EP2186916B1 - Process and installation for continuous case hardening - Google Patents

Process and installation for continuous case hardening Download PDF

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Publication number
EP2186916B1
EP2186916B1 EP08169293.1A EP08169293A EP2186916B1 EP 2186916 B1 EP2186916 B1 EP 2186916B1 EP 08169293 A EP08169293 A EP 08169293A EP 2186916 B1 EP2186916 B1 EP 2186916B1
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EP
European Patent Office
Prior art keywords
workpiece
quenching
loading
case hardening
continuous case
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Not-in-force
Application number
EP08169293.1A
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German (de)
French (fr)
Other versions
EP2186916A1 (en
Inventor
Horst Barth
Wolfgang Schalberger
Karl Nolte
Friedhelm Kühn
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LOI Thermprocess GmbH
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LOI Thermprocess GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by LOI Thermprocess GmbH filed Critical LOI Thermprocess GmbH
Priority to SI200831082T priority Critical patent/SI2186916T1/en
Priority to ES08169293T priority patent/ES2434954T3/en
Priority to PL08169293T priority patent/PL2186916T3/en
Priority to EP08169293.1A priority patent/EP2186916B1/en
Priority to PCT/EP2009/065254 priority patent/WO2010055163A1/en
Publication of EP2186916A1 publication Critical patent/EP2186916A1/en
Application granted granted Critical
Publication of EP2186916B1 publication Critical patent/EP2186916B1/en
Not-in-force legal-status Critical Current
Anticipated expiration legal-status Critical

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    • 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
    • C21D9/0037—Rotary furnaces with vertical axis; Furnaces with rotating floor
    • 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
    • C21D11/00—Process control or regulation for heat treatments
    • C21D11/005—Process control or regulation for heat treatments for cooling
    • 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
    • C21D9/0006—Details, accessories not peculiar to any of the following furnaces
    • C21D9/0018—Details, accessories not peculiar to any of the following furnaces for charging, discharging or manipulation of charge
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/14—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment
    • F27B9/16—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a circular or arcuate path
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/0024—Charging; Discharging; Manipulation of charge of metallic workpieces

