DE102020106139A1 - Thermal treatment of a component - Google Patents

Abstract

A method for the thermal treatment of a component (2), comprising: a) heating the component (2) in a first continuous furnace (3), which in the transport direction (r) of the component (2) into a first zone (6) and one to this subsequent second zone (7) through which the component (2) passes later, the first zone (6) and the second zone (7) extending in the transport direction (r) of the component (2) together over at least 70% of the first Continuous furnace (3), with an average temperature in the first zone (6) below the AC3 temperature (TAC3) of the component (2), and with an average temperature in the second zone (7) above the AC3 temperature (TAC3) of the component (2) lies, b) transferring the component (2) from the first continuous furnace (3) to a temperature control station (4), c) thermal treatment of the component (2) in the temperature control station (4), a first area of the Component (2) exposed to a temperature that is on average above the AC3 tempera temperature (TAC3) of the component (2), and a second area of the component (2) is cooled. Due to the different thermal treatment in areas, the component (2) has a different ductility in areas. This is advantageous for a B-pillar for a motor vehicle, for example. The different temperatures (TZ1, TZ2) in the zones (6, 7) of the first continuous furnace (3) have the effect that the areas of different ductility are particularly sharply separated from one another.

Description

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.

In the automotive industry in particular, it is known to specifically harden steel components by means of thermal treatment. For this purpose, steel components such as B-pillars are thermally treated differently in areas. Correspondingly, there is a different ductility in certain 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.

The object of the present invention is to present a method for the thermal treatment of components on the basis of the prior art described, with which areas of the component can be thermally treated with particularly sharp separation from one another. In addition, a corresponding device will be presented.

These objects are achieved with the method and the device according to the independent claims. Further advantageous refinements are given in the dependent claims. The features shown in the claims and in the description can be combined with one another in any desired, technologically meaningful manner.

1. a) Erwärmen des Bauteils in einem ersten Durchlaufofen, welcher in Transportrichtung des Bauteils in eine erste Zone und eine an diese anschließende und von dem Bauteil später durchlaufene zweite Zone unterteilt ist, wobei sich die erste Zone in Transportrichtung des Bauteils über mindestens 70 % des ersten Durchlaufofens erstreckt, wobei eine Durchschnittstemperatur in der ersten Zone unterhalb der AC3-Temperatur des Bauteils liegt, und wobei eine Durchschnittstemperatur in der zweiten Zone oberhalb der AC3-Temperatur des Bauteils liegt,
2. b) Transferieren des Bauteils von dem ersten Durchlaufofen in eine Temperierstation,
3. c) thermisches Behandeln des Bauteils in der Temperierstation, wobei ein erster Bereich des Bauteils einer Temperatur ausgesetzt wird, die im Durchschnitt oberhalb der AC3-Temperatur des Bauteils liegt, und ein zweiter Bereich des Bauteils gekühlt wird.

According to the invention, a method for the thermal treatment of a component is presented. The procedure includes:

1. a) Heating the component in a first continuous furnace, which is divided into a first zone in the transport direction of the component and a second zone adjoining this and later passed through by the component, the first zone extending over at least 70% of the first in the transport direction of the component Continuous furnace extends, 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,
2. b) Transferring the component from the first continuous furnace to a temperature control station,
3. c) thermal treatment of the component in the temperature control station, wherein a first area of the component is exposed to a temperature which is on average above the AC3 temperature of the component, and a second area of the component is cooled.

A component can be thermally treated with the method described. The component is preferably a steel component. The steel is preferably 22MnB5. For example, a component for a motor vehicle, in particular a B-pillar, can be thermally treated with the method described. After the thermal treatment, the component is preferably press-hardened in a press and, to that extent, hot-formed. The method preferably includes as a further step that the component is transferred to a press after the thermal treatment and is press-hardened there. In this case, the method described is a method for thermal treatment and press hardening of a component.

The component preferably has a material thickness of at least 1 mm, in particular in the range from 1 to 4 mm. The material thickness of the component is preferably constant over the entire component. Alternatively, the component can also have a different material thickness in certain areas. For example, 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)”, in which locally different material thicknesses are obtained by welding several sheets together. A combination of TRB and TWB is also possible. Furthermore, the method can be applied equally to components with and without a coating. In particular, an Al / Si coating can be considered as the coating.

