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WO2022111929A1 - Traitement thermique d'élément - Google Patents

Traitement thermique d'élément Download PDF

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Publication number
WO2022111929A1
WO2022111929A1 PCT/EP2021/079579 EP2021079579W WO2022111929A1 WO 2022111929 A1 WO2022111929 A1 WO 2022111929A1 EP 2021079579 W EP2021079579 W EP 2021079579W WO 2022111929 A1 WO2022111929 A1 WO 2022111929A1
Authority
WO
WIPO (PCT)
Prior art keywords
component
temperature
continuous furnace
zone
area
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.)
Ceased
Application number
PCT/EP2021/079579
Other languages
German (de)
English (en)
Inventor
Frank WILDEN
Andreas Reinartz
Jörg Winkel
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.)
Schwartz GmbH
Original Assignee
Schwartz 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 Schwartz GmbH filed Critical Schwartz GmbH
Priority to EP21802221.8A priority Critical patent/EP4153789A1/fr
Publication of WO2022111929A1 publication Critical patent/WO2022111929A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • 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
    • C21D1/25—Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten")
    • 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
    • C21D1/26—Methods of annealing
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0294—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a localised treatment
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0494—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing involving a localised treatment
    • 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
    • C21D9/0056—Furnaces through which the charge is moved in a horizontal straight path
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/0062—Heat-treating apparatus with a cooling or quenching zone
    • C—CHEMISTRY; METALLURGY
    • 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
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • 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
    • F27B9/02—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity of multiple-track type; of multiple-chamber type; Combinations of furnaces
    • 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
    • F27B9/06—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated
    • 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
    • F27B9/06—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated
    • F27B9/10—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated heated by hot air or gas
    • 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
    • F27B9/20—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 substantially straight path
    • F27B9/24—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 substantially straight path being carried by a conveyor
    • 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
    • F27B9/30—Details, accessories or equipment specially adapted for furnaces of these types
    • 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
    • C21D2221/00—Treating localised areas of an article
    • C21D2221/10—Differential treatment of inner with respect to outer regions, e.g. core and periphery, respectively

