CN115210388A

CN115210388A - Heat treated component

Info

Publication number: CN115210388A
Application number: CN202180019439.7A
Authority: CN
Inventors: J·温克尔; A·赖纳茨; F·威尔顿
Original assignee: Schwartz GmbH
Current assignee: Schwartz GmbH
Priority date: 2020-03-06
Filing date: 2021-02-23
Publication date: 2022-10-18
Anticipated expiration: 2041-02-23
Also published as: DE102020106139A1; WO2021175663A1; MX2022010937A; JP2023516732A; EP4114992A1

Abstract

A method for heat treating a component (2), comprising a) heating the component (2) in a first continuous furnace (3), the first continuous furnace (3) being divided in the transport direction (r) of the component (2) into a first zone (6) and a second zone (7), the second zone (7) adjoiningSaid first zone and the component (2) subsequently passing through said second zone, the first zone (6) and the second zone (7) together extending over at least 70% of the first continuous furnace (3) in the conveying direction (r) of the component (2), the average temperature in the first zone (6) being lower than the AC3 temperature (T) of the component (2) _AC3 ) The average temperature in the second zone (7) being higher than the AC3 temperature (T) of the component (2) _AC3 ) (ii) a b) Transferring the component (2) from the first continuous furnace (3) to a temperature control station (4); and c) heat-treating the component (2) in a temperature control station (4), a first zone of the component (2) being exposed to an AC3 temperature (T) which is higher on average than the component (2) _AC3 ) And the second zone of the component (2) is cooled. The part (2) acquires ductility in different zones due to the heat treatment of the different zones. This is advantageous, for example, in B-pillars for motor vehicles. Different temperatures (T) in the region (6,7) of the first continuous furnace (3) _Z1 ，T _Z2 ) So that the zones of different extensibility are separated from each other in a particularly defined manner.

Description

Heat treated component

Technical Field

The invention relates to a method and a device for heat treating components, in particular steel components for motor vehicles.

Background

In the automotive industry in particular, the prior art selectively hardens steel parts by heat treatment. For this reason, the heat treatment method of steel members such as the B-pillar varies depending on the region. Therefore, ductility varies from zone to zone, which is advantageous for the crash performance of these components. For example, an occupant may be protected at seat height by a hard region of the B-pillar, while soft regions in the upper and lower regions of the B-pillar absorb energy by deforming.

Disclosure of Invention

Summary of the inventionstarting from the prior art described, it is an object of the present invention to provide a method for the heat treatment of components, by means of which regions of the components can be heat treated in such a way that the components are separated from one another in a particularly defined manner. In addition, the invention provides a corresponding device.

These objects are achieved by a method and an arrangement according to the independent claims. Further advantageous developments are specified in the dependent claims. The features presented in the claims and the description can be combined with each other in any technically meaningful way.

According to the present invention, a method for heat treating a component is provided. The method comprises the following steps:

a) Heating the components in a first continuous oven, which in the transport direction of the components is divided into a first zone and a second zone, which second zone adjoins the first zone and through which the components subsequently pass, the first zone extending over at least 70% of the first continuous oven in the transport direction of the components, the average temperature in the first zone being lower than the AC3 temperature of the components and the average temperature in the second zone being higher than the AC3 temperature of the components;

b) Transferring the component from the first continuous furnace to a temperature control station; and

c) Heat treating the component in the temperature control station, a first zone of the component being exposed to a temperature that is on average higher than the AC3 temperature of the component, and a second zone of the component being cooled.

The method may be used to heat treat a component. The component is preferably a steel component. The steel is preferably 22MnB5. For example, the method described can be used for heat treating components for motor vehicles, in particular B-pillars. After the heat treatment, the component is preferably press hardened in a press and in this respect thermoformed. As a further step, the method preferably comprises transferring the component after the heat treatment into a press and press hardening in the press. In this case, the method is a method of heat-treating and press-hardening a component.