Definitions

  • the present invention relates to a method and apparatus for heat treating workpieces, and more particularly to a method and apparatus for continuous case hardening of workpieces.
  • a method and a system of the type mentioned are, for example, from WO 86/02104 A known.
  • workpieces are heated to a certain temperature in a separate preheat oven, then placed in a heat treatment furnace, with each work piece in the heat treatment furnace separately monitored and eventually removed from the oven, regardless of the treatment time in the heat treatment furnace.
  • the plant as such comprises a preheating furnace and a ring furnace with a rotary support for the workpieces, the outlet opening of the preheating furnace being in direct contact with the feed opening of the ring furnace.
  • a rotary hearth furnace for heat treatment of workpieces known.
  • This comprises a rotary hearth, which is separated by means of closable doors in a heating zone and at least one treatment zone, and a closable door opening for loading and unloading of workpieces in the outer wall adjacent to the heating zone.
  • the rotary hearth furnace further comprises a second closable opening for loading and unloading in the outer wall, which is adjacent to the heating zone and spaced from the first opening, wherein the rotary hearth of the furnace is rotatable in both directions.
  • the state of the art is the batchwise heat treatment of these wind power gears.
  • the gears are brought to austenitizing temperature in shaft or chamber furnaces and kept for a corresponding time at austenitizing temperature and thereby subjected to a carburizing process. It is the Randkohlenstoffgehalt brought to about 0.8%.
  • the workpiece is removed from the oven, predominantly manually with discharge devices, and placed under atmospheric conditions, ie in the air, in an open quench bath.
  • a quenching agent for example, oils or polymer solutions are used.
  • the temperatures of the quenching agent are between 60 ° C and 150 ° C.
  • the parts are removed manually with, for example, a crane and fed to a washing bath.
  • the temperatures during the washing process are between about 60 ° C and 80 ° C.
  • the parts again mostly manually, are fed to a tempering process.
  • This manual procedure repeatedly results in different transport and storage times between the individual treatment steps, which cause a different starting structure in the workpieces with different contents of retained austenite before the tempering process. If stored too long, the retained austenite is stabilized and remains at this high level before the tempering furnace.
  • a workpiece is first activated in a pre-oxidation at a temperature between 400 ° C and 500 ° C. At the same time as the activation of the workpiece, cutting oil and detergent residues present on the workpiece surface are possibly burned off.
  • the workpiece After leaving the pre-oxidation furnace, the workpiece is introduced with a first loading / unloading manipulator via a closable loading / unloading in a rotary hearth furnace and heated to a predetermined carburizing temperature. Subsequently, the workpiece is carburized until reaching a predetermined carburizing depth (CD) and at a hardened predetermined hardening temperature.
  • CD carburizing depth
  • the choice of the carburizing agent, the carburization depth and the hardening temperature are each adapted to the workpiece to be machined.
  • the workpiece is removed from the rotary hearth furnace with the first loading / unloading manipulator via the loading / unloading opening and deposited on a lifting device of a quenching device, the lifting device being associated with the loading / unloading opening of the rotary hearth furnace.
  • the workpiece is then lowered with the lifting device into a quenching medium and quenched to a core temperature between 60 ° C and 150 ° C to reach a given depth of hardening (CHD) and to reach a predetermined hardness, wherein, for example, toothed edges as workpieces at a depth of 5 CHD times a given hardness in the tooth base is to be achieved by quenching.
  • CHD hardening
  • the above-mentioned core temperature between 60 ° C and 150 ° C causes no excessive stresses and thus distortions during the austenite to martensite crystal lattice reversal typical of quenching.
  • the workpiece is lifted from the quench media and fed to a post-treatment with a load / unload manipulator, wherein post-processing the workpiece to prepare for starting the workpiece includes washing, cooling, and drying.
  • post-processing the workpiece to prepare for starting the workpiece includes washing, cooling, and drying.
  • the workpiece has a core temperature between 25 ° C and 35 ° C, wherein a core temperature in this area ensures that heat flow from the core of the workpiece to the edge structure is avoided or at least severely restricted and thus the microstructure setting for the edge structure is not Negatively influenced (when using gears as workpieces, for example, a negative effect on the microstructure setting of the edge structure is avoided, especially in the tooth base and in a depth of the tooth base of 5 times CHD).
  • the workpiece may be fed to the post-treatment with the first loading / unloading manipulator, but it is preferred that the feeding for aftertreatment with a second Loading / unloading manipulator is performed, since it can be avoided that the first manipulator is contaminated with quenching medium.
  • the individual steps of the aftertreatment are preferably carried out in separate zones of an aftertreatment device.
  • the workpieces are preferably moved between the individual zones with the second loading / unloading manipulator, but it is also possible for a third loading / unloading manipulator to be used for moving the workpieces between the individual zones of the after-treatment device.
  • the workpiece Following the post-treatment of the workpiece, it is annealed at a temperature between 160 ° C and 180 ° C to further complete the folding of the austenite-martensite crystal lattice.
  • workpiece encompasses both a large workpiece which passes through the individual method steps “as such” as well as a plurality of workpieces which are arranged on a grate and pass through the method steps.
  • At least one fully automatic loading / unloading manipulator allows a continuous process, since all loading and unloading, for example, from the pre-oxidation in the rotary hearth furnace and from this to the first lifting device of the quenching device, do not have to be performed manually and so fluctuating storage and transport times are avoided.
  • the cycle rate of automated continuous processes is always determined by the slowest process step. Quenching is a relatively time-consuming process, especially in the case of particularly heavy workpieces, since the workpieces must be quenched to a certain temperature in order to achieve a sufficient transformation of the edge austenite. Since the quenching device is associated with the rotary hearth furnace, i. the rotary hearth furnace is loading and unloading in the radial direction via the quenching device, the rotary hearth furnace is blocked when a workpiece is quenched, whereby quenching slows down the process in the case of time-consuming workpieces and thus impairs the efficiency of the process.
  • the quenching of the workpiece is such that the workpiece is first quenched in a first chamber of the quenching device associated with the rotary hearth furnace with a first quenching medium for a predetermined period of time, the workpiece after the first quenching with a loading / unloading manipulator is deposited on a second lifting device in a second chamber of the quenching device, is lowered into a second quenching medium and quenched with the second quenching medium, wherein the core temperature of the workpiece after the Automatabschreckvorgang between 60 ° C and 150 ° C.
  • the method can be operated faster even with protracted work pieces, since the first chamber of the quenching device, which blocks the loading and unloading of the rotary hearth furnace during quenching, is occupied for a shorter period of time. Once the quenched workpiece is removed from the first chamber, the rotary hearth furnace can be re-unloaded and / or loaded.
  • a load / unload manipulator wherein either the first loading / unloading manipulator, which also serves to load the rotary hearth furnace, or a second loading / unloading manipulator can be used.
  • the second loading / Entlademanipulator is used, since it can be avoided that the first manipulator is contaminated with quenching medium.
  • either the same or different quench media may be used, thereby greatly increasing the flexibility of the process itself in terms of quenching.
  • the workpiece is deposited by the first lifting device in the first quenching medium on a turntable with a turntable, wherein the turntable, the workpiece is rotated at an adjustable speed in the quenching medium.
  • the first lifting device is lowered over the outer circumference of the turntable of the rotary device down. It is also preferred, especially for special workpieces such as gears, that special outdoor areas, such as the sprocket, be flown with a nozzle system.
  • the core temperature of the workpieces after post-treatment is 25 ° C to 35 ° C. It is also important to ensure that not one step slows down the whole procedure because of its duration. In the case of special large workpieces, however, it may happen that the time available for cooling, given by the remaining process steps, is insufficient to achieve the abovementioned core temperature of the workpieces.
  • the aftertreatment comprises a further cooling step in which the workpiece is further cooled so that it is ensured at the end of the aftertreatment that the workpieces reach the above-mentioned core temperature.
  • This second cooling step can be carried out either after drying or directly after the first cooling.
  • the second cooling step is carried out after drying, in particular, when it is desired to cool with a coolant other than the first step and to prevent contamination of the second coolant by the first one.
  • the second cooling step is carried out after drying, and yet must be cooled with a water-containing cooling liquid due to the workpiece, it should be ensured that the workpiece is tempered quickly to avoid oxidation on the workpiece surface.
  • the post-treatment steps are carried out for 20 minutes per millimeter (20 min / mm) of cure depth.
  • the workpiece is aligned cold immediately after cooling, in order to eliminate possibly occurring distortions of the workpiece.
  • the workpiece after tempering is at least partially subjected to a shot peening process.
  • an inventive plant for continuous case hardening of workpieces having a pre-oxidation furnace and a rotary hearth furnace with at least one loading / unloading and with a plurality of vertically movable doors via separate treatment zones.
  • the loading / unloading of the rotary hearth furnace is associated with a quenching device with at least one lifting device, and the quenching device is a After treatment device downstream of a washing zone, a cooling zone and a drying zone.
  • the plant further comprises a tempering furnace and at least one loading / unloading manipulator, with which the workpieces are introduced into the rotary hearth furnace and are removed after the heat treatment, and deposited on the lifting device of the quenching device.
  • the loading / unloading manipulator also serves to remove the workpiece from the quenching device and supply it to the aftertreatment device.
  • the loading / unloading manipulator can also be used to move the workpieces between the individual devices.
  • the aftertreatment device can also be designed such that the workpieces are transported on transport rollers or with conveyor chains from one zone to the next.
  • the system has a second loading / unloading manipulator, wherein it is preferably provided that the first loading / unloading manipulator is used only for loading and unloading the rotary hearth furnace and the second loading / unloading manipulator removes the workpiece from the quenching device and supplies it to the aftertreatment device.
  • the use of at least two loading / unloading manipulators also has the advantage that the first loading / unloading manipulator is not contaminated with quenching medium and that the cycle times of the equipment can be reduced since the loading, unloading and feeding operations described above are reduced to two Manipulators can be split.
  • a preferred embodiment of the plant comprises a quenching device with two quenching chambers, each of these quenching chambers comprising a lifting device.
  • the two lifting devices are separated from each other vertically movable.
  • the first quenching chamber of the quenching device is associated with the rotary hearth furnace, i. arranged directly before the loading / unloading of the rotary hearth furnace that a loading / unloading manipulator for unloading the rotary hearth furnace and settling of the workpiece on the first lifting device must be moved only in the radial direction.
  • the quenching process is critical because it may possibly be rate-determining for the process.
  • the quenching device or a chamber of the quenching device comprises a rotating device with a turntable, wherein the turntable of the rotating device is designed such that the lifting device over the outer circumference of the turntable after can be lowered down, and in this way the workpiece can be placed on the turntable.
  • the quenching device or one or both of the chambers of the quenching device can or can be equipped with nozzle systems in order to allow a targeted flow against certain areas of the workpiece.
  • the quenching device or the first chamber of the quenching device is associated with a gas-tight inlet / outlet lock with a plurality of gastight-sealable doors.
  • the number and arrangement of the gas-tight-lockable doors depends on how the workpieces are introduced into the rotary hearth furnace, if necessary moved between the individual chambers of the quenching device, and taken from the quenching device.
  • the aftertreatment device comprises a further cooling zone, which cooling zone may be upstream or downstream of the drying zone .
  • cooling zone may be upstream or downstream of the drying zone .
  • the same coolant, or different coolant can be used, it must be ensured when using water as a coolant and the arrangement of the cooling zone behind the drying zone (based on the process flow) that the workpiece is fed quickly to the tempering furnace ,
  • the system comprises a cold rectifying device connected downstream of the aftertreatment device for straightening the workpieces.
  • the system may comprise a ball-beam hardening device arranged downstream of the at least one tempering furnace.
  • FIG. 1 shows a plan view of the embodiment of the system according to the invention.
  • the plant comprises a pre-oxidation furnace (1) in which workpieces (100) for activation a temperature between 400 ° C and 500 ° C are heated. If the workpieces have cutting oil or detergent residues, they are burned off in the pre-oxidation oven.
  • the heating of the workpieces in the pre-oxidation is preferably carried out by vertically arranged (not shown) gas burner.
  • Fans arranged in the furnace roof serve to circulate the atmosphere in the pre-oxidation furnace. Transport through the oven is either via powered transport rollers or conveyor chains. At the entrance and exit of the pre-oxidation furnace this is provided with lockable doors.
  • FIG. 1 shows a plan view of the embodiment of the system according to the invention.
  • the plant comprises a pre-oxidation furnace (1) in which workpieces (100) for activation a temperature between 400 ° C and 500 ° C are heated. If the workpieces have cutting oil or detergent residues, they are burned off in the
  • the Verfahrwagen is perpendicular to the pre-oxidation furnace movable.
  • the plant according to the invention further comprises a rotary hearth furnace (50) with five vertically movable, possibly gas-tight doors (51a, 51b, 51c, 51d, 51e), the doors having a heating zone (52a), a first carburizing zone (52b), a second carburizing zone (52c), a hardening zone (52d) and a loading / unloading zone (52e).
  • the rotary hearth furnace is driven via a (not shown) controlled drive via gear and rack.
  • Absolute encoders (not shown) are distributed over the rotary hearth furnace to enable shutdown of one or more treatment zones.
  • the rotary hearth furnace is mounted on roller blocks, and the positionally accurate side guide is produced by centering rollers.
  • the rotary hearth furnace is sealed to the outside via an inner and outer oil cup and is heated by vertically arranged, gas-heated, full-ceramic Mantelstrahlrohre.
  • the rotary hearth furnace has in its outer wall (54) a preferably gas-tight sealable loading / unloading opening (53).
  • the loading / unloading opening is associated with a quenching device (40) such that a loading / unloading manipulator (10, 10 ', 20) ejects the workpiece by a radial movement the loading / unloading zone (52e) and can settle on a lifting device of the quenching device (40).
  • the quenching device (40) will now be described with reference to FIG. 2 described in more detail.
  • the quenching device (40) shown comprises two quenching chambers, each quenching chamber comprising an oil bath for quenching the workpieces and a lifting device with lifting plate (43a, 43b).
  • the first quenching chamber (shown in the drawing below) is associated with a gas-tight inlet / outlet lock (41) having a plurality of gas-tight lockable doors, the doors not being shown for reasons of clarity.
  • a rotating device with turntable (44) is arranged, wherein the turntable is moved by a drive (42).
  • a nozzle system is further arranged to allow the flow of certain areas of the workpieces, and the oil in the oil baths is circulated by axial nozzles.
  • other quenching means may be used, with the quenching means being adapted to the quenching media (s) used, the choice of quenching agent primarily depending on the size and nature of the workpiece.
  • the system according to the invention further comprises an aftertreatment device (60) having a washing zone (61), a first cooling zone (62), a second cooling zone (63) and a drying zone (64), wherein in the embodiment shown the respective zones are designed as separate devices (and hereinafter also so called).
  • an aftertreatment device 60
  • the workpiece is washed via a nozzle system with a washing liquid, wherein the choice of the washing liquid is primarily dependent on the or the quenching medium. It is customary to use water, if appropriate with additives, as washing liquid.
  • the washing process is carried out at temperatures between 40 ° C and 80 ° C.
  • the workpiece is moved into the first cooling device (62) and there with a first Cooling liquid, usually water, cooled, wherein it is preferred that the workpiece is lowered into the liquid.
  • a first Cooling liquid usually water, cooled
  • the workpiece is removed and supplied to either the second cooling device (63) or the drying device (64) depending on the core temperature of the workpiece.
  • the workpiece is fed to the second cooling device (63), otherwise the drying device (64).
  • the workpiece of the second cooling device is removed and the drying device (64) supplied and dried in this, for example with a fan and / or a fan.
  • the individual devices of the aftertreatment device (60) are virtually "connected in series", with the result that the treatment times are the same in all devices (ie also the first cooling time corresponds to the second cooling time).
  • the workpieces are removed from the drying device (64) and fed via a transverse carriage (70) to one of two tempering furnaces (81, 82), wherein the tempering furnaces in an alternative embodiment can be preceded by a cold rectifying device.
  • the tempering furnaces may further be followed by a shot peening apparatus in an alternative embodiment.
  • the illustrated embodiment further includes two loading / unloading manipulators (10, 20), wherein the first loading / unloading manipulator (10) is shown in two positions (10, 10 ').
  • the two loading / unloading manipulators (10, 20) are movable on a common guide system (30), so that it is ensured that in the event of failure of a loading / unloading manipulator, the other loading / unloading manipulator can take over the tasks of the failed loading / unloading manipulator.
  • the first loading / unloading manipulator (10) is for loading and unloading the rotary hearth furnace
  • the second loading / unloading manipulator (20) serves to move the workpiece from the first lifting device to the second lifting device is intended to move, and is also intended to supply the workpieces to the aftertreatment device and to move it between the individual devices of the aftertreatment device.
  • the loading / Entlademanipulatoren are designed as lifting / Senkmanipulatoren, ie they engage under the workpiece for lifting and are retracted for lowering in appropriate exceptions, wherein the workpiece is stored, for example in the rotary hearth furnace. After the workpiece has been deposited, the respective loading / unloading manipulator is removed via the recesses.
  • the workpiece (100) is first introduced into a pre-oxidation furnace (1) in which the workpiece is pre-oxidized at a temperature between 200 ° C and 500 ° C.
  • the workpiece may be, for example, large gears made of, for example, 18CrNiMo7 / 6 or 16MnCr5 steel. If the workpiece has cutting oil or detergent residues, they will be burned off.
  • the workpiece is extended to a movable lifting table and supplied from this to the first loading / unloading manipulator (10).
  • the loading / unloading manipulator engages under the workpiece, raises it and moves with the resting workpiece in the direction of quenching device (40) in front of the loading / unloading opening (53) of the rotary hearth furnace (50).
  • the first loading / unloading manipulator (10) is shown in two positions (10, 10 '), namely once the receiving position (10) and once in the position in which the workpiece is introduced into the rotary hearth furnace.
  • the loading / unloading manipulator together with the workpiece is introduced via (not shown) closable openings of the input / output lock (41) through the open loading / unloading opening (53) of the rotary hearth furnace in this and the workpiece deposited in the loading / unloading zone (52e).
  • all receiving or Absetzpositionen are designed in the system such that a loading / Entlademanipulator can engage under the workpieces.
  • the workpiece is first heated in the heating zone (52a) to a predetermined carburizing temperature, wherein the temperatures in the heating zone between 400 ° C and 960 ° C. After the workpiece reaches the required temperature, it is introduced into the first carburizing zone (52b) via the opened door (51a) and carburized with a predetermined gas, such as endogas or propane. At the in FIG. 1 In the embodiment shown, carburizing is subdivided into two sub-steps in order to increase the flexibility of carburizing itself. After the treatment of the workpiece in the first carburizing zone (52b), it is guided via the opened door (51b) into the second carburizing zone (52c). Carburizing itself takes place at temperatures between 900 ° C and 1000 ° C.
  • the workpiece is transferred via the open door (51c) to the hardening zone (52d) where the workpiece is set at a predetermined hardening temperature, which temperature is preferably in the range between 820 ° C and 860 ° C.
  • a predetermined hardening temperature which temperature is preferably in the range between 820 ° C and 860 ° C.
  • the workpiece now lingers for a predetermined quenching time in the first oil bath.
  • the oil is circulated through at least one (not shown) axial, wherein the speed of the pump is infinitely adjustable, and the edge regions of the workpiece are targeted by a nozzle system with oil flows.
  • the workpiece is rotated via the rotating device, wherein the speed is continuously adjustable between 1 to 10 revolutions per minute.
  • the workpiece with the lifting plate (43a) of the lifting device is lifted out of the oil bath and, if necessary, after a predetermined dripping time, the outer door for the second loading / Entlademanipulator is opened.
  • the workpiece is then gripped by the second loading / unloading manipulator (20) and removed via an opening (not shown) from the inlet / outlet lock of the first chamber of the quenching device (40), the open door, when removing the workpiece with a gas curtain is occupied.
  • the workpiece is then deposited by the loading / unloading manipulator (20) on the lifting plate (43b) of the second lifting device, and the workpiece is then deposited in the second oil bath, wherein in an alternative embodiment also a rotating device is arranged in the oil bath of the second quenching chamber can.
  • the workpiece is lifted out of the oil bath via the lifting plate (43b) of the second lifting device, the core temperature of the workpiece being between 60 ° C and 150 ° C after the total quenching operation.
  • the workpiece is then, preferably after a certain ⁇ labtropfzeit attacked by the second loading / unloading manipulator (20) and the after-treatment device (60), wherein the workpiece is first deposited in the washing device (61) of the aftertreatment device (60).
  • the workpiece is washed via a (not shown) nozzle system with washing liquid, which is preferably water with optionally an additive.
  • washing liquid has a temperature between 60 ° C and 90 ° C.
  • the workpiece After the workpiece has been washed, it is fed with the second loading / unloading manipulator to the first cooling device (62), in which the workpiece is immersed in a cooling liquid, preferably water, and cooled, the temperature of the cooling liquid being between 20 ° C and 40 ° C is.
  • a cooling liquid preferably water
  • the workpiece After the end of the first cooling time, the workpiece is removed from the first cooling device and the core temperature of the workpiece is determined. If this should not be in the range between 25 ° C and 35 ° C, the workpiece with the loading / unloading manipulator of the second cooling device (63) of the aftertreatment device (60) is supplied, in which the workpiece to a core temperature between 25 ° C and 35 ° C is cooled.
  • the workpiece with the second loading / unloading manipulator (20) of the drying device (63) is supplied, in which the workpiece is dried by fans and / or gas nozzles.
  • Such drying is necessary because the surface temperature of the workpiece has already been lowered by the previously performed cooling of the workpiece so that the washing liquid still adhering to the cooling process does not evaporate quickly enough and therefore, if cooled with water, can use oxidation of the workpiece surface ,
  • the workpiece After drying, the workpiece is fed to one of the two tempering furnaces, in which the workpieces are tempered at a temperature between 160 ° C and 180 ° C.
  • the workpiece may be subjected to a shot peening at least in some areas after tempering.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Thermal Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
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  • Heat Treatment Of Articles (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)

Description

Die vorliegende Erfindung betrifft ein Verfahren und eine Anlage zum Wärmebehandeln von Werkstücken, und insbesondere ein Verfahren und eine Anlage zum kontinuierlichen Einsatzhärten von Werkstücken.The present invention relates to a method and apparatus for heat treating workpieces, and more particularly to a method and apparatus for continuous case hardening of workpieces.

