Parts heat treatment

Abstract

An apparatus (1) for heat-treating a part (2), wherein the part (2) can be arranged in the apparatus (1) in a part plane (E) defined by a first direction (x) and a second direction (y) perpendicular to the first direction, the apparatus (1) comprising: a heating section (3) having heating means (5) for heating a first region (7) of the part (2); and a cooling section (4) having cooling means (6) for cooling a second region (8) of the part (2), the cooling section (4) being downstream of the heating section (3) in the second direction (y), the cooling means (6) having a nozzle (9) for discharging a cooling fluid (10) onto the part (2), the nozzle (9) being oriented downward in the second direction (y), and the nozzle (9) having a fluid flow path (15) with a nozzle opening (16). The described device (1) allows the heat treatment of different areas of a part (2), more particularly of a steel automotive part, separately, with particularly clear demarcation between the areas (7, 8). For this purpose, a nozzle (9) is directed away from the heating section 3 and has a fluid flow channel (15) with a nozzle opening (16).

Description

[Technical Field]

[0001] The present invention relates to an apparatus for the heat treatment of parts, in particular steel parts for motor vehicles. [Background technology]

[0002] In particular in the automotive industry, it is known to selectively harden steel parts by heat treatment. For this purpose, different areas of a steel part, such as a B-pillar, are heat treated differently, resulting in different hardnesses in different areas, which is advantageous for the behavior of such parts in a crash.

[0003] There are various known methods for treating steel components differently in different regions, but all known methods have in common that the boundaries between the individual temperature ranges are poorly defined, which makes it particularly difficult to simulate the accident behavior of components treated in this way.

[0004] The object of the present invention, which arises from the prior art described, is to provide an apparatus for heat treating parts, which is capable of heat treating the areas of the part in such a way that they are separated from one another in a particularly clear manner.

[0005] This object is achieved by a device according to the independent claims. Advantageous embodiments of the device are defined in the dependent claims. The features presented in the claims and in the description can be combined with one another in any technically significant manner. Summary of the Invention [Means for solving the problem]

[0006] In accordance with the present invention, an apparatus for heat treating a component is provided. In the apparatus, the component can be placed in a component plane defined by a first direction and a second direction perpendicular to the first direction. a heating section having heating means for heating a first region of the component; a cooling section having cooling means for cooling a second region of the component; Equipped with The cooling section is downstream of the heating section in the second direction, and the cooling means has a nozzle for ejecting cooling fluid onto the component, the nozzle being oriented downward in the second direction, and the nozzle having a fluid flow path with a nozzle opening.

[0007] The device is described using a coordinate system having a first direction, a second direction, and a third direction, where any two of these directions are perpendicular to one another. The first direction and the second direction together define a plane called the part plane. The device does not contain a part, but is intended and configured to receive a part. In this way, a part can be inserted into the device so that the part lies in the part plane. The extent of the part's extension in the third direction is negligible.

[0008] The apparatus is particularly suitable for the heat treatment of steel parts, in particular steel parts for automobiles. For example, a B-pillar may be such a part. The apparatus may also be referred to as a temperature control station. Parts treated using the apparatus are preferably hardened after removal from the apparatus. In that case, the apparatus is part of a system having a press downstream of the apparatus.

[0009] In this apparatus, the part can be heat-treated in different ways in different regions. For this purpose, the apparatus comprises a heating section and a cooling section. The cooling section is downstream of the heating section in the second direction. Therefore, the cooling section and the heating section are arranged such that one is behind the other when viewed along the second direction. The second direction is from the heating section toward the cooling section. Preferably, the cooling section and the heating section are adjacent to each other.

[0010] A first region of the part can be heated in the heating section. A second region of the part can be cooled in the cooling section. This can be done simultaneously. The part can be inserted into the device, preferably in a first direction or the opposite direction. The part can be heat-treated in the device. During the heat treatment, the part is preferably stationary. After the heat treatment, the part can be moved out of the device, preferably in the first direction or the opposite direction. It should be noted, however, that the first direction is essentially defined independently of the direction of movement of the part. When the part moves in the first direction, the direction of movement of the part coincides with the first direction. However, instead of this, the part can also be moved in any other direction.

