DE102018129446B4 - Beam for beam conveyor furnace - Google Patents

Abstract

Beam (1) for a beam conveyor furnace for placing a material to be heated, which comprises: - an elongated base body (2), which is a hollow profile, which has a profile wall (5) delimiting an internal cavity (3), - one or more receptacles (19 ) in the elongated base body (2), in each of which an insert part (21) is accommodated, the profile wall (5) having one or more openings (4) into which the insert parts (21) are each inserted, the insert parts (21 ) - are positively connected to the receptacle (19) that accommodates them in the direction perpendicular to the longitudinal extent of the elongated base body (2), - protrude in relation to the elongated base body (2) and together form a support (23) for the material to be heated, - each have a convex area which engages behind an upper profile wall section (5-1) of the profile wall (5) on the inside, the upper profile wall section (5-1) forming an undercut (22), and have a concave area which is complementary to the convex area is shaped.

Description

The present invention lies in the technical field of heating material to be heated in a continuous furnace and relates to a beam for a beam conveyor oven, which is used to support material to be heated in the beam conveyor oven. The invention further relates to a method for producing the beam according to the invention and the use of the beam according to the invention in a beam conveyor furnace.

Sheet metal parts in automobile construction can be produced by hot forming at relatively low manufacturing costs. For this purpose, preformed components are heated in a continuous oven to 900°C to 1000°C, placed in a press by an industrial robot and pressed into the desired shape at around 700°C. Roller or beam conveyor ovens are used as continuous ovens, in which the material to be heated is heated and fed to the press at a suitable time.

In a roller kiln, actively driven rollers serve as a support for sheet metal parts or for transport containers on which sheet metal parts are placed. In a beam conveyor oven, sheet metal parts are moved step by step through a coordinated movement of two sets of beams, each of which has a plurality of parallel beams that extend in the transport direction and serve to support the material to be heated. Here, the bars of a first set of bars and the bars of a second set of bars are arranged nested within one another, with one or more bars of the first set located next to one or more bars of the second set. Depending on the design, the beams can move vertically and/or horizontally as moving beams or stand still as fixed beams. The material to be heated is always stationary in relation to the beams on which it is currently resting.

For example, one is off DE 21 17 148 A or WO 2018/ 019 920 A1 known design, the beams of the first set of beams are vertically movable walking beams and the beams of the second set of beams are horizontally movable moving beams. With the material to be heated in place, the walking beams moving downwards have the task of placing the material to be heated onto the moving beams, which move the material to be heated a certain distance in a horizontal direction to the oven exit, whereby the material to be heated is then picked up again by the walking beams moving upwards, so that the moving beams can be moved back to their starting position towards the furnace exit. The next time the material to be heated is placed on the moving beam, it can be transported towards the oven exit and then picked up again by the walking beam.

The moving beams perform a reciprocal movement in the horizontal direction, which is made possible, for example, by roller bearings, and the walking beams perform a reciprocal movement in the vertical direction. For beam conveyor furnaces that operate at temperatures of more than 600°C, which is usually the case, ceramic walking beams are necessary due to temperature resistance, creep resistance and thermal shock resistance. For cost reasons, the driving beams can also be made of a metallic material.

It has now been shown in practice that various problems arise when using beam conveyor furnaces, which significantly affect the production process. The sheet metal parts, which are typically at room temperature, are placed on the lifting or moving beams at the furnace entrance, which have a very high temperature in the range of, for example, 900 ° C to 1000 ° C. Only as the sheet metal parts gradually move towards the oven exit do they become increasingly heated. Due to the very high temperature difference to the sheet metal parts, the beams on the input side of the beam conveyor furnace are subjected to high thermal loads.

