Method for operating a heat treatment section for flexible heat treatment of metal primary products

Abstract

The present invention relates to a method for operating a heat treatment zone for flexible heat treatment of metallic primary products, a heat treatment zone adapted and adapted to carry out the method, a casting and rolling mill and a method for operating a casting and rolling mill having a heat treatment zone according to the invention. Compared to conventional heat treatment zones and / or methods for operating heat treatment zones, the heat treatment zone according to the invention allows for flexible operation, which reduces emissions and production costs of the method.

Description

[Technical Field]

[0001] The present invention relates to a method for operating a heat treatment zone for the flexible heat treatment of metallic primary products, a heat treatment zone adapted and adapted to carry out the method, a casting and rolling plant and a method for operating a casting and rolling plant having a heat treatment zone according to the invention. [Background technology]

[0002] The charge material in the rolling mill is brought to process temperature in a conventional manner by a gas-operated reheating furnace. Typically, the preformed charge material, e.g., from the continuous casting section, is cooled on a cooling bed and fed to a cold storage section. The cold charge material is then removed from the storage section and fed to a gas-operated reheating furnace. This process route is called cold charging.

[0003] Alternatively, so-called hot charging is used, in which the formed charge material coming from the continuous casting section is fed, with only slight cooling, via roller conveyors, cranes and / or other feeding devices into a reheating furnace where it is heated to the process temperature. For small primary materials, so-called billets, continuous induction furnaces are used, which bring the temperature up to the required rolling temperature.

[0004] However, this method of heating with induction furnaces is limited to small square, rectangular or round charge materials and is partly used in conjunction with combustion furnaces as hybrid heating.

[0005] Gas-operated preheating furnaces are used for gases such as CO, CO2, and NO xThe use of natural gas also results in high operating costs, which are heavily dependent on the resource consumption of fossil energy carriers and gas prices. Preheating furnaces also cannot be easily switched on and off and must be started and stopped slowly, which results in additional gas consumption and emissions. Regular start-ups and shutdowns shorten the service life of the furnace walls, which in turn results in unwanted downtime and increased furnace maintenance costs.

[0006] The use of pure induction furnaces for heating to the rolling temperature is limited to the aforementioned small size, and heating from ambient temperature to the rolling temperature is not possible or is only possible with small throughputs (so-called pendulum operation). If a problem occurs in the rolling mill or in the induction furnace, the hot charge material can no longer be fed to the rolling mill and must therefore be cooled and then treated as scrap in the steelworks.

[0007] The heating process is limited to one or a few heating routes and has limited flexibility to deal with possible problems. Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the invention is to improve the known heat treatment zone, the known casting and rolling plant with the heat treatment zone, and the known methods of operating both plants so that they can be operated more flexibly and at the same time emissions and production costs are reduced. [Means for solving the problem]

[0009] invention The problem of the present invention is solved by a method for operating a heat treatment zone having the features of claim 1, a heat treatment zone having the features of claim 8, a casting and rolling plant comprising a heat treatment zone according to the invention having the features of claim 15, and a method for operating a casting and rolling plant having the features of claim 16.

[0010] The flexible heat treatment section comprises at least an input bed for introducing the hot or cold metal primary product into the heat treatment section, an output bed for discharging the hot or cold metal primary product from the heat treatment section, at least one first heating device for heat treating the metal primary product, at least one second heating device for heat treating the metal primary product, in particular for heating the metal primary product to a deformation processing temperature, at least three transport devices for transporting and / or intermediately storing the metal primary products and at least two transfer points for transferring the metal primary products between the transport devices, wherein a first transport device connects the input bed to at least the first heating device and the first transfer point, a second transport device connects the first heating device and the first transfer point to the second heating device and the second transfer point, and a third transport device connects the second heating device and the second transfer point to the output bed.

[0011] In the method for operating a heat treatment section for the flexible heat treatment of a metal primary product, at least the following work steps can be carried out: - introducing the hot or cold metal primary product into the heat treatment section, - intermediate storage and / or transport of the metal primary products from the loading bed to the first transfer point or the first heating device by means of a first transport device, - heat treating the metal primary products in a first heating device and transferring the metal primary products to a second conveying device after heat treating the metal primary products in the first heating device or transferring the metal primary products from the first conveying device to a second conveying device, - intermediate storage and / or transport of the metal primary product to a second transfer point or a second heating device using a second transport device, - heat treating the metal primary products in the second heating device and transferring the metal primary products to the third conveying device after heat treating the metal primary products in the second heating device or transferring the metal primary products from the second conveying device to the third conveying device, - intermediate storage and / or transport of the metal primary products to the discharge bed using a third transport device, - Discharge of hot or cold metal primary products from the heat treatment section.