Ein Verfahren sowie eine Anlage der eingangs genannten Art sind beispielsweise aus der WO 86/02104 A bekannt. Bei dem Verfahren werden Werkstücke in einem separatem Vorheizofen auf eine bestimmte Temperatur erhitzt, dann in einen Wärmebehandlungsofen verbracht, wobei jedes Werkstück in dem Wärmebehandlungsofen getrennt überwacht und ggf. aus dem Ofen entfernt wird, und zwar unabhängig von der Behandlungszeit in dem Wärmebehandlungsofen. Die Anlage als solche umfasst einen Vorheizofen und einen Ringofen mit einem Rotationsträger für die Werkstücke, wobei die Auslassöffnung des Vorheizofens in direktem Kontakt mit der Zuführöffnung des Ringofens steht.A method and a system of the type mentioned are, for example, from WO 86/02104 A known. In the method, workpieces are heated to a certain temperature in a separate preheat oven, then placed in a heat treatment furnace, with each work piece in the heat treatment furnace separately monitored and eventually removed from the oven, regardless of the treatment time in the heat treatment furnace. The plant as such comprises a preheating furnace and a ring furnace with a rotary support for the workpieces, the outlet opening of the preheating furnace being in direct contact with the feed opening of the ring furnace.

Aus der WO 03/081156 A ist ein Drehherdofen zur Wärmebehandlung von Werkstücken bekannt. Dieser umfasst einen Drehherd, der mittels verschließbarer Türen in eine Aufheizzone und mindestens eine Behandlungszone getrennt ist, und eine verschließbare Tür Öffnung zum Be- und Entladen von Werkstücken in der Außenwand benachbart zur Aufheizzone. Der Drehherdofen umfasst ferner eine zweite verschließbare Öffnung zum Be- und Entladen in der Außenwand, die benachbart zur Aufheizzone und beabstandet zur ersten Öffnung angeordnet ist, wobei der Drehherd des Ofens in beide Richtungen drehbar ist.From the WO 03/081156 A is a rotary hearth furnace for heat treatment of workpieces known. This comprises a rotary hearth, which is separated by means of closable doors in a heating zone and at least one treatment zone, and a closable door opening for loading and unloading of workpieces in the outer wall adjacent to the heating zone. The rotary hearth furnace further comprises a second closable opening for loading and unloading in the outer wall, which is adjacent to the heating zone and spaced from the first opening, wherein the rotary hearth of the furnace is rotatable in both directions.

Beispielsweise bei der Wärmebehandlung von Windkraftzahnrädern, Sonnenrädern und Planetenrädern aus höher legierten Stählen und Abmessungen von z.B. 300 mm Durchmesser ist Stand der Technik die satzweise durchgeführte Wärmebehandlung dieser Windkraftzahnräder. Die Zahnräder werden in Schacht- oder Kammeröfen auf Austenitisierungstemperatur gebracht und eine entsprechende Zeit auf Austenitisierungstemperatur gehalten und dabei einem Aufkohlungsprozess unterzogen. Dabei wird der Randkohlenstoffgehalt bis auf ca. 0,8 % gebracht. Anschließend wird, vorwiegend manuell mit Austragvorrichtungen, das Werkstück aus dem Ofen entnommen und unter Atmosphärenbedingungen, also an der Luft, in ein offenes Abschreckbad eingebracht. Als Abschreckmittel werden beispielsweise Öle oder Polymerlösungen eingesetzt. Bei dem Abschreckvorgang liegen die Temperaturen des Abschreckmittels zwischen 60°C und 150°C. Nach einer festgelegten Abschreckzeit werden die Teile manuell mit beispielsweise einem Kran entnommen und einem Waschbad zugeführt. Die Temperaturen bei dem Waschvorgang liegen zwischen ca. 60°C und 80°C. Nach diesem Prozess werden die Teile, wiederum zumeist manuell, einem Anlassprozess zugeführt. Bei dieser manuellen Verfahrensweise entstehen immer wieder unterschiedliche Transport- und Lagerzeiten zwischen den einzelnen Behandlungsschritten, die vor dem Anlassprozess ein unterschiedliches Ausgangsgefüge in den Werkstücken mit unterschiedlichen Gehalten an Restaustenit verursachen. Bei einer zu langen Lagerung wird dabei der Restaustenit stabilisiert und verbleibt vor dem Anlassofen auf diesem hohen Niveau.For example, in the heat treatment of wind turbine gears, sun gears and planetary gears made of higher-alloyed steels and dimensions of, for example, 300 mm diameter, the state of the art is the batchwise heat treatment of these wind power gears. The gears are brought to austenitizing temperature in shaft or chamber furnaces and kept for a corresponding time at austenitizing temperature and thereby subjected to a carburizing process. It is the Randkohlenstoffgehalt brought to about 0.8%. Subsequently, the workpiece is removed from the oven, predominantly manually with discharge devices, and placed under atmospheric conditions, ie in the air, in an open quench bath. As a quenching agent, for example, oils or polymer solutions are used. In the quenching process, the temperatures of the quenching agent are between 60 ° C and 150 ° C. After a specified quenching time, the parts are removed manually with, for example, a crane and fed to a washing bath. The temperatures during the washing process are between about 60 ° C and 80 ° C. After this process, the parts, again mostly manually, are fed to a tempering process. This manual procedure repeatedly results in different transport and storage times between the individual treatment steps, which cause a different starting structure in the workpieces with different contents of retained austenite before the tempering process. If stored too long, the retained austenite is stabilized and remains at this high level before the tempering furnace.

Es ist Aufgabe dieser Erfindung, ein Verfahren und eine Anlage bereitzustellen, mit welchem bzw. welcher Werkstücke einheitlicher Qualität hergestellt werden können, bei welchen der Restaustenitgehalt vor dem Anlassprozess auf einen vorgegebenen Gehalt eingestellt ist.It is an object of this invention to provide a method and a plant, with which or which workpieces of uniform quality can be produced, in which the Austenititgehalt is set to a predetermined content before the tempering process.

Diese Aufgabe wird erfindungsgemäß gelöst durch ein Verfahren gemäß Patentanspruch 1. Bei dem erfindungsgemäßen Verfahren wird ein Werkstück zunächst in einem Voroxidationsofen bei einer Temperatur zwischen 400°C und 500°C aktiviert. Zeitgleich mit der Aktivierung des Werkstückes werden ggf. auf der Werkstückoberfläche vorhandene Schneidöl- und Waschmittelrückstände abgebrannt.This object is achieved by a method according to claim 1. In the method according to the invention, a workpiece is first activated in a pre-oxidation at a temperature between 400 ° C and 500 ° C. At the same time as the activation of the workpiece, cutting oil and detergent residues present on the workpiece surface are possibly burned off.

Nach dem Verlassen des Voroxidationsofens wird das Werkstück mit einem erstem Belade/Entlademanipulator über eine verschließbare Belade/Entladeöffnung in einen Drehherdofen eingebracht und auf eine vorgegebene Aufkohlungstemperatur erwärmt. Anschließend wird das Werkstück bis zum Erreichen einer vorgegebenen Aufkohlungstiefe (CD) aufgekohlt und bei einer vorgegebenen Härtetemperatur gehärtet. Die Wahl des Aufkohlungsmittels, die Aufkohlungstiefe sowie die Härtetemperatur werden jeweils an das zu bearbeitende Werkstück angepasst.After leaving the pre-oxidation furnace, the workpiece is introduced with a first loading / unloading manipulator via a closable loading / unloading in a rotary hearth furnace and heated to a predetermined carburizing temperature. Subsequently, the workpiece is carburized until reaching a predetermined carburizing depth (CD) and at a hardened predetermined hardening temperature. The choice of the carburizing agent, the carburization depth and the hardening temperature are each adapted to the workpiece to be machined.

Nach dem Härten wird das Werkstück mit dem ersten Belade/Entlademanipulator über die Belade/Entladeöffnung aus dem Drehherdofen entnommen und auf einer Hebeeinrichtung einer Abschreckeinrichtung abgesetzt, wobei die Hebeeinrichtung der Belade/Entladeöffnung des Drehherdofens zugeordnet ist. Das Werkstück wird dann mit der Hebeeinrichtung in ein Abschreckmedium abgesenkt und auf eine Kerntemperatur zwischen 60°C und 150°C zum Erreichen einer vorgegebenen Einhärtungstiefe (CHD) und zum Erreichen einer vorgegebenen Härte abgeschreckt, wobei bei beispielsweise Zahnrändern als Werkstücke in einer Tiefe von 5 mal CHD eine vorgegebene Härte im Zahngrund durch das Abschrecken erreicht werden soll. Die oben genannte Kerntemperatur zwischen 60°C und 150°C bedingt, dass keine zu großen Spannungen und damit Verzüge während des für das Abschrecken typischen Kristallgitterumklappens von Austenit nach Martensit entstehen.After hardening, the workpiece is removed from the rotary hearth furnace with the first loading / unloading manipulator via the loading / unloading opening and deposited on a lifting device of a quenching device, the lifting device being associated with the loading / unloading opening of the rotary hearth furnace. The workpiece is then lowered with the lifting device into a quenching medium and quenched to a core temperature between 60 ° C and 150 ° C to reach a given depth of hardening (CHD) and to reach a predetermined hardness, wherein, for example, toothed edges as workpieces at a depth of 5 CHD times a given hardness in the tooth base is to be achieved by quenching. The above-mentioned core temperature between 60 ° C and 150 ° C causes no excessive stresses and thus distortions during the austenite to martensite crystal lattice reversal typical of quenching.

Sobald die vorgegebene Einhärtungstiefe erreicht ist, wird das Werkstück aus dem Abschreckmedium gehoben und mit einem Belade/Entlademanipulator einer Nachbehandlung zugeführt, wobei das Nachbehandeln des Werkstücks zur Vorbereitung auf ein Anlassen des Werkstücks ein Waschen, Kühlen und Trocknen umfasst. Nach dem Nachbehandeln weist das Werkstück eine Kerntemperatur zwischen 25°C und 35°C auf, wobei eine Kerntemperatur in diesem Bereich gewährleistet, dass ein Wärmefluss von dem Kern des Werkstücks zum Randgefüge vermieden oder zumindest stark eingeschränkt wird und so die Gefügeeinstellung für das Randgefüge nicht negativ beeinflusst wird (bei der Verwendung von Zahnrädern als Werkstücke wird beispielsweise eine negative Beeinflussung der Gefügeeinstellung des Randgefüges vor allem im Zahngrund und in einer Tiefe am Zahngrund von 5 mal CHD vermieden).Once the predetermined depth of cure is achieved, the workpiece is lifted from the quench media and fed to a post-treatment with a load / unload manipulator, wherein post-processing the workpiece to prepare for starting the workpiece includes washing, cooling, and drying. After the aftertreatment, the workpiece has a core temperature between 25 ° C and 35 ° C, wherein a core temperature in this area ensures that heat flow from the core of the workpiece to the edge structure is avoided or at least severely restricted and thus the microstructure setting for the edge structure is not Negatively influenced (when using gears as workpieces, for example, a negative effect on the microstructure setting of the edge structure is avoided, especially in the tooth base and in a depth of the tooth base of 5 times CHD).

Das Werkstück kann der Nachbehandlung mit dem ersten Belade/Entlademanipulator zugeführt werden, es ist jedoch bevorzugt, dass das Zuführen zum Nachbehandeln mit einem zweiten Belade/Entlademanipulator durchgeführt wird, da so vermieden werden kann, dass der erste Manipulator mit Abschreckmedium verunreinigt wird. Die einzelnen Schritte des Nachbehandelns werden vorzugweise in getrennten Zonen einer Nachbehandlungseinrichtung durchgeführt. Die Werkstücke werden vorzugsweise mit dem zweiten Belade/Entlademanipulator zwischen den einzelnen Zonen bewegt, wobei es jedoch auch möglich ist, dass für das Bewegen der Werkstücke zwischen den einzelnen Zonen der Nachbehandlungseinrichtung ein dritter Belade/Entlademanipulator zur Anwendung kommt.The workpiece may be fed to the post-treatment with the first loading / unloading manipulator, but it is preferred that the feeding for aftertreatment with a second Loading / unloading manipulator is performed, since it can be avoided that the first manipulator is contaminated with quenching medium. The individual steps of the aftertreatment are preferably carried out in separate zones of an aftertreatment device. The workpieces are preferably moved between the individual zones with the second loading / unloading manipulator, but it is also possible for a third loading / unloading manipulator to be used for moving the workpieces between the individual zones of the after-treatment device.

Im Anschluss an das Nachbehandeln des Werkstücks wird dieses bei einer Temperatur zwischen 160°C und 180°C angelassen, um das Umklappen des Kristallgitters von Austenit nach Martensit noch weiter zu vervollständigen.Following the post-treatment of the workpiece, it is annealed at a temperature between 160 ° C and 180 ° C to further complete the folding of the austenite-martensite crystal lattice.

