Heat sink and method for producing a heat sink

Abstract

The invention relates to a heat sink (1) for a metallurgical furnace, wherein the heat sink (1) has a plate body (5) having inner cooling channels (2) for conducting a coolant, which run at a distance from the front side (3) and the rear side (4) thereof, wherein the cooling channels (2) are introduced into the plate body (2) as grooves (7) from the rear side (4) and / or the front side (3) by means of a machining method, and are closed in the longitudinal course thereof by a cover (6) which is fluid-tightly welded to the plate body (5), wherein the milled groove (7) has at least in certain regions a mouth portion and a channel portion (9) adjoining the mouth portion. The cover (6) has a cover head (14) and a cover shaft (15) which is narrower than the cover head (14), wherein laterally projecting head strips are formed in the transition from the cover shaft (15) to the cover head (14) in each case on the longitudinal side of the cover shaft (15), wherein the mouth portion has a cross section adapted to the cross section of the cover (6), with a shaft portion for receiving the cover shaft (15) and a head portion for receiving the cover head (15) and with a support strip (20) for the head strip.

Description

[0001] Heat sink and method for manufacturing a heat sink

[0002] The invention relates to a heat sink with the features of claim 1 and a method for manufacturing such a heat sink according to the features of claim 8.

[0003] Cooling elements are used, for example, in shaft furnaces behind a refractory lining. The refractory lining is located on cooling elements, known as staves, which have grooves on their front face facing the furnace interior for receiving refractory material. The staves are made of copper or a low-alloy copper alloy with internal water cooling. Typical weights for such cooling elements are in the range of 1,500 to 2,000 kg. Cooling channels in the staves can be produced by deep drilling. It is also known to mill cooling channels into the base of a cooling element and close them with a cover or a cap plate (DE 198 06 788 C2, DE 10120614 A 1, DE 40 35 893 C1). The connection is made by welding, for example, by inserting a cover into a cooling channel and welding it in place with a butt weld. A cap plate can be installed using an explosive welding process. That's complicated.A cover plate can also be welded along its edges and connected via additional openings in the cover plate to create fillet welds (hole welds). These openings must be created before welding.

[0004] The invention is based on the objective of improving a cooling body for a metallurgical furnace in such a way as to allow greater variability with regard to the shape of the cooling channels, and of demonstrating a method by which such a cooling body can be manufactured more cost-effectively.

[0005] The invention solves the first part of the problem by means of a heat sink with the features of claim 1. A method for manufacturing a heat sink with the features of claim 1 is the subject of claim 8. The dependent claims relate to advantageous embodiments of the invention.

[0006] The cooling element according to the invention is intended for use in a metallurgical furnace. The term "cooling element" is not limited to a specific geometric shape. The shape is determined by its use in a metallurgical furnace. Generally, these are plate-like bodies whose thickness is smaller in relation to their other dimensions. The term "plate-like" includes components spread out in a plane as well as singly curved (e.g., cylindrical) and doubly curved (e.g., spherical) shells. These cooling elements are, in particular, staves, which are preferably used in shaft furnaces, especially blast furnaces. Cooling elements of this type are also called cooling plates and have a considerable volume and weight. Typical dimensions of a cooling element according to the invention in the form of a stave are, for example, 2.The heat sinks are 000 mm long and 900 mm wide, with a thickness of 140 mm, and the advantages of the invention are also present at thicknesses of 140 mm. To reduce weight, the thickness can be less than 140 mm, preferably less than 120 mm, particularly 90 to 110 mm, and most preferably 100 mm. If the boundary conditions permit, thicknesses below 100 mm are also desirable. Preferably, the heat sinks are made of copper or a copper alloy. In the installed position, one front face of the heat sink faces the interior of the furnace and is preferably lined with a refractory material. To secure the refractory material, the front face can be profiled, in particular having retaining grooves, preferably in a horizontal direction. The rear face of the heat sink faces the furnace wall. The heat sinks are secured to the furnace wall via the rear face.The coolant is supplied and discharged via coolant connections attached to the heat sink. These connections are located at the rear of the heat sink and pass through the furnace wall. The coolant flows through the heat sink via several internal cooling channels, which are spaced apart from the hot front and the rear of the heat sink that faces the furnace wall.