The component preferably has a material thickness of at least 1 mm, in particular in the range of 1 to 4 mm. Preferably, the material thickness of the component is constant over the entire component. Optionally, the component may also have a material thickness that varies from region to region. For example, the component may be a "Tailor Rolled Blank (TRB)" which is rolled by local variations to obtain a locally varying material thickness. The component may also be a "Tailor Welded Blank (TWB)" which is obtained by welding together a plurality of metal plates with a locally varying material thickness. Combinations of TRBs and TWBs are also possible. Furthermore, the method is equally applicable to parts with and without a coating. Al/Si coatings are particularly suitable as coatings.

In step a), the component is heated in the first continuous furnace. A furnace is a device that reaches a settable temperature inside it and into which components can be inserted. Over time, the component may reach the temperature inside the furnace. Thus, heat is transferred to the component from the gas located in the furnace, which may be in particular air. A continuous furnace is a furnace through which a part may be moved and heated as the part passes through the furnace.

Preferably, the first continuous furnace is a roller hearth furnace. In the first continuous furnace, the components are preferably heated by means of burners, in particular gas burners. The component can thus have a particularly uniformly distributed temperature. In particular, the heating is not merely a layer on the surface of the component. The entire part is heated in a first continuous furnace. The part is completely contained in the first continuous furnace. In addition, particularly large temperature differential heating can be achieved by using a continuous furnace. Using a continuous oven, the component can be heated, in particular from room temperature to a temperature in the AC3 temperature range of the component. It is not possible, or at least not possible without excessive effort, to use many other heating methods.

Heating in a continuous furnace is in sharp contrast to so-called "direct-on" heating. This would make it difficult to heat the part uniformly and to a sufficiently high amount. In the case of direct energization, the rate of heating is more important. Furthermore, direct electrical conduction requires contact with the component. In step a) of the method, the heating is preferably carried out without contact. This does not exclude the use of conveyor rollers for moving the component through the first continuous oven and in this respect being in contact with the conveyor rollers. If the heat input into the component takes place by means of gas and/or heat radiation, the heating is not contact-free.

The first continuous furnace and the rest of the apparatus for the method are described with reference to the "direction of transport of the components". This is the direction in which the device and its components move parts. The direction of transport of the components is thus in particular the direction in which the components move through the first continuous oven.

The first continuous furnace has a first zone and a second zone when viewed in the conveying direction so defined. The fact that the first continuous furnace is "divided" into these two regions in the transport direction of the components means that the first continuous furnace has only these two regions, when seen in the transport direction of the components. Preferably, each of said zones extends on said first continuous oven transversely to the direction of transport of said components.

The component passes first through the first zone and then through the second zone. In this respect, the second zone is arranged downstream of the first zone, as viewed in the conveying direction. The first region and the second region are directly adjacent. The first zone is adjacent to an inlet of the first continuous furnace and the second zone is adjacent to an outlet of the first continuous furnace. The component may be introduced into the first continuous furnace through an inlet. The component may exit the first continuous furnace through an outlet.

The average temperature in the first zone is below the AC3 temperature of the component; the average temperature in the second zone is higher than the AC3 temperature of the component. In the first continuous oven, the components are first heated relatively slowly to a temperature below the AC3 temperature and then briefly exposed to a temperature above the AC3 temperature. Preferably, the component is heated in the second zone to a temperature above the AC3 temperature. This may be the temperature set in the second zone if the residence time of the component in the second zone is sufficiently long.

Preferably, the temperature in the first zone and the temperature in the second zone are constant. As a result, the component is heated uniformly in the region. It should be noted, however, that short term and/or locally limited temperature variations within the first continuous furnace are almost independent of the heating of the component. This is because the temperature of the component is adapted relatively slowly to the temperature in the first continuous oven. To take this fact into account, the zones are defined by the average temperature in each case. The average temperature of the first zone is lower than the AC3 temperature and the average temperature of the second zone is higher than the AC3 temperature. For example, the first zone is not destroyed by temperatures in a small range above the component AC3 temperature. The same applies to the second area. The average temperature is understood to mean the average of the temperatures to which the component is exposed in the relevant area. This is the temperature in the plane of the components of the first continuous furnace, i.e. the plane in which the components are conveyed through the first continuous furnace. In particular, in the case of a first continuous furnace which is gas fired, locally increased temperatures in the burner region should be ignored if the burner is at a distance from the component.