In step a) the component is heated in the first continuous furnace. A furnace is to be understood as a device which is brought to an adjustable temperature inside and into which a component can be introduced. Over time, the component adopts the temperature inside the furnace. The heat is thus transferred to the component from the gas in the furnace, 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. In the first continuous furnace, the component is preferably heated by burners, in particular gas burners. This allows the component to have a particularly evenly distributed temperature. In particular, not only one layer on the surface of the component is heated. The entire component is heated in the first continuous furnace. The component is completely picked up by the first continuous furnace. In addition, a Heating by a particularly large temperature difference can be achieved. With a continuous furnace, a component can in particular be heated from room temperature to a temperature in the range of the component's AC3 temperature. Such extensive heating is not possible with many other heating methods, or at least not possible without a disproportionate amount of effort.

The heating in a continuous furnace is in particular in contrast to heating by the so-called "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 warming is more important. In addition, direct energization requires contact with the component. In step a) of the method described, the heating is preferably carried out without contact. This does not rule out that the component is moved through the first conveyor oven with transport rollers and is in contact with the transport rollers. The heating is contactless if the heat input into the component takes place via a gas and / or via thermal radiation.

The first continuous furnace and also the rest of the device used for the process are described with the aid of 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 in which the component is moved through the first continuous furnace.

When viewed along the transport direction defined in this way, 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 direction of transport of the component means that the first continuous furnace only has these two zones when viewed along the direction of transport of the component. The zones preferably each extend across the entire first continuous furnace at right angles to the direction of transport of the component.

The component first passes through the first zone and then the second zone. When viewed in the direction of transport, the second zone is subordinate to the first zone. The first zone and the second zone directly adjoin one another. The first zone adjoins an inlet of the first continuous furnace, the second zone adjoins 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 component's AC3 temperature. The component is therefore first heated comparatively slowly in the first continuous furnace 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 preferably heated to a temperature above the AC3 temperature. If the component remains in the second zone for a sufficiently long time, 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 each constant. This means that 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 the heating of the component. This is because the temperature of the component adapts comparatively slowly to the temperature in the first continuous furnace. In order to take this fact into account, the zones are defined by the respective average temperature. The average temperature in the first zone is below the AC3 temperature, the average temperature in the second zone above the AC3 temperature. The first zone is therefore not interrupted, for example, by the fact that the temperature is in a small range above the AC3 temperature of the component. The same applies to the second zone. The average temperature is the average temperature to which the component is exposed in the respective zone. This is the temperature in a building level of the first continuous furnace, i.e. the level in which the component is transported through the first continuous furnace. In particular, in the case of a gas-fired first continuous furnace, locally increased temperatures in the area of the burners should be disregarded if they are spaced from the component.

The first zone extends in the direction of transport of the component 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 initially warmed up comparatively slowly and then only briefly exposed to a temperature above the AC3 temperature. Accordingly, it is preferred that the first zone is made significantly longer than the second zone. Such heating results in a particularly small transition area between the areas of different ductility. The areas of different ductility are therefore particularly sharply delimited from one another. This is surprising insofar as there is a connection between the expansion of the transition area and the type and manner of heating prior to setting a Temperature above AC3 was previously unknown.

It is sufficient that the zones are only separated from one another by the set temperature. In addition, it is not necessary for the zones to differ or for the boundaries between the zones to be recognizable as such. In addition, it is possible that a first zone and a second zone can be defined in the first continuous furnace in various ways. It is sufficient if there is a possible assignment of a first zone and a possible assignment of a second zone, with all of the conditions set up for the two zones being met. Alternative allocation options are then irrelevant. However, the zones are preferably not assigned arbitrarily. If the temperature profile has clearly recognizable jumps along the direction of transport of the component, the boundary between the zones preferably coincides with such a clearly recognizable jump. It is particularly preferred for the temperature at the boundary between the first zone and the second zone to be 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.

Furthermore, it is preferred that 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. Likewise, it is preferred that the temperature over at least 80% of an expansion 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. These statements also relate to the temperature to which the component is exposed in the first continuous furnace.

