MXPA97007338A - Method for welding ingots that come out of an oven and a line of lamination that adopts the met - Google Patents

Abstract

The present invention relates to a method for welding ingots that leave a heating furnace in a rolling line, comprises the line, in the segment (10) between the heating furnace (11) and the first station, at least one unit of extraction (14), a roller path for transporting the ingots, a movable welding assembly (20) with welding jaws (31), and an emergency ripper (13), wherein the rear end of the ingot (12a) which is being rolled, is welded with the forward end of the ingot (12b) discharged after the furnace (11) while the ingots (12) are in motion by means of a welding assembly (20) mounted on a movable trolley (19), being characterized the method because the movable trolley (19) has a first stationary condition while waiting for the contact position between the ends of the ingots (12) to be coupled, a second condition as it advances, where it is carried usually up to the rolling speed, it holds the ingots (12) with the jaws (31) of the welding unit (20) and welds the ends of the ingots (12) and a third condition of recoil, where the movable cart ( 19) returns to its starting position, the welding step preceded by a step of descaling performed by a descaling unit (16), where the front faces of the ingots (12) and then the areas of the ingots (12) that cooperating with the jaws (31) are de-scaling, and by a parallel plane cutting step of the rear end and the forward end of the ingots (12), performed by a trimmer unit (29) equipped with at least one rotating blade (27). ), and mounted on the movable trolley (19) immediately upstream of the welding assembly (20), the welding step being followed by a step to remove the burrs, performed by a burr removal unit (38) while the Ingot (12) is in motion

Description

METHOD FOR WELDING INGOTS THAT COME OUT OF AN OVEN, AND A LINE OF LAMINATION THAT ADOPTS THE METHOD This invention relates to a method for welding ingots coming out of a heating furnace, and also to the rolling line which adopts this method, as stipulated in the respective main claims. The invention is applied in a particular way, but not exclusively, in the rolling of ingots, where it is desired to have a substantially continuous feed, either of a completely hot load, or also a hot and cold mixed load, from the heating furnace to the rolling txen. In rolling processes for ingots where the rolling mill is located in line with the continuous casting machine, the state of the art covers the need to ensure high productivity of the plant, but without causing a reduction in surface quality and in the internal quality of the final product. It is also necessary to make the working times of the rolling mill compatible with the casting times, in order to prevent a discontinuous operation of the rolling stations, with all the problems related to the correct use of the rolling rolls and its activation ..

In the technique of rolling mills, systems have been proposed which teach welding the rear end of the ingot which is already being rolled, with the leading end of the next ingot coming from the casting machine, or fed from the intermediate stores associated with the line, in order to ensure a substantially continuous feed to the rolling mill. U.S. Patent No. US-- 2, 214, 618 discloses welding the leading end of a strip with the trailing end of the strip being worked while stationary. In order to do this, it is necessary to slow down the cycle, or use intermediate warehouses that can be included only when the plate or the wide plate is being worked on. These intermediate storage systems are not only complicated and complex, they must also work at temperature, and require a considerable vertical space. In addition, these systems can not be adopted in the case of ingots, in such a way that the stationary welding machine would block the downstream rolling cycle, causing a loss of productivity, marking the product, problems in restarting, and so on. r. German Patent Number DE-A-2, 836, 338 generally indicates a welding process with a movable welding system that follows the ingot. The indications are very generic and not cpu. information about the way in which the ingot of the front end and the ingot of the rear end are treated, or the way in which the welding machine works. However, welding systems known in the state of the art have shown that they have great problems, both in operation and in technology, which have so far prevented this technique from being used reliably on a larger scale of products and processes , without altering the productivity of the line and / or the quality of the final product. One of the main problems is that, if the surfaces of the two ends that are going to be welded are not exactly flat and parallel, the welding is imprecise, it needs more time to be done, and the fine result is not satisfactory. Moreover, the presence of a large amount of ingots in the ingots when they leave the furnace, prevents welding, makes it difficult and unreliable, since the incrustations prevent the correct passage of the current on the clamping jaws that perform the welding . A further problem is that, once the weld has been made, the surface area that has been welded has a temperature that is not uniform with reppeolo to the core of the ingot, and this creates problems in the initial tightening step performed by the rolling rolls, and a consequent poorer quality of the product. • It is also a problem to remove burrs caused by "flame-pressure welding." An additional problem is the need to include a system to intervene quickly in order to separate the ingot that has been rolled from the ingot to be rolled. When a blockage in the rolling mill Another problem is the uneven geometry of the leading end of an ingot, compared to the rear end of the previous ingot, the present applicants have designed, tested, and incorporated this invention to overcome these drawbacks of the prior art. state of the art, and to achieve other advantages This invention is stipulated and characterized in the respective main claims, while the dependent claims describe variants of the idea of the main embodiment.The main purpose of the invention is to provide a method for welding ingots that come out of a heating furnace, which will overcome the problems mentioned above, and makes it possible to use this solder (<; M a reliable and efficient way, to obtain a continuous feed to the rolling mill. Another purpose of the invention is to provide a rolling line which, by adopting the above welding method, makes it possible to optimize the productivity without in any way reducing the surface quality and the external quality of the final product. The welding method according to the invention is applied to ingots that come out of a heating furnace, inside which the ingots produced by one or more continuous casting machines accumulate progressively, or the cold ingots taken from intermediate warehouses. , or a mixture of hot and cold ingots. According to the invention, the welding machine, at the outlet of the heating furnace, is placed on a movable trolley, and moves, in a coordinated manner with the ingot being rolled, to perform the welding as it is move the ingot. At the outlet of the heating furnace, and upstream of the movable trolley, there is a first descaling unit attached to the floor. In one embodiment of the invention, this first descaling device has rotating nozzles; according to a variant, the first descaling device is of the mixed type, with both stationary and rotating nozzles.