Im Rahmen dieser Anmeldung umfasst der Begriff "Werkstück" sowohl ein großes Werkstück, welches "als solches" die einzelnen Verfahrensschritte durchläuft, als auch eine Mehrzahl von Werkstücken, die auf einem Rost angeordnet die Verfahrensschritte durchlaufen.In the context of this application, the term "workpiece" encompasses both a large workpiece which passes through the individual method steps "as such" as well as a plurality of workpieces which are arranged on a grate and pass through the method steps.

Bei dem oben beschriebenen kontinuierlichen Verfahren zum Einsatzhärten von Werkstücken werden Transportzeiten minimiert und konstant gehalten und Lagerzeiten zwischen den einzelnen Behandlungsschritten vermieden, und es ist gewährleistet, dass vor dem Anlassen des Werkstückes dieses einen durch das Verfahren bestimmten Austenitgehalt aufweist, da das Werkstück, unabhängig von seiner Größe und Zusammensetzung, vor dem Anlassen stets auf eine Kerntemperatur zwischen 25°C und 35°C abgekühlt wird, wobei u.a. eine solche Kerntemperatur diesen definierten Austenitgehalt bedingt. Ein derart abgekühltes Werkstück neigt, zumindest bei der Verwendung von Wasser als Kühlmittel, zur Oxidation. Um dies zu vermeiden, wird das Werkstück erfindungsgemäß nach dem Kühlen getrocknet.In the continuous process for case hardening of workpieces described above, transport times are minimized and kept constant and storage times between the individual treatment steps are avoided, and it is ensured that prior to the tempering of the workpiece, this has a austenite content determined by the method, since the workpiece, irrespective of its size and composition, is always cooled before tempering to a core temperature between 25 ° C and 35 ° C, among others such a core temperature requires this defined austenite content. Such a cooled workpiece tends to oxidize, at least when water is used as the coolant. To avoid this, the workpiece is dried according to the invention after cooling.

Die Verwendung von zumindest einem vollautomatischen Belade/Entlademanipulatoren ermöglicht eine kontinuierliche Verfahrensführung, da sämtliche Belade- und Entladevorgänge, beispielsweise von dem Voroxidationsofen in den Drehherdofen und von diesem auf die erste Hebeeinrichtung der Abschreckeinrichtung, nicht manuell ausgeführt werden müssen und so schwankende Lager- und Transportzeiten vermieden werden.The use of at least one fully automatic loading / unloading manipulator allows a continuous process, since all loading and unloading, for example, from the pre-oxidation in the rotary hearth furnace and from this to the first lifting device of the quenching device, do not have to be performed manually and so fluctuating storage and transport times are avoided.

Die Taktrate bzw. Geschwindigkeit von automatisierten kontinuierlichen Verfahren wird stets durch den langsamsten Verfahrensschritt bestimmt. Insbesondere bei besonders schweren Werkstücken ist das Abschrecken ein relativ zeitaufwendiger Vorgang, da die Werkstücke unbedingt auf eine bestimmte Temperatur abgeschreckt werden müssen, um eine ausreichende Umwandlung des Randaustenits zu erreichen. Da die Abschreckeinrichtung dem Drehherdofen zugeordnet ist, d.h. der Drehherdofen über die Abschreckeinrichtung in radialer Richtung Be- und Entladen wird, ist der Drehherdofen blockiert, wenn ein Werkstück abgeschreckt wird, wodurch bei zeitaufwendig abzuschrekkenden Werkstücken das Abschrecken das Verfahren ausbremst und so die Effizienz des Verfahrens beeinträchtigt.The cycle rate of automated continuous processes is always determined by the slowest process step. Quenching is a relatively time-consuming process, especially in the case of particularly heavy workpieces, since the workpieces must be quenched to a certain temperature in order to achieve a sufficient transformation of the edge austenite. Since the quenching device is associated with the rotary hearth furnace, i. the rotary hearth furnace is loading and unloading in the radial direction via the quenching device, the rotary hearth furnace is blocked when a workpiece is quenched, whereby quenching slows down the process in the case of time-consuming workpieces and thus impairs the efficiency of the process.

Um dies zu verhindern, erfolgt bei einem bevorzugten Ausführungsbeispiel des erfindungsgemäßen Verfahrens das Abschrecken des Werkstücks derart, dass das Werkstück zunächst in einer dem Drehherdofen zugeordneten ersten Kammer der Abschreckeinrichtung mit einem ersten Abschreckmedium für eine vorgegebene Zeitdauer abgeschreckt wird, das Werkstück nach dem ersten Abschrecken mit einem Belade/Entlademanipulator auf einer zweiten Hebeeinrichtung in einer zweiten Kammer der Abschreckeinrichtung abgesetzt wird, in ein zweites Abschreckmedium gesenkt wird und mit dem zweiten Abschreckmedium abgeschreckt wird, wobei die Kerntemperatur des Werkstücks nach dem Gesamtabschreckvorgang zwischen 60°C und 150°C beträgt.In order to prevent this, in a preferred embodiment of the method according to the invention, the quenching of the workpiece is such that the workpiece is first quenched in a first chamber of the quenching device associated with the rotary hearth furnace with a first quenching medium for a predetermined period of time, the workpiece after the first quenching with a loading / unloading manipulator is deposited on a second lifting device in a second chamber of the quenching device, is lowered into a second quenching medium and quenched with the second quenching medium, wherein the core temperature of the workpiece after the Gesamtabschreckvorgang between 60 ° C and 150 ° C.

Mit der Unterteilung des Abschreckens in zwei Teilschritte wird erreicht, dass das Verfahren auch bei langwierig abzuschreckenden Werkstücken schneller betrieben werden kann, da die erste Kammer der Abschreckeinrichtung, welche beim Abschrecken ein Beladen und Entladen des Drehherdofens blokkiert, für eine geringere Zeitdauer belegt ist. Sobald das abzuschreckende Werkstück aus der ersten Kammer entfernt ist, kann der Drehherdofen neu Entladen und/oder Beladen werden.With the subdivision of the quenching into two sub-steps it is achieved that the method can be operated faster even with protracted work pieces, since the first chamber of the quenching device, which blocks the loading and unloading of the rotary hearth furnace during quenching, is occupied for a shorter period of time. Once the quenched workpiece is removed from the first chamber, the rotary hearth furnace can be re-unloaded and / or loaded.

Um das Werkstück von der ersten in die zweite Kammer der Abschreckeinrichtung zu bewegen wird ein Belade/Entlademanipulator verwendet, wobei entweder der erste Belade/Entlademanipulator, welcher auch zum Beladen des Drehherdofens dient, oder aber ein zweiter Belade/Entlademanipulator verwendet werden kann. Vorzugsweise wird der zweite Belade/Entlademanipulator verwendet, da so vermieden werden kann, dass der erste Manipulator mit Abschreckmedium verunreinigt wird.To move the workpiece from the first to the second chamber of the quench device becomes a load / unload manipulator wherein either the first loading / unloading manipulator, which also serves to load the rotary hearth furnace, or a second loading / unloading manipulator can be used. Preferably, the second loading / Entlademanipulator is used, since it can be avoided that the first manipulator is contaminated with quenching medium.

Bei dem ersten und dem zweiten Abschreckvorgang können entweder die gleichen oder verschiedene Abschreckmedien verwendet werden, wodurch die Flexibilität des Verfahrens im Hinblick auf das Abschrecken selber erheblich erhöht wird. Um die Effizienz des Abschreckens zu erhöhen ist es bevorzugt, das bzw. die Abschreckmedien während des Abschreckens mit einer entsprechenden Pumpe umzuwälzen.In the first and second quenching processes, either the same or different quench media may be used, thereby greatly increasing the flexibility of the process itself in terms of quenching. In order to increase the efficiency of quenching, it is preferable to agitate the quench media during quenching with a corresponding pump.

Um die Effizienz und Gleichmäßigkeit des Abschreckens weiter zu steigern ist es bei einem bevorzugten Ausführungsbeispiels vorgesehen, dass das Werkstück von der ersten Hebeeinrichtung im ersten Abschreckmedium auf einer Dreheinrichtung mit Drehteller abgesetzt wird, wobei der Drehteller das Werkstück mit einer einstellbaren Drehzahl im Abschreckmedium gedreht wird. Um das Werkstück auf dem Drehteller der Dreheinrichtung absetzen zu können wird die erste Hebeeinrichtung über den äußeren Umfang des Drehtellers der Dreheinrichtung nach unten abgesenkt. Es ist ferner bevorzugt, besonders bei speziellen Werkstücken wie beispielsweise Zahnrädern, dass spezielle Außenbereiche, wie beispielsweise die Zahnkranzfläschen, mit einem Düsensystem angeströmt werden.In order to further increase the efficiency and uniformity of the quenching, it is provided in a preferred embodiment that the workpiece is deposited by the first lifting device in the first quenching medium on a turntable with a turntable, wherein the turntable, the workpiece is rotated at an adjustable speed in the quenching medium. In order to be able to deposit the workpiece on the turntable of the rotary device, the first lifting device is lowered over the outer circumference of the turntable of the rotary device down. It is also preferred, especially for special workpieces such as gears, that special outdoor areas, such as the sprocket, be flown with a nozzle system.

Wie bereits oben ausgeführt, ist es von wesentlicher Bedeutung für das Verfahren, dass die Kerntemperatur der Werkstücke nach dem Nachbehandeln 25°C bis 35°C beträgt. Ferner ist darauf zu achten, dass nicht ein Verfahrensschritt aufgrund seiner Dauer das gesamte Verfahren verlangsamt. Bei besonderes großen Werkstücken kann es jedoch vorkommen, dass die Zeitspanne, die für das Kühlen, vorgegeben durch die übrigen Verfahrensschritte, zur Verfügung steht, nicht ausreichend ist, um die oben genannte Kerntemperatur der Werkstücke zu erreichen.As stated above, it is essential for the process that the core temperature of the workpieces after post-treatment is 25 ° C to 35 ° C. It is also important to ensure that not one step slows down the whole procedure because of its duration. In the case of special large workpieces, however, it may happen that the time available for cooling, given by the remaining process steps, is insufficient to achieve the abovementioned core temperature of the workpieces.

Bei einem bevorzugten Ausführungsbeispiel umfaßt daher das Nachbehandeln einen weiteren Kühlschritt, bei welchem das Werkstück weiter abgekühlt wird, so dass am Ende des Nachbehandelns sichergestellt ist, dass bei den Werkstücken die oben genannte Kerntemperatur erreicht ist. Dieser zweite Kühlschritt kann entweder nach dem Trocknen oder aber direkt nach dem ersten Kühlen ausgeführt werden. Der zweite Kühlschritt wird insbesondere dann nach dem Trocknen ausgeführt, wenn mit einem anderen Kühlmittel als im ersten Schritt gekühlt werden soll und eine Verunreinigung des zweiten Kühlmittels durch das erste vermieden werden soll. Für den Fall, dass der zweite Kühlschritt nach dem Trocknen ausgeführt wird, und trotzdem werkstückbedingt mit einer wasserhaltigen Kühlflüssigkeit gekühlt werden muss, so ist darauf zu achten, dass das Werkstück rasch angelassen wird, um eine Oxidation an der Werkstückoberfläche zu vermeiden. Vorzugsweise werden die Schritte des Nachbehandelns für 20 Minuten pro Millimeter (20 min/mm) Einhärtungstiefe durchgeführt.In a preferred embodiment, therefore, the aftertreatment comprises a further cooling step in which the workpiece is further cooled so that it is ensured at the end of the aftertreatment that the workpieces reach the above-mentioned core temperature. This second cooling step can be carried out either after drying or directly after the first cooling. The second cooling step is carried out after drying, in particular, when it is desired to cool with a coolant other than the first step and to prevent contamination of the second coolant by the first one. In the event that the second cooling step is carried out after drying, and yet must be cooled with a water-containing cooling liquid due to the workpiece, it should be ensured that the workpiece is tempered quickly to avoid oxidation on the workpiece surface. Preferably, the post-treatment steps are carried out for 20 minutes per millimeter (20 min / mm) of cure depth.

Bei dem Nachbehandeln kann es vorkommen, dass sich, in Abhängigkeit von der für das Werkstück verwendeten Legierung und der Ausformung des Werkstücks, dieses beim Waschen und Kühlen geringfügig verzieht. Daher ist es bevorzugt, dass das Werkstück direkt nach dem Kühlen kalt ausgerichtet wird, um ggf. aufgetretene Verzüge des Werkstückes zu beseitigen.In the after-treatment, it may happen that, depending on the alloy used for the workpiece and the shape of the workpiece, this slightly warps during washing and cooling. Therefore, it is preferred that the workpiece is aligned cold immediately after cooling, in order to eliminate possibly occurring distortions of the workpiece.