[0007] In the first manufacturing step, the cooling channels are machined into the back surface as grooves, primarily by milling. Theoretically, machining, especially milling the cooling channels, is also possible from the front surface; however, connection openings for the coolant lines must be created on the back surface anyway, which can also be done by milling. Machining from the back surface is therefore more advantageous, especially since no openings on the front surface need to be sealed. Furthermore, profiles for a refractory material, particularly horizontal retaining grooves, are preferably formed on the front surface. The material thickness on the front surface is therefore preferably slightly greater than on the back surface.

[0008] Preferably, the cooling channels are located closer to the back than to the front. It should be noted that the wall thickness up to the front is not constant due to the retaining grooves for the refractory material. For example, the groove runs 45 mm from the front, with the retaining grooves having a depth of 30 mm. In the area of ​​the retaining groove, the wall thickness is therefore only 15 mm. The groove can have a depth of 30 mm, so that for a plate body 100 mm thick, the distance of the groove to the back is 25 mm.

[0009] The machining process, particularly the milling of the cooling channel, has the advantage that the finished cooling channel can have any desired shape, although in the most cost-effective version it is preferably straight and oriented vertically from top to bottom. It can, in particular, have a curved longitudinal profile.

[0010] A curved profile means that the cooling channel does not run in a straight line, but has a curved or bent shape. The cooling channel runs within the plane of the plate, i.e., curved parallel to the plate plane. The curvature can also change perpendicular to the plate plane, meaning that the distance of the cooling channel from the front surface can change along its length. The cooling channel can therefore have sections with differing distances from the front surface. The cooling channels according to the invention can be easily adapted to local thermal requirements during manufacturing.

[0011] The open groove for the cooling channel is sealed along its length by a cover, creating a fluid- and gas-tight seal. For this purpose, the cover is welded to the plate body. Several covers or cover sections can be arranged along the length of the cooling channel, with the covers being welded together at the joints. Multiple cover sections are particularly advantageous when the cooling channel has a curved path. The cover has a consistent cross-section along its entire length. In this case, it can be manufactured cost-effectively as a pressed bar. To improve dimensional accuracy, the cover can also be manufactured as a drawn bar.

[0012] The advantage of milling the cooling channel over drilling lies not only in the fact that curved cooling channel profiles can be realized much more cost-effectively and with less effort, but also in the fact that the groove can have a special cross-section. This cross-section can be narrower in the opening section of the groove and wider in the channel section following the opening. The milled groove can thus be undercut. An undercut groove can preferably have a relatively small thickness and a greater width than its thickness. Using appropriate milling cutters, such as disc cutters, it is significantly easier and faster to produce larger cross-sectional areas of the cooling channel than with several circular cooling bores of smaller diameter. The cooling channel is therefore flat and wide in cross-section, and not circular as with deep-drilled channels.The advantage is that a larger wall area of ​​the cooling channel is positioned closer to the front, allowing a greater proportion of the coolant to be guided through the heat sink at a shorter distance from the front. This improves heat dissipation from the heat sink. By flattening the cooling channel, the thickness of the plate body can be significantly reduced, for example, from 140 mm to approximately 100 mm. In this case, material usage is reduced by approximately 30% compared to deep-drilled channels. This makes the heat sinks considerably more cost-effective and lighter. Furthermore, the heat sink is particularly cost-effective to manufacture when the cooling channels have a curved profile. Higher machining performance and shorter production times are additional advantages of the invention.

[0013] The invention also simplifies hydraulic balancing. Hydraulic balancing ensures that specific flow rates are maintained in a branched hydraulic system. Balancing is achieved by throttling the flow in certain cooling channels to increase the flow elsewhere. Hydraulically optimized cooling can be implemented much more easily if the channel cross-section can be modified during the manufacturing process. While the cross-section of a deep borehole is generally constant, the channel width of a milled cooling channel can be adjusted relatively easily, thus controlling the flow rate.

[0014] The milled groove can theoretically be produced in one pass, preferably in several passes. In a first pass, the opening section can be produced, and in a second pass, the channel section, particularly the widened section, is produced by guiding the shank of a milling cutter through the opening section to form the undercut groove. After the groove is produced, the cover is inserted into the opening section of the groove and welded fluid-tight to the plate body. Each cover covers only a single groove.