[0012] In a first operating mode, the hot metal primary product is transported without heat treatment from the input bed to the output bed by means of at least three transport devices.

[0013] In a second operating mode, the first two conveying devices are used to convey the hot or cold metal primary product to the second heating device, where it is subjected to a heat treatment, and the third conveying device is used to convey the metal primary product from the second heating device to the discharge bed.

[0014] In a third operating mode, the hot or cold metal primary product is transported by a first transport device to a first heating device where it is heat treated, the second transport device is used to transport the metal primary product to a second heating device where it is heat treated, and the third transport device is used to transport the metal primary product from the second heating device to an unloading bed.

[0015] In a fourth operating mode, the hot or cold metal primary product is transported by the first transport device to the first heating device, where it is subjected to a heat treatment, and the second and third transport devices transport the metal primary product from the first heating device to an unloading bed.

[0016] In the context of the present invention, the hot metal primary product has a temperature above 200°C, preferably above 500°C, and even more preferably above the material-specific austenitizing temperature. The temperature taken into account is the average temperature of the metal primary product. This average temperature may differ from the surface temperature of the metal primary product and can be derived from the surface temperature via expert experience or calculated by a corresponding process model.

[0017] The cold-worked metal primary product has a temperature below 200° C. Usually, the temperature of the cold-worked metal primary product corresponds to the ambient temperature.

[0018] Heat treatment, in the sense of the present invention, is any method step in which the temperature of a metal primary product is purposefully changed, maintained or homogenized, in particular including method steps in which the core and surface temperatures are compensated or the structure of the primary product is purposefully adjusted.

[0019] The control device selects the operating mode depending on process variables, in particular the material, the material flow, the temperature of the metal primary product on the input bed, the target temperature of the metal primary product on the output bed, the energy supply capacity and / or the energy cost. By selecting the operating mode for each metal primary product, the control device optimizes the total energy consumption of at least the heat treatment section.

[0020] The loading and unloading devices, in the sense of the present invention, are adapted and configured as interfaces to allow material exchange with preceding or succeeding equipment. They are freely dimensionable as interfaces, provided that the interface function of the device according to the present invention is fulfilled. In particular, when introducing or discharging cold metal primary products, they can interact with external transport means, such as cranes or floor transporters.

[0021] Further advantageous embodiments of the method are described in the dependent claims 2 to 8. At least one conveying device is preferably configured at least partially as a cooling section and / or cooling bed, in order to purposefully cool the metal primary product, preferably as it is conveyed by the conveying device.

[0022] The second heating device is preferably configured as an induction furnace and serves to inductively heat the preferably metallic primary product.

[0023] The first heating device is preferably configured as a gas-operated furnace and heats the metal primary product, preferably by means of an exothermic gas reaction. The gas may be, for example, natural gas, hydrogen, biogas, coke oven gas, or a mixture thereof. This can be done directly via a burner flame or indirectly via a radiant heating furnace.

[0024] When heating the metal primary products, the heating device preferably combines different heating methods, more preferably induction and gas combustion.

[0025] A separator is preferably provided in the heat treatment section, by means of which the metal primary product is separated into smaller units.

[0026] A connecting device is preferably provided in the heat treatment section, by means of which the metal primary products are connected into larger units.

[0027] Furthermore, the problem of the present invention is solved by a heat treatment section for soft heat treatment of metal primary products having the features of claim 8, which is adapted and configured to carry out the method according to any one of claims 1 to 7.

[0028] Advantageous configurations of the heat treatment section are set out in dependent claims 9 to 14. At least one conveying device preferably comprises means, preferably driven rollers, feed chains and / or sliders, for moving the metal primary product on the conveying bed in various directions, preferably along the main feed section and transversely to the main feed section. The main feed section is, in the sense of the invention, the section with the lowest energy losses in combination with the highest throughput. The energy losses are the energy required to heat or maintain the primary product at the process temperature.