Um eine weitere Aushärtung insbesondere der Randbereiche des Werkstücks zu erzielen, ist es bei einer bevorzugten Ausführungsform des Verfahrens vorgesehen, dass das Werkstück nach dem Anlassen zumindest in Teilbereichen einer Kugelstrahlverfestigung unterzogen wird.In order to achieve a further curing, in particular of the edge regions of the workpiece, it is provided in a preferred embodiment of the method that the workpiece after tempering is at least partially subjected to a shot peening process.

Die oben genannte Aufgabe wird ferner gelöst durch eine erfindungsgemäße Anlage zum kontinuierlichen Einsatzhärten von Werkstücken, wobei die Anlage einen Voroxidationsofen und einen Drehherdofen mit zumindest einer Belade/Entladeöffnung und mit mehreren über vertikal bewegbare Türen getrennte Behandlungszonen aufweist. Der Belade/Entladeöffnung des Drehherdofens ist eine Abschreckeinrichtung mit zumindest einer Hebeeinrichtung zugeordnet, und der Abschreckeinrichtung ist eine Nachbehandlungseinrichtung mit einer Waschzone, einer Kühlzone und einer Trockenzone nachgeschaltet. Die Anlage umfaßt ferner einen Anlassofen sowie zumindest einen Belade-/Entnahmemanipulator, mit welchem die Werkstücke in den Drehherdofen eingeführt werden und nach der Wärmebehandlung aus diesem entnommen werden, und auf der Hebeeinrichtung der Abschreckeinrichtung abgesetzt werden. Der Belade-/Entnahmemanipulator dient ferner dazu, das Werkstück aus der Abschreckeinrichtung zu entnehmen und der Nachbehandlungseinrichtung zuzuführen.The above object is further achieved by an inventive plant for continuous case hardening of workpieces, the plant having a pre-oxidation furnace and a rotary hearth furnace with at least one loading / unloading and with a plurality of vertically movable doors via separate treatment zones. The loading / unloading of the rotary hearth furnace is associated with a quenching device with at least one lifting device, and the quenching device is a After treatment device downstream of a washing zone, a cooling zone and a drying zone. The plant further comprises a tempering furnace and at least one loading / unloading manipulator, with which the workpieces are introduced into the rotary hearth furnace and are removed after the heat treatment, and deposited on the lifting device of the quenching device. The loading / unloading manipulator also serves to remove the workpiece from the quenching device and supply it to the aftertreatment device.

Für den Fall, dass die Waschzone, die Kühlzone und die Trockenzone als separate Einrichtungen ausgebildet sind, kann der Belade-/Entnahmemanipulator ferner dazu verwendet werden, die Werkstücke zwischen den einzelnen Einrichtungen zu bewegen. Die Nachbehandlungseinrichtung kann jedoch auch so ausgebildet sein, dass die Werkstücke auf Transportrollen oder mit Förderketten von einer Zone zur nächsten transportiert werden.In the event that the washing zone, the cooling zone and the drying zone are formed as separate devices, the loading / unloading manipulator can also be used to move the workpieces between the individual devices. However, the aftertreatment device can also be designed such that the workpieces are transported on transport rollers or with conveyor chains from one zone to the next.

Um den Ausfall des Belade-/Entnahmemanipulators zu kompensieren, kann es ferner vorgesehen sein, dass die Anlage einen zweiten Belade-/Entnahmemanipulator aufweist, wobei vorzugsweise vorgesehen ist, dass der erste Belade-/Entnahmemanipulator lediglich zum Be- und Entladen des Drehherdofens dient und der zweite Belade-/Entnahmemanipulator das Werkstück aus der Abschreckeinrichtung entnimmt und der Nachbehandlungseinrichtung zuführt. Die Verwendung von zumindest zwei Belade-/Entnahmemanipulatoren hat ferner den Vorteil, dass der erste Belade-/Entnahmemanipulator nicht mit Abschreckmedium verunreinigt wird, und dass die Taktzeiten der Anlage verringert werden können, da die oben beschriebenen Belade-, Entlade- und Zuführungsoperationen auf zwei Manipulatoren aufgeteilt werden können. Ferner besteht der Vorteil, dass bei einem Ausfall eines Belade/Entlademanipulators mit dem zweiten Belade/Entlademanipulator noch die Drehherdofenanlage nach den vorgesehenen Verfahrensschritten entleert werden kann, so dass der finanzielle Schaden in Grenzen gehalten werden kann. Hierfür müsste unter Umständen ein Belade/Entlademanipulator innerhalb einer Taktzeit in eine Parkposition gebracht werden, die den Verfahrablauf nicht stört. Bei der Verwendung von Belade-/Entnahmemanipulatoren weisen die beiden Manipulatoren ein gemeinsames Führungssystem auf, da nur so gewährleistet ist, dass der eine Manipulator als Ersatz des anderen eingesetzt werden kann.To compensate for the failure of the loading / unloading manipulator, it may further be provided that the system has a second loading / unloading manipulator, wherein it is preferably provided that the first loading / unloading manipulator is used only for loading and unloading the rotary hearth furnace and the second loading / unloading manipulator removes the workpiece from the quenching device and supplies it to the aftertreatment device. The use of at least two loading / unloading manipulators also has the advantage that the first loading / unloading manipulator is not contaminated with quenching medium and that the cycle times of the equipment can be reduced since the loading, unloading and feeding operations described above are reduced to two Manipulators can be split. Furthermore, there is the advantage that, in the event of a failure of a loading / unloading manipulator with the second loading / unloading manipulator, the rotary hearth furnace system can still be emptied after the intended method steps, so that the financial damage can be kept within limits. For this, under certain circumstances, a loading / unloading manipulator would have to be brought into a parking position within a cycle time, which does not disturb the course of the procedure. When using Loading / unloading manipulators, the two manipulators on a common guide system, as only so it is guaranteed that the one manipulator can be used as a substitute for the other.

Um, wie bereits oben ausgeführt, zu verhindern, dass ggf. das Abschrecken das Gesamtverfahren ausbremst, weist eine bevorzugte Ausführungsform der Anlage eine Abschreckeinrichtung mit zwei Abschreckkammern auf, wobei jede dieser Abschreckkammern eine Hebeeinrichtung umfaßt. Um die Verfahrensführung möglichst flexibel zu halten, sind die beiden Hebeeinrichtungen getrennt voneinander vertikal bewegbar. Um einen raschen und möglichst einfachen Transport des Werkstücks aus dem Drehherdofen in die Abschreckeinrichtung zu gewährleisten, ist die erste Abschreckkammer der Abschreckeinrichtung dem Drehherdofen zugeordnet, d.h. derart direkt vor der Belade-/Entladeöffnung des Drehherdofens angeordnet, dass ein Belade-/Entnahmemanipulator zum Entladen des Drehherdofens und Absetzen des Werkstücks auf der ersten Hebeeinrichtung lediglich in radialer Richtung verfahren werden muss.In order, as stated above, to prevent the quenching from possibly slowing down the overall process, a preferred embodiment of the plant comprises a quenching device with two quenching chambers, each of these quenching chambers comprising a lifting device. In order to keep the process management as flexible as possible, the two lifting devices are separated from each other vertically movable. In order to ensure a quick and easy transport of the workpiece from the rotary hearth furnace into the quenching device, the first quenching chamber of the quenching device is associated with the rotary hearth furnace, i. arranged directly before the loading / unloading of the rotary hearth furnace that a loading / unloading manipulator for unloading the rotary hearth furnace and settling of the workpiece on the first lifting device must be moved only in the radial direction.

Wie bereits angedeutet, ist der Abschreckvorgang kritisch, da dieser ggf. für das Verfahren geschwindigkeitsbestimmend sein kann. Um das Abschrecken zu beschleunigen, ist bei einer bevorzugten Ausführungsform der Anlage vorgesehen, dass die Abschreckeinrichtung bzw. eine Kammer der Abschreckeinrichtung eine Dreheinrichtung mit einem Drehteller umfaßt, wobei der Drehteller der Dreheinrichtung derart ausgebildet ist, dass die Hebeeinrichtung über den äußeren Umfang des Drehtellers nach unten abgesenkt werden kann, und auf diese Weise das Werkstück auf dem Drehteller abgelegt werden kann. Die Abschreckeinrichtung bzw. eine oder beide der Kammern der Abschreckeinrichtung kann bzw. können mit Düsensystemen ausgerüstet sein, um ein gezieltes Anströmen bestimmter Bereiche des Werkstücks zu ermöglichen.As already indicated, the quenching process is critical because it may possibly be rate-determining for the process. In order to accelerate quenching, it is provided in a preferred embodiment of the system that the quenching device or a chamber of the quenching device comprises a rotating device with a turntable, wherein the turntable of the rotating device is designed such that the lifting device over the outer circumference of the turntable after can be lowered down, and in this way the workpiece can be placed on the turntable. The quenching device or one or both of the chambers of the quenching device can or can be equipped with nozzle systems in order to allow a targeted flow against certain areas of the workpiece.

Um zu verhindern, dass das Werkstück bei der Entnahme aus dem Drehherdofen und dem Absetzen auf der Hebeeinrichtung der Abschreckeinrichtung bzw. der ersten Kammer der Abschreckeinrichtung durch Atmosphäreneinflüsse beeinträchtigt wird, ist es bevorzugt, dass der Abschreckeinrichtung bzw. der ersten Kammer der Abschreckeinrichtung eine gasdichte Eingangs-/Ausgangsschleuse mit einer Mehrzahl von gasdicht-verschließbaren Türen zugeordnet ist. Die Anzahl und die Anordnung der gasdicht-verschließbaren Türen ist abhängig davon, wie die Werkstücke in den Drehherdofen eingebracht werden, ggf. zwischen den einzelnen Kammern der Abschreckeinrichtung bewegt werden, und der Abschreckeinrichtung entnommen werden.In order to prevent the workpiece from being affected by atmospheric influences when it is removed from the rotary hearth furnace and deposited on the lifting device of the quenching device or the first chamber of the quenching device it is preferred that the quenching device or the first chamber of the quenching device is associated with a gas-tight inlet / outlet lock with a plurality of gastight-sealable doors. The number and arrangement of the gas-tight-lockable doors depends on how the workpieces are introduced into the rotary hearth furnace, if necessary moved between the individual chambers of the quenching device, and taken from the quenching device.

Um auch bei großen Werkstücken sicherzustellen, dass die Kerntemperatur der Werkstücke vor dem Anlassen zwischen 25°C und 35°C beträgt, umfasst bei einer bevorzugten Ausführungsform der erfindungsgemäßen Anlage die Nachbehandlungseinrichtung eine weitere Kühlzone, wobei diese Kühlzone der Trockenzone vor- oder nachgeschaltet sein kann. In beiden Kühlzonen kann das gleiche Kühlmittel, oder aber unterschiedliche Kühlmittel verwendet werden, wobei bei der Verwendung von Wasser als Kühlmittel und der Anordnung der Kühlzone hinter der Trokkenzone (bezogen auf den Verfahrensablauf) darauf zu achten ist, dass das Werkstück rasch dem Anlassofen zugeführt wird.In order to ensure that the core temperature of the workpieces is between 25 ° C and 35 ° C even before starting, in a preferred embodiment of the system according to the invention, the aftertreatment device comprises a further cooling zone, which cooling zone may be upstream or downstream of the drying zone , In both cooling zones, the same coolant, or different coolant can be used, it must be ensured when using water as a coolant and the arrangement of the cooling zone behind the drying zone (based on the process flow) that the workpiece is fed quickly to the tempering furnace ,

Um eine Überarbeitung des Werkstücks vor dem Anlassen zu ermöglichen, ist es bevorzugt, dass die Anlage eine der Nachbehandlungseinrichtung nachgeschaltete Kaltrichteinrichtung zum Richten der Werkstücke umfasst. Ferner kann die Anlage eine dem zumindest einen Anlassofen nachgeschaltete Kugelstrahlverfestigungseinrichtung umfassen.In order to enable a reworking of the workpiece before tempering, it is preferred that the system comprises a cold rectifying device connected downstream of the aftertreatment device for straightening the workpieces. Furthermore, the system may comprise a ball-beam hardening device arranged downstream of the at least one tempering furnace.