The first continuous furnace preferably has a plurality of heating elements, the temperature of which can preferably be set 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 done by a control device and in this respect does not have to be recognizable from the heating elements themselves. The only decisive factor is the temperature distribution. By changing the temperature setting of a heating element at the boundary between the first zone and the second zone, the assignment of this heating element can be changed from the first zone to the second zone, and vice versa. In general, the expansion of the zones can be changed by changing the assignment of heating elements at the border 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.

In step b) of the method, the component is transferred from the first continuous furnace to the temperature control station. There, the component is thermally treated differently in areas in step c) 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 temperature control station facilitates the cooling of the component between the heating in the first continuous furnace and the thermal treatment in the temperature control station. In any case, the component is cooled down as quickly as possible in certain areas in the temperature control station. Rapid cooling can be done more efficiently outside of the hot first continuous furnace. In this way, the cooling can begin during the transfer. In this respect, the spatial separation of the first continuous furnace from the temperature control station accelerates the process. This is in contrast to a solution in which all process steps are carried out in the same device without having to transfer the component. Such solutions typically aim to keep the expense of component transfers low or to avoid them altogether. The spatial separation between the first continuous furnace and the temperature control station also facilitates the construction because the requirements for the first continuous furnace and the temperature control station are different. Integrating both in one facility would therefore be correspondingly complicated.

In the temperature control station, 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. Depending on the temperature of the first area when entering the temperature control station and depending on the length of stay in the temperature control station, 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 with the first area is held against a chamber that is open on the component side the chamber is kept at this temperature by means of a heating device. The heating device is preferably an electrical heating device. The heating device can, for example, have a heating element such as a heating loop. Alternatively or additionally, 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 with a cooling fluid, in particular with compressed air. The compressed air preferably has a pressure in the range from 2 to 4.5 bar. As a result of this comparatively high pressure, a large amount of the compressed air can be directed to the second area of the component within a very short time, so that a sufficiently high cooling speed can be achieved.

Whether and to what extent the temperature of the component is above or below the AC3 temperature of the component has a decisive influence on the structure composition obtained. As a result of the different thermal treatment of the areas of the component, the two areas can have different structural compositions and, in this respect, different ductilities. The first area will be harder than the second area. For example, in the case of a B-pillar for a motor vehicle, the crash properties can be set in a targeted manner.

The first area and the second area are not necessarily connected areas. In particular, it is possible that a middle part of a B-pillar represents 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, only has the first area and the second area, that is to say no further areas.

• d) Transferieren des Bauteils von der Temperierstation in einen zweiten Durchlaufofen,
• e) thermisches Behandeln des Bauteils in dem zweiten Durchlaufofen.

In a preferred embodiment, the method further comprises:

• d) Transferring the component from the temperature control station to a second continuous furnace,
• e) thermal treatment of the component in the second continuous furnace.

The temperature control station and the second continuous furnace are different components that are spatially separated from each other. The transfer between the temperature control station and the second continuous furnace facilitates the cooling of the component between the thermal treatment in the temperature control station and in the second continuous furnace. In this way, the second area of the component can also be cooled down during the transfer. This reduces the required size of the temperature control station and speeds up the process. This is in contrast to a solution in which all process steps are carried out, if possible, in the same device without having to transfer the component. Such solutions typically aim to keep the expense of component transfers low or to avoid them altogether. The spatial separation between the temperature control station and the second continuous furnace also facilitates the construction because the requirements for the temperature control station and the second continuous furnace are different. Integrating both in one facility would therefore be correspondingly complicated.

The second continuous furnace is preferably a roller hearth furnace. The entire component is thermally treated in the second continuous furnace. The component is completely picked up by the second continuous furnace. The thermal treatment in a continuous furnace stands in particular in contrast to a heating by the so-called "direct energization".

The thermal treatment in the second continuous furnace gives the component a different structural composition than would otherwise be the case. In this respect, the present embodiment is directed to applications in which corresponding structural compositions are desired. It has been found that, particularly in these applications, the advantage described is achieved that particularly sharply delimited areas of different ductility can be obtained through the zones with different temperatures in the first continuous furnace. This advantage is achieved in a special way with the combination of steps a) to e).