[0029] A connecting device, preferably a driven roller conveyor, for connecting the various input beds, output beds, transport devices, heating devices and / or separating devices is preferably arranged in the heat treatment section.

[0030] The connection device is preferably constructed to be at least partially insulated.

[0031] At least one of the transport devices is preferably configured to be at least partially insulated.

[0032] The heat treatment section preferably has a cooling section and / or a cooling bed for purposefully cooling the metal primary product, the cooling section and / or the cooling bed being connected to a conveying device, a heating device and / or an input or output bed.

[0033] The object of the present invention is further achieved by a casting and rolling installation having the features of claim 15. The casting and rolling installation comprises a series of units for casting and rolling a metal primary product into a semi-finished or finished product and a heat treatment zone for flexible heat treatment of the metal primary product according to any one of claims 8 to 14, the heat treatment zone being arranged at least between the casting installation and the first rolling stand. The casting and rolling installation further comprises a higher-level control device for controlling the units and the heat treatment zone as the production method steps proceed.

[0034] The object of the present invention is further achieved by a method for operating a casting and rolling mill having the features of claim 16. In the method for operating a casting and rolling mill according to claim 15, a control device of the casting and rolling mill monitors the material flow through the casting and rolling mill, and when a planned or unplanned difference in the mass flow rate through the casting mill relative to the mass flow rate through the rolling line occurs, the control device uses the heat treatment section as an intermediate storage for the metal primary product or introduces or discharges the metal primary product. The planned or unplanned difference can occur, for example, as a result of equipment malfunctions or a difference in the casting speed relative to the rolling speed due to material and / or dimensions.

[0035] The higher-level control device optimizes the material flow through the casting and rolling mill with respect to the supply capacity of the cold primary product, furnace emissions, costs, material production volume and / or quality. The higher-level control device optimizes at least the casting speed, the cooling water flow rate and the process variables of the heat treatment section with respect to the total emissions and total production costs of the casting and rolling mill.

[0036] The specification of the present invention is accompanied by the following two drawings: [Brief explanation of the drawings]

[0037] [Figure 1] Possible method routes for operating modes of the heat treatment section [Figure 2] Material flow through the heat treatment section DETAILED DESCRIPTION OF THE INVENTION

[0038] The invention will now be described in more detail by way of example with reference to the aforementioned drawings, in which like technical elements are provided with like reference numerals.

[0039] 1 shows a possible method route within the heat treatment section as a flow chart. As a charge, a cold (low temperature) or hot (high temperature) primary product can be fed into the heat treatment line. In the illustrated case, the hot primary product originates from a continuous casting plant 2. Alternatively, a primary product can also be fed hot from the casting process, e.g., coming from an insulating hood or another device for controlled cooling.

[0040] The supply of the primary products to the heat treatment section is effected by an input bed 3, which may for example be connected to the continuous casting section 2 via a roller conveyor. For cold charging from the cold store 1, the input bed 3 is equipped, for example, with a crane. In addition to this, the input bed 3 may have devices that make it possible to separate or group the primary products.

[0041] The loading bed 3 is connected to a first transport bed 6 so that the primary product can be transported from the loading bed 3 to a first transfer point 18 or to a first gas furnace 7. The first gas furnace 7 can suitably heat-treat the primary product, for example by heating it to and holding it at a temperature at which it has a substantially austenitic structure.

[0042] A first transfer point 18 connects the first transport bed 6 to the second transport bed 8. This allows the primary product to reach the second transport bed 8 without passing through the first gas furnace 7. The second transport bed 8 may likewise receive the primary product from the first gas furnace 7. The second transport bed 8 is suitable for transporting the primary product to a second transfer point 19 or for transferring it to a second furnace 9, for example an induction furnace. In the second furnace 9, the surface of the primary product can be heated to the target temperature in a short time.

[0043] Both the second transfer point 19 and the second furnace 9 can transfer the primary product to the third transport bed 10. The third transport bed 10 has an integral cooling section 11. The cooling section 11 allows the primary product to be cooled in a targeted manner. The cooling section 11 does not necessarily run through the third transport bed 10 in all transport processes.

[0044] The third transport bed 10 transfers the primary products to an output bed 12, which may again be configured as a feed directly to the first rolling stand 14 or to the descaler 13. Furthermore, the output bed 12 also allows for the discharge of the primary products. The output bed 12 may further comprise means which allow the primary products to be singulated or grouped together.