The first zone extends over at least 70%, preferably even over at least 80%, of the first continuous furnace in the transport direction of the components. It has been found that this is sufficient if the component is initially heated relatively slowly and then only briefly exposed to a temperature above the AC3 temperature. Accordingly, the first region is preferably designed to be significantly longer than the second region. Due to this heating, particularly small transition zones are obtained between the zones with different ductility. The zones of different extensibility are therefore delimited from one another in a particularly defined manner. This is surprising because the connection between the extent of the transition region and the heating regime is unknown before setting the temperature above AC 3.

It is sufficient to delimit the zones from each other only by setting the temperature. Furthermore, it is not necessary that the zones differ, nor that the boundaries between the zones can be so identified. It is also possible that the first zone and the second zone may be defined in the first continuous furnace in a different manner. It is sufficient if there is a possible allocation of the first zone and a possible allocation of the second zone, all conditions set for these two zones being satisfied in each case. The alternative allocation option is then irrelevant. Preferably, however, the allocation of the zones is not random. If the temperature distribution in the transport direction of the component has clearly identifiable jumps, the boundaries between the zones preferably coincide with such clearly identifiable jumps. It is particularly preferred that the temperature at the boundary between the first zone and the second zone is the AC3 temperature of the component. This is especially the case if the boundary between the two regions is located at a jump in temperature 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 in the range of at least 80% of the first zone in the transport direction of the component is lower than the AC3 temperature of the component. Also, it is preferred that the temperature in at least 80% of the second zone in the transport direction of the component is higher than the AC3 temperature of the component. Particularly preferably, the temperature in the entire first zone is below the AC3 temperature. Particularly preferably, the temperature in the entire second zone is higher than the AC3 temperature. These statements also relate to the temperature to which the components are exposed in the first continuous oven.

Preferably, the first continuous oven has a plurality of heating elements, the temperature of which can preferably be set individually. Preferably, the first zone and the second zone correspond to respective groups of the heating elements. The assignment of the heating element to a zone is carried out by the control device and need not be recognizable in this respect on the heating element itself. Only the temperature distribution is significant. By changing the temperature setting of the heating element at the boundary between the first zone and the second zone, the distribution of the heating element can be changed from the first zone to the second zone and vice versa. In general, the extent of the zones can be varied by varying the distribution of heating elements at the boundaries between the zones. The temperature distribution of the zones can also be set by the relative temperature settings 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. In the temperature control station, in step c), the component is heat treated in different zones by exposing a first zone of the component to a temperature that is on average higher than the AC3 temperature of the component, and by cooling a second zone of the component.

The first continuous furnace and the temperature control station are distinct components spatially separated from each other. The transfer between the first continuous furnace and the temperature control station facilitates cooling of the component between heating in the first continuous furnace and heat treatment in the temperature control station. In the temperature control station, the component is cooled as quickly as possible, at least in certain areas. The rapid cooling can be performed more efficiently outside the high-temperature first continuous furnace. In this way, cooling may already start during the transfer. In this respect, the physical separation of the first continuous furnace from the temperature control station accelerates the process. This is in contrast to solutions where all method steps are performed in the same device without having to transfer components. Such solutions generally aim to reduce the effort involved in component transport or to avoid them altogether. Due to the different requirements of the first continuous furnace and the temperature control station, the space interval between the first continuous furnace and the temperature control station is convenient for construction. Therefore, integrating both into one device becomes correspondingly complicated.

