Method for preventing head and tail breakage of sk85 hot rolled strip

Abstract

The application discloses a method for preventing head and tail breakage of SK85 hot-rolled strip steel. The method comprises the following steps: increasing the length of the head and tail of the flying shear strip steel during the shearing process; reducing the input of the finishing rolling process water during the finishing rolling process; adopting the sparse cooling mode and the hot head and tail process during the layer cooling process; selecting the appropriate range of the strip steel, closing the front side water spraying function of the coiler, and controlling the coiling tension of the tail of the strip steel and increasing the number of the coiling assisting rollers during the coiling process. The technical scheme provided by the application can reduce the possibility of the head and tail breakage of the SK85 hot-rolled strip steel.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hot-rolled strip rolling, and particularly relates to a method for preventing head and tail breakage of SK85 hot-rolled strip. BACKGROUND

[0002] At present, since SK85 has a high carbon content, the hardenability of SK85 is strong and the brittleness is large, so SK85 is very sensitive to water cooling. In the hot rolling process, the head and tail of the strip are extremely prone to breakage due to uneven cooling. Therefore, a method is needed to reduce the possibility of head and tail breakage of SK85 hot-rolled strip. SUMMARY

[0003] Embodiments of the application provide a method for preventing head and tail breakage of SK85 hot-rolled strip, which can reduce the possibility of head and tail breakage of SK85 hot-rolled strip.

[0004] Other characteristics and advantages of the application will become apparent from the detailed description that follows, or can be learned by practice of the application.

[0005] According to a first aspect of the embodiments of the application, a method for preventing head and tail breakage of SK85 hot-rolled strip is provided, characterized in that the method comprises: increasing the length of the head and tail of the strip cut by the flying shear during the cutting process; reducing the input of process water during the finishing rolling process; adopting a sparse cooling mode and a hot head and hot tail process during the layer cooling process; and during the coiling process, by selecting a suitable range of the strip, closing the front side water spraying function of the coiler, controlling the coiling tension of the tail of the strip, and increasing the number of coiling rollers.

[0006] In some embodiments of the application, based on the foregoing scheme, the length of the head and tail of the strip cut by the flying shear is increased, and the length is greater than or equal to 200 mm.

[0007] In some embodiments of the application, based on the foregoing scheme, the input of process water during the finishing rolling process is reduced, which comprises: no inter-stand cooling water and inter-stand descaling water is input during the finishing rolling process.

[0008] In some embodiments of the application, based on the foregoing scheme, the input of process water during the finishing rolling process is reduced, which comprises: stopping the input of anti-peeling water in the 5m area of the head and tail of the strip during the finishing rolling process.

[0009] In some embodiments of the application, based on the foregoing scheme, the hot head and hot tail process is adopted during the layer cooling process, which comprises: by adopting the hot head and hot tail process of the strip during the layer cooling process, the temperature of the head and tail of the strip is greater than the temperature of the middle part of the strip.

[0010] In some embodiments of the present application, based on the foregoing scheme, the temperature of the head and tail of the strip is greater than the temperature of the middle of the strip by using the strip hot head and tail process, comprising: by using the strip hot head and tail process, the temperature of the head and tail of the strip is greater than the temperature of the middle of the strip, wherein the difference between the temperature of the head of the strip and the temperature of the middle of the strip is greater than 50 DEG C, and the difference between the temperature of the tail of the strip and the temperature of the middle of the strip is greater than 50 DEG C.

[0011] In some embodiments of the present application, based on the foregoing scheme, during the process of using the strip hot head and tail process on the head and tail of the strip, the method further comprises: using the strip hot head and tail process on the 80m region of the head and tail of the strip, respectively.

[0012] In some embodiments of the present application, based on the foregoing scheme, the method of closing the front side water spraying function of the coiler by selecting the appropriate range of the strip, comprising: during the coiling process, the front side water spraying function of the coiler is closed in the 50m region of the head of the strip.

[0013] In some embodiments of the present application, based on the foregoing scheme, the control of the coiling tension of the tail of the strip, comprising: during the coiling process, the coiling tension of the tail of the strip is controlled to be less than 9MPa.

[0014] In some embodiments of the present application, based on the foregoing scheme, the number of the coiling roller is increased, comprising: during the coiling process, the number of the coiling roller in the coiler is increased to 3 to realize the tail fixing of the tail of the strip.

[0015] The present application has the beneficial effects: in the process of the present application, by increasing the length of the head and tail of the strip in the shearing process, and / or reducing the water input in the finishing process, and / or using the sparse cooling mode and the hot head and tail process in the layer cooling process, and / or selecting the appropriate range of the strip to close the front side water spraying function of the coiler, and controlling the coiling tension of the tail of the strip and increasing the number of the coiling roller, the broken head and tail of the SK85 hot rolled strip can be prevented.