Im Nachfolgenden wird unter Bezugnahme auf die beigefügte Zeichnung ein Ausführungsbeispiel des erfindungsgemäßen Verfahrens sowie ein Ausführungsbeispiel der erfindungsgemäßen Anlage beschrieben. In der Zeichnung zeigt:

  • Figur 1 eine Draufsicht auf das Ausführungsbeispiel der erfindungsgemäßen Anlage und
  • Figur 2 eine detaillierte Draufsicht auf die Abschreckeinrichtung gemäß dem Ausführungsbeispiel der erfindungsgemäßen Anlage.
In the following, an embodiment of the method according to the invention and an embodiment of the system according to the invention will be described with reference to the accompanying drawings. In the drawing shows:
  • FIG. 1 a plan view of the embodiment of the system according to the invention and
  • FIG. 2 a detailed plan view of the quenching device according to the embodiment of the inventive system.

Figur 1 zeigt eine Draufsicht des Ausführungsbeispiels der erfindungsgemäßen Anlage. Die Anlage umfasst einen Voroxidationsofen (1), in welchem Werkstücke (100) zur Aktivierung auf eine Temperatur zwischen 400°C und 500°C erwärmt werden. Sollten die Werkstücke Schneidöl- oder Waschmittelrückstände aufweisen, werden diese im Voroxidationsofen abgebrannt. Die Beheizung der Werkstücke im Voroxidationsofen erfolgt vorzugsweise durch senkrecht angeordnete (nicht darstellte) Gasbrenner. In der Ofendecke angeordnete Lüfter dienen zur Umwälzung der Atmosphäre im Voroxidationsofen. Der Transport durch den Ofen erfolgt entweder über angetriebene Transportrollen oder Förderketten. Am Eingang und Ausgang des Voroxidationsofens ist dieser mit verschließbaren Türen versehen. Am in Figur 1 links dargestellten Ende des Ofens ist schematisch ein Verfahrwagen mit Hubtisch dargestellt, auf welchen die Werkstücke nach Durchlaufen des Voroxidationsofens befördert werden. Bei dem in Figur 1 dargestellten Ausführungsbeispiel ist der Verfahrwagen senkrecht zu dem Voroxidationsofen bewegbar. FIG. 1 shows a plan view of the embodiment of the system according to the invention. The plant comprises a pre-oxidation furnace (1) in which workpieces (100) for activation a temperature between 400 ° C and 500 ° C are heated. If the workpieces have cutting oil or detergent residues, they are burned off in the pre-oxidation oven. The heating of the workpieces in the pre-oxidation is preferably carried out by vertically arranged (not shown) gas burner. Fans arranged in the furnace roof serve to circulate the atmosphere in the pre-oxidation furnace. Transport through the oven is either via powered transport rollers or conveyor chains. At the entrance and exit of the pre-oxidation furnace this is provided with lockable doors. At the in FIG. 1 At the left end of the furnace shown schematically is a carriage with lifting table, on which the workpieces are transported after passing through the pre-oxidation furnace. At the in FIG. 1 illustrated embodiment, the Verfahrwagen is perpendicular to the pre-oxidation furnace movable.

Die erfindungsgemäße Anlage umfasst ferner einen Drehherdofen (50) mit fünf vertikal bewegbaren, ggf. gasdichten Türen (51a, 51b, 51c, 51d, 51e), wobei die Türen eine Aufheizzone (52a), eine ersten Aufkohlungszone (52b), eine zweiten Aufkohlungszone (52c), eine Härtezone (52d) sowie eine Belade-/Entladezone (52e) begrenzen. Der Drehherdofen wird über einen (nicht dargestellten) geregelten Antrieb über Zahnrad und Zahnstange angetrieben. Über den Drehherdofen sind (nicht gezeigte) Absolutwertgeber verteilt, um ein Abschalten einzelner oder mehrerer Behandlungszonen zu ermöglichen. Gelagert ist der Drehherdofen auf Rollenböcken, und die lagegenaue Seitenführung wird durch Zentrierrollen hergestellt. Der Drehherdofen ist nach außen über eine innere und äußere Öltasse abgedichtet und wird durch senkrecht angeordnete, gasbeheizte, vollkeramische Mantelstrahlrohre beheizt. Zum Beladen und Entladen weist der Drehherdofen in seiner Außenwand (54) eine vorzugsweise gasdicht verschließbare Belade-/Entladeöffnung (53) auf.The plant according to the invention further comprises a rotary hearth furnace (50) with five vertically movable, possibly gas-tight doors (51a, 51b, 51c, 51d, 51e), the doors having a heating zone (52a), a first carburizing zone (52b), a second carburizing zone (52c), a hardening zone (52d) and a loading / unloading zone (52e). The rotary hearth furnace is driven via a (not shown) controlled drive via gear and rack. Absolute encoders (not shown) are distributed over the rotary hearth furnace to enable shutdown of one or more treatment zones. The rotary hearth furnace is mounted on roller blocks, and the positionally accurate side guide is produced by centering rollers. The rotary hearth furnace is sealed to the outside via an inner and outer oil cup and is heated by vertically arranged, gas-heated, full-ceramic Mantelstrahlrohre. For loading and unloading, the rotary hearth furnace has in its outer wall (54) a preferably gas-tight sealable loading / unloading opening (53).

Der Belade-/Entladeöffnung ist eine Abschreckeinrichtung (40) derart zugeordnet, dass ein Belade-/Entlademanipulator (10, 10', 20) das Werkstück durch eine radiale Bewegung aus der Belade-/Entladezone (52e) entnehmen kann und auf einer Hebeeinrichtung der Abschreckeinrichtung (40) absetzen kann.The loading / unloading opening is associated with a quenching device (40) such that a loading / unloading manipulator (10, 10 ', 20) ejects the workpiece by a radial movement the loading / unloading zone (52e) and can settle on a lifting device of the quenching device (40).

Die Abschreckeinrichtung (40) wird nun unter Bezugnahme auf Figur 2 detaillierter beschrieben. Die in Figur 2 dargestellte Abschreckeinrichtung (40) umfasst zwei Abschreckkammern, wobei jede Abschreckkammer ein Ölbad zum Abschrecken der Werkstücke und eine Hebeeinrichtung mit Hebeteller (43a, 43b) umfasst. Der ersten Abschreckkammer (in der Zeichnung unten dargstellt) ist eine gasdichte Eingangs/Ausgangsschleuse (41) mit einer Mehrzahl von gasdicht verschließbaren Türen zugeordnet, wobei die Türen aus gründen der Übersichtlichkeit nicht dargestellt sind. Im Ölbad der ersten Abschreckkammer ist eine Dreheinrichtung mit Drehteller (44) angeordnet, wobei der Drehteller über einen Antrieb (42) bewegt wird. In mindestens dem ersten Ölbad ist ferner ein Düsensystem angeordnet, um das Anströmen bestimmter Bereiche der Werkstücke zu ermöglichen, und das Öl in den Ölbädern wird mit Axialdüsen umgewälzt. Bei anderen Ausführungsbeispielen können andere Abschreckmittel verwendet werden, wobei die Abschreckeinrichtung jeweils an das bzw. die verwendeten Abschreckmedien anzupassen ist, wobei die Wahl des Abschreckmittels primär von der Größe und Beschaffenheit des Werkstücks abhängt.The quenching device (40) will now be described with reference to FIG FIG. 2 described in more detail. In the FIG. 2 The quenching device (40) shown comprises two quenching chambers, each quenching chamber comprising an oil bath for quenching the workpieces and a lifting device with lifting plate (43a, 43b). The first quenching chamber (shown in the drawing below) is associated with a gas-tight inlet / outlet lock (41) having a plurality of gas-tight lockable doors, the doors not being shown for reasons of clarity. In the oil bath of the first quenching chamber a rotating device with turntable (44) is arranged, wherein the turntable is moved by a drive (42). In at least the first oil bath, a nozzle system is further arranged to allow the flow of certain areas of the workpieces, and the oil in the oil baths is circulated by axial nozzles. In other embodiments, other quenching means may be used, with the quenching means being adapted to the quenching media (s) used, the choice of quenching agent primarily depending on the size and nature of the workpiece.

Die erfindungsgemäße Anlage umfasst ferner eine Nachbehandlungseinrichtung (60) mit einer Waschzone (61), einer ersten Kühlzone (62), einer zweiten Kühlzone (63) und einer Trockenzone (64), wobei bei dem gezeigten Ausführungsbeispiel die jeweiligen Zonen als separate Einrichtungen ausgebildet sind (und nachfolgend auch so bezeichnet werden). Sobald das Werkstück in die Wascheinrichtung eingebracht ist, wird das Werkstück über ein Düsensystem mit einer Waschflüssigkeit gewaschen, wobei die Wahl der Waschflüssigkeit primär von dem bzw. den Abschreckmedium abhängig ist. Üblich ist die Verwendung von Wasser, ggf. mit Zusätzen, als Waschflüssigkeit. Um die Effizienz des Waschens zu erhöhen wird der Waschvorgang bei Temperaturen zwischen 40°C und 80°C durchgeführt.The system according to the invention further comprises an aftertreatment device (60) having a washing zone (61), a first cooling zone (62), a second cooling zone (63) and a drying zone (64), wherein in the embodiment shown the respective zones are designed as separate devices (and hereinafter also so called). As soon as the workpiece is introduced into the washing device, the workpiece is washed via a nozzle system with a washing liquid, wherein the choice of the washing liquid is primarily dependent on the or the quenching medium. It is customary to use water, if appropriate with additives, as washing liquid. To increase the efficiency of washing, the washing process is carried out at temperatures between 40 ° C and 80 ° C.

Von der Wascheinrichtung (61) wird das Werkstück in die erste Kühleinrichtung (62) bewegt und dort mit einer ersten Kühlflüssigkeit, üblicherweise Wasser, abgekühlt, wobei bevorzugt ist, dass das Werkstück in die Flüssigkeit abgesenkt wird. Nach Ablauf einer vorgegebenen ersten Kühlzeit wird das Werkstück entnommen und in Abhängigkeit von der Kerntemperatur des Werkstücks entweder der zweiten Kühleinrichtung (63) oder der Trockeneinrichtung (64) zugeführt. Für den Fall, dass die takt- und verfahrensbedingte erste Kühlzeit nicht ausreichte, um die Kerntemperatur auf zwischen 25°C und 35°C abzusenken, wird das Werkstück der zweiten Kühleinrichtung (63) zugeführt, ansonsten der Trockeneinrichtung (64). Wiederum nach Ablauf einer vorgegebenen zweiten Kühlzeit wird das Werkstück der zweiten Kühleinrichtung entnommen und der Trockeneinrichtung (64) zugeführt und in dieser getrocknet, beispielsweise mit Ventilator und/oder einem Gebläse. Die einzelnen Einrichtungen der Nachbehandlungseinrichtung (60) sind quasi "in Reihe" geschaltet, was zur Folge hat, dass die Behandlungszeiten in allen Einrichtungen gleich sind (d.h. auch die erste Abkühlzeit entspricht zweiter Abkühlzeit).From the washing device (61), the workpiece is moved into the first cooling device (62) and there with a first Cooling liquid, usually water, cooled, wherein it is preferred that the workpiece is lowered into the liquid. After a predetermined first cooling time, the workpiece is removed and supplied to either the second cooling device (63) or the drying device (64) depending on the core temperature of the workpiece. In the event that the cycle-related first cooling time was insufficient to lower the core temperature to between 25 ° C and 35 ° C, the workpiece is fed to the second cooling device (63), otherwise the drying device (64). Again, after a predetermined second cooling time, the workpiece of the second cooling device is removed and the drying device (64) supplied and dried in this, for example with a fan and / or a fan. The individual devices of the aftertreatment device (60) are virtually "connected in series", with the result that the treatment times are the same in all devices (ie also the first cooling time corresponds to the second cooling time).

Nach dem Trocknen werden die Werkstücke der Trockeneinrichtung (64) entnommen und über einen Querfahrwagen (70) einem von zwei Anlassöfen (81, 82) zugeführt, wobei den Anlassöfen bei einem alternativen Ausführungsbeispiel eine Kaltrichteinrichtung vorgeschaltet sein kann. Den Anlassöfen kann bei einem alternativen Ausführungsbeispiel ferner eine Kugelstrahlverfestigungseinrichtung nachgeschaltet sein.After drying, the workpieces are removed from the drying device (64) and fed via a transverse carriage (70) to one of two tempering furnaces (81, 82), wherein the tempering furnaces in an alternative embodiment can be preceded by a cold rectifying device. The tempering furnaces may further be followed by a shot peening apparatus in an alternative embodiment.