[0011] The first and second regions of the part are different from each other. Preferably, the part is divided into the first and second regions, i.e., has no further regions. However, instead of this, the part can have further regions in addition to the first and second regions. The first and second regions preferably, but not necessarily, form a continuous region in any case. The first and second regions of the part are defined in a part plane.

[0012] The differential heat treatment makes the first region harder than the second region during subsequent hardening. This can be used, for example, to make the flange of the B-pillar (as the second region) softer than the rest of the B-pillar (as the first region). As a result, in addition to targeted adjustment of the crash properties, it also facilitates the assembly of the B-pillar, making riveting and crimping in particular possible. During welding, the risk of cracks is reduced in the heat-affected zone of the weld spot.

[0013] Cooling in the cooling section is preferably achieved by applying a cooling fluid to the component in the second region, which is discharged from a nozzle. The cooling fluid is preferably gaseous. Compressed air or compressed nitrogen is preferred as the cooling fluid. The cooling fluid is preferably discharged at a pressure in the range of 2 to 4 bar. The nozzle preferably does not come into contact with the component. This makes the device particularly resistant to misalignment and deformation of the component due to temperature and inherent stresses.

[0014] The nozzle is preferably designed as a slot nozzle. Preferably, the nozzle opening and, in particular, the upstream fluid flow path, have a flow cross-section with an aspect ratio of at least 1:5. This means that the extent of the flow cross-section in one direction (preferably along a first direction) is at least five times greater than the extent of the flow cross-section perpendicular to that direction. The nozzle is preferably oriented so that the longer side of the nozzle opening is parallel to the component plane. A slot nozzle allows for a particularly uniform flow of the cooling fluid. For this purpose, it is particularly preferred that the nozzle opening has sharp edges.

[0015] The nozzle is oriented downward in the second direction. Therefore, when viewed from the heating section to the cooling section, the nozzle is inclined downward toward the plane of the part. When the part is placed in the apparatus, the nozzle is oriented obliquely relative to the part in the second direction. The nozzle orientation refers to the direction in which the cooling fluid is ejected from the nozzle. If the ejection is in the form of a flat jet, the orientation is determined by the center of gravity of the flat jet, i.e., along the axis of the flat jet.

[0016] Due to the aforementioned orientation of the nozzle, the cooling fluid is ejected in a direction toward the component located in the apparatus and away from the heating element. After hitting the component, the cooling fluid flows along the component surface in a second direction. Therefore, the cooling fluid has a momentum component in the second direction and away from the heating element. As a result, the second region of the component can be cooled with particularly little penetration of the cooling fluid into the heating element. In this respect, a particularly clear demarcation can be achieved during the heat treatment of the first and second regions. The width of the transition region can be reduced to the minimum width unavoidable as a result of heat conduction within the component. The described embodiment can be referred to as an "aerodynamic seal" between the heating element and the cooling element.

[0017] Tests have also shown that a nozzle having a fluid flow path with a straight section upstream of the nozzle can further strengthen the demarcation between the first and second regions, which is consequently preferable. Therefore, the fluid flow path is preferably formed straight, at least in the section adjacent to the nozzle opening. In this case, the cooling fluid flows along the straight flow path immediately before exiting the nozzle opening. This results in a particularly uniform jet formation. As a result, the cooling fluid reaches the heated section particularly little. This results in a particularly clear demarcation of the part regions. Furthermore, the second region can be cooled particularly uniformly due to the uniform jet formation. Instead of a straight section upstream of the nozzle opening, a curved section can also be arranged upstream of the nozzle opening. This may be preferable depending on the part geometry.

[0018] In particular, it has been found that a particularly uniform jet formation is achieved in a preferred embodiment of the device in which the fluid flow path has a straight portion, which is upstream of the nozzle opening and has a length of at least 5 mm.