Definitions

  • the invention relates to a method and a device for the thermal treatment of a component, in particular a steel component for a motor vehicle.
  • steel components such as B-pillars are thermally treated differently in some areas. Accordingly, there is a different ductility in some areas, which is advantageous for the crash behavior of such components. For example, occupants can be protected by a hard area of the B-pillar at seat height, while soft areas in the upper and lower areas of the B-pillar absorb energy through deformation.
  • a method for the thermal treatment of a component comprises: a) heating the component in a first continuous furnace to a temperature above the AC3 temperature of the component, b) transferring the component from the first continuous furnace into a temperature control station, c) thermally treating the component in the temperature control station, wherein a exposing a first portion of the component to a temperature that is on average above the AC3 temperature of the component and cooling a second portion of the component. d) transferring the component from the temperature control station into a second continuous furnace, e) thermally treating the component in the second continuous furnace, so that the first area is brought to a first temperature and the second area is brought to a second temperature, the first temperature above the
  • Austenite reverse transformation temperature of the component is.
  • the second temperature is below the austenite reverse transformation temperature of the component.
  • a component can be thermally treated using the method described.
  • the component is preferably a steel component.
  • the steel is preferably 22MnB5.
  • a component for a motor vehicle, in particular a B pillar can be thermally treated using the method described.
  • the component is preferably press-hardened in a press and, to this extent, hot-formed.
  • the method preferably includes transferring the component after the thermal treatment into a press and press-hardening it there.
  • the process described is a process for thermal treatment and press hardening of a component.
  • the component preferably has a material thickness of at least 0.7 mm, in particular in the range of 1 to 4 mm.
  • the material thickness of the component is preferably constant over the entire component.
  • the component can also have a different material thickness in some areas.
  • the component can be a "Tailor Rolled Blank (TRB)", in which locally different material thicknesses are obtained by locally different rolling.
  • the component can also be a "Tailor Welded Blank (TWB)", where locally different material thicknesses are obtained by welding several metal sheets together.
  • TRB Trim Rolled Blank
  • TWB Teilor Welded Blank
  • the method can be applied equally to components with and without a coating.
  • An Al/Si coating is particularly suitable as the coating.
  • step a) the component is heated in the first continuous furnace.
  • a furnace is a device that is brought to an adjustable temperature inside and into which a component can be placed. Over time, the component takes on the temperature prevailing inside the oven. The heat is thus transferred to the component from the gas in the oven, which can in particular be air.
  • a continuous furnace is a furnace through which the component can be moved, with the component being heated as it passes through the furnace.
  • the first continuous furnace is preferably a roller hearth furnace.
  • the component is preferably heated by burners, in particular gas burners.
  • burners in particular gas burners.
  • the component can receive a particularly evenly distributed temperature.
  • the entire component is heated in the first continuous furnace.
  • the component is completely taken from the first continuous furnace.
  • heating by a particularly large temperature difference can be achieved with a continuous furnace.
  • a component can be heated in particular from room temperature to a temperature in the range of the AC3 temperature of the component. Such extensive heating is not possible with many other heating methods, or at least not without a disproportionate amount of effort.
  • Heating in a continuous furnace stands in particular in contrast to heating by what is known as "direct energization". This would make it difficult to heat the component evenly and by a sufficiently high amount. With direct energization, the speed of the Heating. In addition, direct energization requires contact with the component.
  • heating preferably takes place without contact. This does not exclude the component being moved through the first continuous furnace with transport rollers and thus being in contact with The heating is non-contact if the heat input into the component is via gas and/or thermal radiation.
  • step b) of the method the component is transferred from the first continuous furnace into the temperature control station. There, the component is thermally treated differently in different areas in steps), in that a first area of the component is exposed to a temperature that is on average above the AC3 temperature of the component, and a second area of the component is cooled.
  • the first continuous furnace and the temperature control station are different components that are spatially separated from one another.
  • the transfer between the first continuous furnace and the tempering station facilitates the cooling of the component between heating up in the first continuous furnace and the thermal treatment in the tempering station.
  • the component In the tempering station, the component is cooled down as quickly as possible in certain areas. Rapid cooling can be done more efficiently outside of the hot first continuous furnace. In this way, cooling can already begin during the transfer.
  • the physical separation of the first continuous furnace from the tempering station accelerates the process. This is in contrast to a solution where all process steps are performed in the same facility without having to transfer the component. Such solutions typically aim to keep the effort involved in component transfers low or to avoid them altogether.
  • the spatial separation between the first continuous furnace and the tempering station also facilitates the construction, because the requirements for the first continuous furnace and the tempering station are different.