The stationary nozzles are used to descale the leading ends of the ingots, while the rotating nozzles are used to descale the contact area with the welding jaws, or according to an additional variant, for the entire length of the ingot. According to the invention, the jaws of the welding machine center the ingots on a geometric axis of the section, in such a way that the ingots center correctly, even when the ingots do not have homogeneous sections. According to a variant of the invention, on the movable trolley carrying the welding machine, and upstream of it, there is a second descaling unit, which cleans the surface of the ingots to be welded, and particularly the area in where the ingots come together. In a formulation of the invention, this second descaling unit is of the rotating kind. The combination of a rotating descaling device placed immediately upstream of the welding machine, together with the fact that the second descaling device moves with the machine and follows its movement, causes an extremely efficient removal action of the scale, - what's more, the incrustations do not have time to re-form before welding takes place. The complete absence of incrustations on the surface of the ingots that are welding, facilitates the passage of current between the welding jaws, and therefore, improves and accelerates the start of the welding cycle. According to a variant of the invention, at least the second descaler can be adjusted automatically with respect to the descaling times, the water flow, and / or the pressure, according to the type of scale to be removed, and / or the type of product being read. According to the invention, between the second descaler and the welding machine, on the moveable trolley, there is at least one trimmer unit for trimming the front and rear ends of the ingots to be coupled. This trimmer unit configures the two surfaces in such a way that, apart from being without incrustations, they also remain perfectly flat and parallel with one another, which considerably improves the efficiency of the welding. In one embodiment of the invention, the racortnciora unit is composed of a cutting machine with at least one rotating blade.

According to a variant, the trimmer machine has two rotating blades installed on a single blade support mandrel, and the blades trim the forward end of the ingot and the rear end of the other ingot at the same time. According to another embodiment of the invention, on the welding truck there is a unit for removing burrs from the welding. According to the invention, the transport path for the ingots coming out of the furnace is of the type with a channel, and is composed of successive rollers mounted on pivoting supports. During the welding cycle, these pivoting supports are bent by the advance of the movable trolley carried by the welding machine, and they rise again after the moveable trolley passes, to act as a support for the ingot again. Downstream of the pivoting roller path, there is an emergency extraction unit that is used to send back the ingot that has yet to be rolled, in the case of a blockage in the rolling mill. This emergency extraction unit cooperates with an emergency ripper located downstream of the extraction unit, which can separate the rolled ingot from the ingot that is still to be rolled.

