Strip steel continuous rolling production line and method of operating the same

Abstract

The present application relates to a kind of strip steel continuous rolling production line, including rolling mill unit, the inlet side of the rolling mill unit is arranged with induction heating device, the induction heating device includes induction heater, the induction heater adopts closed loop induction coil and forms strip steel running passage in the loop of closed loop induction coil, the induction heater is configured with translation drive mechanism to have working position and offline position.In addition, it also relates to the operation method of the strip steel continuous rolling production line when being configured with emergency shear.The present application uses closed loop induction coil to carry out fast supplementary heating to strip steel, heating efficiency and effect are significantly improved, and since it is closed magnetic field, except the import and export of induction heater, it is fully closed magnetic shielding treatment, operation safety is high, production operation and maintenance are convenient, spare part cost is reduced.

Description

Technical Field

[0001] This invention relates to a continuous strip rolling production line and its operation method, which is particularly suitable for the continuous rolling production of high-grade brittle steel (high-grade non-oriented silicon steel, oriented silicon steel and 65Mn steel, etc.). Background Technology

[0002] Before strip rolling, high-grade non-oriented silicon steel, oriented silicon steel and 65Mn brittle steel are reheated so that the strip can be continuously rolled above the critical temperature of brittleness and hardness, so as to avoid edge cracks or strip breakage. This can improve the product yield while ensuring the unit's operating rate.

[0003] Induction heating has the advantages of fast heating speed and good heating effect. It can quickly replenish heat in a limited space on site and is increasingly favored by steel companies. At present, the induction heating of strip before rolling mainly adopts the open-type inductor technology, that is, the open-type induction coil is used to complete the replenishment of the strip. This heating method can directly move the induction heating device out of the production line station while the strip is online, freeing up space for other operations, etc., so it has good flexibility, but there are the following problems: (1) There is obvious magnetic leakage at the opening of the coil, which requires special magnetic shielding; (2) The upper movable coil is prone to poor contact due to frequent movement, which can burn out the coil; (3) The opening can easily lead to water vapor, impurities, etc. entering and damaging the coil. Summary of the Invention

[0004] This invention relates to a continuous strip rolling production line and its operation method, which can at least solve some of the defects of the prior art.

[0005] This invention relates to a continuous strip rolling production line, including a rolling mill unit. An induction heating device is arranged on the inlet side of the rolling mill unit. The induction heating device includes an induction heater. The induction heater adopts a closed-loop induction coil and forms a strip running channel within the coil. The induction heater is equipped with a bottom translation drive mechanism, thus having a working position and an offline position.

[0006] As one implementation method, an emergency shear is arranged on the working position inlet side or the working position outlet side of the induction heater.

[0007] As one embodiment, roller frames are arranged on the inlet side and outlet side of the work station, respectively. The roller frames are equipped with idler rollers for supporting the strip and pressure rollers for stabilizing the strip to prevent collision with the induction heater. The pressure rollers are located above the idler rollers on the corresponding sides and are equipped with lifting drive units.

[0008] As one implementation method, the roller frame adjacent to the emergency shear is directly integrated and installed on the frame of the emergency shear.

[0009] As one of the embodiments, a pinch roll is arranged at the entrance side of the working position, and the pinch roll is driven by a pneumatic cylinder or a hydraulic cylinder.

[0010] As one of the embodiments, the emergency shear is arranged at the exit side of the working position, and a blowing device is arranged near the exit of the emergency shear.

[0011] As one of the embodiments, the induction heater is configured with a tank circuit to form a resonant system, and the tank circuit is arranged on the top or side of the induction heater.

[0012] As one of the embodiments, a weld seam detection unit is arranged at the entrance side of the working position.

[0013] As one of the embodiments, a deviation correction roller and a matching photoelectric CPC deviation correction detection unit are arranged at the entrance side of the working position.

[0014] The present application also relates to a method for operating a strip continuous rolling production line as described above, comprising:

[0015] When the induction heater is in the working position, after receiving an offline instruction of the induction heater, the emergency shear is started to cut the strip, and no strip is ensured in the induction heater, so that the induction heater is moved to the offline position.

