MX2008005988A - Method and apparatus for heating steel components in a continuous furnace - Google Patents

Abstract

The invention relates to a method and an apparatus for heating steel components in a continuous furnace, wherein a first transport device having an external drive (12) receives the components in a precise position and transports them through the furnace (3) in order to heat them, and a second transport device (20) receives the parts, after the heating, from the first transport device at a predetermined transfer point or transfer region and conveys them out of the furnace (3) at an increased speed and places them in a precise position at a further receiving point ready for further processing. The components are mounted on a support having engagement means for the different transport devices.

Description

METHOD AND DEVICE FOR HEATING STEEL COMPONENTS IN A CONTINUOUS OVEN FIELD OF THE INVENTION The invention relates to a method for heating steel components and to a device for this purpose. BACKGROUND OF THE INVENTION It is known to heat steel components to the so-called austenitic temperature and then quench them by abrupt cooling. For heating to the austenitic temperature, so-called quenching furnaces are known in which the components are placed and heated correspondingly, and then removed. Since the beginning of the 90s, not only components of machines made of steel, such as, for example, arrows or supports, but also body parts have been tempered. This procedure is also known as temper press steels (PHS for its acronym in German). With this technology, to obtain high-strength body parts, a steel plate is heated to the austenitic temperature, and then subjected to simultaneous deformation and cooling in a molding tool, so that the known quenching effect is produced. By means of this tempering process, the strength of the body material increases up to, for example, 1,500 MPa. By means of this resistance as high as possible of the material Ref .: 192646 it was possible to increase the safety in case of accidents in modern vehicles considerably, conserving the same weight of the bodywork. For the heating of these steel plates, continuous furnaces and in particular roller furnaces were used in which the plates or preformed parts were heated. Because at these temperatures there is already considerable oxidation on the surface of the components (scale formation), this type of quenching or heating furnaces is usually operated with protective gas. It is further known to configure the plates or preformed components with an aluminum coating or an alloy consisting approximately half of aluminum or zinc, respectively. In the case of these coatings, it is possible to dispense with the protective gas atmosphere. For the heating of body parts, continuous furnaces are currently used as roller furnaces, but also rotary hearth furnaces in which the components remain for a longer time. Then the body parts are transported to the presses and there they are provided with the desired shape. The existing ovens suffer from the disadvantage that the transport system is placed inside the oven, and for this reason is very prone to failures. Maintenance of the transport system can only be carried out when the oven has cooled down. To this we must add that the position of the body parts is not fixed, and that during displacement through the oven displacements of position of the pieces occur, so that when leaving the oven the pieces must first be placed again in position to finally be removed and transported to the press. In this aspect, it is a disadvantage that the pieces are rapidly cooled during the relocation because they are not in an orderly and perfect position. To compensate for these heat losses, the components are heated in the furnace beforehand to temperatures that are notably higher than those that are necessary for press hardening. The temperature required for press tempering is usually 930 ° C. Due to the fact that all the pieces are heated to higher temperatures than necessary, but that it is only necessary to reposition a portion of the pieces, pieces of different temperatures arrive at the deformation tools. But different temperatures also mean that the hardnesses obtained are not unitary and that there are fluctuations in this aspect. This also means that the components that have different outlet temperatures eventually also have different final temperatures, so that deformation can also occur. In conventional ovens, it is additionally a disadvantage that product supports weighing more than 60 kg are used. After the heating of the body part, these supports leave the furnace and are transported on the outside back to the entrance, where it is then possible to reposition a new part on these supports. During the movement of exit, return and entry the support loses up to 200 ° C. It is necessary to compensate again this thermal loss in the furnace, that is, the furnace not only has to heat the body parts but also the supports, which costs additional energy. A further disadvantage in the case of known roll hearth furnaces is that the width of the roll hearth furnaces is limited. Because the rollers are made of ceramic or thermally resistant steel, under the influence of heat, bending occurs in the case of too large a width of the furnace which in the present case can not be tolerated. This also causes damage due to alteration of the load on the rollers. BRIEF DESCRIPTION OF THE INVENTION The object of the invention is to create a method with which it is possible to heat steel components quickly, effectively and economically, and in particular steel sheet components that will be subjected to a press tempering, to standardize the product quality and save energy. This problem is solved with a method according to claim 1. Favorable improvements are characterized in the subordinate claims. An additional object is to create a device to carry out the method. This problem is solved with the features of claim 5. Favorable improvements are characterized in the dependent claims thereof. The method according to the invention proposes to provide in a quenching furnace a first transport device which, by means of defined seats that run the furnace from the entrance to the exit, transports the pieces through the furnace with absolute precise location and precise position. The method according to the invention further proposes transferring the parts at the exit of the furnace to a second transport device that receives the parts of the first transport device with precise location and removes them from the furnace at high speed with precise location and precise position, and in a transfer station transfers them to a corresponding transfer device to place them in a press or molding tool for press tempering.