In a further preferred embodiment of the method, the average temperature in the first zone of the first continuous furnace is in the range from 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 from 10 to 30 K above the component's AC3 temperature.

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.

Tests have shown that the advantages described can be achieved, in particular with the specified temperature values. That is surprising in that a deviation of 10 to 30 K from the AC3 temperature is comparatively small. For example, the AC3 temperature of steel 22MnB5 is 846 ° C. A deviation of 10 K from this results in just around 1%. Nonetheless, this slight deviation resulted in a significant reduction in a transition area between the areas of different ductility.

In the case of 22MnB5, it is preferred that the temperature in the first zone is on average 814 to 836 ° C and in the second zone on average 856 to 876 ° C. 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.

In a further preferred embodiment of the method, the component dwell time in the second zone of the first continuous furnace is in the range from 10 to 30 s.

The dwell time in the first continuous furnace is preferably in the range from 250 to 400 s. Accordingly, a dwell time in the range from 10 to 30 s in the second zone is comparatively short. However, tests have shown that such a short dwell time in the second zone is sufficient for the advantages described. A longer residence time could have a detrimental effect on the structure composition.

In a further preferred embodiment of the method, the cooling of the second area begins in step c) with a delay of 0.5 to 15 s after the end of step b).

The cooling does not begin immediately after the component has entered the temperature control station. In this way, the cooling can also be used for cooling through free radiation to the environment, whereby, for example, cooling fluid can be saved. The cooling that starts after the delay is active cooling. This allows the strength properties of the component to be set particularly precisely. Tests have shown that a delay that is too long is also disadvantageous and, in particular, can lead to an increase in the transition area between areas of different ductility. The combination of the described zone-wise heating in the first continuous furnace with the comparatively low delay showed in tests a particularly sharp separation between the different ductility areas.

In a further preferred embodiment of the method, the first area of the component is exposed in step c) to a temperature which is on average 170 to 250 K above the AC3 temperature of the component.

It has been found that the temperature control in the temperature control 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 temperature control station resulted in a smaller transition area in tests.

In step c), the component is preferably exposed to a temperature which is constantly in the range from 170 to 250 K above the AC3 temperature of the component. In the case of 22MnB5, it is preferred that the first area in step c) is exposed to an average temperature in the range from 900 to 1100 ° C., in particular a constant temperature in this area.

In a further preferred embodiment of the method, the component remains in step c) for a dwell time in the range of 10 and 30 s in the temperature control station.

• - einen ersten Durchlaufofen, welcher in Transportrichtung des Bauteils in eine erste Zone und eine an diese anschließende und dieser nachgeordnete zweite Zone unterteilt ist, wobei sich die erste Zone in Transportrichtung des Bauteils über mindestens 70 % des ersten Durchlaufofens erstreckt,
• - eine dem ersten Durchlaufofen in Transportrichtung des Bauteils nachgeordnete Temperierstation,
• - eine Steuereinrichtung, die dazu eingerichtet ist, in der ersten Zone des ersten Durchlaufofens eine Durchschnittstemperatur unterhalb der AC3-Temperatur des Bauteils einzustellen, und in der zweiten Zone des ersten Durchlaufofens eine Durchschnittstemperatur oberhalb der AC3-Temperatur des Bauteils einzustellen.

As a further aspect of the invention, a device for the thermal treatment of a component is presented. The device comprises:

• - A first continuous furnace, which is subdivided into a first zone in the direction of transport of the component and a second zone adjoining and following this, the first zone extending in the direction of transport of the component over at least 70% of the first continuous furnace,
• - a temperature control station downstream of the first continuous furnace in the transport direction of the component,
• a control device which is 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 described particular advantages and design features of the method can be used 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 with the device. The device preferably has a second continuous furnace, which is arranged downstream of the temperature control station in the transport direction of the component.

The fact that the second zone of the first continuous furnace is arranged downstream of 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 same applies to the temperature control station and the second continuous furnace, which are arranged downstream of the first continuous furnace or the temperature control station in the transport direction of the component.

• 1: eine erfindungsgemäße Vorrichtung zum thermischen Behandeln eines Bauteils,
• 2: einen Temperaturverlauf, der sich mit der Vorrichtung aus 1 bei Durchführung eines erfindungsgemäßen Verfahrens zum thermischen Behandeln des Bauteils einstellt.