In addition, steel sheets used in modern automobile construction are often covered with a protective layer made of an aluminum (Al)-silicon (Si) alloy. This serves as effective protection against scaling and, as an alloy component, ensures better hardening of the heated material, so that the amount of material used for a sheet metal part can be advantageously reduced. When the AlSi-coated steel sheets are heated, the AlSi protective layer softens and, as a result, contact corrosion occurs when it comes into contact with the beams. This applies in particular to the vertically movable walking beams, with which the steel sheets usually come into contact for a longer period of time. Possible corrosion mechanisms include diffusion of AlSi into the porous structure of the beams, adhesion of AlSi to the beam surface or a reaction in the form of a chemical transformation with the beam material. If AlSi diffuses into the beam structure, differences in the expansion coefficient between the beam matrix, infiltrated AlSi and corrosion-related reaction products lead to thermal stresses and, due to the large temperature difference between the beam and colder sheet metal parts, spalling on the beam surface or even beam breakage.

In addition, AlSi can build up up to several millimeters of adhesion to the beam material, causing the steel sheets to shift during transport through the furnace and, as a result, causing damage to the fiber-lined beam lined oven wall or problems with the industrial robot taking over the sheets.

As a result of the problems described, individual beams are damaged and must be replaced. In particular, an unexpected beam break can lead to a production stoppage. In addition, changing beams is technically complex and time-consuming and increases the amount of industrial waste that needs to be disposed of. The manufacturing costs for the sheet metal parts increase in an undesirable manner.

DE 72 14 686 U discloses holders and riders for heat carriers in industrial ovens, which are different from the inserts of the invention.

DE 41 33 698 A1 discloses a walking beam furnace having support webs attached to the walking beams and/or the fixed beams. In contrast to this, in the invention the insert parts should be easy to remove and reinsert and there should only be a positive connection to the base body.

DE 42 03 595 A1 discloses a device for supporting feedstock in a heating furnace, showing a support tube through which coolant flows and which is provided with at least one attachment piece. To support the material to be used, each attachment piece has a support surface that runs off-center in the longitudinal direction of the support tube. The adjacent support surfaces are at a lateral distance from one another and run at least partially laterally next to the support tube

DE 197 10 870 A1 discloses a walking beam furnace in which support webs are placed on longitudinal webs on the top sides of the walking and fixed beams.

Further prior art can DE 43 24 421 A1 and DE 103 12 802 B3 be removed.

In contrast, the object of the present invention is to improve beam conveyor furnaces known in the prior art in such a way that heat treatment of material to be heated, in particular AlSi-coated sheet metal parts, is possible with fewer production interruptions due to changing damaged beams and at lower costs. In addition, unexpected beam breakage should be avoided.

These and other tasks are solved according to the proposal of the invention by a beam for a beam conveyor furnace according to the features of the independent patent claim. Advantageous embodiments of the invention are indicated by the features of the subclaims.

According to the invention, a novel beam for a beam conveyor furnace is shown. In general, the beam (in cooperation with other beams of the same set of beams) is used to place material to be heated in the beam conveyor oven, whereby the material to be heated, depending on the type of use of the beam in the beam conveyor oven, is subjected to horizontal and/or vertical transport using the beam or stationary in the beam conveyor oven is stored. There is no relative movement between the material to be heated and the beam on which the material to be heated is placed. For example, the beam can be used as a walking beam that can only be moved in the vertical direction, according to the in WO 2018/ 019 920 A1 described design for a beam conveyor furnace. The material to be heated is preferably a metal part, in particular a sheet steel part, which has an AlSi protective layer.

The beam according to the invention comprises an elongated base body which is designed as a hollow profile. The base body has a profile wall that delimits an internal cavity.

What is important here is that one or more receptacles are formed in the elongated base body, each of which accommodates an insert part. The inserts are designed in such a way that they protrude in relation to the elongated base body and together form a support for the material to be heated. In the working position of the beam in the beam conveyor oven, the inserts protrude upwards relative to the base body, so that the material to be heated can be placed on the inserts. For this purpose, the receptacles are preferably formed in a base body surface which is on top in the working position of the beam in the beam conveyor furnace. The material to be heated therefore does not rest on the elongated base body, but rather rests exclusively on the inserts inserted into the receptacles of the base body. The respective support surfaces of the inserts together form the support or support level for the material to be heated. This can advantageously ensure that the contact area between the material to be heated and the beam is smaller than the contact area that would result if the material to be heated were to lie directly on the base body (i.e. rest on a base body surface lying on top in the working position of the beam in the beam conveyor furnace). Due to a lower heat transfer between the material to be heated and the base body, thermal stresses in the base body are advantageously reduced.