In another favorable embodiment there is a third transport device which, in the oven entrance area, introduces the components from outside with very high speed into the oven and transfers them with precise location to the first transport device or seat of the first transport device. The method further proposes that the second and / or third transport device drives the parts to be hardened through respectively an inlet gate to the furnace and respectively a furnace outlet gate which is only opened for the moment of passage of the piece and then it closes immediately. By means of the high speed of feeding and exit made inside and outside the furnace, the floodgates are only open for a very short period of time, so that the loss of energy is reduced. The method according to the invention further proposes that the components to be hardened, for example, plates or preformed components or that already have the final shape are placed on specific supports for the respective piece and transported with the transport devices. However, only partial regions of the supports are conducted inside the oven itself, most of it is conducted outside the oven, and for the transportation with precise location through the oven there are corresponding reception means in which they can intervene. means for receiving the first transport device, the second transport device and optionally the third transport device. The coupling or coupling of the supports with the transport devices takes place outside the oven. Also the conduction of the supports. In the method according to the invention it is an advantage that by means of optional high speeds of entry and exit of the oven and transport with precise location of the pieces, the pieces lose less heat and for this reason it is not necessary to heat them at such high temperatures as in the state of the art. By means of the transport with precise location and due to the low thermal loss, all the pieces also have approximately equal temperatures in the pressing process, by means of which homogeneous material properties are obtained along the entire production line. By the fact that the supports are heated only in a small proportion and that gates are also provided and it is possible to keep the thermal loss by heat coming out of the furnace reduced, it is possible to carry out the process in an energy optimized way. The device according to the invention is a furnace having a furnace enclosure. At the bottom of the furnace enclosure at least one slit of longitudinal extension is arranged, wherein a transport space or a transport area is arranged below the base of the furnace. In the transport area, at least one transport chain or a transport belt is located below the slit below the slit, so that the upper section of the chain moves along the slot and the slit. Lower section moves back. To prevent heat from coming out through the slit, in particular by convection or radiation, and between air, the slit preferably has a seal. The sealing can be constituted in the simplest case by means of brushes in the manner of brushes that from an edge that limits the slit protrude into the slit with closely arranged fibers of a thermally resistant synthetic material such as PTFE and / or metallic fibers and / or glass fibers and / or ceramic fibers. In a further favorable embodiment, the slit 45 is sealed from the two surfaces that limit the slit by Teflon lips which preferably have an overlap region. Additionally it is possible to provide along the slit a multitude of metal lamellas parallel to the wall of the base of the oven and that with spring load perpendicular to the slit are tilted on the slit. Both the brush fibers and the synthetic lips as well as the metal lamellae with spring loading are displaced or laterally deflected by a support column when the support is in motion, and after passing the support column they swing back to the region of the slit, so that a reliable barrier against heat and / or unwanted air is obtained. The barrier can also be implemented by means of an air curtain. The investment crowns or chain reversing rollers are arranged in the region at the beginning of the furnace or a gate zone respectively. Regularly spaced pins or projections are provided in the chain. In the region of the investment crowns or reversing rollers of the chain, or of the chains if several adjacent chains are arranged, linear drives aligned with the direction of movement of the furnace are arranged towards the furnace inlet and towards the furnace outlet. chain. The linear drives have in each case a seat which, like the chain, has a spigot or a projection. This spigot or protrusion is also configured so that it points toward the base of the furnace or upwards, while the spigot or protrusion of the linear drive is provided telescopically. The spike can be operated, for example, in pneumatic or hydraulic form. For the transport of the pieces, supports are provided which are configured, for example, in the form of flat plates. These supports, in the form of flat plates, have at least one hole in their lower part, in which a pin of the linear drive and / or of the conveyor chain can intervene. The supports are guided laterally in U-shaped profiles or in corresponding sliding rails or the like, so that they are pushed along these guide rails or U-shaped profiles by the pegs engaging in their lower part. These supports pass through the slits of the