[0016] Meanwhile, the present application realizes the purpose of high quality, high stability and large scale production of hot rolling SK85. It can also reduce the defect rate and avoid accidents. It can also make the operation of the SK85 hot rolled strip simple, and the implementation is high, and the practicality is strong. In the implementation process, the production line equipment does not need to be transformed, and the production cost is reduced, and it has good economic benefit and social benefit.

[0017] Based on this, the method for preventing the broken head and tail of the SK85 hot rolled strip in the present application can reduce the possibility of the broken head and tail of the SK85 hot rolled strip.

[0018] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application, as claimed. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and serve to explain the principles of the application. It is readily apparent to one skilled in the art that the following description is merely exemplary and explanatory of the application and that various embodiments of the application can be made without departing from the spirit and scope of the application. In the drawings:

[0020] Figure 1 A flow chart of the method for preventing head and tail breakage of SK85 hot-rolled strip steel in the embodiment of the application is shown;

[0021] Figure 2 A graph showing the overall distribution trend of coiling temperature in the embodiment is shown;

[0022] Figure 3 A graph showing the indentation caused by tail breakage of the steel coil in the embodiment is shown;

[0023] Figure 4 A graph showing the head breakage in the embodiment is shown;

[0024] Figure 5 A graph showing the tail breakage in the embodiment is shown. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the application will be apparently and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all the other embodiments obtained by those of ordinary skill in the art without any creative effort belong to the scope of protection of the application.

[0026] Moreover, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the application. One skilled in the relevant art will recognize, however, that the application can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the application.

[0027] The block diagrams shown in the drawings are merely functional entities, and do not necessarily correspond to physically independent entities. That is, the functional entities can be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0028] The flowcharts shown in the drawings are merely exemplary illustrations, and do not necessarily include all contents and operations / steps, nor are they necessarily executed in the order described. For example, some operations / steps can be further divided, and some operations / steps can be combined or partially combined, so the actual execution order can be changed according to actual conditions.

[0029] Next, the present application will be described in detail:

[0030] Figure 1 A flowchart of the method for preventing head and tail breakage of SK85 hot-rolled strip steel in the embodiment of the present application is shown. Referring to Figure 1 The method for preventing head and tail breakage of SK85 hot-rolled strip steel at least includes steps 110 to 170, which are described in detail as follows:

[0031] In step 110, the length of the head and tail of the strip steel is increased during shearing.

[0032] In the present application, by increasing the length of the head and tail of the strip steel, the shape of the head and tail of the strip steel can be ensured, thereby avoiding the head and tail breakage caused by the abnormal shape of the head and tail of the strip steel impacting the inside of the coiler.

[0033] Continuing to refer to Figure 1 In step 130, the input of the finishing process water is reduced during finishing.

[0034] In the present application, by reducing the input of the finishing process water, the variation range of the temperature difference of the head and tail of the strip steel can be controlled, thereby avoiding the head and tail breakage caused by the excessive temperature difference of the head and tail of the strip steel.

[0035] Continuing to refer to Figure 1 In step 150, the sparse cooling mode and the hot head and tail process are adopted during laminar cooling.

[0036] In the present application, by adopting the sparse cooling mode for cooling during laminar cooling, the head and tail breakage caused by the rapid cooling of the strip steel in a short time can be avoided.

[0037] Continuing to refer to Figure 1 In step 170, by selecting the appropriate range of the strip steel, the water spraying function of the front side of the coiler is turned off, and the tail coiling tension of the strip steel is controlled and the number of coiling rollers is determined during coiling.

[0038] In the present application, by selecting the appropriate range of the strip steel to close the front side of the coiler water spray function during the coiling process, the rapid cooling of the strip steel during the coiling process can be avoided, thereby avoiding the occurrence of the strip steel head breakage. At the same time, by controlling the coiling tension of the strip steel tail and increasing the number of coiling rollers, the occurrence of the strip steel tail breakage can also be avoided.

[0039] Further, in some embodiments of the present application, the length of the strip steel head and the strip steel tail cut by the flying shear is increased, including: increasing the length of the strip steel head and the strip steel tail cut by the flying shear, which is greater than or equal to 200mm.

[0040] Further, in some embodiments of the present application, the input of the finishing process water is reduced, including: during the finishing process, no inter-stand cooling water and inter-stand descaling water is input.

[0041] Further, in some embodiments of the present application, the method further comprises: during the finishing process, stopping the input of the anti-peeling water in the 5m area of the strip steel head and the strip steel tail.