According to the invention, in a position adjacent to the path of the rollers and outside the line, there is a storage surface on which the ingots present in the path of the rollers can be unloaded., in the case of a blockage in the rolling mill. According to a variant of the invention, at the exit of the path of the pivoting rollers, and downstream from the end of travel of the movable trolley of the welding machine, there is a heating system that can uniform the temperature, particularly of the edges and / or pl area where the ingots meet. This heating system, according to one modality, is of the induction type. According to a variant, the heating system is configured as a tunnel kiln with heating elements. According to a further variant, the heating system is of the flame type. In cooperation with the heating system, there are also containment elements with funds that can be opened to unload and remove scale and debris that occur during the passage and heating of the ingots. The attached Figures are given as a non-restrictive example, and show a preferred Evolution of the invention as follows: Figure 1 shows a longitudinal section of a segment of the rolling line, which adopts the welding -o in accordance with the invention . Figure 2 shows the section from A to A of the Figure 1. Figure 3 shows the section from B to B and Figure 1. Figure 4 shows the section from C to C of Figure 1. Figure 5 shows the section from D to D of Figure 1. Figure 6 shows a detail of the movable trolley carried by the welding machine shown in Figure 1. Figure 7 shows the welding cycle employed in the method according to the invention. In Figure 1, the number 10 denotes in general the segment of a rolling line, placed between a heating furnace 11, which is only partially shown here, for the ingots 12, and a ripper of emergency pendulum 13 placed before the entrance to the rolling mill, which is not shown here, served by an extraction unit 33. The heating furnace 11 is of the type configured to accumulate ingots 12 from several melting lines, and / or to feed mixed the hot / cold ingots 12; it cooperates upstream with the transport and feeding elements, of a type known in the state of the art. According to a variant not shown here, for the products that do not need particularly high quality standards, the furnace 11 cooperates upstream with a trimmer element, for trimming the front and rear ends of the ingots 12 to be sent for welding. * In this case, the cutting is carried out cold, for example, with disc-type rotary saws, to cut the ingots 12 of different lengths.At the outlet of the heating furnace 11, there is an extraction unit 14 with rollers Tightening unit 15. This extraction unit 14 serves to move the ingot 12 as it leaves the oven, at a variable speed according to the need. Downstream of the extraction unit 14, there is a first descaling device 16 of the type mixed with the supporting surface 17, with nozzles 18 both of the stationary type and of the rotating type, Bn in particular, in the case of the case, the nozzles 18 of the stationary type serve to remove the incrustations from the surface of the ingots 12, in correspondence with the front ends, while the nozzles 18 of the rotating type, serve to remove the incrustations at least from the area of the ingots which, in the next stage, will be the area of contact with the welding jaws 31. If necessary, the nozzles 18 of the rotating type perform the descaling over the entire length of the ingot 12 Downstream of the first descaling device 16, there is the movable carrier 19, on which the welding assembly is mounted 20. In this case, between the first descaler 16 and the movable trolley 19, there is a retractable clamping device 21, which holds the ingot 12 in the event of a downstream blockage. The movable trolley 19 has wheels 22, and moves with an axternado movement on the tracks 23, such as rails, guides, or the like, according to the advancement of the ingots 12 to be coupled. The advancement of the movable trolley 19 causes the pivoting supports 24 to be lowered, on which the rollers 25 are mounted, which constitute the motorized roller path 37 that supports and feeds the ingots 12. This descent is achieved by means of an element of type of fork 26, solid during the advancement of the movable trolley 19, in such a way that the supports 24 with the relative rollers 25 are lowered below the movable trolley 19 during the advancement of the latter (see rolls 25a), and stand up again, thanks to a lifting or counterbalancing system, once the movable trolley 19 has passed them, to support the ingots that advance 12 again. The complete retraction of the roller 25 under the movable trolley 19 is achieved by the very low position of the center of rotation of the relative pivoting support 24. In this case, on the movable trolley 19 and upstream of the welding assembly 20, there is a cutting device 29 with a double rotary blade, respectively the front 27a and the rear 27b, which are used to cut the rear or rear end of the ingot 12 placed opposite, and the front or front end of the ingot 12 placed behind. The blades 27a and 27b are mounted, in this case, on a single mandrel 28 to reduce as much as possible the cutting times, and