furnace with a support arm that extends upwards from the chain and away from the iron, while at a free end of the support arm that protrudes into the interior of the furnace is disposed detachably , a seat for a piece to be tempered. The seat for the piece can be exchanged depending on the shape of the pieces, and has, for example, a flat contour on which the piece rests, but nevertheless, in the case of pieces in which a pattern has already been made of holes, it is also possible that only have branched support arms that intervene from below in the respective holes and thus allow a good heating of the component. The dimensions of the oven and those of the seat and the support column are such that the component to be heated is at a minimum distance of 200 mm from all the walls of the oven. Preferably the wall of the base of the furnace is configured thicker than the other walls to keep the thermal losses through the slit due to radiation and convection reduced. With a wall thickness in the furnace of, for example, 200 mm, the base has a thickness of 300 mm. The plate-like component of the support has, for example, three recesses in the lower part for the pins or projections which are arranged successively in the transport direction. To insert a support of this type in a corresponding oven, the support is placed completely automatically on a first spike of a linear drive that must push the support into the interior of the oven. The linear drive is controlled so that at a certain moment it approaches the support or the plate in the U-profiles or guide rails towards an inlet gate of the furnace which, for example, consists of two doors arranged in a known manner one after the other. other. When the support passes a certain area of the furnace or the entrance of the furnace, being that this zone is defined, for example, with detectors arranged in the guide rails, the first door of the furnace opens, and closes after passing this zone. The support is now driven through the intermediate gate until passes through another area that causes the opening of the inner gate. Then this gate opens equally and the linear drive pushes the support also through this zone. The cold control is carried out in such a way that the support is placed in the region of a first reversing crown or of a first reversing roller of the conveyor chain when a corresponding spigot or protrusion of the conveyor chain moves upwards over the periphery of the conveyor chain. the transport crown. This pin or projection then engages in the centered hole, during this time the linear drive already retracted its projection and moves back to its initial position and there receives and transports to the next support. The support is then moved through the furnace guided laterally along the guide rails or U-profiles, with control of the furnace gate at the outlet of the furnace taking place in the same way as at the entrance. Naturally it is also possible to use oven doors with a single door. The linear drives at the beginning and at the end of the furnace are able to accelerate very much the supports and the pieces that are on them, and drive them with very high speed outside the furnace. By virtue of the fact that the supports are guided with location and precise position in the U-profiles or guide rails, and that in addition the spigot or projection of transport of the linear drives but also of the transport chain precisely define the position in the course, the support and the pieces leave the oven with a precise position. As soon as the pieces and the supports came out of the oven it is possible to remove the pieces and drive them to a press. The supports are removed from the corresponding guide rail and are automatically guided above or below the furnace back to the furnace inlet, where they are reinserted into the rails and transported with the linear drive. Instead of a transport chain it is also possible to use two conveyor chains with synchronous drive that extend parallel to each other. In this aspect it is an advantage that the respective linear drives can be moved between the chains to deliver or receive the support. The engagement means, such as, for example, cams, move parallel to each other on a chain, respectively, so that there are two engaging means engaging in the support or corresponding engagement means on both sides of a central area. The linear drives intervene with their means of intervention preferably in a single intervention means in the central transverse area of the support, between the means of engagement for the cams of the chain. It is true that also with this device according to the invention the supports are removed from the oven and are introduced back into the oven at the entrance of the oven, but nevertheless with the transport system according to the invention only a fraction of the support, so that the thermal loss is considerably lower than in the state of the art. The invention was explained for a transport chain, a slit and a single piece placed. However, it is also possible to move two or more parallel transport chains under the furnace and to provide a slit for each transport chain. By this it is possible to transport a corresponding multiple of pieces through the furnace and then press them. On the other hand it is also possible to synchronize the conveyor chains and the linear drives in relation to their movement, and to place, for example, large individual