EP4261291A1 - Procédé de fabrication de pièces traitées thermiquement, en particulier de roues dentées à denture hélicoidale et presse de trempe correspondante - Google Patents

Procédé de fabrication de pièces traitées thermiquement, en particulier de roues dentées à denture hélicoidale et presse de trempe correspondante Download PDF

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Publication number
EP4261291A1
EP4261291A1 EP23167649.5A EP23167649A EP4261291A1 EP 4261291 A1 EP4261291 A1 EP 4261291A1 EP 23167649 A EP23167649 A EP 23167649A EP 4261291 A1 EP4261291 A1 EP 4261291A1
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EP
European Patent Office
Prior art keywords
workpiece
support tool
quenching
temperature
target
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.)
Pending
Application number
EP23167649.5A
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German (de)
English (en)
Inventor
Ben Taylor
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Aerospace Transmission Technologies
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Aerospace Transmission Technologies
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Publication date
Application filed by Aerospace Transmission Technologies filed Critical Aerospace Transmission Technologies
Publication of EP4261291A1 publication Critical patent/EP4261291A1/fr
Pending legal-status Critical Current

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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
    • C21D9/32—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for gear wheels, worm wheels, or the like
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/62—Quenching devices
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/62—Quenching devices
    • C21D1/673—Quenching devices for die quenching
    • 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
    • C21D9/04—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails
    • C21D9/06—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails with diminished tendency to become wavy
    • 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
    • C21D9/34—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tyres; for rims
    • 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
    • C21D9/40—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rings; for bearing races

Definitions

  • the invention relates to a method for producing heat-treated workpieces, in particular for producing double-row, helical gears for a planetary gear transmission of an engine. Furthermore, the invention also relates to a hardening press for producing such workpieces using the method mentioned.
  • Double-row helical gears such as those used in particular in epicyclic gears of aircraft engines, are subjected to a carburizing treatment as part of their production, during which an edge layer with a correspondingly increased carbon content and thus changed material properties results in the edge area of a gear body that has been prefabricated almost to its final size.
  • the carburized gears are placed in a hardening press, supported from the inside using a mandrel that acts as a support tool and axially loaded by axial pressure between structures of an upper tool and a lower tool, ie clamped in a dimensionally stable manner.
  • the workpiece secured in this way by the mandrel and the axial clamping against deformation in the hardening press is quenched by applying a cooling medium to the workpiece to achieve a high heat transfer rate.
  • the respective workpiece is cooled to a target quenching temperature which typically corresponds to room temperature - or approximately the temperature of the quenching medium.
  • the mandrel sitting in the workpiece and supporting the workpiece is pressed out of the workpiece.
  • the mandrel is tailored to the geometry of the hole to be supported during quenching in such a way that the pressing of the mandrel that occurs after the initially thermally expanded workpiece shrinks still enables it to be pressed out at room temperature.
  • the workpiece freed from the mandrel can then be subjected to further treatment and machining steps to treat the structure and obtain the final geometry.
  • the invention is based on the object of showing solutions through which it is possible to create workpieces, in particular gears, hardened by press hardening, which are characterized by a further reduced component distortion or a more comprehensive hardening compared to previous approaches, so that these can be achieved in a reliably reproducible manner with narrow Shape tolerances can be manufactured.
  • This object is achieved according to the invention by a method for accomplishing the hardening of an initially heated workpiece, in which the workpiece is supported against deformation by means of a support tool and is brought into contact with a quenching medium for cooling to a target quenching temperature, the support tool and the workpiece being brought into contact with the quenching medium before reaching the The quenching target temperature can be decoupled and the workpiece is further cooled to the quenching target temperature.
  • the workpiece is clamped in a dimensionally stable manner before the quenching step is initiated in the hardening press by structures that contact the workpiece under pressure.
  • the workpiece is also supported in zones that are further apart from the support tool, which has a supporting effect due to its own rigidity.
  • the workpiece is supported against changes in geometry caused by component distortion, in particular changes in geometry in which the workpiece bulges or curves compared to its target geometry.
  • the method according to the invention is carried out in such a way that the support tool is removed from the workpiece while still in the press clamped state of the workpiece. This continues to counteract deformation in the workpiece area supported by the workpiece clamping.