[0015] The welded-on cover should ideally not protrude beyond the front or back. Therefore, the cover is preferably completely enclosed within the opening section. The cross-sectional area of ​​the groove not occupied by the cover serves as a channel for a cooling fluid.

[0016] The cooling elements can have undercut or non-undercut grooves. A groove is considered undercut when a portion of the outlet section has a narrower width than the lower channel section. The outlet section itself can have different widths in cross-section, particularly stepped sections, which are adapted to the cross-section of the cover. The cross-section of the channel section can also vary in width. In an advantageous embodiment of the invention, the cooling channels have a front wall facing the front of the plate body, a rear wall facing the back of the plate body, and side walls connecting the front wall to the rear wall, the front wall being longer than the side walls with respect to the cross-section of the cooling channel.This applies in particular to rectangular or trapezoidal cross-sections that widen towards the hot side, as well as to essentially elongated cross-sections with rounded or concave sidewalls, which are easy to manufacture. Rounded sidewalls prevent pressure-induced stresses within the plate body caused by high cooling medium pressures. The cross-section of the cooling channels is preferably dimensioned such that they are wider than they are high, and in particular at least twice as wide as they are high, with the height being measured from the front to the back of the heat sink and the width parallel to the back of the heat sink. Preferably, the cooling channels are at least three times as wide as they are high in cross-section, which could only be achieved with multiple drilling operations during deep drilling, thus increasing the effort required.

[0017] The at least one groove preferably has a constant depth, i.e., a constant distance to the hot side (front side). To adjust the cooling capacity locally or regionally, the at least one groove, or at least one of several grooves, can be manufactured such that the groove depth varies along its length. If several grooves are present, at least one groove can also have a different overall depth, e.g., be deeper than one of the other grooves. The groove depth is measured from the back side. As the depth increases, the distance to the hot side decreases, and the cooling capacity there increases. For this purpose, the groove can be deeper in at least one length region than in at least one other length region. The groove can have length regions of different depths, with the depth remaining constant in each length region. Transition sections with smooth transitions between adjacent length regions are possible.The depth can also change continuously, e.g., increasing or decreasing continuously in the direction of flow. The change in depth is primarily linear. Multiple changes in depth along the length of the body are possible.

[0018] The cooling element according to the invention is closed with a cover having a cover head and a cover shaft that is narrower than the cover head. At the transition from the cover shaft to the cover head, laterally projecting head ridges are formed along the longitudinal side of the cover shaft. The opening section of the milled groove has a cross-section adapted to the cross-section of the cover, with a shaft section for receiving the cover shaft and a head section for receiving the cover head, as well as a support ridge for the cover's head ridge to position the cover at the desired depth within the opening section. The support ridge in the groove thus limits the insertion depth of the cover. The cover head is welded to the plate body via the longitudinal flanks of its head ridges.

[0019] The weld serves to seal the cooling channel fluid-tight towards the outlet and to secure the cover. It is not always necessary to weld the butt joints of the cover head to the adjacent outlet section of the plate body completely through to the weld seam, especially not with a thick cover head or a cooling channel located somewhat deeper. In this case, the weld can end before reaching the support strip.

[0020] However, it is preferred that in other cases, i.e., with a cover head of lesser thickness, the weld joint preferably extends at least to the support strip. The expression "to the support strip" is to be understood as meaning that the weld can also extend into the support strip itself. The butt weld can extend so deeply into the material of the plate body that the weld root reaches below the cover head. This is then a combination of a butt weld and a lap weld. The exact design can be clearly identified from the cross-sectional image. However, it is not necessary to weld through the cover to the wall of the narrower cooling channel, regardless of whether it is undercut or not. The fluid- and gas-tight welding is carried out via the cover head.

[0021] The lid is welded to the plate body, in particular by friction stir welding (FSW). In friction stir welding, a rotating tool is guided along the contact surfaces of the workpieces. This generates frictional heat, which plastically degrades the material. The material is mixed in the joining zone. This results in high weld strength with minimal weld distortion. When producing the weld, individual spot welds are first applied, preferably using the FSW process, to fix the lid in place, and then the desired butt joint is formed. The spot welds are preferably positioned so that they are located within the butt joint.