  • the first area is exposed to a temperature above the AC3 temperature of the component.
  • the first area in the temperature control station is preferably heated as a result.
  • the first area in the temperature control station can also be kept at its temperature or cooling of the first area can be slowed down.
  • the first area of the component is preferably exposed to a temperature above the AC3 temperature of the component to the extent that the component is held with the first area against an open chamber on the component side, the chamber being kept at this temperature by a heating device.
  • the heating device is preferably one electric heater.
  • the heating device can, for example, have a heating element such as a heating loop.
  • the heating device can comprise a radiant tube which is heated with a burner, in particular with a gas burner.
  • the second area is cooled in the temperature control station. This is preferably done by keeping the second area outside the chamber described above. There, the second area is preferably acted upon by a cooling fluid, in particular compressed air.
  • the compressed air preferably has a pressure in the range from 2 to 4.5 bar. Due to this comparatively high pressure, a large amount of compressed air can be directed to the second area of the component within a very short time, so that a sufficiently high cooling rate can be achieved.
  • the temperature of the component is above or below the AC3 temperature of the component has a significant influence on the microstructure obtained. Due to the different thermal treatment of the areas of the component, the two areas can have different microstructure compositions and, to that extent, different ductility. The first area thus becomes harder than the second area. For example, in the case of a B-pillar for a motor vehicle, the crash properties can be adjusted in a targeted manner.
  • the first area and the second area are not necessarily contiguous areas, respectively.
  • a middle part of a B-pillar to represent the first area, while an upper and a lower part of the B-pillar together represent the second area.
  • the component preferably, but not necessarily, has only the first area and the second area, ie no further areas.
  • step d) the component is transferred from the tempering station to a second continuous furnace.
  • step e) the component is treated thermally in the second continuous furnace, preferably heated, so that the first area is brought to a first temperature, preferably heated, and the second area is brought to a second temperature, preferably heated, the first Temperature is above the austenite reverse transformation temperature of the component and the second temperature is below the austenite reverse transformation temperature of the component.
  • the austenite reverse transformation temperature is defined by the fact that austenite disintegrates as soon as the austenite reverse transformation temperature is undershot.
  • the first temperature is above the AC3 temperature.
  • the temperature control station and the second continuous furnace are different components that are spatially separated from each other.
  • the transfer between the tempering station and the second continuous furnace facilitates the cooling of the component between the thermal treatment in the tempering station and in the second continuous furnace. In this way, the second area of the construction part can be cooled down even during the transfer. This reduces the required residence time in the temperature control station and speeds up the process. This is in contrast to an approach where all process steps are performed in the same facility whenever possible without having to transfer the component. Such solutions typically aim to keep the effort involved in component transfers low or to avoid them altogether.
  • the spatial separation between the tempering station and the second continuous furnace also facilitates the construction because the requirements for the tempering station and the second continuous furnace are different.
  • the second continuous furnace is preferably a roller hearth furnace.
  • the entire component is thermally treated, preferably heated, in the second continuous furnace.
  • the component is constantly taken up by the second continuous furnace.
  • the thermal treatment in a continuous furnace is in particular in contrast to heating by the so-called "direct energization".
  • the separation between the regions is particularly sharp in the method described, in particular because the component is heated in the first continuous furnace to a temperature above the AC3 temperature of the component. If the AC3 temperature in the first continuous furnace was not exceeded, no stable austenite could be formed.
  • the first area would first have to be heated above the AC3 temperature in the temperature control station and this over a comparatively long time. Due to the residence time required for this in the temperature tion, heat conduction within the component and radiation losses at the edge of the temperature control station could result in a comparatively large transition area. With the method described, this can be prevented.
  • the heating in the second continuous furnace can also accelerate the diffusion processes of the carbon in the steel in the second area of the component.
  • the thermal treatment of the two areas is as different as possible.
  • the component does not have any major temperature differences, so that no distortions occur during press hardening.
  • a difference between the first temperature and the second temperature in the range of 200 to 300 K has proven to be a good compromise.
  • the first temperature is 20 to 150 K above the AC3 temperature of the component and/or the second temperature is 100 to 200 K below the AC3 temperature of the component.
  • the combination is preferred that the first temperature is 50 to 150 K above the AC3 temperature of the component and the second temperature is 100 to 200 K below the AC3 temperature of the component.
  • the first temperature is significantly above the AC3 temperature and/or the second temperature is significantly below the AC3 temperature. This significantly influences the strength properties of the component.
  • the first region is heated by at least 20 K in step e) and/or the second region is heated by at least 100 K in step e).