pieces on two or more supports and to drive them through the furnace. Naturally, in addition to the transport system described, other transport systems are also conceivable. Thus, the transport chain under the support can intervene in corresponding recesses of lateral areas of the support, adjacent to the transport or sliding rails or to the U-profiles. For this purpose the support has, for example, longitudinally to the center, only a hollow for the two linear drives. In this mode it is possible that instead of a chain with two projections or spikes that are arranged parallel to each other In the transport direction, two transport chains are additionally used whose movements are synchronized so that the linear drive can transport in the region between the two transport crowns or reversing rollers to ensure a safe transfer. In addition, it is also possible for the plate-like components of the supports to have protrusions projecting laterally beyond the U-profiles in which the spikes or chain protrusions mesh in a rack fashion. For this purpose, the guide rails are then configured in the side region of the plate-like components either as U-shaped profiles with an open base or simply as an L-shaped support rail which ensures the lateral guidance of the plates with a high ridge that however does not exceed the plates above. Additionally, it is also possible that the spines of the conveyor chain that move the iron-like components below the furnace do not intervene behind lateral protrusions or engage in holes in the lower part but simply rise behind the rear transverse edge of a iron, attack against the rear transversal edge and in this way push the iron through the oven. If, for technical reasons of maintenance, a return transport of the plates is necessary, this does not also constitute a problem because the spikes of a chain that moves back then attack the front edge accordingly. Moreover, for the device according to the invention it is only essential that the supports are transported into the furnace in a precise position and at a relatively high speed by means of a linear drive, they are transported through the furnace in a precise position with a The corresponding transport device and at the end of the furnace are transported out of the furnace at high speed in a precise position with a linear drive and are arranged in a precise position in a transfer station. In addition, the entire transport device is arranged in a zone of non-critical temperature. In the invention, it is furthermore an advantage that the transport system is not arranged inside the oven but underneath a base of the oven, so that only a small support which receives the components protrudes through a slit in the base into the oven. , but the rest of the support is guided outside the oven. The linear drives can be spindle drives, pneumatic drives or conventional hydraulic drives. Control of precise position and trajectory is decisive for use with the invention. Therefore, instead of intervention means, the linear drives can also have end claws that grip the supports on one edge. The transport pins or projections and the chains are arranged, for example, spaced by 200 mm, but however any other distance is optionally possible in the direction of transport, which is adjusted to the corresponding supports. Naturally, instead of the chains, according to the invention it is also possible to use toothed belts, trapezoidal belts or all other known belt types. Naturally, it is also conceivable to carry out the transport in the area of the base of the furnace with a spindle drive, a pneumatic or hydraulic drive instead of a chain drive, belt or the like which is driven with an upper and lower section. Naturally, it is also possible to use a single linear drive that transports at different speeds in different areas of the furnace. This is possible, in particular, in the case of units in which forms must be heated in which, by virtue of an inductive heating, the heating is rapid or in the that it is not necessary to reach a particularly large number of pieces or that by virtue of their small size they heat up very fast. This type of introduction intervals and such rapid exit intervals of the supports or the components can not be achieved in the prior art with roller hearth furnaces. On the one hand it is impossible to obtain a quick introduction with roller hearth furnaces by virtue of the fact that the resistance of the transport rollers is too low to allow acceleration. Second, it is not possible to perform different roller speeds within a roller conveyor, since with this, in areas where the component goes from faster rollers to slower rollers, the component would deviate uncontrollably. The same happens at the transfer point of slower rollers to faster rollers. Fundamentally, it should be noted again that, in roller hearth furnaces, transport with a precise position and location is not possible. However, a transport with precise position and location as those of the invention is also necessary because at the end of the heating usually the piece is removed from the second transport device by robots. In this respect it is an advantage of the invention that with a servo-driven linear drive it is possible to establish in a simple manner a controlled coupling between the linear drive or the position of the component and a robot, so that it is also possible to takes "on the fly" by the robot.