Das in Figur 1 gezeigte Ausführungsbeispiel umfasst ferner zwei Belade/Entlademanipulatoren (10, 20), wobei der erste Belade/Entlademanipulator (10) in zwei Stellungen (10, 10') dargstellt ist. Die beiden Belade/Entlademanipulatoren (10, 20) sind auf einem gemeinsamen Führungssystem (30) verfahrbar, so dass gewährleistet ist, dass bei dem Ausfall eines Belade/Entlademanipulators der andere Belade/Entlademanipulator die Aufgaben des ausgefallenen Belade/Entlademanipulators übernehmen kann. Der erste Belade/Entlademanipulator (10) dient zum Beladen und Entladen des Drehherdofens, während der zweite Belade/Entlademanipulator (20) dazu dient, das Werkstück von der ersten Hebeeinrichtung auf die zweite Hebeeinrichtung zu bewegen, und ferner dazu vorgesehen ist, die Werkstücke der Nachbehandlungseinrichtung zuzuführen und es zwischen den einzelnen Einrichtungen der Nachbehandlungseinrichtung zu bewegen. Bei dem gezeigten Ausführungsbeispiel sind die Belade/Entlademanipulatoren als Hebe/Senkmanipulatoren ausgebildet, d.h. sie untergreifen das Werkstück zum Anheben und werden zum Absenken in geeignete Ausnehmen eingefahren, wobei das Werkstück abgelegt wird, beispielsweise im Drehherdofen. Nach dem Ablegen des Werkstücks wird der jeweilige Belade/Entlademanipulator über die Ausnehmungen entfernt.This in FIG. 1 The illustrated embodiment further includes two loading / unloading manipulators (10, 20), wherein the first loading / unloading manipulator (10) is shown in two positions (10, 10 '). The two loading / unloading manipulators (10, 20) are movable on a common guide system (30), so that it is ensured that in the event of failure of a loading / unloading manipulator, the other loading / unloading manipulator can take over the tasks of the failed loading / unloading manipulator. The first loading / unloading manipulator (10) is for loading and unloading the rotary hearth furnace, while the second loading / unloading manipulator (20) serves to move the workpiece from the first lifting device to the second lifting device is intended to move, and is also intended to supply the workpieces to the aftertreatment device and to move it between the individual devices of the aftertreatment device. In the embodiment shown, the loading / Entlademanipulatoren are designed as lifting / Senkmanipulatoren, ie they engage under the workpiece for lifting and are retracted for lowering in appropriate exceptions, wherein the workpiece is stored, for example in the rotary hearth furnace. After the workpiece has been deposited, the respective loading / unloading manipulator is removed via the recesses.

Im Nachfolgenden wird ein Ausführungsbeispiel des erfindungsgemäßen Verfahrens anhand der Figuren 1 und 2 beschrieben. Das Werkstück (100) wird zunächst in einen Voroxidationsofen (1) eingebracht, in welchem das Werkstück bei einer Temperatur zwischen 200°C und 500°C voroxidiert wird. Bei dem Werkstück kann es sich beispielsweise um Großzahnräder handeln, die beispielsweise aus 18CrNiMo7/6- oder 16MnCr5-Stahl hergestellt sind. Sollte das Werkstück Schneidöl- oder Waschmittelrückstände aufweisen, werden diese abgebrannt. Am Ende des Ofens wird das Werkstück auf einen verfahrbaren Hubtisch ausgefahren und von diesem dem ersten Belade/Entlademanipulator (10) zugeführt. Der Belade/Entlademanipulator untergreift das Werkstück, hebt es an und verfährt mit dem aufliegendem Werkstück in Richtung Abschreckeinrichtung (40) vor die Belade/Entladeöffnung (53) des Drehherdofens (50). In Figur 1 ist der erste Belade/Entlademanipulator (10) in zwei Positionen (10, 10') gezeigt, nämlich einmal der Aufnahmeposition (10) und einmal in der Position, in welcher das Werkstück in den Drehherdofen eingebracht wird.In the following, an embodiment of the method according to the invention will be described with reference to FIG FIGS. 1 and 2 described. The workpiece (100) is first introduced into a pre-oxidation furnace (1) in which the workpiece is pre-oxidized at a temperature between 200 ° C and 500 ° C. The workpiece may be, for example, large gears made of, for example, 18CrNiMo7 / 6 or 16MnCr5 steel. If the workpiece has cutting oil or detergent residues, they will be burned off. At the end of the furnace, the workpiece is extended to a movable lifting table and supplied from this to the first loading / unloading manipulator (10). The loading / unloading manipulator engages under the workpiece, raises it and moves with the resting workpiece in the direction of quenching device (40) in front of the loading / unloading opening (53) of the rotary hearth furnace (50). In FIG. 1 the first loading / unloading manipulator (10) is shown in two positions (10, 10 '), namely once the receiving position (10) and once in the position in which the workpiece is introduced into the rotary hearth furnace.

Zum Einbringen des Werkstückes (100) in den Drehherdofen (50) wird der Belade/Entlademanipulator samt Werkstück über (nicht dargestellte) verschließbare Öffnungen der Eingangs-/Ausgangsschleuse (41) durch die geöffnete Belade/Entladeöffnung (53) des Drehherdofens in diesen eingebracht und das Werkstück in der Belade/Entladezone (52e) abgesetzt.For introducing the workpiece (100) into the rotary hearth furnace (50), the loading / unloading manipulator together with the workpiece is introduced via (not shown) closable openings of the input / output lock (41) through the open loading / unloading opening (53) of the rotary hearth furnace in this and the workpiece deposited in the loading / unloading zone (52e).

Vorzugsweise sind sämtliche Aufnahme- oder Absetzpositionen bei der Anlage derart gestaltet, dass ein Belade/Entlademanipulator die Werkstücke untergreifen kann.Preferably, all receiving or Absetzpositionen are designed in the system such that a loading / Entlademanipulator can engage under the workpieces.

Das Werkstück wird zunächst in der Aufheizzone (52a) auf eine vorgegebene Aufkohlungstemperatur erwärmt, wobei die Temperaturen in der Aufheizzone zwischen 400°C und 960°C liegen. Nachdem das Werkstück die erforderliche Temperatur erreicht hat, wird es über die geöffnet Tür (51a) in die erste Aufkohlungszone (52b) eingebracht und mit einem vorgegebenen Gas, wie beispielsweise Endogas oder Propan, aufgekohlt. Bei dem in Figur 1 gezeigten Ausführungsbeispiel ist das Aufkohlen auf zwei Teilschritte unterteilt, um die Flexibilität des Aufkohlens selber zu erhöhen. Nach der Behandlung des Werkstücks in der ersten Aufkohlungszone (52b) wird dieses über die geöffnete Tür (51b) in die zweite Aufkohlungszone (52c) geführt. Die Aufkohlung selber findet bei Temperaturen zwischen 900°C und 1000°C statt. Nach dem Aufkohlen wird das Werkstück über die geöffnete Tür (51c) in die Härtezone (52d) überführt, in welcher das Werkstück auf eine vorgegebenen Härtetemperatur eingestellt wird, wobei diese Temperatur vorzugsweise in dem Bereich zwischen 820°C und 860°C liegt. Nach der Verweilzeit in der Härtezone (52d) wird das Werkstück über die geöffnete Tür (51d) in die Belade/Entladezone (52e) geführt, wobei die Atmosphäre aus der Härtezone in die Belade/Entnahmezone entweicht und über einen separaten Austritt und mit einer Fackel abgebrannt wird. Zur Entnahme des Werkstücks aus dem Drehherdofen (50) wird dieses von dem ersten Belade/Entlademanipulator (10) untergriffen und durch die verschließbar Tür (53) des Drehherdofens (50) bewegt und auf dem Hebeteller (53a) der ersten Hebeeinrichtung angeordnet. Dabei wird ein Teil der Ofenatmosphäre über einen Flammenschleier am Eintritt des Manipulators in die Abschreckkammer abgebrannt, um den Eintritt von zuviel Sauerstoff in die Anlage zu vermeiden. Vor dem Absenken des Hebetellers wird die Ofentüre wieder verschlossen, der Manipulator verlässt die Abschreckeinrichtung (40) und die Außentüre wird geschlossen. Der Hebeteller (53a) der Hebeeinrichtung wird dann abgesenkt und das Werkstück im ersten Ölbad auf dem Drehteller (44) der Dreheinrichtung abgesetzt. Das Werkstück verweilt nun für eine vorgegebene Abschreckzeit im ersten Ölbad. Während dieser Zeit wird das Öl durch zumindest eine (nicht gezeigte) Axialpumpe umgewälzt, wobei die Drehzahl der Pumpe stufenlos verstellbar ist, und die Randbereiche des Werkstücks werden von einem Düsensystem gezielt mit Öl angeströmt. Während des Abschreckvorgangs wird das Werkstück über die Dreheinrichtung gedreht, wobei deren Drehzahl stufenlos zwischen 1 bis 10 Umdrehungen pro Minute verstellbar ist.The workpiece is first heated in the heating zone (52a) to a predetermined carburizing temperature, wherein the temperatures in the heating zone between 400 ° C and 960 ° C. After the workpiece reaches the required temperature, it is introduced into the first carburizing zone (52b) via the opened door (51a) and carburized with a predetermined gas, such as endogas or propane. At the in FIG. 1 In the embodiment shown, carburizing is subdivided into two sub-steps in order to increase the flexibility of carburizing itself. After the treatment of the workpiece in the first carburizing zone (52b), it is guided via the opened door (51b) into the second carburizing zone (52c). Carburizing itself takes place at temperatures between 900 ° C and 1000 ° C. After carburizing, the workpiece is transferred via the open door (51c) to the hardening zone (52d) where the workpiece is set at a predetermined hardening temperature, which temperature is preferably in the range between 820 ° C and 860 ° C. After the residence time in the hardening zone (52d), the work is guided via the opened door (51d) into the loading / unloading zone (52e), with the atmosphere escaping from the hardening zone into the loading / unloading zone and via a separate exit and with a torch is burned off. To remove the workpiece from the rotary hearth furnace (50), this is engaged by the first loading / unloading manipulator (10) and moved through the closable door (53) of the rotary hearth furnace (50) and arranged on the lifting plate (53a) of the first lifting device. In this case, a portion of the furnace atmosphere is burned via a flame veil at the entrance of the manipulator in the quenching chamber to prevent the entry of excessive oxygen in the system. Before lowering the lifting plate, the oven door is closed again, the manipulator leaves the quenching device (40) and the outer door is closed. The lifting plate (53a) of the lifting device is then lowered and the workpiece in the first oil bath placed on the turntable (44) of the rotating device. The workpiece now lingers for a predetermined quenching time in the first oil bath. During this time, the oil is circulated through at least one (not shown) axial, wherein the speed of the pump is infinitely adjustable, and the edge regions of the workpiece are targeted by a nozzle system with oil flows. During the quenching process, the workpiece is rotated via the rotating device, wherein the speed is continuously adjustable between 1 to 10 revolutions per minute.

Nach Ablauf der vorgegebenen Zeitdauer wird das Werkstück mit dem Hebeteller (43a) der Hebeeinrichtung aus dem Ölbad gehoben und, ggf. nach einer vorgegebenen Abtropfzeit, wird die Außentüre für den zweiten Belade/Entlademanipulator geöffnet. Bei der in Figur 1 gezeigten Anlage wird das Werkstück dann von dem zweiten Belade/Entlademanipulator (20) untergriffen und über eine (nicht gezeigte) Öffnung aus der Eingangs/Ausgangsschleuse der ersten Kammer der Abschreckeinrichtung (40) entfernt, wobei die geöffnete Tür beim Entfernen des Werkstücks mit einem Gasschleier belegt wird. Das Werkstück wird nun von dem Belade/Entlademanipulator (20) auf den Hebeteller (43b) der zweiten Hebeeinrichtung abgesetzt, und das Werkstück wird dann in dem zweites Ölbad abgesetzt, wobei bei einem alternativen Ausführungsbeispiel auch in dem Ölbad der zweiten Abschreckkammer eine Dreheinrichtung angeordnet sein kann. Nach dem Ablauf einer vorgegebenen Abschreckzeit wird das Werkstück über den Hebeteller (43b) der zweiten Hebeeinrichtung aus dem Ölbad gehoben, wobei die Kerntemperatur des Werkstücks nach dem Gesamtabschreckvorgang zwischen 60°C und 150°C beträgt.After the predetermined period of time, the workpiece with the lifting plate (43a) of the lifting device is lifted out of the oil bath and, if necessary, after a predetermined dripping time, the outer door for the second loading / Entlademanipulator is opened. At the in FIG. 1 The workpiece is then gripped by the second loading / unloading manipulator (20) and removed via an opening (not shown) from the inlet / outlet lock of the first chamber of the quenching device (40), the open door, when removing the workpiece with a gas curtain is occupied. The workpiece is then deposited by the loading / unloading manipulator (20) on the lifting plate (43b) of the second lifting device, and the workpiece is then deposited in the second oil bath, wherein in an alternative embodiment also a rotating device is arranged in the oil bath of the second quenching chamber can. After the lapse of a predetermined quenching time, the workpiece is lifted out of the oil bath via the lifting plate (43b) of the second lifting device, the core temperature of the workpiece being between 60 ° C and 150 ° C after the total quenching operation.