The elongated beam for a beam conveyor furnace can have different cross-sectional shapes. The beam preferably has a rectangular or square cross-sectional shape che in the working position of the beam in the beam conveyor furnace has an overhead beam surface.

Typically, the elongated base body and the inserts are made of a fireproof material. The insert parts, and optionally also the elongated base body, preferably consist of a ceramic material, which is preferably selected from the group of mullite, alumina, SiC, or mixtures thereof. The insert parts, and optionally also the elongated base body, preferably consist of a SiC material, such as Si-SiC, in particular of a porous SiC material, such as N-SiC and R-SiC, preferably of silicon nitride, silicon oxynitride, silicon M- oxynitride, or mixtures thereof.

In principle, the insert parts and the elongated base body can consist of one and the same, in particular ceramic, material. However, it is also possible that the inserts on the one hand and the elongated base body on the other hand consist of different materials. In particular, the insert parts and the elongated base body can consist of different ceramic materials, with, for example, a more durable ceramic material being used for the insert parts than for the base body, with the more durable ceramic material generally also being more expensive than the ceramic material of the base body. Costs can be saved due to the cheaper ceramic material of the base body. It is also possible for the inserts to be made of a ceramic material and the elongated base body to be made of a non-ceramic material, in particular a metallic material. By choosing a metallic material for the base body and a ceramic material for the inserts, costs can be saved in the production of the beam according to the invention.

In the beam designed in the form of a hollow profile, an opening (breakthrough) is formed in the profile wall delimiting the cavity for the formation of a respective receptacle for an insert. The opening opens into the cavity. Preferably, the openings are formed in a profile wall section lying on top in the working position of the beam in the beam conveyor furnace, which applies in particular to a hollow profile with a square or rectangular cross-sectional shape. The receptacles for the inserts are each formed by the opening of the profile wall and the underlying area of the cavity of the hollow profile. The inserts preferably lie on the opposite profile wall section (lower in the working position of the beam in the beam conveyor oven). In this way, the inserts are securely accommodated in the base body.

Preferably, an inner surface of the profile wall section facing the cavity is provided opposite the openings with a recess into which a lower end face of the insert received in the receptacle is inserted. This allows the tight fit of the insert in the receptacle to be further improved.

The inserts are preferably loosely inserted into the receptacles, i.e. can be removed without being destroyed. Accordingly, there is no force-fitting and/or material connection between the insert parts and the base body. On the one hand, this enables simple production of the beam and, on the other hand, easy replacement of individual or all insert parts, especially if they are damaged, whereby the base body and undamaged insert parts can be reused if necessary, which can save costs.

In the beam according to the invention, the inserts received in the receptacles are each positively connected to the associated receptacle in the direction perpendicular to the direction of extension of the base body (in the direction out of the receptacle), so that the insert part is not pulled out of the receptacle exclusively by pulling perpendicular to the direction of extension of the base body can be removed. This has the particular advantage that inserts cannot be pulled out of the holders if they possibly stick to the material to be heated when the material to be heated is removed from the beam. For this purpose, the inserts each have a convex area (bulge) which engages in an undercut area of the receptacle. With a hollow profile, it is sufficient if the convex area of the insert engages behind the profile wall (upper profile wall section) on the inside. In order to enable easy insertion of the insert part, the insert part is advantageously designed in such a way that it has a concave area opposite the convex area which is shaped complementary to the convex area. The insert can then be easily inserted into the receptacle by tilting it, particularly in a direction perpendicular to the extension of the base body.

In the beam according to the invention, the contact area between the cooler material to be heated and the base body can be reduced by the insert parts, which together form a support for the material to be heated, compared to a direct support on the base body, which prevents large thermal stresses from building up. In this regard, it is particularly advantageous if the insert parts are designed according to an embodiment of the invention in such a way that they each have one or more (in the working position of the beam in the beam conveyor oven) have upwardly directed projections, which together form the support for the material to be heated. The material to be heated then rests exclusively on these projections of the inserts. This measure allows the contact area between the material to be heated and the beam to be reduced even further.