[0016] When the induction heater is in the offline position, after receiving an online instruction of the induction heater, the emergency shear is started to cut the strip, and no strip is ensured in the working position, so that the induction heater is moved to the online position.

[0017] The present application has at least the following beneficial effects:

[0018] The present application adopts a closed-loop induction coil to quickly heat the strip, and the heating efficiency and the heating uniformity are significantly improved.

[0019] The present application further has the following beneficial effects:

[0020] The present application arranges an emergency shear at the entrance side or the exit side of the working position of the induction heater, and through the cooperation of the emergency shear and the movable structure of the induction heater, the induction heating device with the closed-loop induction coil can achieve the real-time online and offline effect of the open-loop induction heating device. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only represent some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative effort based on these drawings.

[0022] Figure 1 The structural schematic diagram of the induction heating device provided in the embodiments of the present application is shown in the figure.

[0023] Figure 2 The translation structural schematic diagram of the induction heater provided in the embodiments of the present application is shown in the figure. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments only represent some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative effort belong to the protection scope of the present application.

[0025] As Figure 1 The present application provides a strip steel continuous rolling production line, which comprises a rolling mill unit, an induction heating device arranged at the inlet side of the rolling mill unit, and an induction heater 11 in the induction heating device. The induction heater 11 adopts a closed loop induction coil and forms a strip steel running channel in the loop of the closed loop induction coil. The induction heater 11 is configured with a translation driving mechanism to have a working position and an offline position.

[0026] Different from the conventional pre-rolling opening coil induction heating mode, in the present embodiment, the closed loop induction coil is adopted to rapidly heat the strip steel, and the heating efficiency and the heating uniformity effect are significantly improved. Moreover, due to the closed coil structure, the closed magnetic shielding mode is adopted except at the inlet and outlet of the induction heater 11, the operation safety is high, and the operation and maintenance are convenient.

[0027] Based on the above movable design of the induction heater 11, the working flexibility and applicability of the induction heating device can be effectively improved. For example, for high-value-added products with high carbon content such as high-grade non-oriented silicon steel and oriented silicon steel, the induction heater 11 can be moved to the online state by the above translation driving mechanism to produce fast reheat, especially, the high-grade silicon steel can be heated to a temperature above the hard brittle point (≥65℃), realizing high-speed stable operation of high-grade silicon steel, and completely solving the bottleneck of high-speed continuous and stable production of high-grade silicon steel (silicon content ≥2.2% or more). For conventional steel products that do not require fast reheat, the induction heater 11 can be moved to the offline state to reduce production costs and avoid collision risks of the induction heater 11 caused by high-speed operation and strip shape of conventional steel.

[0028] Preferably, the ring inner region of the induction coil is preferably surrounded by a muffle structure to form an induction heating cavity. The induction coil structure and the muffle structure are conventional techniques in the art, and will not be described here. In one preferred embodiment, the muffle structure includes a support layer and a heat-resistant insulation layer. The support layer can be a SIC (silicon carbide) support layer or a non-magnetic stainless steel water-cooled pipe support layer. The support layer can be protected by a heat-resistant layer, which can be a heat-resistant cotton and / or heat-resistant blanket layer. The above-mentioned support layer not only can support the heat-resistant insulation layer, but also can protect the strip during operation, avoiding collision between the strip and the muffle structure.

[0029] Generally, the induction heater 11 is provided with a tank circuit cabinet 17, which forms a resonant system with the induction heater 11. As a preferred embodiment, the tank circuit cabinet 17 is arranged on the top or side of the induction heater 11, which can simplify the equipment layout of the induction heating device, on the one hand, reducing the floor area of the device, on the other hand, in the case of movable induction heater 11, the above-mentioned tank circuit cabinet design makes the tank circuit cabinet 17 and the induction heater 11 follow the movement, ensuring the reliability of the connection between them, thereby ensuring the stability and reliability of the induction heating work.