Das Werkstück wird dann, vorzugsweise nach einer gewissen Ölabtropfzeit, von dem zweiten Belade/Entlademanipulator (20) untergriffen und der Nachbehandlungseinrichtung (60) zugeführt, wobei das Werkstück zunächst in der Wascheinrichtung (61) der Nachbehandlungseinrichtung (60) abgesetzt wird. Das Werkstück wird über ein (nicht dargestelltes) Düsensystem mit Waschflüssigkeit, bei welcher es sich vorzugsweise um Wasser mit gegebenenfalls einem Zusatz handelt, gewaschen. Um eine effiziente Entfernung des Öls von dem Werkstück zu gewährleisten, hat die Waschflüssigkeit eine Temperatur zwischen 60°C und 90°C. Nachdem das Werkstück gewaschen wurde, wird es mit dem zweiten Belade/Entlademanipulator der ersten Kühleinrichtung (62) zugeführt, in welcher das Werkstück in eine Kühlflüssigkeit, vorzugsweise Wasser, abgetaucht und gekühlt wird, wobei die Temperatur der Kühlflüssigkeit zwischen 20°C und 40°C beträgt. Nach dem Ablauf der ersten Abkühlzeit wird das Werkstück der ersten Kühleinrichtung entnommen und die Kerntemperatur des Werkstücks ermittelt. Falls diese nicht in dem Bereich zwischen 25°C und 35°C liegen sollte, wird das Werkstück mit dem Belade/Entlademanipulator der zweiten Kühleinrichtung (63) der Nachbehandlungseinrichtung (60) zugeführt, in welcher das Werkstück auf eine Kerntemperatur zwischen 25°C und 35°C abgekühlt wird.The workpiece is then, preferably after a certain Ölabtropfzeit attacked by the second loading / unloading manipulator (20) and the after-treatment device (60), wherein the workpiece is first deposited in the washing device (61) of the aftertreatment device (60). The workpiece is washed via a (not shown) nozzle system with washing liquid, which is preferably water with optionally an additive. To one To ensure efficient removal of the oil from the workpiece, the washing liquid has a temperature between 60 ° C and 90 ° C. After the workpiece has been washed, it is fed with the second loading / unloading manipulator to the first cooling device (62), in which the workpiece is immersed in a cooling liquid, preferably water, and cooled, the temperature of the cooling liquid being between 20 ° C and 40 ° C is. After the end of the first cooling time, the workpiece is removed from the first cooling device and the core temperature of the workpiece is determined. If this should not be in the range between 25 ° C and 35 ° C, the workpiece with the loading / unloading manipulator of the second cooling device (63) of the aftertreatment device (60) is supplied, in which the workpiece to a core temperature between 25 ° C and 35 ° C is cooled.

Nach Ablauf der vorgegebenen zweiten Abkühlzeit, die aus oben genannten Gründen der ersten Abkühlzeit entspricht, wird das Werkstück mit dem zweiten Belade/Entlademanipulator (20) der Trockeneinrichtung (63) zugeführt, in welcher das Werkstück über Ventilatoren und/oder Gasdüsen getrocknet wird. Eine solche Trocknung ist notwendig, da durch die zuvor erfolgte Kühlung des Werkstücks die Oberflächentemperatur des Werkstücks bereits soweit erniedrigt wurde, dass die noch von dem Kühlvorgang anhaftende Waschflüssigkeit nicht schnell genug verdampft und daher, falls mit Wasser gekühlt wurde, eine Oxidation der Werkstückoberfläche einsetzen kann.After expiration of the predetermined second cooling time, which corresponds to the reasons of the first cooling time, the workpiece with the second loading / unloading manipulator (20) of the drying device (63) is supplied, in which the workpiece is dried by fans and / or gas nozzles. Such drying is necessary because the surface temperature of the workpiece has already been lowered by the previously performed cooling of the workpiece so that the washing liquid still adhering to the cooling process does not evaporate quickly enough and therefore, if cooled with water, can use oxidation of the workpiece surface ,

Nach dem Trocknen wird das Werkstück einem der beiden Anlassöfen zugeführt, in welchen die Werkstücke bei einer Temperatur zwischen 160°C und 180°C angelassen werden. Bei einem alternativen Ausführungsbeispiel kann das Werkstück nach dem Anlassen zumindest in Teilbereichen noch einer Kugelstrahlverfestigung unterzogen wird.After drying, the workpiece is fed to one of the two tempering furnaces, in which the workpieces are tempered at a temperature between 160 ° C and 180 ° C. In an alternative embodiment, the workpiece may be subjected to a shot peening at least in some areas after tempering.

Claims (15)

  1. Method for continuous case hardening of workpieces, comprising the steps of:
    a) activating the workpiece (100) in a pre-oxidation furnace (1) at a temperature of between 400 °C and 500 °C,
    b) introducing the workpiece into a rotary hearth furnace (50) via a closable loading/unloading opening (53) of the rotary hearth furnace by means of a first loading/unloading manipulator (10, 10'), heating the workpiece to a predetermined carburising temperature, carburising the workpiece until a predetermined carburisation depth (CD) is achieved and hardening the workpiece at a predetermined hardening temperature,
    c) removing the workpiece from the rotary hearth furnace (50) via the loading/unloading opening (53) by means of the first loading/unloading manipulator (10, 10') and arranging the workpiece on a first lifting device of a quenching device (40), wherein the lifting device is associated with the loading/unloading opening of the rotary hearth furnace,
    d) lowering the workpiece into a quenching medium and quenching the workpiece to a core temperature of between 60 °C and 150 °C to achieve a predetermined hardening depth (CHD) and to achieve a predetermined hardness,
    e) post-treating the workpiece to prepare for tempering, wherein the post-treatment comprises washing, cooling and drying, and wherein the workpiece has a core temperature of between 25 °C and 35 °C after the post-treatment, and
    f) tempering the workpiece at a temperature of between 160 °C and 180 °C.
  2. Method for continuous case hardening of workpieces according to claim 1, characterised in that the quenching of the workpiece according to step d) takes place in such a way that the workpiece is initially quenched in a first chamber, associated with the rotary hearth furnace, of the quenching device by means of a first quenching medium for a predetermined duration, after the first quenching the workpiece is deposited by means of a loading/unloading manipulator (10, 10', 20) on a second lifting device in a second chamber of the quenching device, is lowered into a second quenching medium and is quenched by means of the second quenching medium, the core temperature of the workpiece after the entire quenching process being between 60 °C and 150 °C.
  3. Method for continuous case hardening of workpieces according to either claim 1 or claim 2, characterised in that the workpiece is deposited by the first lifting device in the first quenching medium on a rotary plate (44) of a rotary device which rotates the workpiece at an adjustable rotational speed in the quenching medium, the first lifting device being lowered downwards over the outer periphery of the rotary plate of the rotary device to deposit the workpiece.
  4. Method for continuous case hardening of workpieces according to any of claims 1 to 3, characterised in that, during the post-treatment according to step e), further cooling takes place.
  5. Method for continuous case hardening of workpieces according to any of claims 1 to 4, characterised in that each post-treatment step is performed for 20 minutes per mm hardening depth.
  6. Method for continuous case hardening of workpieces according to any of claims 1 to 5, characterised in that, directly after the cooling according to step e), the workpiece is cold-straightened.
  7. Method for continuous case hardening of workpieces according to any of claims 1 to 6, characterised in that, after the tempering according to step f), the workpiece is subjected to shot peening, at least in portions.
  8. System for continuous case hardening of workpieces, comprising
    a pre-oxidation furnace (1),
    a rotary hearth furnace (50) comprising at least one loading/unloading opening (53) and comprising a plurality of treatment zones (52a, 52b, 52c, 52d, 52e) separated via vertically movable doors (51 a, 51 b, 51 c, 51 d, 51 e),
    a quenching device (40) which is associated with the loading/unloading opening (53) and comprises at least one lifting device,
    a post-treatment device (60) comprising a washing zone, a cooling zone and a drying zone,
    at least one loading/removal manipulator (10, 10', 20), and
    at least one tempering furnace (81, 82).
  9. System for continuous case hardening of workpieces according to claim 8, characterised in that the quenching device (40) comprises two quenching chambers and two lifting devices, the two lifting devices being vertically movable separately from each other and the first quenching chamber being associated with the rotary hearth furnace.
  10. System for continuous case hardening of workpieces according to either claim 8 or claim 9, characterised in that the quenching device (40) or one chamber of the quenching device comprises a rotary device comprising a rotary plate (44), the rotary plate of the rotary device being designed such that the lifting device can be lowered downwards over the outer periphery of the rotary plate.
  11. System for continuous case hardening of workpieces according to any of claims 8 to 10, characterised in that a gas-tight entry/exit gate (41), comprising a plurality of doors which can be closed in a gas-tight manner, is associated with the quenching device (40) or the first chamber of the quenching device.
  12. System for continuous case hardening of workpieces according to claim 11, characterised in that at least one of the doors which can be closed in a gas-tight manner comprises a device for producing a liquid fog.
  13. System for continuous case hardening of workpieces according to any of claims 8 to 12, characterised in that the post-treatment device (60) comprises a further cooling zone.
  14. System for continuous case hardening of workpieces according to any of claims 8 to 13, characterised in that the system further comprises a cold-straightening device downstream of the post-treatment device (60).
  15. System for continuous case hardening of workpieces according to any of claims 8 to 14, characterised in that the system further comprises a shot peening device downstream of the at least one tempering furnace (81, 82).
EP08169293.1A 2008-11-17 2008-11-17 Process and installation for continuous case hardening Not-in-force EP2186916B1 (en)

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Application Number Priority Date Filing Date Title
SI200831082T SI2186916T1 (en) 2008-11-17 2008-11-17 Process and installation for continuous case hardening
ES08169293T ES2434954T3 (en) 2008-11-17 2008-11-17 Procedure and installation for continuous cementation
PL08169293T PL2186916T3 (en) 2008-11-17 2008-11-17 Process and installation for continuous case hardening
EP08169293.1A EP2186916B1 (en) 2008-11-17 2008-11-17 Process and installation for continuous case hardening
PCT/EP2009/065254 WO2010055163A1 (en) 2008-11-17 2009-11-16 Method and system for continuous case hardening

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EP08169293.1A EP2186916B1 (en) 2008-11-17 2008-11-17 Process and installation for continuous case hardening

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EP2186916A1 EP2186916A1 (en) 2010-05-19
EP2186916B1 true EP2186916B1 (en) 2013-10-02

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ES (1) ES2434954T3 (en)
PL (1) PL2186916T3 (en)
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CN102766749B (en) * 2012-07-14 2014-01-01 安徽省宣城市乾坤回转支承有限公司 Process for quenching ball track of slewing bearing
CN109097538B (en) * 2018-09-27 2023-05-09 深圳市和胜金属技术有限公司 Metal surface treatment equipment
CN113564514B (en) * 2021-08-11 2023-05-12 闽侯县捷恒热处理有限公司 Carburizing process and machining structure of guide series
CN115287422A (en) * 2022-08-11 2022-11-04 董永 Quenching device and quenching method for machining of mechanical castings

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SE450389B (en) 1984-10-02 1987-06-22 Volvo Ab METHOD AND PLANT FOR HEAT TREATMENT OF DETAILS WITH VARIOUS REQUIREMENTS FOR HEAT TREATMENT TIME
DE10310739A1 (en) 2002-03-27 2003-10-09 Loi Thermprocess Gmbh Device for heat treating workpieces has an opening for charging/discharging in the outer wall of a rotary furnace in a last treatment zone
DE102007048041A1 (en) * 2007-10-05 2009-04-09 Loi Thermprocess Gmbh Rotary hearth furnace

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ES2434954T3 (en) 2013-12-18
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EP2186916A1 (en) 2010-05-19
WO2010055163A1 (en) 2010-05-20

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