  • step e) The combination that the first area is heated by at least 20 K in step e) and the second area is heated by at least 100 K in step e) is preferred.
  • both areas of the component are heated in step e). Since the first area is warmer than the second area before passing through the second continuous furnace, this means that the first area is heated less than the second area. In this respect, the temperatures of the two areas are approaching each other.
  • the first area can cool down in step e), in particular by up to 100 K.
  • the first continuous furnace is divided into a first zone in the direction of transport of the component and a second zone adjoining this and through which the component later passes, with the first zone extending over at least 70% of the first continuous furnace in the direction of transport of the component wherein an average temperature in the first zone is below the AC3 temperature of the component and wherein an average temperature in the second zone is above the AC3 temperature of the component. It is sufficient for the AC3 temperature to be briefly exceeded in the first continuous furnace. In the present embodiment, this is realized in that the first zone with a temperature below the AC3 temperature is larger than the second zone with a temperature above the AC3 temperature.
  • the AC3 temperature of the component is exceeded for a long time, stable austenite would be formed, which only slowly decomposes when it cools down. This would lead to a long cycle time in the process, especially if the second area of the component is to be particularly soft. This is due to the time it takes for the austenite to disintegrate. This is particularly the case with components made of 22MnB5, because this steel is delayed in transformation due to the alloying elements.
  • the AC3 temperature in the first continuous furnace is only briefly exceeded. As a result, the austenite can disintegrate comparatively quickly. The austenite breaks down more slowly in the first area than in the cooled second area.
  • the first area can be completely converted back to austenite more quickly in the tempering station, particularly if the conversion back has already begun during the transfer.
  • the comparatively low component temperature at the end of the first continuous furnace and the less stable austenite contribute to softening the second areas of the component in a shorter time. This in turn can shorten the cycle time.
  • the first continuous furnace and also the rest of the device used for the process are described using a "transport direction of the component". This is the direction in which the component is moved through the device and its elements.
  • the transport direction of the component is therefore in particular the direction , with which the component is moved through the first continuous furnace.
  • the first continuous furnace When viewed along the transport direction thus defined, the first continuous furnace has a first zone and a second zone.
  • the fact that the first continuous furnace is "divided" into these two zones in the transport direction of the component means that the first continuous furnace only has these two zones when viewed along the transport direction of the component.
  • the zones Transversely to the transport direction of the component, the zones preferably each extend over the entire first continuous furnace.
  • the component first passes through the first zone and then the second zone.
  • the second zone When viewed in the direction of transport, the second zone is subordinate to the first zone in this respect.
  • the first zone and the second zone directly adjoin each other.
  • the first zone is adjacent to an inlet of the first continuous furnace
  • the second zone is adjacent to an outlet of the first continuous furnace.
  • the component can be introduced into the first continuous furnace via the inlet.
  • the component can leave the first continuous furnace via the outlet.
  • the average temperature in the first zone is below the AC3 temperature of the component; the average temperature in the second zone is above the AC3 temperature of the component.
  • the component is first heated to a temperature below the AC3 temperature and then briefly exposed to a temperature above the AC3 temperature.
  • the component in the second zone is heated to a temperature above the AC3 temperature. If the dwell time of the component in the second zone is long enough, this can be the temperature set in the second zone. It is preferred that the temperatures in the first zone and in the second zone are constant. As a result, the component is heated evenly within the zones. It should be noted, however, that short-term and/or locally limited temperature changes within the first continuous furnace have almost no relevance for heating the component.
  • the zones are defined by their respective average temperatures.
  • the average temperature in the first zone is below the AC3 temperature
  • the average temperature in the second zone is above the AC3 temperature.
  • the first zone is not interrupted by the fact that the temperature is in a small range above the AC3 temperature of the component.
  • the average temperature is the average temperature to which the component is exposed in the respective zone. This is the temperature in a component level of the first continuous furnace, i.e. the level in which the component is transported through the first continuous furnace.
  • locally elevated temperatures in the area of the burners should be disregarded if they are at a distance from the component.
  • the first zone extends over at least 70% of the first continuous furnace, preferably even over at least 80%. It has been found that it is sufficient if the component is first heated up comparatively slowly and then only briefly exposed to a temperature above the AC3 temperature. Accordingly, it is preferable for the first zone to be significantly longer than the second zone. It has been found that a particularly small transition area between the areas of different ductility can be obtained as a result. The areas of different ductility are therefore particularly sharply delimited from one another. This is surprising insofar as a connection between the expansion of the transition region and the type of heating before a temperature above the AC3 temperature was set was not previously known. It is sufficient that the zones are only separated from each other by the set temperature.
