis 12 is parallel and oriented in the same direction as the longitudinal axis 12 of the previous cell.
• the inlet orifice 16 of the input module 10a is thus arranged facing the outlet orifice 17 of the output module 10b of the previous cell 2 and the outlet orifice 17 of the output module 10b of the cell 3 is disposed on the same side of the cell 3 as the inlet port 16 of the input module 10a, with respect to the longitudinal axis 12.
• the carbon diffusion cell 4 which also comprises two standard modules 13, is arranged parallel to the other two, with its longitudinal axis 12 oriented in the same direction, and aligned with the carburizing temperature setting cell 2.
• the inlet and outlet orifices 16 and respectively of the input and exit modules 10a and 10b are therefore arranged on the same side of the cell 4 with respect to the longitudinal axis 12.
• the quenching cell 5 is connected to the outlet orifice 17 of the cell 4 and the airlock 6 is connected to the inlet port 16 of the cell 2.
• the input 10a and output 10b modules of the cells 2, 3, 4 are advantageously arranged such that they form compartments 20 for connection between two adjacent cells.
• the compartments 20 of the machine 1 may then comprise systems 21 for isolating gases and pressure from one cell to another during the treatment phases. They may also include check valve systems to control the flow of gases between cells.
• the machine 1 comprises a pressure-tight door 21 placed between the inlet module 10a of the carburizing temperature-setting cell 2 and the entry airlock 6.
• the low-carburizing treatment machine 1 comprises the three cells 2, 3 and 4 arranged parallel to each other.
• the longitudinal axis 12 of the cell 3 is parallel and oriented in opposition with respect to the longitudinal axis 12 of the cells 2 and 4.
• the inlet orifice 16 of the input module 10a of the cell 3 is arranged opposite of the output module 10b of the cell 2, while the outlet orifice 17 of the output module 10b of the cell 3 is disposed on the other side of the cell 3, with respect to the longitudinal axis 12, opposite of the input module 10a of the cell 4.
• This particular orientation in opposition of the inlet and outlet orifices 16 of the modules 10a and 10b of the cell 3 makes it possible, in particular, to implant the machine 1 in a generally S-shaped form. , with the cells 2, 3, 4 facing each other. This results in a significant space saving, the overall length of the machine being relatively low.
• the machine 1 may comprise a load storage area 22 at the beginning of the treatment cycle, waiting to be introduced into the entry lock 6, and a load storage area 11 at the end of the operating cycle. treatment, downstream of the quenching cell 5 and waiting for evacuation, for example at another site.
• the longitudinal axes 12 of the cells 2 and 3 are oriented in the same direction and the longitudinal axis 12 of the cell 4 is oriented in opposition to the other two.
• the cells 3 and 4 are then offset relative to the cell 2.
• the machine 1 therefore has a larger overall length.
• This particular implantation, substantially U-shaped, allows in particular to integrate in the machine 1 the pumping systems 7, 8 and 9 associated, respectively, to the cells 3, 6 and 5.
• the machine 1 may comprise supervisory, verification and / or control systems 24 adjacent to the cells, in order to verify and / or control the smooth running of the carburizing treatment cycle.
• the variant embodiment of the machine 1, shown in FIG. 6, differs from the embodiment shown in FIG. 5 by the number of standard intermediate modules 13 of the cells 2, 3 and 4. Indeed, these comprise respectively three, two and three standard modules 13, arranged between the input modules 10a and 10b output. This results in an increase in the passage time of the parts in the corresponding cell.
• the machine 1 therefore has a completely reconfigurable architecture according to the applications, the size of the location, the desired processing time, particularly thanks to the shape of the standard input modules 10a, output 10b and standard intermediate modules 13 of each cell 2, 3, 4 of the machine 1. This results in particular gains in time, space and productivity.
• the machine 1 may comprise, downstream of the cell 4, two quenching cells, for example an oil quenching cell and a quenching cell under gas or two quenching cells under gas .