  • the workpiece can be tensioned by axial loading, ie compressive loading of the workpiece in the demolding direction of the support tool, which acts to provide support through its own structural rigidity.
  • the workpiece and the support tool can be joined together by placing the workpiece on the support tool or inserting it into it.
  • the support tool and the workpiece can also be joined together by introducing the support tool into the workpiece held here, in particular by retracting it.
  • the temporal history of bringing the workpiece together with the support tool is preferably carried out identically by using drive elements in accordance with a defined process sequence for similar workpieces. It is possible to provide a period of time after the workpiece and support tool have been brought together in which the support tool heats up under the influence of the workpiece's own heat and expands, so that in this phase there is already a reduction in play or even a defined transition or There is a press fit between the support tool and the workpiece. After this phase, the workpiece is brought into contact with the quenching medium in accordance with a predetermined process. In a first phase in which the workpiece comes into contact with the quenching medium, heat transfer occurs partially with film evaporation.
  • This phase can be detected using process technology; it can be detected in particular acoustically and through pressure fluctuations in the quenching medium. It is possible to recognize the end of this phase of film evaporation and to implement a process concept for separating the workpiece and supporting tool that is based on or takes this point in the quenching process into account. It is also possible to record the thermal state of the workpiece or its ongoing changes in another way and to use the signals collected to determine a point in time for separating the workpiece and the supporting tool.
  • the method according to the invention is carried out in such a way that the support tool is deployed at a defined intermediate temperature.
  • This intermediate temperature is preferably recorded by measurement.
  • This detection can advantageously be carried out by measuring the temperature of the quenching medium after it has come into contact with the workpiece, in particular in the area of a channel section close to the workpiece. It is possible to carry out the method in such a way that the workpiece and support tool are separated, in particular the support tool is removed by pressing out or pulling it out when there is a defined outlet temperature of the quenching medium.
  • the method according to the invention is preferably carried out in such a way that the decoupling of the workpiece and the support tool, in particular the removal of the support tool from the workpiece, takes place at a temperature of the workpiece in a temperature range close to, but below, the martensite formation transition region.
  • the decoupling of the workpiece and the support tool, in particular the deployment of the support tool, can also be timed in such a way that this takes place at a defined shrinkage state of the workpiece, which is preferably recorded for this purpose by measurement.
  • This defined shrinkage state represents an excess state compared to the state of the workpiece at the target quenching temperature.
  • the method according to the invention is further preferably carried out in such a way that after the support tool has been deployed, the contact between the workpiece and the quenching medium is continued, in particular by applying the quenching medium to the workpiece.
  • the quenching medium can also advantageously flow through the spatial area initially filled by the support tool. It is also possible, after the support tool has been removed, in particular pressed out, to insert a further support tool into the workpiece, the dimensions of which are tailored to the shrinkage state when the target quenching temperature is reached. This insertion can take place by replacing the support tool that is matched to the expansion state in the strongly heated state, ie "oversized" support tool, with a support tool that is matched to the quenching target temperature, in particular by pressing it out.
  • the method according to the invention is particularly suitable for the treatment of workpieces in which the inner opening is a cylindrical bore.
  • the support tool is then formed by a mandrel whose dimensions are matched, for example, to the intermediate shrinkage state of the workpiece that occurs just below the martensite transformation compared to the expansion before quenching.
  • a defined temperature fluid, in particular oil, is advantageously used as the quenching medium.
  • the quenching target temperature preferably corresponds at least approximately to the supply temperature of the quenching medium, which in turn can preferably be in the range of room temperature or up to 90 ° C above.
  • the method according to the invention is preferably carried out in such a way that the support tool is removed from the workpiece in a workpiece temperature range between 260 ° C and 190 ° C.
  • the support tool can be dimensioned relatively large and thus develop a high support effect in the high temperature range.
  • the temperature for the removal of the support tool, in particular the mandrel, from the workpiece is chosen to be lower, the support tool or the mandrel must be dimensioned correspondingly smaller.