The invention is explained in more detail below with reference to the figures. The figures show a particularly preferred exemplary embodiment to which, however, the invention is not limited. The figures and the proportions shown therein are only schematic. Show it:

• 1 : a device according to the invention for the thermal treatment of a component,
• 2 : a temperature profile that is related to the device 1 adjusts when carrying out a method according to the invention for the thermal treatment of the component.

1 shows an apparatus 1 for thermal treatment of a component 2 . The device 1 comprises a first continuous furnace 3 , which in the transport direction r of the component 2 a first zone 6th and one of the first zone 6th downstream second zone 7th having. The second zone 7th is therefore from the component 2 run through later and is therefore in 1 to the right of the first zone 6th . The first continuous furnace 3 is in the direction of transport r on the first zone 6th and the second zone 7th divided, so has no further zones in this direction. The first zone 6th extends in the direction of transport r of the component 2 over 70% of the first continuous furnace 3 . The first zone 6th and the second zone 7th extend transversely to the direction of transport r - so in 1 up and down as well as perpendicular to the plane of the drawing - over the entire first continuous furnace 3 .

The device 1 furthermore has one of the first continuous furnace 3 in transport direction r of the component 2 downstream temperature control station 4th on. Furthermore, the device 1 a second continuous furnace 5 in the direction of transport r of the component 2 the temperature control station 4th is subordinate. The temperatures in the first zone 6th of the first continuous furnace 3 , in the second zone 7th of the first continuous furnace 3 , in the temperature control station 4th and in the second continuous furnace 5 are via a control device 8th adjustable. This is indicated by dotted lines. The control device 8th is especially designed to be in the first zone 6th of the first continuous furnace 3 an average temperature below the AC3 temperature T _AC3 of the component 2 set, and in the second zone 7th of the first continuous furnace 3 an average temperature above the AC3 temperature T _AC3 of the component 2 to adjust.

2 shows a temperature profile in the component 2 adjusts when it is through the device 1 the end 1 is moved. The representation of 2 is schematic. A plot of the temperature is shown T over time t in any units. The component 2 is first in the first continuous furnace 3 warmed up. The dwell time of the component 2 in the first continuous furnace 3 is with t _D1 and in the with t _Z1 designated length of stay in the first zone 6th and the with t _Z2 designated length of stay in the second zone 7th divided. In the first zone 6th the temperature is constant at a value T _Z1 set that is below the AC3 temperature T _AC3 of the component 2 lies. In the second zone 7th the temperature is constant at a value T _Z2 set that is above the AC3 temperature T _AC3 of the component 2 lies. The temperature of the component 2 this initially rises to the value T _Z1 on which until the end of t _Z1 saturation occurs. In t _Z2 a further heating takes place T _Z2 .

Then the component 2 in the temperature control station 4th transferred. The associated transfer time is with t _T1 designated. The component cools during this transfer 2 away. It can already be between the temperature T _A a first range of the component and the temperature T _B a second area of the component can be distinguished. This is possible, for example, through different isolation in certain areas during the transfer.

In the temperature control station 4th the component remains 2 over a dwell time t _TS . During this time the component will 2 in the temperature control station 4th thermally treated by a first area of the component 2 is exposed to a temperature that is constant at a value T _TS above the AC3 temperature T _AC3 of the component 2 and a second area of the component 2 is cooled. The cooling of the second area of the component 2 starts with a delay t _v . The delay t _v begins with the entry of the component 2 in the temperature control station 4th , i.e. at the end of t _T1 and start of t _TS . Even in spite of the cooling, there is an increase in temperature T _B of the second area. This is due to the release of latent heat. This effect is also known as “recalescence”.

After the thermal treatment of the component 2 in the temperature control station 4th becomes the component 2 in the second continuous furnace 5 transferred. The transfer time for this is with t _T2 designated. The component also cools here 2 which may vary depending on the area.

In the second continuous furnace 5 becomes the component 2 further thermally treated by heating it as a whole. For this purpose the component 2 exposed to a temperature above the AC3 temperature T _AC3 of the component 2 lies. The colder second area of the component 2 is heated more than the warmer first area. The dwell time of the component 2 in the second continuous furnace 5 is denoted by T _D2.