[0022] Friction stir welding exerts relatively high forces on the components being joined. When using this welding process, it can be advantageous to perform the welding at a considerable distance from the central longitudinal axis of the groove to reduce the risk of local deformation in the groove area. This is particularly relevant for undercut grooves. In this case, the cover is preferably at least as wide as the channel section because the weld seam is then located further away from the central longitudinal axis of the groove. Consequently, the pressure generated during friction stir welding, perpendicular to the front or back of the heat sink, is not transferred into a cantilevered section of the support rail, but rather into the base of the support rail, i.e., at the transition to the plate body. This prevents deformation of the support rail and thus avoids any change in the cross-section of the channel section.For large total weld thicknesses exceeding 5 mm, considerable forces act on the friction stir tool, necessitating robust machine designs and the precise interplay of coordinated parameters such as speed, feed rate, and tool material, as well as a tailored tool geometry. The butt weld produced according to the inventive method is clearly identifiable as such externally. It is characterized by the distinctive path created on the workpiece surface by a shoulder of the friction stir tool. This shoulder displaces material protruding from the welded-in cover. The excess material is milled off after welding. What remains is the typical characteristic path of the friction stir tool and the entry point of the rotating pin. A friction stir weld is also clearly identifiable in a micrograph.A fine-grained structure forms, exhibiting the silhouette of the FSW tool's stirring pin. This allows a weld produced using the FSW process to be distinguished from other welds, such as those produced by conventional MIG welding or electron beam welding.

[0023] The FSW process is particularly well-suited for creating fluid-tight joints in heat sinks with large masses because the large mass allows for good heat dissipation during welding. The components are less prone to warping. When alternative welding processes are used, such as electron beam welding or oxyfuel welding, little to no force is exerted on the welding partners. In this case, the cover can also be narrower than with friction stir welding, meaning the weld seam can be positioned closer to the centerline of the groove.

[0024] The material of the heat sink is preferably a copper alloy, in particular oxygen-free copper or a low-alloy copper alloy. It can be a copper-chromium-zirconium alloy. This alloy is not weldable using the conventional MIG welding process, but it is weldable using the FSW process. This material has significantly higher heat resistance, which is a major advantage in material selection, especially for a heat sink. A bimetallic design of the heat sink is possible by using a cover made of a different alloy.

[0025] Just like the milling of the cooling channels and the production of the cover, welding, such as friction stir welding, can be carried out in any desired path, so that the cooling channels can have at least one cost-effectively producible curvature in their longitudinal direction, without significantly increasing the manufacturing effort compared to deep drilling.

[0026] The inventive method for manufacturing a cooling element thus provides a plate body having a front and a back, wherein at least one preferably undercut groove for forming a cooling channel is machined, in particular milled, into the back and / or the front. The machining of the groove creates a channel section that is particularly wide, through which the coolant subsequently flows, and a correspondingly narrower opening section, which is closed by a cover. This cover is preferably inserted into the opening section and welded to the plate body via the cover head. The cover is welded to the plate body only in the area of ​​the opening section via the cover head.This has the advantage that the cover, with its shaft, can have an internal contour that defines the cooling channel without being altered in its contour by melting material from the cover or the plate body. No welding-related irregularities occur within the cooling channel.

[0027] The cover head is positioned on the recessed support rib in the outlet section, opposite the rear or front surface. This precisely determines the insertion depth of the cover head. According to a first preferred embodiment, the cover does not protrude into the cooling channel but forms, as far as possible, a seamlessly adjoining wall section of the cooling channel. Alternatively, the cover can be designed to project into the cooling channel in a controlled manner to reduce its cross-section and thus increase the flow velocity of the cooling water. For this purpose, the cross-section of the cover can vary along its length. Alternatively, several different covers can be arranged along the length of a cooling channel, projecting to varying degrees into the channel to achieve local adjustment of the flow velocities.The cover head is preferably welded to the plate body in such a way that, depending on the insertion direction, the cover does not protrude beyond the front or back of the plate body. The cover preferably has a thickness corresponding to the distance of the cooling channel from the front or back. At least the end face of the cover shaft forms part of the wall of the cooling channel. If the cover shaft projects into the cooling channel, the longitudinal flanks of the cover shaft also form walls of the cooling channel.