  • the support tool can then be deployed, for example, at a workpiece temperature of 200°C. At this temperature value there is still considerable thermal expansion of the workpiece, but after removal of the support tool, in particular the mandrel, there is no longer any significant component distortion.
  • the support tool and the inner opening are geometrically coordinated with one another in such a way that a demoulding or decoupling force that is borderline for squeezing is reached before cooling to the target quenching temperature and is overcome to move the support tool.
  • the timing of the start of the deployment of the support tool can also be advantageously determined by modeling of the quenching process can be calculated so that the process can be carried out with the expected parameters and further optimization only requires small corrections.
  • this preferably takes place within the middle third or the penultimate quarter of the quenching time that runs after the first entry of the quenching medium until the workpiece target temperature is reached.
  • the quenching of the workpiece can advantageously be carried out in such a way that it is carried out by applying quenching media to defined areas of the workpiece in a time-controlled manner.
  • the zones of the workpiece that are less relevant for the pressing of the support tool, in particular of the mandrel can be quenched primarily, while the zones that are relevant for the shrinkage of the workpiece in the surrounding area of the support tool, in particular of the mandrel, can be quenched with secondary priority.
  • the support tool is designed to complement the geometry of the inner opening and can be inserted into that inner opening of the heated workpiece.
  • the hardening press includes a quenching device through which the workpiece can be brought into contact with a quenching medium in order to bring about rapid heat transfer from the workpiece and cooling the workpiece by the quenching medium to a target quenching temperature.
  • the support tool is tailored to an expansion state of the workpiece, which results at a workpiece temperature in the upper half of the temperature range between the quenching target temperature and the martensitic transformation range.
  • the support tool is preferably oversized by 4/1000 compared to the dimensions of the inner opening at the target quenching temperature.
  • the support tool can have internal cooling channels, so that the support tool can be cooled to or below the target quenching temperature of the workpiece before the workpiece has completely cooled down.
  • the hardening press in such a way that a complementary geometry is formed in an area of the die base surface and/or an area of the die cover surface, which is coordinated with interim geometries of the respective workpiece, such that the workpiece is formed through the interaction of the interim geometry and the die-side Complementary geometry in the hardening press is positioned radially to the press axis.
  • the hardening press according to the invention is preferably designed in such a way that the complementary geometry on the die side appears as a flat annular groove.
  • two opposite and facing annular grooves can be formed in the upper die and the lower die.
  • the workpiece-side interim geometry is then preferably represented as an annular disk or annular web section.
  • the workpiece is clamped axially at its interim geometries between the mutually facing annular surfaces of the annular grooves.
  • These ring surfaces can be designed as flat surfaces.
  • the workpiece and support tool are decoupled, in particular a support tool designed as a mandrel is moved out when a criterion is met.
  • This criterion can, without this list being exhaustive, include in particular the temperature of the workpiece, the time, a pressure, a shrinkage, a structural state, an amount of energy that is dissipated, a point, and/or an area, and/or a contour section in the thermal Be the cooling profile of the workpiece and/or a temperature value of the cooling medium.
  • the concept according to the invention ensures that the geometries of the support tool used to support the workpiece in the high-temperature phase of the quenching process do not cause an impermissibly tight fit of the support tool in the workpiece when the workpiece cools to the target workpiece temperature.
  • the concept according to the invention achieves a high and narrowly tolerated support effect for workpieces made of a steel material and thus an advantageous shape retention of the workpiece for the most deformation-critical phase of the quenching process.
  • the support tool is designed for a thermal expansion state of the workpiece, which occurs when the component temperature is still considerable, but which is already below the temperature value at which a required structural transformation has occurred.
  • the decoupling of the workpiece and the support tool occurs through a relative movement of these components against each other while overcoming a frictionally present coupling force.
  • the concept according to the invention is preferably implemented in such a way that the decoupling of the workpiece and the support tool takes place in a thermal state of the workpiece in which the coupling force is still below a critical value, for example a force that can be reliably provided and transmitted by the apparatus, or is below a force value at which a significant Wear of the support tool or damage to the workpiece is to be expected.
  • the workpiece can be brought into contact with the quenching medium by filling a spatial area surrounding the workpiece with the quenching medium. This fulfillment can be achieved by supplying the quenching medium or by immersing the workpiece or raising a level of the quenching medium.