[0019] The length of the straight portion is measured along the fluid flow path. Preferably, the straight portion of the fluid flow path has a length in the range 5mm and 40mm, especially in the range 10 to 15mm.

[0020] In a further preferred embodiment of the device, an outer wall of the nozzle facing towards the heating section points at least partially downwards in the second direction.

[0021] The cooling fluid exits the nozzle opening with a very high exit velocity. According to the laws of physics, a strong negative pressure is created, which entrains a large amount of air from around the nozzle opening. The total mass flow can be up to 100 times greater than the mass flow of the cooling fluid. This situation allows for particularly efficient cooling of the component. This is even more true in the present embodiment, since the entrained air flow is guided around the nozzle opening in a targeted manner. To this end, the outer wall of the nozzle facing the heated element serves as a guide surface. This outer wall of the nozzle is at least partially downwardly oriented in the second direction. This downward orientation ensures that the entrained air flows from around the nozzle opening toward the component and away from the heated element. Therefore, the entrained air, like the cooling fluid itself, flows in such a way that it barely reaches the heated element. This also contributes to a particularly clearly defined boundary of the component area.

[0022] It is preferred that the outer wall of the nozzle has no sharp edges, so that the air can flow around the nozzle with as little resistance as possible, thereby allowing the air to reach the nozzle opening as unhindered as possible.

[0023] In a further preferred embodiment, the device further comprises a dividing wall between the heating section and the cooling section, and an outer wall of the nozzle facing towards the heating section is positioned away from the dividing wall in the second direction.

[0024] The dividing wall may also be referred to as a partition wall. The dividing wall can be used to particularly clearly separate the first and second regions from each other. The dividing wall is preferably arranged parallel to the outer wall of the nozzle facing the heating section. The dividing wall preferably extends directly above the component, thereby minimizing the gap remaining between the component and the dividing wall. To enable components of different thicknesses to be processed in the device, the dividing wall is preferably designed so that its gap has an adjustable range.

[0025] The outer wall of the nozzle facing the heating section is positioned away from the dividing wall in the second direction. A gap is thus formed between the dividing wall and the nozzle, through which air entrained by the cooling fluid at the nozzle opening can flow. This air flow allows a particularly large amount of air to be entrained by the cooling fluid at the nozzle opening, thereby allowing particularly efficient cooling of the second region of the part.

[0026] The dividing wall is preferably part of a nozzle box, which has a cover plate next to the dividing wall. In a preferred embodiment, the device has a cover plate, which is arranged above the nozzle in the cooling section. The dividing wall and the cover plate are preferably adjacent to each other, and can also be formed as a single part.

[0027] The nozzle box formed by the dividing wall and the cover plate preferably forms at least part of the boundary of the cooling section. The second region of the component can be cooled particularly efficiently by the nozzle box. In particular, the nozzle box can limit the spread of the cooling fluid, which allows cooling fluid consumption to be kept low.

[0028] In a further preferred embodiment, the apparatus further comprises a guide plate, which is arranged in the cooling section on a side of the nozzle remote from the heating section and parallel to the part plane.

[0029] When viewed along the second direction, the arrangement in this embodiment is the heating section, the optionally provided dividing wall, and the cooling section, in that order, and the cooling section has a nozzle and a guide plate, in that order.

[0030] The guide plate is preferably positioned at a distance from the nozzle so that air can flow between the nozzle and the guide plate and be entrained by the cooling fluid exiting the nozzle opening, in addition to the air flowing along the outer wall of the nozzle facing the heated section and also entrained by the cooling fluid exiting the nozzle opening.

[0031] The guide plate is arranged parallel to the component plane, i.e., in a plane defined by the first and second directions. In that plane, the guide plate preferably extends far enough to almost completely cover the second region of the component. The guide plate preferably extends in the first direction by a distance of 10 to 200 mm. The guide plate preferably extends in the second direction by a distance of 50 to 250 mm.