[0028] The lid and / or the plate body are preferably both made of copper or a conductive copper alloy. Copper or low-alloy copper alloys are ideally suited for dissipating large amounts of heat. It is possible to manufacture the lid and the plate body from different materials, for example, using a plate body made of a copper alloy and welding it to a lid made of a steel or aluminum alloy, or of another copper alloy. The heat sinks according to the invention are particularly suitable for applications in blast furnaces, electric arc furnaces, or other reactors; in particular, they are staves for shaft furnaces.

[0029] The invention is explained below with reference to an exemplary embodiment, which is shown purely schematically in the drawings. The drawings show:

[0030] Figure 1 shows a perspective view of a plate body;

[0031] Figure 2 shows the plate body of Figure 1 with the lid inserted;

[0032] Figure 3 shows a heat sink according to the invention in a perspective view;

[0033] Figure 4 shows a rear view of the plate body of Figure 1;

[0034] Figure 5 detail AA of Figure 4;

[0035] Figure 6 Detail X of Figure 5;

[0036] Figure ? Detail Y of Figure 4;

[0037] Figure 8 Detail BB of Figure 4; Figure 9 a lid in cross-section;

[0038] Figure 10 shows the lid of Figure 9 in a perspective view;

[0039] Figure 11 shows a rear view of the plate body of Figure 2;

[0040] Figure 12 Section along line DD according to Figure 11;

[0041] Figure 13 Section along line CC of Figure 11;

[0042] Figure 14 Section along line EE of Figure 12;

[0043] Figure 15 detail W of Figure 13;

[0044] Figure 16 detail Z of Figure 14;

[0045] Figure 17 shows a rear view of another plate body;

[0046] Figure 18 Section along line FF of Figure 17;

[0047] Figure 19 Section along line GG of Figure 17 and

[0048] Figure 20 horizontal partial section through a heat sink according to the prior art.

[0049] Figure 20 shows a section of a cross-section through a purely schematic representation of a cooling element 1, representing the prior art. The cooling element 1 is a stave for a metallurgical shaft furnace. The plane of section is the horizontal plane. A cooling channel 2 with a circular cross-section runs inside the cooling element 1. In its installed position, it runs vertically from top to bottom. It is formed by a deep bore. It runs at a distance from a front face 3 (bottom in the plane of the image) and a rear face 4 of the plate body 5. The plate body 5 is made of copper or a copper alloy. The front face 3 faces the interior of the furnace. In its installed position, the rear face 4 faces the furnace wall, which is not shown in detail. Several cooling channels 2 can be arranged parallel to each other in the plate body 5 by means of deep bores.Cooling channels in the form of a narrower but wider elongated hole can theoretically be produced by several overlapping deep bores, but this involves significantly increased manufacturing effort, especially since the feed rate of a thinner drill bit must be reduced. The machining performance would be considerably lower than with a single bore of a larger diameter.

[0050] The solution according to the invention is explained with reference to Figures 1 to 19. The reference numerals introduced in Figure 20 are used in the same way for functionally equivalent components in the design according to the invention.

[0051] Figures 1 to 3 show the essential manufacturing steps for producing the heat sink 1. Figure 1 shows the plate body 1 in a first processing stage. Figure 2 shows the plate body with the covers 6 inserted. Figure 3 shows the finished plate body 5 with the covers 6 and coolant connections 16.

[0052] Figures 4 to 8 show details of the milled plate body 5 of Figure 1. The plate body 5 has a total of four parallel milled grooves 7, which were milled into the plate body 5 from the rear side 4. The grooves 7 are equidistant from each other and of equal length. The grooves 7 terminate before an upper and lower end face. They are produced by a milling operation. In this embodiment, the plate body 5 has a width of 900 mm and a length of 2,000 mm. The thickness is 100 mm. The grooves 7 are arranged at a distance of 230 mm and terminate 110 mm from the upper and lower ends of the plate body 5 (center of the coolant connection 16).

[0053] Figure 4 shows, in the direction of view towards the rear surface 4, that the grooves 7 open at their upper and lower ends into circular connection openings 22 in the rear surface 4. Figures 6 and 7 show details. These connection openings 22 are provided for connection to the coolant connections 16.