[0030] Generally, the induction heater 11 is provided with a power supply unit. Optionally, the power supply unit includes a incoming line rectifier cabinet and an inverter cabinet. After being rectified by the rectifier and filtered by the filter, the three-phase current becomes smooth direct current and is sent to the inverter. The inverter converts the direct current into high-frequency alternating current to supply the above-mentioned resonant system. Preferably, the incoming line rectifier cabinet and the inverter cabinet are designed and arranged in the transmission side of the unit. Figure 2 For the connection between the tank circuit cabinet 17 and the power supply unit, the connection cable between them can be wired in the drag chain 21.

[0031] In the optional embodiment, as Figure 2The translation driving mechanism includes a translation track 20, and the induction heater 11 is slidingly arranged on the translation track 20. The translation of the induction heater 11 can be achieved by motor driving or cylinder push-pull driving. Further, online and offline position detection devices (such as photoelectric switches) can be arranged beside the translation track 20 to ensure the accuracy of the state of the induction heater 11.

[0032] Based on the structure of the closed-loop induction coil, the induction heater 11 cannot be directly moved out of the production line in the online state of the strip steel. In the accident state (for example, the induction heater 11 fails) or the strip steel does not need to be heated (at this time, the induction heater 11 occupies the space of the production line, and the area cannot be reasonably used for auxiliary production such as cutting and taking materials), which is not conducive to the normal operation of the production line. In the embodiment, preferably, the working position entrance side or the working position exit side of the induction heater 11 is arranged with an accident shear 15. Through the cooperation of the accident shear 15 and the movable structure of the induction heater 11, the induction heating device with the closed-loop induction coil can achieve the real-time online and offline effect of the open-loop induction heating device. The cooperation mode of the accident shear 15 and the translation driving mechanism will be described in subsequent embodiments, which is omitted here.

[0033] In one of the embodiments, as shown in Figure 1 The roller frame 13 is arranged on the working position entrance side and the working position exit side, and the roller frame 13 is arranged with a supporting roller (not shown) for supporting the strip steel. The strip steel is supported by the two groups of supporting rollers to define the running height of the strip steel, for example, to make the strip steel at the center height of the induction heating cavity, so as to avoid the contact or collision between the strip steel and the bottom or top of the induction heating cavity. Further, the roller frame 13 is also arranged with a pressing roller (not shown) above the corresponding supporting roller and is provided with a lifting driving unit. The lifting driving unit can be a linear driving device such as a cylinder or a hydraulic cylinder. By arranging the pressing roller, the supporting roller and the pressing roller can improve the running stability of the strip steel and constrain the strip shape, so as to avoid the collision between the strip steel and the induction heater cavity, and to achieve reasonable conveying during the strip head and tail threading process, so as to avoid the strip head and tail from being stuck due to the head or tail lifting. At the same time, considering the special working conditions such as strip breaking and strip reversing, when the strip breaking and strip reversing and emergency stop signals are encountered, the pressing roller is pressed down to relieve the impact of the strip steel on the induction heater 11.

[0034] The accident shear 15 is preferably arranged on the working position exit side, so that the strip steel is reversed after being cut to exit the induction heater 11, which is more reliable in operation.

[0035] In one embodiment, the roller stand 13 adjacent to the accident shears 15 is directly integrated and installed on the rack of the accident shears 15. In another embodiment, both the roller stands 13 on the two sides are integrated and installed on the column of the induction heater 11, and are moved in and out integrally with the induction heater 11, so as to compact the layout of the production line, reduce the number of equipment and the occupied space. Alternatively, the accident shears 15 can also be installed together with the induction heater 11 on a sliding platform, and the accident shears 15 and the induction heater 11 are moved in and out together by sliding on the above-mentioned translation track 20.

[0036] Further preferably, as Figure 1 A bypass support plate table 18 can be provided, which is moved out of the working position when the induction heater 11 is in the working position, and is moved into the working position when the induction heater 11 leaves the working position, so as to assist in completing the strip threading and tail running. The above-mentioned bypass support plate table 18 can be installed on the rack of the corresponding equipment, for example, the bypass support plate table 18 on the exit side of the working position can be installed on the rack of the accident shears 15.