[0032] In the third direction, the guide plate is positioned above the plane of the component, i.e., on the side of the component where the nozzle is also located. The guide plate, together with the component, forms a flow path through which the cooling fluid and the air entrained by the cooling fluid can flow over the component. This flow path should be distinguished from the fluid flow path in the nozzle. The guide plate can prevent undesirable turbulence, which may occur when the component has a large extension in the second direction. Therefore, the presence of the guide plate makes the device particularly suitable for large components.

[0033] In a further preferred embodiment of the device, the edge of the guide plate facing towards the nozzle is curved.

[0034] The curved edges can be obtained in particular by bending the edges of thin guide plates or by machining the edges of thick guide plates, whereby the originally sharp edges are destroyed.

[0035] The curved edges of the guide plates improve the flow of the cooling fluid and the air entrained by it, in particular reducing or even preventing turbulence that may occur with sharp edges. Furthermore, the stability of thin guide plates can be improved by the curved edges.

[0036] In a further preferred embodiment of the device, at least one spacer pin is arranged on the guide plate to hold the component at a distance from the guide plate.

[0037] The flow velocity is maintained approximately constant in the flow path formed by the guide plate and the component. Therefore, negative pressure in the flow path can create buoyancy. Buoyancy can cause components that are thin and / or large to lift. In this embodiment, this is limited by spacer pins. At least one spacer pin is preferably arranged along the third direction. During normal operation, the at least one spacer pin preferably extends from the guide plate in a direction opposite the third direction, particularly to a position just above the component surface.

[0038] In a further preferred embodiment of the device, the fluid flow path has, in a straight section upstream of the nozzle opening, a constant width perpendicular to the first direction in the range of 0.1 mm to 3 mm.

[0039] The width of the fluid flow path perpendicular to the first direction is defined as the shortest distance between two opposing side walls of the fluid flow path when viewed in a plane perpendicular to the first direction. In this embodiment, the width is the same throughout the entire straight section and is in the range of 0.1 mm to 3 mm. The flow cross section for the cooling fluid depends on the width thus defined and the extent to which the fluid flow path extends along the first direction. Preferably, the fluid flow path extends along the first direction in the range of 10 mm to 300 mm, specifically in the range of 60 mm and 100 mm. As a result, sufficient cooling fluid can be applied to the second region to cool the second region.

[0040] When the width of the fluid flow channel is within a defined range, a clearly defined flow of cooling fluid to the component surface can be achieved. Furthermore, air from around the nozzle opening can be particularly efficiently captured. Therefore, the aforementioned width of the fluid flow channel generally results in particularly efficient cooling of the second region of the component.

[0041] In a further preferred embodiment of the device, the nozzle is arranged at a first angle in the range of 15° to 60° relative to the plane of the part, or the outer wall of the nozzle facing the heating section at least partially encloses, together with the plane of the part, a second angle in the range of 15° to 60°, or both.

[0042] The first angle is defined between the part plane and the direction in which the cooling fluid is discharged from the nozzle. If this occurs in the form of a flat jet, the first angle is defined between the centerline of the flat jet, i.e., the axis of the flat jet, and the part plane.

[0043] Preferably, the flat portion of the nozzle outer wall facing the heating element encloses a second angle with the component plane in the range of 15° to 60°. This flat portion preferably extends to the nozzle opening. According to this embodiment, the air entrained by the cooling fluid flows along a straight path until it leaves the nozzle outer wall. This allows the air to reach the component surface particularly uniformly. This prevents the cooling fluid, the entrained air, or both from entering the heating element. This further allows for particularly uniform cooling of the second region. To this end, it is particularly preferred that the nozzle outer wall facing the heating element be formed parallel to the fluid flow path outside the straight portion of the fluid flow path. This means that the straight portion of the fluid flow path is separated by an outer wall of constant thickness on the side facing the heating element. As a result, the cooling fluid in the fluid flow path and the air entrained by the cooling fluid flow along mutually parallel straight paths on the nozzle outer wall until they leave the nozzle. This results in a particularly uniform flow.

[0044] Preferably, the nozzle is arranged at a first angle in the range of 15° to 60° relative to the plane of the component, and the outer wall of the nozzle facing the heating element, together with the plane of the component, at least partially encloses a second angle in the range of 15° to 60°. Particularly preferably, the first angle and the second angle are the same. Preferably, at least one of the first angle and the second angle is each 45°.