are configured, in this case, to trim the ends according to a desired length. In this case, the mandrel carrying the blades 28 is supported by a movable support, moved by a hydraulic cylinder having a controlled speed. The rotation of the blades 27a and 27b is achieved by means of an electric motor that possibly incorporates a mechanical transmission. The spacing between the two sheets 27a and 27b, in this case, is between about 30 and about 70 millimeters, conveniently between 4 and 50 millimeters. The cutting machine 29 serves to configure the perfectly flat and parallel surfaces for the welding, in such a way that the welding process gives a perfect coupling, and therefore, a perfect union. In the event that the trimming is performed upstream of the furnace 11, cracks and bubbles may rust during the step prior to heating, which creates problems with the products, and reduces the final quality of the laminate. In this case, a second desiccant 30 of the rotating type is mounted on the movable trolley 19, which has the function of terminating the descaling action performed by pr. mer 16, and in particular, to clean in the best possible way the part of the surface of the ingots 12 that will subsequently be in contact with the jaws 31 of the welding assembly 20. The cleaning of this contact area ensures a passage optimum current from the welding jaws 31, and therefore, an efficient and rapid start and finish of the welding cycle. In this case, the second descaler 30 has adjustable working parameters, both with respect to the descaling times, and with respect to the water flow and / or the pressure. Downstream of the welding assembly 20, on the truck 19 itself, there is a unit for removing the burrs 38, which serves to remove the burrs from the weld. Moreover, the jaws 31 center the ingot 12 on the ideal centering axis 39 of the section of the ingot 12 itself, in such a way that this compensates for any geometric differences in the section between the two ingots 12 to be coupled. With respect to the welding cycle, the forward movement of the movable trolley 19 is correlated with the advance of the ingots 12 from an initial position 19a to an end of travel position identified diagrammatically by 19b. The continuous ingot 12 leaving the movable trolley 19, is inserted inside a maintenance system 34, comprising at least one movable dome 32, associated at the exit with an extraction unit 33 configured upstream of the emergency rippers: 3. According to a variant, the maintenance system 34 is associated with a heating system, for example, by means of burners, in order to make the temperature of the ingots 12 uniform, particularly on the edges of the ingot 12. According to another solution, the heating system. or comprises an induction furnace. This maintenance and possibly heating system 34, comprises, in the lower part, doors 36 that can be opened to discharge the waste and the incrustations that are formed on the surface of the ingot 12. The emergency rippers 13 and the extraction unit 33, intervene in the case of a block in the rolling mill, the first to separate the ingot 12 that has already been rolled, from one that is still going to be rolled, and the second to return the last ingot 12 over the path of rollers 37. Then the stationary ingot is transferred, if necessary by means of extensible mechanical hands, onto a storage surface 35 located off-line, on the side of the roller path 37. Figure 7 shows the different steps of the method of welding according to the invention. In Figures 7a, 7b, 7c, and 7d, the ingot 12a is progressively discharged from the furnace 11, until the leading end cooperates with the movable cart 19 carrying the welding assembly. The ingot 12a then becomes slower, until it substantially reaches the rolling speed, and then (Figures 7e, 7f), the ingot 12b is discharged from the furnace 11. The ingot 12b, with a much higher exit velocity than that of the ingot 12a, rapidly approaches the ingot 12a (Figure 7g), until the respective ends are in contact (Figure 7h) inside the movable trolley 19. At this point, the movable trolley 19 is activated until it substantially reaches the rolling speed (Figures 7i, 71). In the part of the travel of the movable trolley 19 which is indicated by the letter 'b', between the position-shown in Figure 71 and that of Figure 7n, Re trim the leading end and the trailing end of the ingots 12a and 12b, and they are welded by means of the welding jaws 31. Once the welding has been carried out, and the position of the end of the stroke has been reached, the movable trolley 19 is stopped, and begins its return travel in the opposite direction, until it is placed again in the starting position (Figures 7o, 7p, 7q, and 7r). L-the return travel of the movable trolley 19, the ingot 12c begins to discharge from the heating furnace 11 at a speed that is much higher than the speed at which the ingots 12a and 12b, joined together, are advancing, until, substantially at the same time as the movable carriage 19 reaches its original starting position, the forward end of the ingot 12c comes into contact with the rear end of the ingot 12b (Figure 7s). At this point, the welding cycle begins again as described above (Figure 7t).