Alternatively and/or additionally, according to a further embodiment of the invention, it is particularly advantageous if the insert parts are each designed such that they have one or more projections directed towards the base body, in particular web-like projections. This can advantageously reduce the contact area and thus the heat transfer between inserts and base body, so that the formation of thermal stresses is even better inhibited. In addition to reducing the heat transfer between the material to be heated and the inserts, the heat transfer between the inserts and the base body is also reduced. Both effects combine in an advantageous way. Furthermore, another important advantage of this design results from the fact that contamination of the base body with AlSi or contact reaction with AlSi due to AlSi, which is located on the insert, is avoided.

In the beam according to the invention, the inserts can be arranged in any way, as long as the material to be heated can be placed securely on the inserts. Advantageously, a plurality of insert parts are distributed, in particular evenly distributed, along the direction of extension of the elongated base body.

The inserts can have any shape, as long as they each have a support or contact surface for the material to be heated. According to an advantageous embodiment of the invention, the insert parts are each plate-shaped, the plate-shaped insert parts being accommodated in the receptacles, for example, with plate planes aligned parallel to the extension of the elongated base body. The support for the material to be heated is formed by the respective (upper) end faces of the plate-shaped inserts. With plate-shaped inserts, projections directed upwards and towards the base body can be formed in a simple manner. The projections forming a support for the material to be heated are formed in the area of the (upper) end face of the plate-shaped insert part. The projections directed towards the base body are formed in the area of the two plate surfaces (which are parallel to one another) extending in the plane of the plate. Likewise, a positive connection with the receptacles in the direction perpendicular to the extension of the base body can be produced in a simple manner.

Due to the reduced contact area between inserts and the material to be heated, the risk of thermally induced breakage of the base body or flaking of base body parts can be reduced. As explained at the beginning, contact corrosion caused by the AlSi protective layer can contribute to mechanical damage to the beam. In order to avoid this, according to a further advantageous embodiment, the base body of the beam according to the invention has a layer on the outer surface made of a fiber material which can absorb and bind molten AlSi. This prevents AlSi from having contact with the base body. For this purpose, the fiber material is arranged on the outer surface that faces upwards in the working position of the beam in the beam conveyor oven, it being advantageous if the insert parts are each guided through the fiber material so that the fiber material has no contact with the material to be heated. The fiber material is preferably a material that is chemically resistant to AlSi, for example Al ₂ O ₃ -containing fiber paper.

• - Herstellen eines länglichen Grundkörpers, wobei der längliche Grundkörper ein Hohlprofil ist, der eine einen innenliegenden Hohlraum umgrenzende Profilwand aufweist,
• - Ausbilden von einer oder mehreren Aufnahmen im länglichen Grundkörper, wobei die Profilwand eine oder mehrere Öffnungen aufweist,
• - Einbringen eines Einlegeteils, das einen konvexen Bereich und einen konkaven Bereich, der zu dem konvexen Bereich komplementär geformt ist, aufweist, in eine jeweilige Aufnahme durch Verkippen in einer Richtung senkrecht zur Längserstreckung des länglichen Grundkörpers, wobei der konvexe Bereich einen oberen Profilwandabschnitt der Profilwand innenseitig hintergreift, wobei der obere Profilwandabschnitt eine Hinterschneidung bildet.

The invention further extends to a method for producing a beam according to the invention for a beam conveyor furnace, which comprises the following steps:

• - producing an elongated base body, the elongated base body being a hollow profile which has a profile wall delimiting an internal cavity,
• - Forming one or more receptacles in the elongated base body, the profile wall having one or more openings,
• - Introducing an insert part, which has a convex area and a concave area which is shaped complementary to the convex area, into a respective receptacle by tilting in a direction perpendicular to the longitudinal extent of the elongated base body, the convex area being an upper profile wall section of the profile wall engages behind on the inside, with the upper profile wall section forming an undercut.