Contrary to roller hearth furnaces of limited width, the furnace according to the invention can have any width at its discretion. For this reason it is possible to provide any number of slits and in addition to provide traps or access records in the lower part to enter the oven enclosure. BRIEF DESCRIPTION OF THE FIGURES The method according to the invention and the device according to the invention are exemplarily explained by means of an exemplary embodiment of the invention by the attached figures. They show: Figure 1: very schematically the device according to the invention in a side elevation view partially sectioned; Figure 2: very schematically the transport device of the invention in a top plan view; Figure 3: very schematically the device according to the invention in a transfer zone between the first transport device and a second transport device; Figure 4: the support of parts according to the invention in a bottom plan view; Figure 5; a longitudinal section through the support of parts in the region of an intervention means for a corresponding intervention means of a linear drive; Figure 6; the support according to Figure 5 in another partial section view showing a gear means for a corresponding engagement means of a chain or belt drive. DETAILED DESCRIPTION OF THE INVENTION The device 1 according to the invention for heating components 2 comprises a continuous furnace 3 with a transport device 4. The oven 3 has an oven inlet 5, a heating zone 6 and an oven outlet 7.

The furnace inlet 5 and the furnace outlet 7 are separated from the zone 6 in each case by a gate gate 8, 9.

Additionally the inlet 5 of the furnace and the outlet 7 of the furnace are insulated against the external atmosphere with respectively a furnace hatch 10, 11. Alternatively it is also possible that only the oven doors 10, 11 or the gate doors 8, 9 exist. The transport device 4 is arranged below the oven 3 itself. The transport device 4 comprises at least under the furnace 3 and below the heating zone 6 of the furnace 3 a belt or chain conveyor device 12 as the first transport device. The belt or chain transport device 12 has at least one chain 12a or one belt 12a with an upper section 13 and a lower section 14. As the upper section 13 and the lower section 14 are guided around corresponding belt pulleys or respectively toothed or chain wheels 15, 16. The belt or chain transport device 12 has in particular two parallel chains or belts 12a, 12b which are arranged parallel to each other, for each of the transport devices 12a, 12b there is in each case a lower section and a upper section 13a, 13b, 14a, 14b. The corresponding toothed wheels and / or belt pulleys 15a, 15b, 16a, 16b are preferably driven rotatably coupled on a common drive shaft (17) respectively (FIG. 3). The upper sections 13a, 13b and the lower sections 14, 14b of the chains 12a, 12b, or respectively the chains or belts 12a, 12b themselves have transport cams, transport projections or transport pins 18 facing outwards, ie , radial to the outside of the wheels 15, 16. These cams, spikes or transport projections protrude outwards from the chains 12 or belts 12 and serve as engagement means 18. In addition, there is at least one linear transport device 20 as a second transport device. The linear transport device 20 is a linear drive that moves hydraulically, pneumatically, electromagnetically or through spindle drives. The direction of movement (arrow 21) of the linear drive 20 extends parallel to the feed direction 22 of the transport device 4, however, while the transport device 4 in operation only moves in one direction, the direction of movement of the linear drive 20 or respectively of the linear drive device 20 is reversible. The linear drive device 20 has a cam or pin 24 which is telescopically disposed in the linear transport device 20, which protrudes and moves in the same direction as the cams 18. The linear drive device 20 can be moved over the shaft 17 and between both belt chains 12a, 12b or belts 12a, 12b or belt pulleys 16a, 16b. In addition, a second linear drive device 25 of the same configuration as the third transport device can exist opposite the first linear drive device 20. The linear drive device 20 is preferably located below the exit zone 7 of the furnace and the linear drive device 25 below the zone 5 for entering the furnace. The linear drives 20, 25 are preferably driven by servomotors. To carry the parts to be tempered through the furnace 3 there are support elements 30. The support elements 30 have a flat base 31 in the manner of a plate having a front edge 32 and a rear edge 33 in the direction of movement, as well as right and left side edges 34. In addition, the base comprises a lower part 35 and a upper part 36. In the upper part 36 of the base 31, a support column 37 is central. The support column 37 extends away from the base 31. The base 31 is guided with its longitudinal edges 34 enclosed in guide rails 40 extending from the furnace inlet to