  • Martensite is a metastable structure that is formed in a diffusionless and athermal manner through a cooperative shear movement from the original structure.
  • the material must be quenched from the temperature of a high-temperature phase (for steel: ⁇ -phase, austenite) below the equilibrium temperature to a low-temperature phase (for steel: ⁇ -phase, ferrite).
  • the supercooling below the equilibrium temperature must be deep enough to generate the necessary driving force for the athermal phase transformation.
  • the cooling must take place quickly enough to prevent diffusion processes.
  • the necessary subcooling and cooling rate depend heavily on the material in question (in the case of steel, on the alloying elements) and vary over a wide range. If the high-temperature phase is preserved metastable, it can transform into martensite induced by stress or strain (so-called retained austenite transformation in steels). Martensitic transformations occur in unalloyed and alloyed steels, as well as in many non-ferrous metals, ceramics and polymers and are not a phenomenon purely limited to metals. Martensitic transformation is a frequently used option for influencing the properties of steels
  • FIG. 1a serves to illustrate the concept according to the invention for accomplishing quench press hardening of a workpiece WS in a hardening press PQ, the workpiece here being formed, for example, from a steel material.
  • the material of the workpiece WS has the property that during a quenching process a structural transformation occurs with the formation of martensite. As shown in graphic G1, this martensite transformation is completed at a temperature of around 380°C.
  • the quenching process is accomplished by actively contacting the workpiece WS with a quenching medium, in particular oil.
  • a quenching medium in particular oil.
  • This oil is kept ready at a defined temperature level for the quenching process.
  • This temperature level is, for example, 40° and also corresponds to the temperature referred to below as the quenching target temperature to which the workpiece WS is at least approximately cooled.
  • Integrated graphic G2 illustrates the temperature profile of the workpiece during the quenching process.
  • the lower graph f1 shows the drop in the temperature of the workpiece WS directly in the area exposed to the quenching medium.
  • the graph f2 shows the workpiece temperature averaged over the entire volume of the workpiece WS.
  • the course of the average workpiece temperature shows a plateau at a temperature of 350°. This plateau corresponds to the martensite transition of the material of the workpiece WS.
  • This temperature state is reached quickly during the quenching process, here for example after a period of time of (approx. 100 to 150 seconds). After passing through this plateau, the cooling process slows down due to the lower temperature gradient between the workpiece WS and the quenching medium as well as the internal heat conduction in the workpiece.
  • the quenching press hardening of the workpiece WS is accomplished by supporting it by a support tool 5 as part of the quenching process.
  • This support tool 5 is designed here as a mandrel, which sits in an inner opening 6 of the workpiece WS during part of the quenching period.
  • the support tool 5 and the workpiece WS are geometrically coordinated with one another.
  • the coordination is such that, as part of the rapid cooling of the workpiece, the support tool 5 supports the workpiece WS with close play in a state that is still thermally expanded.
  • the workpiece WS shrinks onto the support tool 5 with a further reduction in the workpiece temperature f2
  • an increasing press fit occurs.
  • the design is such that the support tool 5 sits in the workpiece WS in a temperature range just below the temperature of the martensite transformation with a pressure that still allows the support tool 5 to be pressed out of the workpiece. Accordingly, the support tool 5 is pressed out of the workpiece WS in this thermal state of the workpiece WS.
  • the hardening press PQ includes a frame R and a tool set inserted into the hardening press PQ, which includes a lower die 1 and an upper die 2.
  • the upper die 2 can be moved by a press ram 4 and can be lifted so far from the lower die 1 that the workpiece WS can be inserted and removed.
  • the frame R is shown here vertically shortened and ultimately dimensioned in such a way that it enables a sufficient relative displacement of the upper die 2 and lower die 1 for the workpiece transfer.
  • the hardening press PQ shown here in simplified form, enables axial loading of the workpiece WS, so that it is supported by the tool set even outside the inner recess 6 by rigid clamping against deformation as part of the quenching process.
  • the hardening press PQ is controlled by a control device C.