Furthermore, the invention extends to the use of the beam according to the invention in a beam conveyor oven as a beam for placing material to be heated. In principle, the beam can be used as a vertically and/or horizontally movable mobile beam or as a stationary fixed beam. For example, the beam is used as a vertically movable walking beam due to a typically longer contact time with the material to be heated.

The various embodiments of the invention can be implemented individually or in any combination. In particular, the features mentioned above and to be explained below can be used not only in the specified combinations, but also in other combinations or on their own, without departing from the scope of the present invention.

• 1a eine schematische Darstellung eines Ausführungsbeispiels für den Grundkörper eines erfindungsgemäßen Balkens mit auf der Oberseite ausgebildeten Öffnungen in Seitenansicht,
• 1b den Grundkörper von 1a in einer Querschnittsansicht,
• 1c den Grundkörper von 1a in einer Ansicht von oben,
• 2a eine schematische Darstellung eines Ausführungsbeispiels für den erfindungsgemäßen Balken mit dem Grundkörper von 1 und eingesetzten Einlegeteilen in Seitenansicht,
• 2b den Balken von 2a in einer Ansicht von oben,
• 2c den Balken von 2a in einer Querschnittsansicht,
• 2d das Einlegeteil des Balkens von 2a in Seitenansicht,
• 3a eine schematische Darstellung eines weiteren Ausführungsbeispiels für den erfindungsgemäßen Balken mit dem Grundkörper von 1 und eingesetzten Einlegeteilen in Seitenansicht,
• 3b den Balken von 3a in einer Ansicht von oben,
• 3c den Balken von 3a in einer Querschnittsansicht,
• 3d das Einlegeteil des Balkens von 3a in Seitenansicht,
• 4a eine schematische Darstellung eines weiteren Ausführungsbeispiels für den erfindungsgemäßen Balken mit dem Grundkörper von 1 und eingesetzten Einlegeteilen in Seitenansicht,
• 4b den Balken von 4a in einer Ansicht von oben,
• 4c den Balken von 4a in einer Querschnittsansicht,
• 4d das Einlegeteil des Balkens von 4a in Seitenansicht.

The invention is explained in more detail below using exemplary embodiments, with reference being made to the attached figures. It shows in a simplified, not to scale representation:

• 1a a schematic representation of an exemplary embodiment for the base body of a beam according to the invention with openings formed on the top in a side view,
• 1b the basic body of 1a in a cross-sectional view,
• 1c the basic body of 1a in a view from above,
• 2a a schematic representation of an exemplary embodiment of the beam according to the invention with the base body of 1 and inserted inserts in side view,
• 2 B the beam of 2a in a view from above,
• 2c the beam of 2a in a cross-sectional view,
• 2d the insert part of the beam from 2a in side view,
• 3a a schematic representation of a further embodiment of the beam according to the invention with the base body of 1 and inserted inserts in side view,
• 3b the beam of 3a in a view from above,
• 3c the beam of 3a in a cross-sectional view,
• 3d the insert part of the beam from 3a in side view,
• 4a a schematic representation of a further embodiment of the beam according to the invention with the base body of 1 and inserted inserts in side view,
• 4b the beam of 4a in a view from above,
• 4c the beam of 4a in a cross-sectional view,
• 4d the insert part of the beam from 4a in side view.

Detailed description of the drawings

First of all, reference is made to the 1a to 1c taken, in which an embodiment of the base body 2 of a beam 1 according to the invention for a beam conveyor furnace is illustrated in various views. Accordingly, the base body 2 is designed in the form of an elongated square hollow profile with a rectangular cross-sectional shape. The base body 2 is shown in a shortened form, which results from the interruption lines drawn.

The hollow profile of the base body 2 is formed by a profile wall 5 which delimits an internal cavity 3. The profile wall 5 comprises an upper profile wall section 5-1 and, opposite, a lower profile wall section 5-2. The profile wall 5 is completed by two parallel side profile wall sections 5-3. The profile wall 5 has an outer profile surface 6 facing the external environment and an inner profile surface 7 facing the cavity 3. In the working position in the beam conveyor furnace, the upper and lower profile wall sections 5-1, 5-2 are typically aligned horizontally and the two side profile wall sections 5-3 are aligned vertically.