[0045] 2 shows the schematic construction of the apparatus according to the invention for carrying out the method. The main feed direction 15 allows the primary product to pass from the continuous casting section 2 to the descaler 13 and the first rolling stand 14 in the shortest possible distance, with heat treatment being carried out only in the second furnace 9. This allows for a continuous casting and rolling process with minimal additional energy consumption through the furnaces.

[0046] A connecting device 4 is arranged between the input bed 3 and the first transport bed 6. This connecting device 4 can be configured, for example, as an insulating roller conveyor, and can thereby bridge the section between the continuous casting part 2 and the separating device 5 without a relatively large temperature loss. The separating device 5 can separate the previously continuous strand coming from the continuous casting part 2 into individual parts.

[0047] Parallel to this main feed direction 15 is arranged another feed direction 16, which connects the cold store 1 with the descaler 13 and the first rolling stand 14 over the shortest distance. This route passes through the first furnace 7 and, if necessary, an integral cooling section 11 arranged on a third conveying bed 10. In addition to their conveying function, the conveying beds 6, 8, 10 can also translate between these two feed directions 15, 16, respectively, or discharge the primary product (17). [Explanation of symbols]

[0048] 1. Cold storage section 2. Continuous Casting Section 3. Imported bed 4 Connecting Devices 5 Separation device 6. First transport bed 7. First heating device / first furnace 8 Second transport bed 9 Second heating device / second furnace 10 Third Transport Bed 11 Cooling section 12. Carry-out bed 13 Descaler 14 First Rolling Stand 15 Main feed direction 16 Parallel feed direction 17 Discharge to cold storage 18 First Delivery Point 19 Second Delivery Point 20 Rolling equipment

Claims

1. 1. A method for operating a heat treatment section for flexibly heat treating a metal primary product, comprising: The heat treatment section includes at least - an input bed (3) for introducing the hot or cold metal primary product into the heat treatment zone; - an unloading bed (12) for unloading the hot or cold metal primary product from the heat treatment zone; at least one first heating device (7) for heat treating the metal primary product; at least one second heating device (9) for heat treating the metal primary product, in particular for warming the metal primary product to a deformation processing temperature; - at least three conveying devices (6, 8, 10) for conveying and / or intermediately storing the metal primary products and at least two transfer points (18, 19) for transferring the metal primary products between the conveying devices (6, 8, 10); Equipped with i. a first transport device (6) connecting the input bed (3) to at least a first heating device (7) and a first transfer point (18); ii. a second conveying device (8) connecting the first heating device (7) and the first transfer point (18) to the second heating device (9) and the second transfer point (19); iii. A third transport device (10) connects the second heating device (9) and the second transfer point (19) to the output bed (12); At least the following work steps can be carried out: - introducing the hot or cold metal primary product into the heat treatment section, - intermediate storage and / or transport of the metal primary products from the input bed (3) to the first transfer point (18) or to the first heating device (7) by means of a first transport device (6), - heat treating the metal primary products in the first heating device (7) and transferring the metal primary products to the second conveying device (8) after heat treating the metal primary products in the first heating device (7) or transferring the metal primary products from the first conveying device (6) to the second conveying device (8), - intermediate storage and / or transport of the metal primary product to a second transfer point (19) or to a second heating device (9) using a second transport device (8), - heat treating the metal primary products in the second heating device (9) and transferring the metal primary products to the second conveying device (10) after heat treating the metal primary products in the second heating device (9) or transferring the metal primary products from the second conveying device (8) to the third conveying device (10); - intermediate storage and / or transport of the metal primary products to the discharge bed (12) using a third transport device (10), - a process for removing a hot or cold metal primary product from a heat treatment section, in a first operating mode, the hot metal primary product is transported without heat treatment from the input bed (3) to the output bed (12) by means of at least three transport devices (6, 8, 10), or in a second operating mode, the hot or cold metal primary product is transported by the first two transport devices to the second heating device, where it is subjected to a heat treatment, and the third transport device transports the metal primary product from the second heating device to an unloading bed, or a third operating mode, in which the hot or cold metal primary product is transported by means of a first transport device (6) to a first heating device (7) where it is subjected to a heat treatment, the second transport device (8) to a second heating device (9) where it is subjected to a heat treatment, and the third transport device (10) to transport the metal primary product from the second heating device (9) to an unloading bed (12), or a fourth operating mode, in which the hot or cold metal primary product is transported by means of the first transport device (6) to the first heating device (7), where it is subjected to a heat treatment, and the metal primary product is transported from the first heating device (7) to the discharge bed (12) by means of the second and third transport devices (8, 10); the control device selects the operating mode depending on the process variables, in particular the material, the material flow, the temperature of the metal primary product on the input bed (3), the target temperature of the metal primary product on the output bed (12), the energy supply capacity, the energy costs, - A method characterized in that the control device selects an operating mode for each metal primary product, thereby optimizing at least the total energy consumption of the method.