  • the control device C controls in particular the closing of the tool set after receiving the workpiece WS, the pressing pressure for tensioning the workpiece WS, the retraction of the support tool 5 into the workpiece WS, the bringing of the quenching medium into contact with the workpiece WS, the decoupling of the support tool 5 from the workpiece WS before reaching the quenching target temperature, the continuation of the quenching process by further applying the quenching medium to the workpiece WS, opening the tool set and releasing the workpiece WS.
  • the range is between 250 and 500°C.
  • the target quenching temperature (or the temperature at which the workpiece is removed from the press) is typically around 50 to 70 °C. This temperature corresponds approximately to the oil temperature if the process is carried out accordingly.
  • the workpiece WS shown here as an example is a two-row helical gear for an epicyclic gear.
  • the inner opening 6 of this workpiece WS is designed as a cylindrical bore.
  • the support tool 5 is designed as a cylindrical mandrel.
  • the outer diameter D of the mandrel is matched to the inner diameter d of the inner opening 6 by implementing the approach described above.
  • the mandrel is therefore oversized compared to conventional approaches.
  • a press fit between the workpiece and the mandrel, which is critical for pressing out the mandrel, occurs when the temperature falls below a pressing limit. This extrusion limit temperature is significantly above the target quenching temperature to which the Workpiece has cooled down at the end of the quenching process.
  • the workpiece At the squeezing limit temperature, the workpiece is in a state of expansion which just allows decoupling of the workpiece and the support tool, for example squeezing or pulling out the support tool 5 from the workpiece WS.
  • the support tool 5 At this temperature at the latest, the support tool 5 is decoupled from the workpiece WS.
  • the diameter D of the support tool 5 is matched to the diameter of the inner opening 6 of the workpiece WS in such a way that the extrusion limit temperature is below the temperature at which the last structural transformation of the material of the workpiece WS, which is highly relevant to deformation, takes place.
  • FIG. 1b illustrates the sequence of a quenching press hardening process according to the invention for accomplishing the hardening of a workpiece WS that is initially heated in an oven, in which the workpiece WS is used in conjunction with the Figures 2 to 8 further specified tool set is supported, fixed and / or held with a support tool 5.
  • the workpiece WS is subjected to a quenching medium for cooling to a target quenching temperature as part of the process steps described below.
  • the support tool is removed before the quenching target temperature is reached and the workpiece WS is further cooled to the quenching target temperature in the tool set after the support tool has been removed.
  • the workpiece WS is heated in a defined manner in an oven F.
  • the workpiece WS is brought to a hardening press PQ and inserted into this hardening press PQ as part of process step S2.
  • the tool set is closed.
  • the workpiece WS is assembled with a support tool 5.
  • the support tool 5 is designed here as an example of a mandrel; the workpiece and support tool are joined by inserting the mandrel into the workpiece.
  • This mandrel has a special dimension in relation to the workpiece WS, it is “oversized” compared to conventional approaches.
  • the workpiece is further axially loaded by the tool set and is thereby clamped in the correct shape and thus additionally supported against deformation.
  • step S5 the workpiece 5 is brought into contact with the quenching medium. This can be done by feeding a quenching fluid into the tool set, or by lowering the workpiece into an oil bath or raising the oil bath toward the workpiece. This is where the first phase of the quenching process begins. As part of this first phase, an ongoing analysis takes place in step S6 according to the presence of a stop criterion.
  • this stop criterion consists of a temperature state of the workpiece WS, which is determined here, for example, by measuring the temperature of the quenching medium flowing out of the tool set.
  • the stop criterion can also be a time value or another measured value, for example a shrinkage value that is recorded on the hardening press or the tool set.
  • the stop criterion can also be a point in time or the expiration of a period of time after the end of the heat transfer by film evaporation.
  • step S7 the supply of the quenching medium is throttled in step S7 and in step S8 the support tool and the partially cooled workpiece are decoupled, for example by pressing or pulling the support tool out of the workpiece WS.
  • step S9 After the support tool has been moved out of the workpiece, the quenching process is continued in step S9 and the workpiece is further exposed to a quenching medium.
  • step S10 the supply of the quenching medium is stopped.
  • the workpiece has now cooled down to a target workpiece temperature, which, for example, approximately corresponds to room temperature.