In the temperature control station, the first zone is exposed to a temperature above the AC3 temperature of the component. Thus, preferably, the first zone in the temperature control station is heated. However, depending on the temperature of the first zone upon entering the temperature control station and depending on the residence time in the temperature control station, the first zone in the temperature control station may also be kept at its temperature or the cooling of the first zone may be slowed down. Preferably, the first region of the component is exposed to a temperature above the AC3 temperature of the component, as long as the first region of the component is held in a chamber at the component-side opening, the chamber being held at this temperature by a heating device. Preferably, the heating device is an electric heating device. The heating device may have a heating element, for example a heating circuit. Alternatively or additionally, the heating device may comprise a radiant-heating pipe which is heated using a burner, in particular using a gas burner.

The second zone is cooled in the temperature control station. This is preferably achieved by keeping the second zone outside the aforementioned chamber. In this position, preferably, a cooling fluid, in particular compressed air, is supplied to the second zone. The pressure of the compressed air is preferably 2 to 4.5nar. Due to this relatively high pressure, a large amount of compressed air can be led to the second zone of the component in a very short time, so that a sufficiently high cooling rate can be achieved.

Whether and to what extent the temperature of the part is above or below the AC3 temperature of the part has a significant effect on the microstructure composition obtained. Due to the different heat treatments of the regions of the component, the two regions may have different microstructure compositions and, in this regard, different ductility. Thus, the first zone becomes harder than the second zone. For example, in the case of a B-pillar for a motor vehicle, the crash characteristics can be set in a targeted manner.

The first region and the second region are not necessarily continuous regions. In particular, the middle portion of the B-pillar may constitute the first zone, while the upper and lower portions of the B-pillar together constitute the second zone. Preferably, but not necessarily, the component has only the first and second zones, i.e. no additional zones.

In a preferred embodiment, the method further comprises:

d) Transferring the part from the temperature control station to a second continuous furnace; and

e) The part is heat treated in a second continuous furnace.

The temperature control station and the second continuous furnace are distinct components spatially separated from each other. The transfer between the temperature control station and the second continuous furnace facilitates cooling of the component between the temperature control station and the heat treatment in the second continuous furnace. In this way, the second zone of the component can also be cooled during the transfer. This reduces the required size of the temperature control station and speeds up the method. This is in contrast to a solution in which all method steps are carried out as much as possible in the same apparatus without having to transfer components. Such solutions generally aim to reduce the effort involved in component transport or to avoid them altogether. The spatial separation between the temperature control station and the second continuous furnace also facilitates construction because of the different requirements placed on the temperature control station and the second continuous furnace. Therefore, integrating both in one device becomes correspondingly complicated.

Preferably, the second continuous furnace is a roller hearth furnace. The entire part is heat treated in a second continuous furnace. The part is completely contained in a second continuous furnace. The heat treatment in a continuous furnace is in sharp contrast to so-called "direct-current" heating.

The heat treatment in the second continuous furnace causes the part to have a microstructure composition that is different from the other cases. In this regard, embodiments of the present invention are directed to applications requiring corresponding microstructure compositions. It has been found that, in particular in these applications, the stated advantages are achieved in that, owing to the zones of different temperature in the first continuous furnace, zones of different ductility, which are delimited in a particularly defined manner, can be obtained. This advantage is achieved in a particular manner by a combination of steps a) to e).

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

A combination wherein the average temperature in the first zone of the first continuous furnace is in the range of 10 to 30K below the AC3 temperature of the component and the average temperature in the second zone of the first continuous furnace is in the range of 10 to 30K above the AC3 temperature of the component is preferred.

Tests have shown that the above-mentioned advantages can be achieved, in particular at specified temperature values. This is surprising because the deviation from the AC3 temperature is relatively small, 10 to 30K. For example, steel 22MnB5 has an AC3 temperature of 846 deg.C. The deviation from this by 10K does not exceed about 1%. However, due to this slight deviation, a significant reduction in the size of the transition zone between the zones of different ductility can be observed.