[0037] Further preferably, a blowing device 16 can be arranged on the exit side of the working position, which can be arranged near the exit of the accident shears 15, for example, integrated and installed on the rack of the accident shears 15. The blowing device 16 can realize protection blowing, and when the signals such as reverse running, strip breaking and mill shutdown are encountered, the blowing device 16 will automatically start blowing until the mill runs normally, so as to avoid the influence of the reverse flow of the mill working fluid on the normal operation of the induction heater 11, especially when an oiling machine is arranged in front of the mill, to prevent the reverse flow of oiling. The oiling machine is preferably of a movable structure, and is only used for oiling treatment of special products. The blowing device 16 can adopt conventional blowing equipment such as air nozzle, and the specific structure is not described here.

[0038] Alternatively, as Figure 1 A pinch roll 14 can also be arranged on the entrance side of the working position of the induction heater 11, so as to facilitate the stable running of the strip during threading and normal production, and the pinch roll 14 can be driven by a pneumatic cylinder or a hydraulic cylinder. The roller stand 13 on the entrance side of the working position can be integrated and installed on the pinch roll 14.

[0039] In an optional embodiment, a weld seam detection unit is arranged on the entrance side of the working position, which is used for accurately positioning the weld seam of the strip, so as to timely adjust the power of the induction heater 11 to improve the microstructure of the strip in the weld seam area, and improve the weld seam quality of the strip. The weld seam detection unit can adopt conventional weld seam detection devices such as hole type laser detection device, and the specific structure is not described here. Similarly, the weld seam detection unit can be arranged on the pinch roll stand on the entrance side of the working position.

[0040] In an optional embodiment, a deviation rectifying roller is arranged at the entrance side of the working position to facilitate deviation rectifying control of the strip steel and ensure the running stability of the strip steel. Further, a photoelectric CPC can be arranged at the entrance side of the working position to detect whether the strip steel deviates in real time, and the photoelectric CPC is not affected by the magnetic field, and thus is more reliable.

[0041] In an optional embodiment, as Figure 1 The induction heating device further comprises a belt conveyor, and the belt of the belt conveyor has an active path including a material receiving section where the belt 121 passes through the induction heating cavity and is located directly below the running channel of the strip steel. By arranging the belt conveyor, the belt 121 passes through the induction heating cavity and is located directly below the running channel of the strip steel, so that the naturally falling mill scale on the surface of the strip steel can be quickly taken out of the induction heating cavity, avoiding the mill scale staying in the magnetic field to continuously heat and damage the insulation material of the cavity and even the induction coil, and avoiding causing power loss, ensuring the working reliability of the induction heater 11, improving the service life of the induction heater 11, and reducing or canceling the mechanical mill scale removal equipment for the strip steel.

[0042] Understandably, in the material receiving section, the running direction of the belt 121 is parallel to the running direction of the strip steel, so as to ensure that the belt 121 can reliably and completely receive the mill scale falling from the surface of the strip steel. The width of the belt 121 is preferably greater than the maximum width of the produced steel type, so as to be suitable for the production requirements of different steel types.

[0043] Further preferably, as Figure 1 The belt conveyor comprises two groups of deflection rollers 123 arranged on both sides of the induction heater 11 along the running direction of the strip steel, and the material receiving section is defined by the two groups of deflection rollers 123. The two groups of deflection rollers 123 ensure the tension of the belt 121 in the material receiving section, avoid the belt 121 from jumping and causing the mill scale to fall, and make the belt 121 turn to facilitate the removal of the received mill scale.

[0044] Further preferably, as Figure 1The belt machine further comprises two groups of scrapers 122 arranged on both sides of the induction heater 11 along the strip running direction, the scrapers 122 are located below the corresponding side turning roller 123 and in contact with the material bearing surface of the belt 121. The iron oxide skin on the surface of the belt 121 can be completely removed by the scrapers 122, avoiding the bonding of the iron oxide skin on the material bearing surface and the back surface of the belt 121 (during the winding process of the belt 121, the iron oxide skin on a certain section of the belt 121 may be bonded on the back surface of the adjacent belt 121). Further, the scrapers 122 can be provided with adsorption cavities and adsorption grooves at the cutter head of the scrapers 122, through the negative pressure suction effect generated in the adsorption cavities, the scraped iron oxide skin is sucked away through the adsorption grooves, ensuring the continuous work of the scrapers 122, avoiding the falling of the iron oxide skin to the lower belt winding station.