  • method step S11 the tool set is opened and in method step S12 the workpiece WS is removed from the tool set.
  • the method described above is characterized by the fact that in the context of the first phase of quenching initiated by process step S5 until the martensite transformation is largely completed, a high supporting effect is achieved by the supporting tool, since its geometry is in a shrinkage state at a still well above the output target temperature the workpiece temperature is adjusted.
  • One the The pressure of the "oversized" support tool which makes removal of the support tool impermissibly difficult, is counteracted by removing this support tool at a decoupling temperature at which there is still sufficient thermal expansion of the workpiece, but the formation of martensite and the overall structural transformation have progressed to such an extent that this does not occur significant deformations are generated.
  • the first quenching phase P1 extends here, for example, over the temperature range from 800 ° C to 250 ° C.
  • the support tool is pressed out here, for example, at 250°C. Subsequently, further cooling to room temperature takes place as part of the second quenching phase P2.
  • the method according to the invention is preferably carried out in conjunction with the tool set described below.
  • the representation according to Figure 2 shows a tool set according to the invention, which is here in an open position.
  • the tool set includes a lower die 1 and an upper die 2.
  • the lower die 1 rests on a base of the hardening press PQ.
  • the upper die 2 is attached to a stamp 4 of the hardening press PQ.
  • the tool set includes a support tool 5, which is designed here as a cylindrical mandrel.
  • the support tool 5 is matched to the geometry of an inner opening 6 of the workpiece WS.
  • the support tool 5 can be moved into the workpiece WS via a mechanism 7.
  • the workpiece WS is moved into the open tool set as in connection with Figure 1 described in the context of a transfer step S1 and an insertion step S2, these steps are preferably carried out automatically using a transfer system, so that the thermal state of the workpiece WS and the effects of the atmosphere on the workpiece WS can be reproduced in terms of process technology.
  • the representation according to Figure 3 shows the tool set with the workpiece WS included in it in the closed state. This is achieved by lowering the upper die 2 onto the lower die 1 using the stamp 4 of the hardening press PQ. In this state, the workpiece WS is clamped with a clamping force that is still below the clamping force used for the quenching process. The support tool 5 is in this State not yet retracted into the workpiece WS in order to prevent the support tool 5 from heating up prematurely.
  • step S4 the support tool 5 is moved into the inner opening 6 of the workpiece WS by the mechanism 7 and the workpiece WS is axially clamped in the tool set.
  • the representation according to Figure 5 illustrates the execution of the first phase P1 of the quenching process.
  • a quenching medium QF is fed into coolant channels 8 of the tool set, in particular coolant channels 8 of the upper die 2.
  • the volume flow and the inlet temperature of the quenching medium QF are monitored and regulated/controlled by process technology.
  • the quenching medium QF flows over and contacts the workpiece WS in the closed tool set and cools it down.
  • the outlet temperature of the quenching medium QF is detected by a sensor 9 integrated into the lower die 1.
  • the thermal state of the workpiece is calculated from this temperature value in conjunction with the volume flow value of the quenching medium. As soon as this condition shows that a certain structural transformation of the material of the workpiece has been achieved, the supply of the quenching medium QF is throttled.
  • the tool set is opened after the quenching process has ended, the workpiece WS can now be easily removed from the tool set, the support tool 5 has already been moved out of the workpiece WS.
  • the support tool WS was also cooled to ambient temperature during the second phase P2 of the quenching process in the tool set by the quenching medium QF flowing from the workpiece WS and is available in this defined temperature state for the quenching press hardening of another workpiece as part of an automated process.