In the case of 22MnB5, it is preferred that the temperature in the first zone averages 814 to 836 ℃ and the temperature in the second zone averages 856 to 876 ℃. The temperature in the first zone is particularly preferably constantly in the range from 816 to 836 ℃ and the temperature in the second zone is constantly in the range from 856 to 876 ℃.

In another preferred embodiment of the method, the residence time of the component in the second zone of the first continuous furnace is in the range of 10 to 30 s.

The residence time in the first continuous oven is preferably in the range of 250 to 400 seconds. Thus, the residence time of 10 to 30s in the second zone is relatively short. Tests have shown, however, that such short residence times in the second zone are sufficient for the advantages described. Longer residence times may adversely affect the microstructure composition.

In another preferred embodiment of the method, in step c), the cooling of the second zone is started with a delay of 0.5 to 15s after the completion of step b).

Cooling does not begin immediately after the part enters the temperature control station. Thus, the cooling of the environment by free radiation can also be used for cooling, so that, for example, cooling fluid can be saved. The cooling started 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 disadvantageous and leads in particular to an increase in the size of the transition zone between zones of different extensibility. In the tests, the combination of zoned heating and relatively short delays described in the first continuous furnace showed a particularly well-defined separation between zones of different ductility.

In another preferred embodiment of the method, the first zone of the component is exposed to a temperature in step c) which is 170 to 250K higher than the AC3 temperature average of the component.

It has been found that the temperature control in the temperature control station also affects the extent of the transition zone between the zones of different ductility. In the test, the relatively high temperature of the heat treatment of the first zone in the temperature control station resulted in a smaller transition zone.

In step c), the component is preferably exposed to a temperature in the range of 170 to 250K above the AC3 temperature of the component. In the case of 22MnB5, the first zone in step c) is preferably exposed to an average temperature in the range of 900 to 1100 ℃, in particular to a constant temperature in this range.

In another preferred embodiment of the method, in step c), the component is left in the temperature control station for a dwell time of 10 to 30 seconds.

As another aspect of the invention, an apparatus for heat treating a component is provided. The device comprises:

-a first continuous furnace divided in the transport direction of the components into a first zone and a second zone adjacent to and downstream of said first zone, the first zone extending over at least 70% of the first continuous furnace in the transport direction of the components;

-a temperature control station arranged downstream of the first continuous oven in the transport direction of the components; and

-a control device designed to set an average temperature lower than the AC3 temperature of the components in a first zone of the first continuous furnace and to set an average temperature higher than the AC3 temperature of the components in a second zone of the first continuous furnace.

The particular advantages and design features of the method can be applied and transferred to the device and vice versa. Preferably, the device is intended and designed for operation according to the method. Preferably, the method is performed using the apparatus. Preferably, the plant has a second continuous furnace arranged downstream of the temperature control station in the direction of conveyance of the components.

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 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 and the temperature control station, respectively, in the transport direction of the components.

Drawings

Detailed description of the inventionthe invention is explained in more detail below with reference to the drawings. Detailed description the drawings show particularly preferred embodiments, to which, however, the invention is not restricted. The drawings and the scale shown therein are purely diagrammatic. In the drawings:

FIG. 1 shows an apparatus for heat treating a component according to the present invention; and

figure 2 shows the temperature profile that occurs when implementing the method for heat treating a component according to the invention using the apparatus of figure 1.

Detailed Description

Fig. 1 shows an apparatus 1 for heat treating a component 2. The device 1 comprises a first continuous furnace 3, the first continuous furnace 3 having a first zone 6 and a second zone 7 downstream of the first zone 6 in the conveying direction r of the component 2. The component 2 thus passes the second zone 7 later on, and said second zone is thus located to the right of the first zone 6 in fig. 1. The first continuous furnace 3 is divided in the conveying direction r into a first zone 6 and a second zone 7, i.e. there are no further zones in this direction. The first zone 6 extends over 70% of the first continuous furnace 3 in the direction of conveyance r of the component 2. The first zone 6 and the second zone 7 extend over the entire first continuous furnace 3 transversely to the conveying direction r (i.e. upwards and downwards in fig. 1 and perpendicular to the plane of the drawing).