The upper profile wall section 5-1 is provided with a plurality of slot-shaped openings (openings) 4, which are arranged in rows along the extent of the base body 2. In 1c Four openings 4 are shown as an example, with the base body 2 having more than four openings 4 due to the shortened representation. The openings 4, which are each delimited by an edge 18 formed by the profile wall 5, open into the cavity 3. Opposite each opening 4, a recess 8 is formed in the profile inner surface 7 of the lower profile wall section 5-2. In the present exemplary embodiment, the openings 4 are each slot-shaped, although different shapes are also possible. An insert 21 can be loosely inserted into the openings 4, which is based on the 2a to 2d is explained in more detail.

In the 2a to 2d a first embodiment of the beam 1 according to the invention is illustrated in a typical working position in the beam conveyor furnace. The beam 1 comprises a base body 2 with slot-shaped openings 4, as in the 1a to 1c is shown. In order to avoid unnecessary repetitions, please refer to the statements regarding the base body 2 1a to 1c referred. An insert 21 is loosely inserted into each opening 4 and passes through the cavity 3 and is supported on the profile inner surface 7 of the lower profile wall section 5-2. Each opening 4, together with the cavity 3, forms a receptacle 19 for the insert 21. The insert 21 is not connected to the base body 2 in a force-fitting or material-locking manner.

The insert part 21 is designed in the form of a plate and has an upper end face 9 and a lower end face 10. The lower end face 10 is supported on the profile inner surface 7, with a lower region of the insert part 21 being accommodated in the recess 8. The plane of the plate-shaped insert part 21 is aligned parallel to the extension of the base body 2 and parallel to the two side profile wall sections 5-3. Since the vertical dimension of the insert 21 (i.e. the shortest or vertical dimension between the upper end face 9 and the lower end face 10) is larger than the vertical dimension of the base body 2 without the lower profile wall section 5-3 in the area of the recess 8, this is the case Insert part 21 extends upwards from the base body 2, i.e. has a protruding area 11 in relation to the profile outer surface 6 of the upper profile wall section 5-1. The protruding area 11 of the insert 21 has the upper end face 9 at the end.

The upper end faces 9 of all insert parts 21 serve as contact or support surfaces and together form a support 23 for the material to be heated in the beam conveyor furnace. Typically, the beam conveyor oven has a large number of parallel beams 1, with the upper end faces 9 of all beams 1 together forming the support 23 for the material to be heated. A material to be heated resting on the upper end faces 9 of a beam 1 does not lie against the outer profile surface 6 of the beam 1, but only has contact with the inserts 21. This has the particular advantage that the upper end faces 9 of a beam 1 in total form a (contact) Have an area that is smaller than the outer profile surface 6 of the upper profile wall section 5-1, whereby (compared to placing the material to be heated directly on the outer profile surface 6) the heat transfer between the material to be heated and the beam 1 is reduced. In principle, all objects to be hot-formed can be used as heat material, in particular metal parts, such as AlSi-coated steel sheets, which are used as vehicle body parts, for example for the B-pillar of a car.

The insert 21 can have different shapes. A possible design is in the 2a to 2d illustrated. The plate-shaped insert part 21 has different end faces, each of which is arranged perpendicular to the plane of the plate. It also has two parallel plate surfaces 14 in the plate plane. The upper end face 9 and the lower end face 10 are each flat, with the sectional views of 2a or 2d a straight line results. When the beam 1 is inserted and in the working position, the upper end face 9 and the lower end face 10 are arranged horizontally. The insert 21 also has two side end faces 12, 13 with a generally vertical orientation, which are curved surfaces in the sectional views of 2a and 2 B visible as curved lines. A first lateral end face 12 has a convex shape and has a bulge 15. The opposite second lateral end face 13 has a concave shape and has a recess 16. The recess 16 is shaped complementary to the bulge 15.