2. at least one conveying device (6, 8, 10) is at least partially configured as a cooling section (11) and / or cooling bed, 2. A method according to claim 1, characterized in that the metal primary product is cooled in a targeted manner as it is conveyed by the conveying device (6, 8, 10).

3. the second heating device (9) is configured as an induction furnace, - A method according to claim 1 or 2, characterized in that the metal primary product is inductively heated.

4. the first heating device (7) is configured as a gas-operated furnace, - A method according to any one of claims 1 to 3, characterized in that the metal primary product is heated by an exothermic gas reaction.

5. 5. The method according to any one of claims 1 to 4, characterized in that one heating device (6, 7) uses various heating methods, preferably a combination of induction and gas combustion, to heat the metal primary product.

6. - the heat treatment section is provided with a separation device (5), - Separation of the primary metal products into relatively small units by means of a separator.

6. The method according to claim 1, wherein the

7. - the heat treatment section is provided with a connecting device (6), - A method according to any one of claims 1 to 6, characterized in that the metal primary products are connected by means of a connecting device to form larger units.

8. A heat treatment section for soft heat treatment of metal primary products, arranged and adapted to carry out the method according to any one of claims 1 to 7.

9. 9. A heat treatment zone according to claim 8, characterized in that at least one conveying device (6, 8, 10) has means, preferably driven rollers, feed chains and / or sliders, for moving the metal primary products on the conveying bed in various directions, preferably along the main feed section (15) and transversely to the main feed section (15).

10. 10. A heat treatment zone according to claim 8 or 9, characterized in that in the heat treatment zone a connecting device (4), preferably a driven roller conveyor, is arranged for connecting various input beds, output beds, transport devices, heating devices and / or separating devices.

11. The connection device (4) is configured to be at least partially insulated.

11. The heat treatment zone according to claim 10, characterized in that

12. 12. A heat treatment section according to any one of claims 8 to 11, characterized in that at least one transport device (6, 8, 10) is designed to be at least partially insulated.

13. the heat treatment section has a preferably integral cooling section (11) and / or a preferably integral cooling bed for the purposeful cooling of the metal primary product, A heat treatment zone according to any one of claims 8 to 12, characterized in that the cooling zone (11) and / or the cooling bed is connected to a conveying device (6, 8, 10), a heating device (7, 9) and / or an input bed (3) or an output bed (12).

14. 14. A heat treatment zone according to any one of claims 8 to 13, characterized in that the transport device (6, 8, 10) comprises an infeed device and / or an unfeed device.

15. - a series of units for casting and rolling metal primary products into semi-finished or finished products and a heat treatment section for soft heat treatment of the metal primary products according to any one of claims 8 to 14, the heat treatment section is arranged at least between the casting facility (2) and the first rolling stand (14), - a higher-level control device is provided which controls the production method steps carried out on the unit and the heat treatment section, Casting and rolling equipment.

16. - a control unit at the casting and rolling plant (2) supervises the flow of material through the casting and rolling plant; - in the event of planned or unplanned differences in the mass flow rate through the casting plant (2) relative to the mass flow rate through the rolling line, the higher-level control device uses the heat treatment zone as an intermediate storage area for the metal primary product or introduces or discharges the metal primary product, and the higher-level control device optimizes the material flow through the casting and rolling plant with regard to the supply capacity, furnace emissions, costs, material output and / or quality of the cold primary product, 16. The method for operating a casting and rolling plant according to claim 15, characterized in that the higher-level control device optimizes at least the process variables of the casting speed, the cooling water amount and the heat treatment section with respect to the total emissions and the total production costs of the casting and rolling plant.

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