[0054] Figure 8 shows a cross-section of the groove 7. The groove 7 has an outlet section and a channel section 9. The outlet section 8 is narrower than the channel section 9, so the groove 7 is undercut. The connection openings 22 are also undercut at their edges (Figure 7). The channel section 9, which is designed to carry a coolant flow, has a rectangular cross-section with a front wall 10, a rear wall 11, and two side walls 12, 13, which connect the rear wall 11 to the front wall 10. Adjacent walls 10, 11, 12, 13 are perpendicular to each other, so that the channel section 9, or the subsequent cooling channel 2, has a rectangular cross-section. The front wall 10 and the rear wall 11 are of equal length and significantly longer than the side walls 12, 13. In this embodiment, they are approximately twice as long.

[0055] Towards the rear side 4, the milling operation results in the opening section 8 adjoining the channel section 9, which is open towards the rear side 4. The opening section 8 is stepped and has a horizontal step in the plane of Figure 8. The cross-sectional contour of the opening section 8, visible in Figure 8, is adapted to the cross-section of a cover 6 (Figure 9). The cover 6 has a cover head 14 and, in contrast, a narrower cover shaft 15 with an end face 21. The basic shape is T-shaped. The narrower shaft 15 transitions into the wider cover head 14 via a head ridge 17 that runs horizontally in the plane of Figure 9. The cover shaft 15 is slightly undercut when viewed from its end face 21, so that the cover shaft 15 has a slightly trapezoidal cross-section. As a result, the head strip 17 protrudes slightly inwards in the installed position relative to a support strip 20 (Figure 6).It is, in a sense, a relief cut in the corner area.

[0056] The cover 6 is shaped like a strip (Figure 10). It has a uniform cross-section along its entire length. It is drawn or pressed from a rod to the desired profile and cut to the appropriate length. In its installed position, it extends from coolant connection 16 to coolant connection 16 of the respective cooling channel 7, as shown in Figure 3.

[0057] Figures 5 to 7 further show that the groove 7 is not only undercut in the area of ​​the cover 6, but also in the area of ​​the end connection openings 22 for the tubular coolant connections 16.

[0058] Figures 11 to 16 show sectional views and details of the finished cooling element 1 according to the perspective view in Figure 3. Figure 11 shows the view of the rear side 4. In the sectional view according to Figure 12, it can be seen that the front side 3 of the plate body 5 has several horizontally extending undercut retaining grooves 23, which serve to hold a refractory material in order to increase the service life of the cooling element 1 and improve its abrasion resistance. At the rear of the cooling element 1 are the tubular coolant connections 16, which are connected to the respective cooling channels 2 according to the section plane CC (Figure 13) and in the enlarged view in detail W (Figure 15). Figure 15 shows in detail W a vertical section plane through an upper coolant connection 16. The tubular coolant connection 16 is welded to the rear side 4 of the plate body 5 by a weld 24 in the form of a V-weld.For this purpose, the pipe end of the coolant connection 16 is flanged outwards. In the area of ​​the inserted cover 6, the coolant connection 16 is also welded directly to the cover 6 via the weld seam 24. Prior to this, however, the cover 6, which is lower when viewed from the perspective of the coolant connection 16, was welded to the plate body 5. This is best seen in Figures 15 and 16, which show a weld seam 25. The cover 6 is flush with the rear wall 11 of the cooling channel 2 at its end face 21. That is, the cover 6 does not protrude into the rectangular coolant channel 7 or the channel section 9 formed by the groove. The cover head 14 of the cover 6 engages only in a head section 19 (Figure 8) of the opening section 8, while its cover shaft 15 engages in a narrower shaft section 18 of the opening section 8.Between the narrower shaft section 18 and the wider head section 19 is a support strip 20, which forms the contact surface for the head strip 17 of the cover 6. The position of the head strip 17 and the support strip 20 define the insertion depth of the cover 6 into the rear side 4 of the plate body 5. The cover 6 neither protrudes beyond the rear side 4 nor does its end face 21 project into the cooling channel 7. The cover 6, thus inserted, i.e., pre-assembled, is then welded to the plate body 5 by friction stir welding. The friction stir welding takes place exclusively in the area of ​​the cover head 14, i.e., within the head section 19. In Figures 15 and 16, the relevant welding zones are marked with a dashed line. In the area of ​​this weld seam 25, the material of the plate body 5 and the cover 6 is melted and joined together to form a gas- and pressure-tight connection.Only then are the connection openings 22 enlarged in diameter to create a step at a distance from the support rail 20, as shown in Figures 2, 15, and 16. Regarding the manufacturing sequence, it is important to first weld the cover 6 to the plate body 5, then prepare the seat for the coolant inlets 16, and only in the next step weld on the coolant connections 16. Figure 15 illustrates that there are two welds, one above the other. The lower weld is between the cover 6 and the plate body 5. It is produced by friction stir welding. The attached flange of the coolant connection 16 partially covers this weld. It is then welded to the rear side 4 of the plate body 5 via a V-groove weld, for example, by MAG welding.