The two plate surfaces 14 are not flat, but have linear webs 17 running in the vertical direction (recognizable in 2 B) , which extend from the upper end face 9 to the lower end face 10 and each protrude vertically from the plate surface 14 (ie in the direction of the opposite edge 18 of the opening 4).

How out 2a results, the bulge 15 engages behind the upper profile wall section 5-1 in the area of the opening 4, which, as it were, forms an undercut 22, so that there is a positive connection between the insert 21 and the base body 2 in the direction perpendicular to the extension of the base body 2 (in the direction out of the opening 4). This prevents the insert part from being removed from the receptacle 19 solely by pulling perpendicular to the base body 2. This prevents the insert 21 from being pulled out of the receptacle 19 when it adheres to the material to be heated and the material to be heated is removed from the beam 1. Due to the depression 16, which is shaped complementary to the bulge 15, the insert part 21 can be inserted into the opening 4 in a simple manner by vertical tilting. Due to the linear webs 17 on the plate surfaces 14, which rest on the edge 18 of the opening 4, the contact area of the insert 21 to the base body 2 or profile wall 5 is reduced. This inhibits the heat transfer between the insert 21 and the base body 2 and reduces the risk of contamination of the base body 2 with AlSi due to AlSi, which is located on the insert 21. Nevertheless, the webs 17 ensure a secure positioning of the insert 21 in the receptacle 19, especially in connection with the lower end face 10 inserted into the recess 8.

Both the base body 2 and the inserts 21 are made of a fireproof material. The insert 21, and optionally the base body 2, consists of a ceramic material, for example a SiC material, such as Si-SiC. The base body 2 can consist of a ceramic or a non-ceramic material.

As in 2c can be seen, the beam 1 in the area of the upper profile wall section 5-1 on the profile outer surface 6 includes a fiber layer 20 made of a fiber material, here for example Al ₂ O ₃ -containing fiber paper. The fiber layer 20 can absorb and bind molten AlSi, thereby preventing AlSi from making contact with the base body 2. The protruding area 11 or the upper end face 9, which forms a contact surface for the material to be heated, breaks through the fiber layer 20.

Further exemplary embodiments of the beam 1 according to the invention are described below, which only differ in the shape of the insert parts 21. The base body 2 is the same in each case. In order to avoid unnecessary repetitions, only the differences in the design of 2a to 2d described and otherwise reference is made to the above statements.

When designing the 3a to 3d the plate surfaces 14 of the insert 21 each have a wave-shaped contour with closely adjacent, elongated webs 17 (wave crests). The webs 17 extend in the vertical direction. On the one hand, this surface design allows the heat transfer between the insert 21 and the base body 2 to be reduced, and on the other hand, the insert 21 is reliably received in the opening 4 with a good fit. As in 3c illustrated, this non-planar surface design can also be formed in the extension direction of the base body 2.

When designing the 4a to 4d the plate surfaces 14 of the insert 21 each have an elongated web 17, analogous to the design of 2 B . In addition to this, the upper end face 9 is not flat and has a wavy contour. The wavy surface shape results in elongated webs 17' (wave crests) in the horizontal direction (transverse to the extent of the base body 2), through which the contact area to the material to be heated can be further reduced in order to inhibit the heat transfer between the material to be heated and the beam 1.

The invention has been described using exemplary embodiments, with a variety of modifications being possible, particularly with regard to the design of the base body 2 and the insert parts 21. It is particularly conceivable to design the base body 2 not as a hollow profile, but as a solid body, with the receptacles 19 for the inserts 21 being designed in the form of recesses in the solid body.

From the above statements it follows that the invention provides an improved beam for a beam conveyor oven for supporting a material to be heated. Due to the reduced contact area between inserts and the material to be heated, heat transfer between the material to be heated and the beam can be reduced in order to reduce thermal stresses and prevent parts of the base body from flaking off or breaking the base body. This is supported by a reduced contact area between inserts and base body, which also has the advantage of reduced contamination of the base body with AlSi and reduced concurrency corrosion. The inserts can be easily inserted into the base body and removed again, which enables easy replacement. Melted AlSi can be absorbed and bound by a fiber layer on the outer profile surface, which further reduces the risk of contact corrosion of the base body with AlSi, which is equally advantageous in terms of avoiding mechanical damage to the base body.