[0042] Further, in some embodiments of the present application, the hot head and hot tail process is adopted during the layer cooling process, including: during the layer cooling process, by adopting the strip steel hot head and hot tail process, the temperature of the strip steel head and the strip steel tail is greater than the temperature of the middle part of the strip steel.

[0043] Further, in some embodiments of the present application, by adopting the strip steel hot head and hot tail process, the temperature of the strip steel head and the strip steel tail is greater than the temperature of the middle part of the strip steel, including: by adopting the strip steel hot head and hot tail process, the temperature of the strip steel head and the strip steel tail is greater than the temperature of the middle part of the strip steel, wherein the difference between the temperature of the strip steel head and the temperature of the middle part of the strip steel is greater than 50℃, and the difference between the temperature of the strip steel tail and the temperature of the middle part of the strip steel is greater than 50℃.

[0044] In the present embodiment, by adopting the strip steel hot head and hot tail process, the difference between the temperature of the strip steel head and the temperature of the middle part of the strip steel is greater than 50℃, thereby avoiding the sharp temperature drop of the strip steel head during the last finishing into the layer cooling process, and avoiding the production of low temperature organization of the strip steel head leading to the increase of hardness, thereby reducing the risk of the strip steel head breakage. At the same time, by the hot tail process, the problem of the strip steel tail breakage at the end of the coiling process of SK85 can be improved.

[0045] Further, in some embodiments of the present application, during the process of adopting the strip steel hot head and hot tail process for the strip steel head and the strip steel tail, the method further comprises: adopting the strip steel hot head and hot tail process for the 80m area of the strip steel head and the strip steel tail.

[0046] Further, in some embodiments of the present application, the method of selecting a suitable range of the strip steel, and closing the water spraying function in front of the coiler, comprises: during the coiling process, closing the water spraying function in front of the coiler in a 50m area of the head of the strip steel;

[0047] Further, in some embodiments of the present application, the method of controlling the coiling tension of the tail of the strip steel, comprises: during the coiling process, controlling the coiling tension of the tail of the strip steel to be less than 9MPa.

[0048] In the present embodiment, by controlling the coiling tension of the tail of the strip steel to be less than 9MPa, the effect of controlling the speed of the tail of the strip steel can be achieved. At the same time, it is necessary to ensure that the number of tail fixing rings of the strip steel is not more than one and a half, so as to avoid the situation of broken head and tail of the strip steel caused by too many tail fixing rings of the strip steel in the coiler.

[0049] Further, in some embodiments of the present application, the method of increasing the number of the coiling rollers, comprises: during the coiling process, increasing the number of the coiling rollers in the coiler to 3, so as to realize the tail fixing of the tail of the strip steel.

[0050] In the present embodiment, by increasing the number of the coiling rollers in the coiler to 3, the tail of the strip steel can be prevented from colliding with the coiling rollers, the arc-shaped plate and the uncoiling trolley in the state of tension loss, so as to reduce the occurrence of the broken tail of the strip steel.

[0051] In summary, in the process of implementing the present application, by increasing the length of the head and the tail of the strip steel in the shearing process, and / or reducing the water input in the finishing process, and / or adopting the sparse cooling mode and the hot head and hot tail process in the layer cooling process, and / or selecting a suitable range of the strip steel, closing the water spraying function in front of the coiler, and controlling the coiling tension of the tail of the strip steel and increasing the number of the coiling rollers in the coiling process, the broken head and tail of the SK85 hot-rolled strip steel can be prevented.

[0052] Specifically, referring to Figure 2, shows the overall distribution trend chart of coiling temperature in the embodiment. In the embodiment, SK85 conventional ingredients are selected for production, wherein the continuous casting slab is directly charged into the furnace, heated to 1220 DEG C and discharged, after rough rolling, enters the finishing rolling, the intermediate blank is cut to 220 mm and the tail is cut to 220 mm. The inter-stand cooling water and the inter-stand descaling water are not put into, the anti-peeling water is allowed to head and tail 5 m. At the same time, the laminar cooling mode is sparse cooling mode, and hot head and hot tail process is adopted, the hot head length is 80 m, and the hot head temperature is 50 DEG C above the target coiling temperature. The hot tail length is 80 m, and the hot tail temperature is 50 DEG C above the target coiling temperature. In the coiling process, the front side water spray of the coiler is closed for the first 50 m of the hot coil head, and the tail is controlled to 8 MPa of the strip tail coiling tension, and the coiler uses three tail setting rollers. In the hot rolling production process of the embodiment, there is no broken head, the coiling is smooth, and there is no broken tail after the line is down. In order to clearly illustrate the method in the application, the embodiment is taken as example 1, which is compared with the subsequent examples.