[0059] The plate body 5 can have further profiling on the front 3 and back.

[0060] 4. The illustrations show, for example, images of fastening points and expansion joints.

[0061] Figure 18 shows a section through a heat sink according to Figure 17. Three differently configured cooling channels 2 are discussed for illustrative purposes only, with identical reference numerals used for functionally equivalent features.

[0062] The cooling channel 2 on the left in the plane of Figure 18 has a rectangular cross-section. However, the groove 7 is undercut overall, because the opening section in the area of ​​the support strips 20 is narrower than the lower channel section 9 of the groove 7. The end face 21 of the cover shaft 15 forms part of the rear wall of the channel section 9, which is located at the top in the plane of the image. The cover 6 is joined longitudinally to the plate body by the welds 25.

[0063] 5 welded. For the sake of simplicity, only one of the two welds 25 is shown. The cover 6 is, of course, welded identically on both longitudinal sides. The welding was carried out by friction stir welding. A butt joint is produced. The vector V indicates the direction in which a force is exerted on the components to be welded during friction stir welding. The vector V runs in the same plane as the side walls 12, 13 of the cooling channel. In contrast to the design according to Figure 16, the cover 6 is not narrower than the cooling channel 9 in the area of ​​the cover head. As a result, the vector V is not directed into the cooling channel 2. The support strip 20 is better supported during friction stir welding. The risk of local deformation is reduced.

[0064] The cooling channel 2, located centrally in the plane of Figure 18, has a trapezoidal channel section 9. The side walls 12, 13 are inclined, with the channel section 9 widening towards the front wall, which is located at the bottom of the plane of Figure 18. Due to their inclination, the side walls 12, 13 also function as the rear wall, as they extend directly from the narrower outlet section of the cooling channel 2. The end face 21 of the cover shaft 15 is flush with the outlet section. The cover shaft 15 does not project between the inclined side walls 12, 13. The cover 6 is welded to the plate body 5 by friction stir welding via the weld seams 25.

[0065] Figure 18 shows on the right another form of a cooling channel 2 with concavely rounded side walls 12, 13. The end face 21 of the cover shaft 15 is flush with the rear wall. The cover 6 is again welded to the plate body 5 by friction stir welding via the weld seams 25.

[0066] Figure 19 shows a section along line GG of Figure 17. The groove 7 has a first longitudinal section 26 adjacent to the lower connection opening 22 for cooling water in the plane of the image, and a further longitudinal section 27 adjacent to the upper connection opening 22 in the plane of the image. In this embodiment, the latter is shorter than the first longitudinal section 26. The groove 7 has a depth in the first longitudinal section 7 that increases linearly from a depth T1 to a depth T2 in the direction of the second longitudinal section. The distance to the front surface 3 decreases, so the cooling effect increases with decreasing distance. The cooling effect is greatest where the depth is greatest. The first longitudinal section 26 is followed by a step in depth from the smaller depth T2 to a larger depth T3 in the second longitudinal section 27. The depth T3 is constant in the second longitudinal section 27.The second length section 27 extends to below the connection opening 22, i.e. to the upper end of the groove 7.