the outlet of the furnace. The guide rails 40 extend above the transport devices 4, 20, 25 and below a base 41 of the oven, and guide the base 31 in both the vertical direction and the horizontal transverse direction relative to the direction 22. of movement. In their side edges 34, the support element can have protruding support rollers which are mounted rotatable in a bearing about an axis extending parallel to the plane of the plate and which are guided by rolling in the guide rails. In addition, it is possible that rollers or guide balls are mounted which rotate in a bearing about an axis perpendicular to the plane of the plate and which have the effect of a transversal guide relative to the direction of transport. A slit 42 is provided in the base 41 of the oven which is continuous from the oven inlet to the outlet of the oven. Through the slit 42 passes the support column 37 which extends for a distance into the interior 6 of the oven. At a free end 42 of the support column 37 a fastening device 43 is provided for the work piece 2 or the piece 2 to be heated. The slit is configured as narrow as possible, but nevertheless at a distance from the support column 37. The support element 30 is configured to be transported by the devices 4, 20, 25 in the direction of the direction 22 of movement through the furnace. For this purpose the base 31 has in its lower part 35 engagement means 50 for interaction with corresponding engagement means of the chain (s) 12 or belt (s) 12 of the transport device 4. The base also has lower intervention means 51 corresponding to the intervention means of the linear actuators 20, 25 in its lower part. If in the case of the means of engagement of the transport device 4 are cams, pins or protrusions 18 protruding from the chains, the engagement means 50 are configured as parallel grooves whose separation corresponds to the separation of the cams 18 from the transport device 4 running parallel along the forward direction 22. The slots 50 are open on a rear face face 33 of the base 31 and terminate with respectively a slot bottom 52 adjacent the edge 32 above.

If one means of intervention of the linear drives is a protruding telescopic protrusion or cam 24, then the corresponding intervention means in the lower part of the base 31 is a corresponding positive connection recess 51. In order to achieve an accurate and precise position, it is preferred (FIG. 5) that the recess 51 be configured, for example, conical or frustoconical and the corresponding cam 24 of the linear actuator 20, 25 have a corresponding shape, so that after being projected adjustment with positive connection within the recess 51 and that by means of the corresponding frustoconical walls 53 not only a positive connection is established, but also a position fixation takes place. Next, the manner of operation of the device according to the invention and the method according to the invention are explained. Before the entrance 5 of the furnace, the supports 30 with their bases 31 are placed in the rails 40. At a free end 42 of the support column 37, a support element 43 is mounted - as soon as it is not already equipped with one - for a component 2. Component 2 is then placed in a precise position. If in the case of component 2 it is a preformed component 2, the support element 43 can be configured in such a way that it attacks certain parts of the contour of component 2 or component. which intervenes with corresponding pins, for example, in holes already manufactured. The linear drive 25 then moves with the cams 24 under the opening 51 of the base 31 of the support 30. The cam 24 is introduced hydraulically, pneumatically or electromagnetically into the intervention hole or means 51. The linear drive 25 then moves the support 30 with the component 2 through a first optionally existing oven door 10, from the zone 5 of entry to the oven and a second optional door separating the entrance zone 5 from the zone 6 of heating. The displacement movement ends when the linear drive 25 with the cam 24 is in the region of the chain wheels 16a, 16b, belt pulleys 16a, 16b and above a shaft 17. Now the cam 24 of the linear drive 25 it is lowered so that the linear drive can again move out of these areas in front of the furnace. Here, it also displaces the second support 30. When providing grooves it is also possible to use supports that are longer than the longitudinal distance between the adjacent cams 18. The further transport of the support 30 which is in the area of the wheels 15a, 15b now takes place when the cams 18 of the wheel 15 are raised along the outer periphery of the transport device 4 and of the respective upper section 13 of the chain or the belt obeying the rotation of the wheels 15, 16, entering from behind in the grooves 50. At the moment in which the cams 18 are in contact with the walls of the groove or the bottoms of the groove the support is transported by the chain through the heating zone 6. If slots are provided that are