The apparatus 1 also has a temperature control station 4 downstream of the first continuous furnace 3 in the direction of conveyance r of the components 2. Furthermore, the device 1 has a second continuous furnace 5, which second continuous furnace 5 is arranged downstream of the temperature control station 4 in the transport direction r of the components 2. The temperatures in the first zone 6 of the first continuous furnace 3, the second zone 7 of the first continuous furnace 3, the temperature control station 4 and the second continuous furnace 5 can all be set by means of a control device 8. This is indicated by the dashed line. The control means 8 are designed in particular to set the temperature T of the AC3 lower than that of the components 2 in the first zone 6 of the first continuous furnace 3 _AC3 And in the second zone 7 of the first continuous furnace 3 is set higher than the AC3 temperature T of the component 2 _AC3 The average temperature of (2).

Fig. 2 shows the temperature profile that occurs in the component 2 when the component 2 is moved from fig. 1 through the device 1. The representation of fig. 2 is a schematic diagram. A graph of temperature T over time T is shown in arbitrary units. The component 2 is first heated in the first continuous furnace 3. The residence time of the component 2 in the first continuous furnace 3 is from t _D1 Represents, and is divided into stops in the first zone 6Retention time (from t) _Z1 Indicated by t) and the residence time in the second zone 7 (indicated by t) _Z2 Representation). In the first zone 6, the temperature is constantly set lower than the AC3 temperature T of the component 2 _AC3 Value T of _Z1 . In the second zone 7, the temperature is constantly set to the value T _Z2 This value is higher than the AC3 temperature T of the component 2 _AC3 . As a result, the temperature of the component 2 initially rises to the value t _Z1 At this value up to T _Z1 Saturation occurs until the end. At t _Z2 Further heating to T _Z2 。

The component 2 is then transferred to the temperature control station 4. Associated transmission time is represented by t _T1 And (4) showing. The component 2 cools during this transfer. Temperature T of the first zone of the component _A And the temperature T of the second zone of the component _B A distinction is made between. This is possible, for example, because the insulation of different areas differs during the transfer process.

The dwell time t of the component 2 in the temperature control station 4 _TS . During this time, by exposing the first zone of the component 2 to a temperature T constantly at a temperature higher than the AC3 temperature of the component 2 _AC3 Temperature value T of _TS The component 2 is heat treated in the temperature control station 4 and heat treated by cooling the second zone of the component 2. Cooling of the second zone of the component 2 to delay t _V And starting. Delay t _V Starting when the component 2 enters the temperature control station 4, i.e. at t _Tl End of and t _TS To begin. Even if cooled, the temperature T of the second zone can be seen _B And (4) rising. This is due to the release of latent heat. This effect is also known as "recalescence".

After the component 2 has been heat treated in the temperature control station 4, the component 2 is transferred to the second continuous furnace 5. T for transmission time _T2 And (4) showing. Here too, the component 2 cools down, and this may vary depending on the area.

In the second continuous furnace 5, the component 2 is further heat treated by bulk heating. For this purpose, the component 2 is exposed to a temperature T higher than the AC3 temperature T of the component 2 _AC3 The temperature of (2). In the process, the component 2 is comparedThe cold second zone heats up more than the hot first zone. The residence time of the component 2 in the second continuous furnace 5 is represented by T _D2 And (4) showing.

The component 2 has different zones of ductility due to the heat treatment of the different zones. This is advantageous, for example, in B-pillars for motor vehicles. Different temperatures T in the

zones

6,7 of the first continuous furnace 3 _Z1 、T _Z2 With the effect that the zones of different extensibility are separated from each other in a particularly defined manner.