The component is given different thermal treatment in areas 2 a ductility that differs in certain areas. This is advantageous for a B-pillar for a motor vehicle, for example. The different temperatures T _Z1 , T _Z2 in the zones 6th , 7th of the first continuous furnace 3 have the effect that the areas of different ductility are particularly sharply separated from one another.

List of reference symbols

1

contraption

2

Component

3

first continuous furnace

4th

Temperature control station

5

second continuous furnace

6th

first zone

7th

second zone

8th

Control device

T

temperature

TAC3

AC3 temperature of the component

TZ1

Temperature in the first zone

TZ2

Temperature in the second zone

TTS

Temperature for the second area in the temperature control station

TA

Temperature of the first area of the component

TB

Temperature of the second area of the component

t

Time

tD1

Dwell time in the first tunnel oven

tZ1

Dwell time in the first zone of the first continuous furnace

tZ2

Dwell time in the second zone of the first continuous furnace

tT1

Transfer time from the first continuous furnace to the temperature control station

tTS

Dwell time in the temperature control station

tv

Delay in the cooling of the second area of the component

tT2

Transfer time from the temperature control station to the second continuous furnace

tD2

Dwell time in the second continuous furnace

r

Transport direction of the component

Claims (8)

A method for the thermal treatment of a component (2), comprising: a) heating the component (2) in a first continuous furnace (3), which in the transport direction (r) of the component (2) into a first zone (6) and one to this subsequent second zone (7) through which the component (2) passes later, the first zone (6) extending in the transport direction (r) of the component (2) over at least 70% of the first continuous furnace (3), with a Average temperature in the first zone (6) is below the AC3 temperature (T _AC3 ) of the component (2), and an average temperature in the second zone (7) is above the AC3 temperature (T _AC3 ) of the component (2) , b) transferring the component (2) from the first continuous furnace (3) to a temperature control station (4), c) thermal treatment of the component (2) in the temperature control station (4), a first area of the component (2) having a temperature exposed on average above the AC3 temperature (T _AC3 ) of the building ils (2) lies, and a second area of the component (2) is cooled. Procedure according to Claim 1 , further comprising: d) transferring the component (2) from the temperature control station (4) into a second continuous furnace (5), e) thermal treatment of the component (2) in the second continuous furnace (5). Method according to one of the preceding claims, wherein the average temperature in the first zone (6) of the first continuous furnace (3) is in the range from 10 to 30 K below the AC3 temperature (T _AC3 ) of the component (2) and / or wherein the Average temperature in the second zone (7) of the first continuous furnace (3) is in the range from 10 to 30 K above the AC3 temperature (T _AC3 ) of the component (2). Method according to one of the preceding claims, wherein a dwell time (t _Z2 ) of the component (2) in the second zone (7) of the first continuous furnace (3) is in the range from 10 to 30s. Method according to one of the preceding claims, wherein in step c) the cooling of the second region of the component (2 _{) begins with a delay (t v} ) of 0.5 to 15 s after the end of step b). Method according to one of the preceding claims, wherein in step c) the first area of the component (2) is exposed to a temperature which is on average 170 to 250 K above the AC3 temperature (T _AC3 ) of the component (2). Method according to one of the preceding claims, wherein the component (2) in step c) remains in the temperature control station (4) _{for a dwell time (t TS) in the range of 10 and 30 s.} Device (1) for the thermal treatment of a component (2), comprising: - a first continuous furnace (3) which, in the transport direction (r) of the component (2), enters a first zone (6) and a second zone (6) adjoining and following this Zone (7) is subdivided, the first zone (6) extending in the transport direction (r) of the component (2) over at least 70% of the first continuous furnace (3), - one of the first continuous furnace (3) in the transport direction (r) the component (2) downstream temperature control station (4), - a control device (8) which is set up in the first zone (6) of the first continuous furnace (3) an average temperature below the AC3 temperature (T _AC3 ) of the component ( _{2) and set an average temperature above the AC3 temperature (T AC3} ) of the component (2) in the second zone (7) of the first continuous furnace (3).

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