  • first zone and a second zone can be defined in the first continuous furnace in different ways. It is sufficient if there is a possible assignment of a first zone and a possible assignment of a second zone, with all the conditions set for the two zones being satisfied, respectively. Alternative assignment options are then irrelevant. However, the assignment of zones is preferably not random. If the temperature curve along the transport direction of the component has clearly recognizable jumps, the boundary between the zones preferably coincides with such a clearly recognizable jump. It is particularly preferred that the temperature at the boundary between the first zone and the second zone is at the AC3 temperature of the component. This is particularly the case when the boundary between the two zones is at a temperature jump from a value below the AC3 temperature of the component to a value above the AC3 temperature of the component.
  • the temperature over at least 80% of an expansion of the first zone in the transport direction of the component is below the AC3 temperature of the component.
  • the temperature over at least 80% of an extension of the second zone in the transport direction of the component is above the AC3 temperature of the component.
  • the temperature in the entire first zone is particularly preferably below the AC3 temperature.
  • the temperature in the entire second zone is particularly preferably above the AC3 temperature.
  • the first continuous furnace preferably has a plurality of heating elements, the temperature of which can preferably be adjusted individually.
  • the first zone and the second zone preferably correspond to a respective group of the heating elements.
  • the assignment of the heating elements to a zone can be direction and does not have to be recognizable on the heating elements themselves. Only the temperature distribution is decisive.
  • the temperature setting of a heating element at the boundary between the first zone and the second zone By changing the temperature setting of a heating element at the boundary between the first zone and the second zone, the association of that heating element from the first zone to the second zone and vice versa can be changed.
  • the expansion of the zones can be changed by changing the allocation of heating elements at the boundary between the zones.
  • the temperature distribution of the zone can be adjusted by the respective temperature setting of the heating elements. All heating elements in a zone are preferably set to the same temperature.
  • the average temperature in the first zone of the first continuous furnace is in the range of 10 to 30 K below the AC3 temperature of the component and/or the average temperature in the second zone of the first continuous furnace is in the range of 10 up to 30 K above the AC3 temperature of the component.
  • the combination is preferred that the average temperature in the first zone of the first continuous furnace is in the range of 10 to 30 K below the AC3 temperature of the component and that the average temperature in the second zone of the first continuous furnace is in the range of 10 to 30 K above the AC3 temperature of the component.
  • 22MnB5 it is preferred that the temperature in the first zone in the
  • the temperature in the first zone is particularly preferably constant in the range from 816 to 836.degree. C. and in the second zone constant at 856 to 876.degree.
  • the component remains in the second zone of the first continuous furnace for between 10 and 30 s.
  • the residence time in the first continuous furnace is preferably in the range from 250 to 400 s.
  • a residence time in the range from 10 to 30 s is corresponding in the second Zone comparatively short. It has been shown that such a short dwell time in the second zone is sufficient for the advantages described.
  • step c) the cooling of the second region starts with a delay of 0.5 to 15 s after the end of step b).
  • Cooling does not begin immediately after the component enters the tempering station.
  • the cooling by free radiation to the environment can thus also be used for cooling, as a result of which cooling fluid can be saved, for example.
  • Cooling starting after the delay is active cooling. This allows the strength properties of the component to be set particularly precisely. A longer delay can lead to an increase in the transition area between areas of different ductility.
  • the combination of the described zoned heating in the first continuous furnace with the comparatively short delay showed a particularly sharp separation between the different ductility ranges.
  • the first region of the component is exposed in step c) to a temperature which is on average 10 to 250 K above the AC3 temperature of the component.
  • the temperature control in the tempering station also has an influence on the expansion of the transition area between the areas of different ductility.
  • a comparatively high temperature for the thermal treatment of the first area in the tempering station resulted in a smaller transition area.
  • the component is preferably exposed to a temperature which is constantly in the range from 10 to 250 K above the AC3 temperature of the component.
  • a temperature which is constantly in the range from 10 to 250 K above the AC3 temperature of the component.
  • the first region in step c) is exposed to an average temperature in the range from 900 to 1100°C, in particular to a constant temperature in this range.
  • the component remains in step c) for a dwell time in the range from 10 to 30 s in the temperature control station.
  • a device for the thermal treatment of a construction part includes:
  • control device which is set up to set an average temperature above the AC3 temperature of the component in at least part of the first continuous furnace and to set an average temperature above the AC3 temperature of the component in the second continuous furnace.
  • the special advantages and design features of the method described can be applied and transferred to the device, and vice versa.
  • the device is preferably intended and set up for operation in accordance with the method.
  • the method is preferably carried out using the device.