[0067] Reference mark:

[0068] 1 - Heat sink

[0069] 2 - Cooling channel

[0070] 3 - Front of 5

[0071] 4 - back of 5

[0072] 5 - Plate body

[0073] 6 - Lids

[0074] 7 - Nut in 5

[0075] 8 - Mouth section of 7

[0076] 9 - Canal section of 7

[0077] 10 - front wall

[0078] 11 - back wall

[0079] 12 - Side wall of 2

[0080] 13 - Side wall of 2

[0081] 14 - Lid head

[0082] 15 - Cover shaft

[0083] 16 - Coolant connection

[0084] 17 - Header strip at 6

[0085] 18 - Shaft section of 8

[0086] 19 - Head section of 8

[0087] 20 - Support rail

[0088] 21 - Front

[0089] 22 - Connection opening

[0090] 23 - Holding groove

[0091] 24 - Weld between 5 and 16

[0092] 25 - Weld between 5 and 6

[0093] 26 - Length section of 5

[0094] 27 - Length section of 5

[0095] V - vector

[0096] T 1 - Depth of 26

[0097] T2 - Depth of 26 T3 - Depth of 27

Claims

Patent claims 1. Cooling element (1) for a metallurgical furnace, wherein the cooling element (1) has a plate body (5) with internal cooling channels (2) for conveying a coolant, which extend at a distance from its front (3) and its back (4), wherein the cooling channels (2) are formed from the back (4) and / or the front (3) as grooves (7) in the plate body (2) by a machining process, and are closed along their longitudinal course by a cover (6) which is fluid-tightly welded to the plate body (5), wherein the milled groove (7) has at least partially an outlet section (8) and a channel section (9) adjoining the outlet section, characterized in that the cover (6) has a cover head (14) and a cover shaft (15) which is narrower than the cover head (14),wherein, in the transition from the lid shaft (15) to the lid head (14), laterally projecting head ridges (17) are formed along the longitudinal side of the lid shaft (15), wherein the mouth section (8) has a cross-section adapted to the cross-section of the lid (6) with a shaft section (18) for receiving the lid shaft (15) and a head section (19) for receiving the lid head (14) and with a support ridge (20) for the head ridge (17).

2. Cooling element (1 ) according to claim 1 , characterized in that the outlet section (8) is widened compared to the channel section (9) so that the milled groove (7) is undercut.

3. Cooling plate (1 ) according to claim 2, characterized in that the cooling channels (2) have a front wall (10) facing the front (3) of the plate body (5), a rear wall (11 ) facing the rear (4) of the plate body (5) and side walls (12, 13) connecting the front wall (10) with the rear wall (11 ), wherein the front wall (10) is longer in cross-section than the side walls (12, 13).

4. Heat sink (1 ) according to claim 3, characterized in that the front wall (10) and the rear wall (11 ) run parallel to each other and the side walls (12, 13) are concavely curved.

5. Cooling sink (1 ) according to one of claims 1 to 4, characterized in that the cooling channels (2) have a cross-section at least twice as wide as they are high.

6. Cooling element (1 ) according to one of claims 1 to 5, characterized in that the cover (6) is welded to the plate body (5) by friction stir welding.

7. Cooling plate (1 ) according to one of claims 1 to 6, characterized in that at least one cooling channel (2) has a curvature in its longitudinal direction, wherein the curvature is parallel and / or perpendicular to the front (3) or back (4).

8. Method for manufacturing a cooling element (1) with the features according to any one of claims 1 to 7, wherein a plate body (5) is provided having a front (3) and a back (4), wherein a groove (7) for forming a cooling channel (7) is machined into the front (3) and / or the back (4), wherein the groove (7) is closed by a cover (6) which is welded to the plate body (5), characterized in that a cover head (14) of the cover (6) is placed on the support strip (20) in the opening section (8) which is recessed relative to the front (3) or back (4), and a narrower cover shaft (15) adjoining the cover head (14) extends towards the cooling channel (2), wherein the cover head (14) is welded to the plate body (5).

9. Method according to claim 8, characterized in that the groove (7) is undercut, so that a widened channel section (9) and a narrower outlet section (8) are formed, wherein the cover (6) is welded to the plate body (5) in the area of ​​the outlet section (8).

10. Method according to claim 9, characterized in that the cover (6) is welded to the plate body (5) by friction stir welding.

11. Method according to claim 8, characterized in that the cover (6) is dimensioned and welded in such a way that it does not extend beyond the front (3) or the rear side (4) of the plate body (5) protrudes, wherein an end face (21) of the cover shaft (15) forms part of one of the walls (11) of the cooling channel (2).

12. Method according to one of claims 8 to 11, characterized in that a cover (6) made of a copper, steel or aluminium material is welded to a plate body (5) made of copper or a copper material.

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