[0045] The invention will now be explained in more detail with reference to the drawings, which show particularly preferred embodiments, but to which the invention is not limited, and the drawings and the proportions shown therein are only schematic. [Brief explanation of the drawings]

[0046] [Figure 1] 1 shows a cross-sectional view of an apparatus for heat treating a part according to the present invention; [Figure 2] 2 shows an enlarged view of the nozzle of the device in FIG. 1. [Figure 3] 2 shows a flow cross section of the nozzle of the device in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0047] 1 shows an apparatus 1 for the heat treatment of a part 2. The apparatus 1 is described using a coordinate system having a first direction x, a second direction y, and a third direction z, where any two of these directions are perpendicular to each other. The first direction x and the second direction y together define a plane called the part plane E. The part 2 lies in the part plane E (ignoring the extent to which the part 2 extends in the third direction z).

[0048] The apparatus 1 comprises a heating section 3 having heating means 5 for heating a first region 7 of the part 2, and a cooling section 4 having cooling means 6 for cooling a second region 8 of the part 2. The cooling section 4 is downstream of the heating section 3 in the second direction y, i.e., is arranged to the right of the heating section 3 in the figure.

[0049] The cooling means 6 comprises a nozzle 9 for discharging a cooling fluid 10 onto the component 2. The cooling fluid 10 is indicated by an arrow. The cooling fluid can be supplied to the nozzle 9 via a connection 18.

[0050] The nozzle 9 is oriented downward in the second direction y. This means that in the example of Fig. 1, the nozzle 9 ejects the cooling fluid 10 downward and to the right. The nozzle 9 has a fluid flow path 15, which has a nozzle opening 16 and a straight portion 17 upstream of the nozzle opening. Furthermore, an outer wall 11 of the nozzle 9, which faces towards the heating section 3, also faces downward in the second direction y. In the illustrated embodiment, the outer wall 11 is formed parallel to the straight portion 17 of the fluid flow path 15.

[0051] The apparatus 1 further comprises a nozzle box 22 having a dividing wall 19 between the heating section 3 and the cooling section 4 and a cover plate 20 arranged above the nozzle 9 in the cooling section 4. The outer wall 11 of the nozzle 9 facing the heating section 3 is spaced apart from the dividing wall 19 in the second direction y. The dividing wall 19 is oriented parallel to the outer wall 11.

[0052] The apparatus 1 further comprises a guide plate 12. The guide plate 12 is arranged in the cooling section 4 on the side of the nozzle 9 that is farther from the heating section 3 and parallel to the part plane E. An edge 13 of the guide plate 12 that faces the nozzle 9 is curved. In the example of FIG. 1, this is the left edge 13 of the guide plate. This edge is bent downwards and curved. A number of spacer pins 14 are arranged on the guide plate 12 to hold the part 2 at a certain distance from the guide plate 12.

[0053] The device 1 further comprises insulation 21 below the heating section 3 and above the nozzle box 22 .

[0054] 2 shows an enlarged view of the nozzle 9 in FIG. 1. The nozzle 9 is part of the cooling means 6. In particular, the straight portion 17 of the fluid flow path 15 can be seen. Furthermore, the outer wall 11 facing towards the heating section 3 (not shown here) can be seen. The length l of the straight portion 17 of the fluid flow path 15 is g The length is at least 5 mm. Furthermore, the width b of the fluid flow path 15 perpendicular to the first direction x is g is shown, its width having a constant value in the range of 0.1 to 3 mm. Furthermore, a first angle α is shown, at which the nozzle 9 is aligned with the part plane E. A second angle β is also shown, which is bounded by the outer wall 11 of the nozzle 9 facing towards the heating section 3 and the part plane E. In the illustrated embodiment, the first angle and the second angle are equal and lie in the range of 15° to 60°.