  • the control device is preferably set up in such a way that it sets such a temperature profile in the first continuous furnace that the component in the second zone of the first continuous furnace is heated to a temperature above the AC3 temperature.
  • the first continuous furnace is preferably divided into a first zone and an adjoining and downstream second zone, with the first zone extending over at least 70% of the first continuous furnace in the transport direction of the component.
  • the control device is preferably set up to set an average temperature below the AC3 temperature of the component in the first zone of the first continuous furnace and to set an average temperature above the AC3 temperature of the component in the second zone of the first continuous furnace.
  • the fact that the second zone of the first continuous furnace follows the first zone in the transport direction of the component means that the component passes through the second zone later than the first zone.
  • the tempering station and the second continuous furnace which are arranged downstream of the first continuous furnace or the tempering station in the transport direction of the component.
  • FIG. 1 a device according to the invention for the thermal treatment of a
  • Fig. 2 a temperature profile that occurs with the device from FIG.
  • FIG. 1 shows a device 1 for the thermal treatment of a component 2.
  • the device 1 comprises a first continuous furnace 3, which has a first zone 6 and a second zone 7 downstream of the first zone 6 in the transport direction r of the component 2.
  • the second zone 7 is thus passed through later by the component 2 and is therefore in FIG. 1 to the right of the first zone 6.
  • the first zone 6 extends in the transport direction r of the component 2 over 70% of the first continuous furnace 3.
  • the first Zone 6 and the second zone 7 extend transversely to the transport direction r - i.e. up and down in Fig. 1 and perpendicular to the plane of the drawing - over the entire first continuous furnace 3.
  • the device 1 also has a temperature control station 4 downstream of the first continuous furnace 3 in the transport direction r of the component 2 . Furthermore, the device 1 has a second continuous furnace 5 which is arranged downstream of the tempering station 4 in the transport direction of the building part 2 .
  • the temperatures in the first zone 6 of the first continuous furnace 3, in the second zone 7 of the first continuous furnace 3, in the temperature control station 4 and in the second continuous furnace 5 are controlled by a control device 8 adjustable. This is indicated by dotted lines.
  • the control device 8 is set up in particular to set an average temperature below the AC3 temperature T A c3 of the component 2 in the first zone 6 of the first continuous furnace 3 and an average temperature above the AC3 temperature T in the second zone 7 of the first continuous furnace 3
  • FIG. 2 shows a temperature profile that occurs in the component 2 when it is moved through the device 1 from FIG.
  • the representation of Fig. 2 is schematic. Shown is a plot of temperature T versus time t in arbitrary units.
  • the component 2 is first heated in the first continuous furnace 3 .
  • the dwell time of the component 2 in the first continuous furnace 3 is denoted by t Di and divided into the dwell time in the first zone 6 denoted t Zi and the dwell time in the second zone 7 denoted t Z 2 .
  • the temperature is constantly regulated to a value T Z ⁇ which is below the AC3 temperature T AC3 of the component 2 .
  • the second zone 7 the temperature is constantly regulated to a value T Z 2, which is above the AC3 temperature T AC 3 of the component 2.
  • T Z which is above the AC3 temperature T AC 3 of the component 2.
  • the component 2 is then transferred to the temperature control station 4 .
  • the associated transfer time is denoted by t Ti .
  • the component 2 cools down during this transfer.
  • the component 2 remains in the temperature control station 4 for a period of time t T s.
  • the component 2 is thermally treated in the temperature control station 4 by exposing a first area of the component 2 to a temperature which is constant at a value T TS above the AC3 temperature T AC 3 of the component 2 is located, and a second region of the component 2 is cooled.
  • the cooling of the second area of the component 2 begins with a delay t v .
  • the delay t v begins when the component 2 enters the temperature control station 4, ie at the end of t Ti and the beginning of t T s.
  • an increase in the temperature T B of the second area can be seen. That is due to the release of latent heat. This effect is also referred to as "recalescence".
  • the component 2 After the component 2 has been thermally treated in the temperature control station 4 , the component 2 is transferred to the second continuous furnace 5 .
  • the transfer time for this is denoted by t T 2 .
  • the component 2 cools down, which can vary depending on the area.
  • the component 2 is further thermally treated in the second continuous furnace 5 .
  • the first area is heated to a first temperature and the second area is heated to a second temperature.
  • the first temperature is above the austenite reverse transformation temperature T AR of the component 2; the second temperature is below the austenite reverse transformation temperature T AR of the component 2.
  • the residence time of the component 2 in the second continuous furnace 5 is denoted by t D2 .
  • the building part 2 receives a regionally different ductility. This is advantageous, for example, in the case of a B pillar for a motor vehicle.
  • the temperature profile described causes the areas of different ductility to be particularly sharply separated from one another.
  • TTS temperature for the second area in the temperature control station T A temperature of the first area of the component T B temperature of the second area of the component t time t Di residence time in the first continuous furnace tzi residence time in the first zone of the first continuous furnace t Z 2 residence time in the second zone of the first continuous furnace t Ti Transfer time from the first continuous furnace to the tempering station t T s Dwell time in the tempering station t v Delay in cooling the second area of the component t T 2 Transfer duration from the tempering station to the second continuous furnace t D2 Dwell time in the second continuous furnace r Transport direction of the component