longer than the longitudinal distance between adjacent cams 18 it is also possible to use support elements 30 which are longer than the longitudinal distance between cams. Preferably the developments of the movements of the linear drives and of the drives of the chains and belts are synchronized. That is to say, the first linear drive moves at high speed, brakes gently in the transfer zone and then moves so that the cams of the chain or belt drive gear without abruptness and continue with the transport. In other words, the linear drive accompanies the chain speed for a short distance until it no longer intervenes. At the transfer point, according to this, the linear drive moves along with the chain, intervenes in the support and then increases the transport speed while the cams of the chain drive turn downwards. At the end of the heating zone 6 the linear drive 20 already awaits the support 30, wherein the cam 24 of the linear drive 20 enters the opening 51 at the moment when the support 30 is on top. This preferably also takes place at the point of inversion of the chain 12 or the respective belt, so that the cams leave the grooves 50 while the cam 24 enters the support 30 in the opening 51. Now the linear drive 20 you can pull the support 30 out of the heating region or heating zone 6 through the door 9, through the exit zone 7 and through the second door 11 in a precise position. The transport speeds of the linear drives 20, 25 can be considerably higher than the transport speed of the transport device 4. In particular, for example, transport speeds of 10 m / sec are possible. Preferably the doors 8, 9 of the gates and the doors 10, 11 are controlled so that the movement of the linear drive causes a door opening at the corresponding moments and immediately closes the doors again after passing the support. By this a cost effective and energy-saving form of operation of the furnace is possible. Disagreeing from the preferred embodiment described above, the transport through the transport device 4 can start already in the zone 5 of entry to the furnace and end in the exit zone 7 of the furnace, being then between the entrance zone 5 the oven and the heating zone 6 and the exit zone 7 of the oven or there are doors that are controlled to open and close corresponding to the passage of the pieces or there are no doors but optionally only gates that are established by corresponding curtains of hot or cold air or air aspirations. After the support 30 with component 2 was completely pulled out of the furnace the part is removed and processed further. The support is also removed from the rails and driven back to the furnace entrance by means of suitable return devices and there it is returned to the rail. In the device according to the invention and the method according to the invention, it is an advantage that the support element or the part support 30 is for the most part carried out outside the furnace. By this only minor parts of the part holder are heated and in this way the loss of energy due to the cooling of the part support outside the furnace is minimized. Due to the fact that the whole transport device is located outside the furnace, it is possible in the case of breakdowns, maintenance or similar to access the transport device and fix the faults or carry out a maintenance without it being necessary to stop the oven. This also increases efficiency and reduces energy consumption. The respective means of engagement of the transport devices 4, 20, 21 and of the supports 30 need not be cams or pins, any type of mutually corresponding shapes are suitable with which an advance can be obtained. In addition, the means of engagement do not necessarily have to be arranged at the base of the support. The cams or other means of the transport devices 4, 20, 25 can also attack on the anterior or posterior transverse edges of the support. In the invention it constitutes a further advantage that in the event that the pieces fall out of the seat and remain on the base of the furnace, it is possible to insert in the guide rails a special support with an evacuation plate that moves on the bottom and that transports this component out of the oven. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (10)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. Method for heating steel components, in which the steel components to be heated are conducted through an oven and heated in the furnace at a predetermined temperature, for transporting the components through the furnace there is a transport device, characterized in that a first transport device receives the components in precise position and transports them through the furnace to heat them, and after heating a second transport device receives the parts of the first transport device at a predetermined transfer point or transfer zone and transports them out of the furnace at a higher speed and makes them available in precise position for further processing at an additional transfer point .