Claims (16)

1. A method for welding ingots exiting an oven, heating in a rolling line, the line comprising, in the segment (10) between the heating furnace (11) and the first rolling station, at least one extraction unit (14), a roller path for transporting the ingots, a movable welding assembly (20) with welding jaws (31), and an emergency ripper (13), wherein the rear end of the ingot (12a) which is being rolled, is welded with the forward end of the ingot (12b) discharged after the furnace (11) while the ingots (12) are in motion by means of a welding assembly (20) mounted on a movable wheelbarrow ( 19), the method being characterized in that the movable trolley (19) has a first stationary condition while waiting for the contact position between the ends of the ingots (12) to engage, a second condition as it advances, where it is substantially carried up to the rolling speed, fastens the ingots (12) with the jaws (31) of the welding unit (20) and welds the ends of the ingots (12), and a third condition of recoil, where the movable cart ( 19) returns to its starting position, the welding step preceded by a step of descaling performed by a disincructor unit (16), where the front faces of the ingots (12) and at least the areas of the ingots (12) cooperating with the jaws (31) are descaled, and by a step of parallel plane cutting of the rear end and the forward end of the ingots (12), performed by a trimmer unit (29) equipped with at least one rotary blade (27), and mounted on the movable trolley (19) immediately upstream of the welding assembly (20), the welding step being followed by a step to remove the burrs, performed by a removal unit of burrs (38) while the ingot (12) is in motion.

A method as in claim 1, wherein the ingots (12) center on the jaws (31) of the welding assembly (20) along an ideal centering axis (39) of the ingot section (20). 12) same.

A method as in any of the preceding claims, wherein the ingot (12) is subjected to a second step of descaling by means of a movable descaling unit (30) immediately upstream of the welding step.

A method as in any of the preceding claims, wherein the trimmer unit (29) comprises a system with a double rotary blade (27a, 27b) associated with a single mandrel (28), the first blade (27a) being configured to cutting the rear end of the ingot (12a) located further forward, and configuring the other blade (27b) for simultaneous and parallel trimming of the forward end of the ingot (12b) located behind.

A method as in any one of the preceding claims, wherein the step of trimming the relative ends of the ingots (12), is preceded by a de-scaling step performed while the ingot is in motion, by means of a second unit Descaling machine (30) mounted on the movable trolley (19).

6. A method as in claim 5, wherein the second scaler (30) is of the rotating type, and acts specifically in correspondence with the area where the ingots (12) are joined.

A method as in claim 5 or 6, wherein the second scaler (30) has times and / or descaling parameters for the flow and / or water pressure, which can be adjusted.

A method as in any of the preceding claims, wherein the welded ingot (12), before entering the rolling mill, is subjected to at least one localized heating action.