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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)
  • Combustion & Propulsion (AREA)
  • Tunnel Furnaces (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)
  • Heat Treatment Of Articles (AREA)

Abstract

Procédé de traitement thermique d'un élément (2), le procédé consistant : a) à chauffer l'élément (2) dans un premier four continu (3) à une température supérieure à la température AC3 (TAC3) de l'élément (2), b) à transférer l'élément (2) du premier four continu (3) vers une station de régulation de la température (4), c) à traiter thermiquement l'élément (2) dans la station de régulation de la température (4), une première région de l'élément (2) étant soumise à une température se situant en moyenne au-dessus de la température AC3 (TAC3) de l'élément (2), et une seconde région de l'élément (2) étant refroidie, d) à transférer l'élément (2) de la station de régulation de la température (4) vers un second four continu (5), e) à traiter thermiquement l'élément (2) dans le second four continu (5) de sorte que la première région est amenée à une première température et que la seconde région est amenée à une seconde température, la première température étant supérieure à la température de re-transformation austénitique de l'élément (2), et la seconde température étant inférieure à la température de re-transformation austénitique de l'élément (2). Le traitement thermique différent dans des régions différentes a pour effet de conférer à l'élément (2) une ductilité différente dans des régions différentes. Ceci est avantageux, par exemple, dans le cas d'un montant de porte pour un véhicule automobile. Le profil de température décrit permet ici aux régions à ductilité différente d'être séparées de manière particulièrement distincte les unes des autres.
PCT/EP2021/079579 2020-11-25 2021-10-25 Traitement thermique d'élément Ceased WO2022111929A1 (fr)

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DE102020131238.5A DE102020131238A1 (de) 2020-11-25 2020-11-25 Thermisches Behandeln eines Bauteils

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DE102022130153A1 (de) * 2022-11-15 2024-05-16 Schwartz Gmbh Thermisches Behandeln eines metallischen Bauteils
DE102022130152A1 (de) * 2022-11-15 2024-05-16 Schwartz Gmbh Thermisches Behandeln eines metallischen Bauteils
DE102022130154A1 (de) * 2022-11-15 2024-05-16 Schwartz Gmbh Thermisches Behandeln eines metallischen Bauteils
DE102023135571A1 (de) * 2023-12-18 2025-06-18 Alexander Wilden Beteiligungen GmbH Thermisches Behandeln eines metallischen Bauteils

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10208216C1 (de) * 2002-02-26 2003-03-27 Benteler Automobiltechnik Gmbh Verfahren zur Herstellung eines metallischen Bauteils
US20130160906A1 (en) * 2011-12-23 2013-06-27 Benteler Automobiltechnik Gmbh Method for producing a motor vehicle component and motor vehicle component

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Publication number Priority date Publication date Assignee Title
DE102016118252A1 (de) 2016-09-27 2018-03-29 Schwartz Gmbh Verfahren und Vorrichtung zur Wärmebehandlung eines metallischen Bauteils

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10208216C1 (de) * 2002-02-26 2003-03-27 Benteler Automobiltechnik Gmbh Verfahren zur Herstellung eines metallischen Bauteils
US20130160906A1 (en) * 2011-12-23 2013-06-27 Benteler Automobiltechnik Gmbh Method for producing a motor vehicle component and motor vehicle component

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DE102020131238A1 (de) 2022-05-25

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