[0045] The above belt machine can adopt a belt 121 circulating operation mode to ensure the sustainability of the work; in another embodiment, as shown in Figure 1 , the belt machine comprises two groups of belt winding units 124 arranged on both sides of the induction heater 11 along the strip running direction, the belt winding units 124 are arranged below the corresponding side turning roller 123, and the two ends of the belt 121 are wound in the two groups of belt winding units 124. For the above scheme provided with the scrapers 122, the belt winding units 124 can be arranged below the corresponding side scrapers 122. The belt winding unit 124 can adopt a structure of a winding crank and a winding motor; specifically, the belt winding unit 124 on the inlet side of the induction heater 11 and the belt winding unit 124 on the outlet side of the induction heater 11 adopt a periodic input operation mode, during the operation of the inlet side winding motor, the outlet side winding crank is in a free state for automatic conveying of the belt 121; after the outlet side winding crank reaches the specified position of the belt 121, the outlet side winding motor is put into operation, the inlet side winding motor is stopped, the inlet side winding crank is in a free state for automatic conveying of the belt 121, and the belt 121 is conveyed in reverse.

[0046] In an optional embodiment, a material blocking plate can be arranged on each of the two sides of the material receiving section in the transverse direction, which can be a straight plate with the plate surface parallel to the vertical direction, and the two side edges of the belt 121 respectively abut the plate surface of the material blocking plate on the corresponding side; or the material blocking plate can be an L-shaped plate, which includes a first plate body with the plate surface parallel to the vertical direction and a second plate body with the plate surface parallel to the horizontal direction, and the two side edges of the belt 121 respectively abut the plate surface of the first plate body on the corresponding side, and the back / bottom surface of the belt 121 abuts the upper plate surface of the second plate body. The above material blocking plate not only can better block the oxide scale to fall on the belt 121, but also can guide the operation of the belt 121 to improve the stability of the belt operation; among them, the effect of the L-shaped material blocking plate is better, and the stability of the belt operation is better. In the above scheme provided with the support layer, the material blocking plate can be fixed on the support layer, for example, integrated with the support layer.

[0047] The embodiment of the present application also relates to a running method of the strip continuous rolling production line, which comprises:

[0048] When the induction heater 11 is in the working position, after receiving an offline instruction of the induction heater 11, the emergency shear 15 is started to shear the strip, and no strip is ensured in the induction heater 11, so that the induction heater 11 is moved to the offline position.

[0049] When the induction heater 11 is in the offline position, after receiving an online instruction of the induction heater 11, the emergency shear 15 is started to shear the strip, and no strip is ensured in the working position area, so that the induction heater 11 is moved to the online position.

[0050] The above method of ensuring no strip in the induction heater 11 can be that the strip is discharged out of the induction heater 11 by the reverse strip mode (based on the condition that the emergency shear 15 is arranged on the exit side of the working position), and the photoelectric switch arranged on the entrance side and the exit side of the working position can also be used to detect whether there is strip in the working position area.

[0051] In one of the embodiments, the strip continuous rolling production line is a strip pickling line, and the induction heating device can be used for pre-rolling rapid heating of high-grade strips with a thickness specification of 2-6 mm and a width specification of 800-1600 mm. In one of the embodiments, the induction heating device occupies a production line length of about 3 m, can heat the high-grade strip to a temperature above the hard brittle point (≥65℃), realizes high-speed stable operation of the high-grade strip, completely solves the bottleneck of high-speed continuous and stable production of high-grade silicon steel (silicon content ≥2.2% or more) and other strips, and greatly improves the production efficiency and yield of high-grade steel.