  • the concept according to the invention results in economic savings potential in that the workpiece is supported with narrow tolerances by the support tool in the phase that is critical for the workpiece distortion and excessive pressure between the workpiece and the support tool, in particular the mandrel, is counteracted by the support tool being switched off well before the target quenching temperature is reached is pressed out of the workpiece.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
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  • Materials Engineering (AREA)
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  • Organic Chemistry (AREA)
  • Heat Treatment Of Articles (AREA)
EP23167649.5A 2022-04-14 2023-04-13 Procédé de fabrication de pièces traitées thermiquement, en particulier de roues dentées à denture hélicoidale et presse de trempe correspondante Pending EP4261291A1 (fr)

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EP4261291A1 true EP4261291A1 (fr) 2023-10-18

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Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3378412A (en) * 1965-10-22 1968-04-16 Norma Hoffmann Bearings Co Quench hardening method for ring-like articles
US4744836A (en) * 1985-07-08 1988-05-17 Tocco, Inc. Method for selectively heating a workpiece subjected to low temperature thermomechanical processing
CN105886746A (zh) * 2014-12-08 2016-08-24 北京金和昌利科贸有限公司 环类零件感应矫形模压淬火回火的工艺方法和设备
EP2398925B1 (fr) * 2009-02-19 2019-05-29 Ema Indutec GmbH Machine de trempe et procédé de durcissement sous contrainte par induction
DE102022108512A1 (de) 2021-04-16 2022-10-20 Aerospace Transmission Technologies GmbH Verfahren zur Wärmebehandlung von metallischen Werkstücken
DE102022108513A1 (de) 2021-04-16 2022-10-20 Aerospace Transmission Technologies GmbH Steuereinrichtung und Verfahren zur Steuerung einer Anlage und eines Prozesses zur Wärmebehandlung von metallischen Werkstücken
DE102022108514A1 (de) 2021-04-16 2022-10-20 Aerospace Transmission Technologies GmbH Steuereinrichtung und Verfahren zur Steuerung einer Presshärteanlage
DE102022108511A1 (de) 2021-04-16 2022-10-20 Aerospace Transmission Technologies GmbH Vorrichtung zur Wärmebehandlung von metallischen Werkstücken
DE102022108515A1 (de) 2021-04-16 2022-10-20 Aerospace Transmission Technologies GmbH Steuereinrichtung und Verfahren zur Steuerung einer Presshärteanlage
DE102022108510A1 (de) 2021-04-16 2022-10-20 Aerospace Transmission Technologies GmbH Verfahren zur Wärmebehandlung metallischer Werkstücke
DE102021109682A1 (de) 2021-04-16 2022-10-20 Aerospace Transmission Technologies GmbH Steuereinrichtung und Verfahren zur Steuerung einer Presshärteanlage

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3378412A (en) * 1965-10-22 1968-04-16 Norma Hoffmann Bearings Co Quench hardening method for ring-like articles
US4744836A (en) * 1985-07-08 1988-05-17 Tocco, Inc. Method for selectively heating a workpiece subjected to low temperature thermomechanical processing
EP2398925B1 (fr) * 2009-02-19 2019-05-29 Ema Indutec GmbH Machine de trempe et procédé de durcissement sous contrainte par induction
CN105886746A (zh) * 2014-12-08 2016-08-24 北京金和昌利科贸有限公司 环类零件感应矫形模压淬火回火的工艺方法和设备
DE102022108512A1 (de) 2021-04-16 2022-10-20 Aerospace Transmission Technologies GmbH Verfahren zur Wärmebehandlung von metallischen Werkstücken
DE102022108513A1 (de) 2021-04-16 2022-10-20 Aerospace Transmission Technologies GmbH Steuereinrichtung und Verfahren zur Steuerung einer Anlage und eines Prozesses zur Wärmebehandlung von metallischen Werkstücken
DE102022108514A1 (de) 2021-04-16 2022-10-20 Aerospace Transmission Technologies GmbH Steuereinrichtung und Verfahren zur Steuerung einer Presshärteanlage
DE102022108511A1 (de) 2021-04-16 2022-10-20 Aerospace Transmission Technologies GmbH Vorrichtung zur Wärmebehandlung von metallischen Werkstücken
DE102022108515A1 (de) 2021-04-16 2022-10-20 Aerospace Transmission Technologies GmbH Steuereinrichtung und Verfahren zur Steuerung einer Presshärteanlage
DE102022108510A1 (de) 2021-04-16 2022-10-20 Aerospace Transmission Technologies GmbH Verfahren zur Wärmebehandlung metallischer Werkstücke
DE102021109682A1 (de) 2021-04-16 2022-10-20 Aerospace Transmission Technologies GmbH Steuereinrichtung und Verfahren zur Steuerung einer Presshärteanlage

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