Reference symbol list

1

bar

2

Basic body

3

cavity

4

opening

5

profile wall

5-1

upper profile wall section

5-2

lower profile wall section

5-3

lateral profile wall section

6

Profile outer surface

7

Profile inner surface

8th

deepening

9

upper face

10

lower face

11

protruding area

12

first lateral end face

13

second lateral end face

14

plate area

15

Bulging

16

depression

17, 17'

web

18

edge

19

Recording

20

fiber layer

21

Insert

22

Undercut

23

edition

Claims (14)

Beam (1) for a beam conveyor oven for placing a material to be heated, which comprises: - an elongated base body (2), which is a hollow profile which has a profile wall (5) delimiting an internal cavity (3), - one or more receptacles (19) in the elongated base body (2), in each of which an insert part (21) is accommodated, the profile wall (5) having one or more openings (4) into which the insert parts (21) are each inserted are, whereby the inserts (21) - are positively connected to the receptacle (19) that accommodates them in the direction perpendicular to the longitudinal extent of the elongated base body (2), - protrude in relation to the elongated base body (2) and together form a support (23) for the material to be heated, - each have a convex area which engages behind an upper profile wall section (5-1) of the profile wall (5) on the inside, the upper profile wall section (5-1) forming an undercut (22), and have a concave area which leads to the convex Area is complementary shaped. Bar (1) after Claim 1 , in which the receptacles (19) in the upper profile wall section (5-1) each have a circumferential opening (4) in the upper profile wall section (5-1), which is spaced from the respective insert part (21). Bar (1) after Claim 1 or 2 , in which the insert parts (21) can be inserted into the receptacles (19) and removed again by tilting in a direction perpendicular to the longitudinal extent of the elongated base body (2). Bar (1) after Claim 1 , in which an inner surface (7) of the profile wall (5) facing the cavity (3) has a recess (8) opposite a respective opening (4), in which a lower surface (10) of the profile wall guided through the opening (4). Insert (21) is included. Bar (1) after one of the Claims 1 until 4 , in which the inserts (21) are loosely inserted into the receptacles (19). Bar (1) after one of the Claims 1 until 5 , in which the insert parts (21) each have one or more projections (17 '), in particular web-like projections, which together form the support (23) for the material to be heated. Bar (1) after one of the Claims 1 until 6 , in which the insert parts (21) each have one or more projections (17), in particular web-like projections, directed towards the base body (2). Bar (1) after one of the Claims 1 until 7 , in which a plurality of insert parts (21) are arranged distributed along the longitudinal extent of the elongated base body (2). Bar (1) after one of the Claims 1 until 8th , in which the insert parts (21) are each plate-shaped, the support (23) for the material to be heated being formed by end faces (9) of the plate-shaped insert parts (21). Bar (1) after one of the Claims 1 until 9 , in which the inserts (21) consist of a material that is different from the material of the base body (2). Bar (1) after one of the Claims 1 until 10 , in which the base body (2) is provided on its outer surface (6) with a layer (20) made of fiber material. Bar (1) after Claim 11 , in which the insert parts (21) are each passed through the layer (20) made of fiber material. Method for producing a beam (1) for a beam conveyor furnace for placing a material to be heated according to one of the Claims 1 until 12 , which comprises the following steps: - producing an elongated base body (2), the elongated base body (2) being a hollow profile which has a profile wall (5) delimiting an internal cavity (3), - forming one or more receptacles ( 19) in the elongated base body (2), the profile wall (5) having one or more openings (4), - inserting an insert part (21) which has a convex area and a concave area which is shaped complementary to the convex area, into a respective receptacle (19) by tilting in a direction perpendicular to the longitudinal extent of the elongated base body (2), the convex region engaging behind an upper profile wall section (5-1) of the profile wall (5) on the inside, the upper profile wall section (5 -1) forms an undercut (22). Use the bar (1) according to one of the Claims 1 until 12 in a beam conveyor oven as a beam for placing the material to be heated.

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