9. A method as in claim 8, wherein the heating action is obtained by an induction system.

10. A method as in claim 8, wherein the heating is obtained with a flame system.

11. A short method in claim 8, wherein the heating is obtained with a heating tunnel system.

12. A rolling mill for ingots, which adopts the method of welding in motion at the exit of the heating furnace as in any of the previous claims, comprising the line, in the segment (10) between the heating furnace (11) and the first rolling station, at least one extraction unit "(14), a roller path for transporting the ingots, a movable welding assembly (20) including welding jaws (31) and an emergency ripper (13). ), the line being characterized in that it comprises, downstream of the extraction unit (14), a first stationary descaling unit (16) a movable trolley (19) with an alternating movement on its relative tracks (23), supporting the truck movable (19) at least to a welding assembly (20) with jaws (31) to hold the ingots (12), a trimmer unit (29), and a movable descaling unit (30), including the moving truck; (19) a first position (19a) while waiting for the ingots (12) that are immediately downstream of the first stationary descaling unit (16), and a second end-of-travel position (19b), a transport path ( 37) with rollers (25) mounted on pivoting supports (24), having a first working position, and a second retracted position, a temperature maintenance system (34), and an emergency ripper (13). A lamination line as in claim 12, wherein the first stationary de-incruting unit (16) includes nozzles (18) of the stationary type, and nozzles (18) of the rotating type. A rolling line, as in claim 12 or 13, wherein the welding jaws (31) can be moved along the ideal centering axis (39) of the section of the ingots (12). 15. A lamination line as in any of claims 12 to 14 inclusive, wherein there is a unit for removing the burrs (38) on the movable trolley (19). 16. A rolling line as in any of claims 12 to 15 inclusive, wherein the second retracted position of the pivoting supports (24) cooperates with the passage of the movable trolley (19). A rolling line as in claim 16, wherein the movable trolley (19) is associated at the front with a clevis element (26) cooperating with the pivoting supports (24), to bring them from the first position of work to the second retracted position, and vice versa. 18. A lamination line as in any of claims 12 to 17 inclusive, wherein, upstream of the emergency rippers (13), there is an extraction unit (33). 19. A rolling line as in any of claims 12 to 18 inclusive, wherein, in a position adjacent to the roller path (37), and out of line, there is a "" storage surface (35) for temporarily accumulating. the ingots (12), in case there is a blockage in the rolling mill 20. A rolling line as in any of claims 12 to 19 inclusive, wherein the temperature maintenance system (34) comprises a additional heating element, and an element for making the temperature of the surface and the core of the ingot (12) uniform, particularly in the area of the joint 21. A lamination line as in claim 20, wherein the The heating system comprises a tunnel associated with heating burners 22. A rolling line as in claim 20, wherein the heating system comprises a rapid heating element of the inductor type. ction. •2. 3. A lamination line as in claim 20, wherein the temperature maintenance system (34) is associated at the bottom with containment elements with a bottom (36) that can be opened to discharge the waste and scale. SUMMARY A method for welding ingots leaving a heating furnace into a rolling line, the line comprising, in the segment (10) between the heating furnace (11) and the first rolling station, at least one extraction unit (14), a roller path for transporting the ingots, a moveable welding assembly (20) with welding rivets (31), and an emergency ripper (13), wherein the rear end of the ingot (12a) being rolled, is welded with the forward end of the ingot (12b) discharged after the furnace (11) while the ingots (12) are in motion by means of a welding assembly (20) mounted on a movable trolley (19), the movable trolley (19) having a first stationary condition while waiting for the contact position between the ends of the ingots (12) to engage, a second condition as it advances, where it is carried substantially up to the rolling speed, holds the ingots (12) with the jaws (31) of the welding unit (20) and welds the ends of the ingots (12), and a third recoil cou- pling, where the movable trolley (19) returns to its starting position, the welding step being preceded by a step of descaling performed by a descaling unit (16). ), wherein the front faces of the ingots (12) and at least the areas of the ingots (12) cooperating with the jaws (31) are descaled, and by a parallel plane cutting step of the rear end and the end front of the ingots (12), made by a trimmer unit (29) equipped with at least one rotary blade (27), and mounted on the movable trolley (19) immediately upstream of the welding assembly (20), the step being of welding followed by a step to remove the burrs, performed by a burr removal unit (38) while the ingot (12) is in motion. A rolling line for ingots, which adopts the method of welding in motion at the exit of the heating furnace as in any of the previous claims, the line comprising, in the segment (10) between the heating furnace '(11) and the first rolling station, at least one extraction unit (14), a roller path for transporting the ingots, a movable welding assembly (20) including welding jaws (31) and an emergency ripper (13), the line comprising, downstream of the extraction unit (14), a first stationary descaling unit (16) a movable trolley (19) with an alternating movement on its relative tracks ( 23), the movable trolley (19) supporting at least one welding assembly (20) with jaws (31) for holding the ingots (12), a trimmer unit (29), and a movable descaling unit (30), including the movable trolley (19) a first position (19a) while waiting for the ingots (12) that are immediately downstream of the first stationary descaling unit (16), and a second end-of-travel position (19b), a path of transport (37) with rollers (25) mounted on pivoting supports (24), having a first working position, and a second retracted position, a temperature maintenance system (34), and an emergency ripper (13).