2. 2. Method according to claim 1, characterized in that there is a third transport device that receives the components in precise position prior to heating and in front of the furnace, and transports the components with precise location and precise position with high speed to the interior of the oven , and at a predetermined transfer point or transfer zone transfers the pieces with precise position and location to the first transport device, which continues with the transportation of the pieces through the oven at a lower speed.
3. Method according to claim 1 and / or 2, characterized in that the parts to be heated are placed on supports, and the supports have first meshing means in which second means of engagement of the conveying device mesh, in a way that at all times a position and precise location of the support is ensured during transportation.
4. Method according to any of the preceding claims, characterized in that the components are heated with radiation and / or by convection and / or induction and / or with microwaves.
5. Device for heating steel components with an oven for heating the steel components and at least one transport device for transporting the parts through the oven, in particular a device for carrying out a method according to any of the preceding claims , characterized in that the minimum of a transport device comprises at least a first transport device which is arranged in or adjacent to a heating zone of the oven and is configured for the transport of the parts during heating, and then of the first device of A second conveying device is configured and extends outwards along the furnace in the conveying direction, so that the parts can be transported out of the furnace by the second conveying device, the conveying device being disposes outside the furnace and comprises means of engagement to engage with means of eng corresponding to at least one supporting element that is transported from the outside of the furnace by the transport device and whose position and location are fixed, the support element traversing a wall of the furnace in partial zones and disposes inside the furnace wall. oven of a device to seat the pieces.
6. Device according to claim 5, characterized in that there is a third transport device which, from a zone which in the transport direction is before the furnace, extends to the first transport device, so that it can transport the pieces to the interior from the oven.
7. Device according to any of claims 5 or 6, characterized in that the minimum of a support device for the parts to be heated in the furnace comprises a first area that is guided in a guide device from the entrance to the furnace up to the exit of the furnace vertically and horizontally transverse direction in relation to the direction of transport, and in the support device there are also means for engaging corresponding meshing means of the second and third transport device, and also meshing means for corresponding engagement means of the first transport device.
8. Device according to any one of claims 5 to 7, characterized in that in a wall of the furnace crossed by a partial area of the support there is a longitudinal slit in the transport direction which is crossed by a partial area of the support.
9. Device according to any one of claims 5 to 8, characterized in that the slit in the wall of the furnace is sealed off from the outside by means of suitable sealing devices so that no outside air penetrates the interior of the furnace and losses are avoided heatings to the outside by radiation and / or conviction, the sealing device being comprised of plastic sealing lips extending along the slit and extending into the slit from the edges of the slit and / or through the slit. of longitudinally extending brush elements provided with metal and / or ceramic fibers and / or tightly placed glass and / or plastic and extending into the slot and / or metal flaps subject to parallel spring loading to a furnace wall surface in which the slit is manufactured and can swing over the slit perpendicularly relative to the slit, so that a support running along the slit causes the sealing device to swing out of the slit area and after passing the support the sealing devices return to the slit in an elastic or moving manner.
10. 10. Furnace for a device according to any of claims 5 to 9, for carrying out a method according to any of claims 1 to 4, characterized in that the furnace has at least one wall a continuous extending slit. from the furnace inlet to the furnace outlet parallel to the longitudinal axis of the furnace to move the pieces to be heated with a support that moves outside the furnace through the gap through the furnace.