[0052] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A continuous strip rolling line comprising a rolling mill train, an induction heating device being arranged at the entry side of the rolling mill train, characterized in that: The induction heating device comprises an induction heater adopting a closed-loop induction coil and forming a strip running channel within the loop of the closed-loop induction coil, and the induction heater is provided with a translation driving mechanism so as to have an operating position and an offline position; The induction heating device further comprises a belt conveyor, and the belt running path of the belt conveyor comprises a material receiving section, at which the belt passes through the induction heating cavity and is located directly below the strip running channel; The belt conveyor comprises two groups of deflection rollers arranged on the two sides of the induction heater along the strip running direction, and the material receiving section is defined by the two groups of deflection rollers; The belt conveyor further comprises two groups of scrapers arranged on the two sides of the induction heater along the strip running direction, and the scrapers are located below the deflection rollers on the corresponding side and are in contact with the material receiving surface of the belt; The induction heating cavity is formed by a muffle structure in the loop region of the induction coil; the muffle structure comprises a support layer and a heat-resistant insulation layer, the support layer adopts an SIC support layer or a non-magnetic stainless steel water-cooled pipe support layer, and the support layer is protected by the heat-resistant insulation layer; A material blocking plate is arranged on the transverse sides of the material receiving section, and the material blocking plate adopts an L-shaped plate comprising a first plate body with a plate surface parallel to the vertical direction and a second plate body with a plate surface parallel to the horizontal direction, the two side edges of the belt are respectively in contact with the plate surface of the first plate body on the corresponding side, and the bottom surface of the belt is in contact with the upper plate surface of the second plate body, and the material blocking plate is fixed on the support layer; An emergency shear is arranged at the inlet side or outlet side of the operating position of the induction heater; Roller racks are arranged at the inlet side and outlet side of the operating position, respectively, and the roller racks are provided with supporting rollers for supporting the strip and pressure rollers for stabilizing the strip to prevent collision with the induction heater, the pressure rollers are located above the supporting rollers on the corresponding side and are provided with lifting driving units; the pressure rollers are used in cooperation with the supporting rollers to improve the running stability of the strip and constrain the strip shape, and when encountering a broken strip, a reversed strip and an emergency stop signal, the pressure rollers are pressed down to relieve the impact of the strip on the induction heater; A bypass supporting plate table is further included, and when the induction heater is in the operating position, the supporting plate table is moved out of the operating position; when the induction heater leaves the operating position, the supporting plate table is moved into the operating position to facilitate the auxiliary completion of strip threading and strip tail running; the bypass supporting plate table is installed on the corresponding side of the equipment rack; An oiling machine is arranged in front of the rolling mill, and the oiling machine adopts a mobile structure and is only used for oiling treatment of special products; a blowing device is arranged at the outlet side of the operating position, which is used to automatically start blowing when encountering a reversed strip, a broken strip and a mill stop signal until the mill runs normally to avoid the influence of reverse flow of the rolling mill working fluid on the normal operation of the induction heater.

2. Strip steel continuous rolling production line according to claim 1, characterized in that: The roller rack adjacent to the emergency shear is directly integrated and installed on the rack of the emergency shear.

3. A strip steel continuous rolling production line as claimed in claim 1, characterized in that: A pinch roll is arranged at the inlet side of the operating position, and the pinch roll is driven by a gas cylinder or a hydraulic cylinder.

4. A strip steel continuous rolling production line as claimed in claim 1, characterized in that: The induction heater is provided with a tank circuit cabinet to form a resonance system, and the tank circuit cabinet is arranged on the top or side of the induction heater.

5. The strip steel continuous rolling production line according to claim 1, characterized in that: A weld detection unit is arranged at the inlet side of the operating position.

6. The strip steel continuous rolling production line according to claim 1, characterized in that: A correction roller and a matching photoelectric CPC correction detection unit are arranged at the inlet side of the operating position.

7. The method of operating a strip steel continuous rolling line as claimed in claim 1, characterized in that, Comprise: When the induction heater is in the working position, after receiving the induction heater off-line instruction, the emergency shear starts to cut the strip and ensures that there is no strip in the induction heater, so that the induction heater moves to the off-line position; When the induction heater is in the off-line position, after receiving the induction heater on-line instruction, the emergency shear starts to cut the strip and ensures that there is no strip in the working position area, so that the induction heater moves to the on-line position.

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