[0055] Figure 3 shows a flow cross section of the nozzle of the device in Figure 1. The nozzle opening 16 is shown, the width of which is the width b of the straight section 17 of the fluid flow path 15. g Furthermore, the extent a of the nozzle opening 16 in the first direction x is shown.

[0056] The described device 1 allows different areas of a part 2, more particularly a steel automotive part, to be heat treated separately, with a particularly clear demarcation between areas 7 and 8. For this purpose, a nozzle 9 is directed away from the heating section 3 and has a fluid flow channel 15 with a nozzle opening 16. [Explanation of symbols]

[0057] 1 device 2 parts 3 Heating section 4 Cooling section 5 Heating means 6 Cooling means 7. First Area 8 Second Area 9 nozzles 10 Cooling fluid 11 Exterior Wall 12 Guide plate 13 Edge 14 spacer pin 15 Fluid flow path 16 Nozzle opening 17 Straight section 18 Connection part 19 Dividing wall 20 cover plate 21. Insulation 22 Nozzle Box x first direction y second direction z Third direction E part plane l g Length of the straight section b g Width of the straight part a Extension of the nozzle opening α First angle β Second angle

Claims

1. An apparatus (1) for heat treating a part (2), comprising: The component (2) can be arranged in the device (1) in a component plane (E) defined by a first direction (x) and a second direction (y) perpendicular to the first direction, The device (1) comprises: a heating section (3) having heating means (5) for heating a first region (7) of the component (2); a cooling section (4) having cooling means (6) for cooling a second region (8) of the component (2); Equipped with the cooling section (4) is downstream of the heating section (3) in the second direction (y), so that the cooling section and the heating section are arranged one behind the other when viewed along the second direction (y); The cooling means (6) has a nozzle (9) for discharging a cooling fluid (10) onto the part (2), the nozzle (9) is oriented downwards in the second direction (y) towards the part plane (E), The nozzle (9) has a fluid flow path (15) with a nozzle opening (16); A partition wall (19) is further provided between the heating section (3) and the cooling section (4), an outer wall (11) of the nozzle (9) facing the heating section (3) is spaced apart from the dividing wall (19) in the second direction (y), so that a gap is formed between the dividing wall and the nozzle, through which air entrained by the cooling fluid (10) at the nozzle opening (16) can flow; Device (1).

2. 2. A device (1) according to claim 1, The fluid flow path (15) extends upstream of the nozzle opening (16) and has a length (l ｇ ) has a straight portion (17) of at least 5 mm; Device (1).

3. A device (1) according to any one of claims 1 to 2, an outer wall (11) of the nozzle (9) facing the heating section (3) is at least partially downwardly directed in the second direction (y) towards the part plane (E); Device (1).

4. A device (1) according to any one of claims 1 to 3, The cooling section (4) further includes a cover plate (20) disposed above the nozzle (9). Device (1).

5. A device (1) according to any one of claims 1 to 4, Further comprising a guide plate (12), The guide plate (12) is arranged in the cooling section (4) on a side farther from the heating section (3) with respect to the nozzle (9) and parallel to the part plane (E). Device (1).

6. The device (1) according to claim 5, the edge (13) of the guide plate (12) facing the nozzle (9) is curved; Device (1).

7. A device (1) according to claim 5 or claim 6, At least one spacer pin (14) is disposed on the guide plate (12) to hold the component (2) at a distance from the guide plate (12). Device (1).

8. The device (1) according to any one of claims 1 to 7, The fluid flow path (15) has a constant width (b) in the range of 0.1 mm to 3 mm, perpendicular to the first direction (x), in a portion (17) upstream of the nozzle opening (16). ｇ ) Device (1).

9. The device (1) according to any one of claims 1 to 8, the nozzle (9) is arranged at a first angle (α) between the component plane and the direction in which the cooling fluid is discharged from the nozzle, the first angle (α) being in the range of 15° to 60° relative to the component plane (E); or the outer wall (11) of the nozzle (9) facing the heating part (3) at least partially encloses with the part plane (E) a second angle (β) lying in the range of 15° to 60°, or It's both. Device (1).

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