List of reference numerals

1. Device

2. Component part

3. First continuous furnace

4. Temperature control station

5. Second continuous furnace

6. First region

7. Second region

8. Control device

T temperature

T _AC3 AC3 temperature of the part

T _Z1 Temperature of the first zone

T _Z2 Temperature of the second zone

T _TS Controlling the temperature of the second zone in the station

T _A Temperature of the first zone of the component

T _B Temperature of the second zone of the component

time t

t _D1 Residence time in first continuous furnace

t _Z1 Residence time in the first zone of the first continuous furnace

t _Z2 Residence time in the second zone of the first continuous furnace

t _T1 Duration of transfer from first continuous furnace to temperature control station

t _TS Dwell time in temperature control station

t _V Delay in cooling of second zone of component

t _T2 From temperature controlDuration of station transfer to second continuous oven

t _D2 Residence time in a second continuous furnace

r direction of conveyance of the parts

Claims

1. Method for heat treating a component (2), characterized in that it comprises:

a) Heating a component (2) in a first continuous furnace (3), in the transport direction (r) of the component (2), into a first zone (6) and a second zone (7), which second zone (7) adjoins the first zone and through which the component (2) passes later, wherein the first zone (6) extends over at least 70% of the first continuous furnace (3) in the transport direction (r) of the component (2), wherein the average temperature in the first zone (6) is lower than the AC3 temperature (T) of the component (2) _AC3 ) And the average temperature in said second zone (7) is higher than the AC3 temperature (T) of the component (2) _AC3 )；

b) Transferring the component (2) from the first continuous furnace (3) to a temperature control station (4); and

c) The component (2) is heat treated in a temperature control station (4), wherein a first zone of the component (2) is exposed to an AC3 temperature (T) which is on average higher than the component (2) _AC3 ) The second zone of the component (2) is cooled.

2. The method of claim 1, further comprising:

d) Transferring the component (2) from the temperature control station (4) to a second continuous furnace (5); and

e) -heat treating the component (2) in the second continuous furnace (5).

3. The method according to any of the preceding claims, characterized in that the average temperature in the first zone (6) of the first continuous furnace (3) is below the AC3 temperature (T) of the component (2) _AC3 ) 10 to 30k, and/or wherein the average temperature of the second zone (7) of the first continuous furnace (3) is higher than the AC3 temperature (T) of the component (2) _AC3 ) High 10 to 30K.

4. The method according to any of the preceding claims, characterized in that the residence time (t) of the component (2) in the second zone (7) of the first continuous furnace (3) _Z2 ) In the range of 10 to 30 s.

5. Method according to any of the preceding claims, characterized in that in step c) the cooling of the second zone of the component (2) is carried out with a delay (t) of 0.5 to 15s after completion of step b) _V ) And starting.

6. Method according to any of the preceding claims, characterized in that in step c) the first zone of the component (2) is exposed to an AC3 temperature (T) which is on average higher than the component (2) _AC3 ) A temperature of 170K to 250K.

7. Method according to any of the preceding claims, characterized in that in step c) the component (2) is kept in the temperature control station (4) for a dwell time (t) in the range of 10 to 30 seconds _Ts )。

8. An apparatus (1) for heat treating a component (2), the apparatus comprising:

-a first continuous furnace (3) which is divided in the transport direction (r) of the components (2) into a first zone (6) and a second zone (7) adjacent to and downstream of said first zone, wherein the first zone (6) extends over at least 70% of the first continuous furnace (3) in the transport direction (r) of the components (2);

-a temperature control station (4) downstream of the first continuous oven (3) in the direction of transport (r) of the component (2); and

-a control device (8) designed to set, in a first zone (6) of the first continuous furnace (3), an AC3 temperature (T) lower than that of the component (2) _AC3 ) And the second zone (7) of the first continuous furnace (3) is set higher than the AC3 temperature (T) of the component (2) _AC3 ) The average temperature of (2).