• the output module 10b of the carbon diffusion cell 4 is different from the output modules 10b of the other cells and comprises two outlet orifices 17, arranged on each wall parallel to the corresponding longitudinal axis 12 of the cell. 4.
• the two quenching cells are then connected to the same output module 10b, the parts being introduced either into the first quenching cell, or into the second, before being removed after treatment.
• the machine 1 may comprise a coin cleaning cell, between the airlock 6 and the 02018
• the cleaning cell is a washing or degreasing machine operating at atmospheric pressure or, possibly, partial pressure in the vapor phase.
• the machine 1 may comprise, upstream of the carburizing temperature setting cell 2, a convective preheating cell parts.
• the preheating cell is a convective preheating furnace for heating the parts to a temperature, for example, of the order of 300 0 C to 500 0 C, before their introduction into the cell 2 of carburizing temperature.
• Convective preheating makes the heating homogeneous and in particular leads to oxidation of the parts and good activation of their surfaces.
• This phase is carried out in air at atmospheric pressure, preferably with a little additional nitrogen.
• the preheating cell thus saves time, the parts can spend less time in the cell 2 of carburizing temperature after their preheating.
• the preheating cell is purged with vacuum before transferring the parts into the next cell.
• the processing machine 1 therefore has the following advantages.
• the machine 1 is cold outside and non-polluting, thanks to the cold walls of the treatment zones 14 of the cells 2, 3, and 4.
• the cells 2, 3, 4 being of standard form R2005 / 002018
• the intermediate modules 13 and the standard input and output modules 10a and 10b can be installed in any existing machine shop and in any large part production facility. series. Productivity is therefore greatly improved.
• the flexibility of the installation also allows, depending on the commands or heat treatments to be performed, to insert or not optional cells, including cleaning cells, preheating and income.
• the parts to be treated may consist of sets of parts arranged on a support.
• the cells can have any suitable shape.
• the transfer and closure means may be constituted by any appropriate means for ensuring sealing properties and predetermined pressure between two adjacent cells.
• the cementing gas may be propane or any other hydrocarbon capable of associating with the temperatures of the enrichment cell 3 to treat the surface of the parts.
• the transfer and advancement means located in the cold zone of the cells may be formed by a completely different evacuation system and a completely different stop system.
• the transfer between two adjacent cells being performed at a predetermined pressure, the machine 1 may comprise additional means (not shown) to adjust and control the pressure in progress. 18
• the machine may comprise additional transfer means (not shown), intended to transfer the parts to another machine, for example, finishing treatment (shot blasting, grinding).
• finishing treatment shot blasting, grinding
• the cells 2 to 4 may include heating equipment, a gas injection circuit and pump outlets for vacuum pumps (not shown).
• a carbonitriding treatment may optionally be applied in the cells 3 and 4.
• the thermochemical treatment machine 1 is then a carbonitriding vacuum processing machine, with a diffusion cell 4 to the inside which is injected a nitriding gas.
• the enrichment of nitrogen can then be carried out by introducing a gas such as ammonia (NH 3 ) into the cells 3 of surface enrichment and 4 of diffusion, at a rate to be determined according to the desired result.
• the operation of the machine remains the same as before, with the workpieces passing successively in each processing cell.
• the cells also have the same configuration, with an input module, an output module and standard intermediate modules arranged between the modules, so as to form a completely reconfigurable machine, depending on the workshop, applications and time desired treatment in the cells.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
• Heat Treatments In General, Especially Conveying And Cooling (AREA)
• Tunnel Furnaces (AREA)

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• 2004
  • 2004-08-06 FR FR0408723A patent/FR2874079B1/fr not_active Expired - Fee Related
• 2005
  • 2005-08-02 DE DE602005005343T patent/DE602005005343T2/de active Active
  • 2005-08-02 EP EP05796230A patent/EP1786944B1/de active Active
  • 2005-08-02 WO PCT/FR2005/002018 patent/WO2006024780A1/fr active IP Right Grant
  • 2005-08-02 US US11/658,261 patent/US20080084011A1/en not_active Abandoned
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