[0053] Referring to Figure 3 , shows the broken tail caused by the steel coil indentation chart in the embodiment. In the embodiment, SK85 conventional ingredients are selected for production, wherein the continuous casting slab is directly charged into the heating furnace, heated to 1220 DEG C and discharged, after rough rolling, enters the finishing rolling, the intermediate blank is cut to 140 mm and the tail is cut to 150 mm. The inter-stand cooling water and the inter-stand descaling water are not put into, the anti-peeling water is allowed to head and tail 5 m. At the same time, the laminar cooling mode is sparse cooling mode, and hot head and hot tail process is adopted, the hot head length is 80 m, and the hot head temperature is 50 DEG C above the target coiling temperature. The hot tail length is 80 m, and the hot tail temperature is 50 DEG C above the target coiling temperature. In the coiling process, the front side water spray of the coiler is closed for the first 50 m of the hot coil head, and the tail is controlled to 8 MPa of the strip tail coiling tension, and the coiler uses three tail setting rollers. Compared with example 1, the broken tail exists in the hot rolling production process of the embodiment. In order to clearly illustrate the method in the application, the embodiment is taken as example 2, which is compared with the subsequent examples.

[0054] Referring to Figure 4, the head fragmentation diagram in the embodiment is shown. In the embodiment, the SK85 conventional ingredients are selected for production, wherein the continuous casting slab is directly loaded into the heating furnace, heated to 1220 DEG C and discharged, after rough rolling, enters the finishing rolling, the head of the intermediate blank is cut by 220mm and the tail is cut by 220mm. The interstand cooling water and the interstand descaling water are not put into, the anti-peeling water is allowed to head and tail 5m. At the same time, the laminar flow cooling mode is the front concentrated cooling mode, and the hot head and hot tail process is not used. In the coiling process, the front side water spray of the coiler is closed for the first 50m of the hot coil head, and the tail coiling tension of the strip steel is controlled to be 8MPa, and the coiler uses 3 tail setting up coilers. Compared with the comparative example 2, the head of the hot-rolled strip steel in the production process of the embodiment has obvious fragmentation, and there is a large risk of steel accumulation. In order to clearly illustrate the method in the application, the embodiment is taken as example 3 for comparison with the subsequent examples.

[0055] Referring to Figure 5 , the tail fragmentation diagram in the embodiment is shown. In the embodiment, the SK85 conventional ingredients are selected for production, wherein the continuous casting slab is directly loaded into the heating furnace, heated to 1220 DEG C and discharged, after rough rolling, enters the finishing rolling, the head of the intermediate blank is cut by 220mm and the tail is cut by 220mm. The interstand cooling water and the interstand descaling water are not put into, the anti-peeling water is allowed to head and tail 5m. At the same time, the laminar flow cooling mode is the sparse cooling mode, and the hot head and hot tail process is used, the hot head length is 80m, and the hot head temperature is 50 DEG C above the target coiling temperature. The hot tail length is 80m, and the hot tail temperature is 50 DEG C above the target coiling temperature. In the coiling process, the front side water spray of the coiler is opened, and the tail coiling tension of the strip steel is controlled to be 10MPa, and the coiler uses 2 tail setting up coilers. Compared with the comparative example 3, in the production process of the hot-rolled strip steel in the embodiment, in the process that the coiler to the tail of the strip steel gradually slows down and presses on the steel coil, the tail of the strip steel under the lost tension state hits the pinch roll, the arc plate and the uncoiler trolley, and brittle fracture occurs, thereby causing the tail fragmentation of the strip steel.

[0056] Therefore, the method for preventing the head and tail fragmentation of the SK85 hot-rolled strip steel can reduce the possibility of the head and tail fragmentation of the SK85 hot-rolled strip steel.

[0057] The above only describes the embodiments of the application and is not used to limit the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the scope of the claims of the application.

Claims

1. A method for preventing head and tail breakage of a hot-rolled SK85 strip, characterized by, The method comprises: increasing the length of the strip head and the strip tail in the flying shear process; reducing the input of the finishing mill process water in the finishing process; adopting the sparse cooling mode and the hot head and hot tail process in the laminar cooling process; in the coiling process, by selecting the appropriate range of the strip, closing the water spraying function of the front side of the coiler, controlling the coiling tension of the strip tail and increasing the number of the coiling assisting rollers; the increasing of the length of the strip head and the strip tail in the flying shear process comprises: increasing the length of the strip head and the strip tail in the flying shear process, and the length is greater than or equal to 200 mm; the reducing of the input of the finishing mill process water comprises: in the finishing process, no inter-stand cooling water and inter-stand descaling water is inputted; the reducing of the input of the finishing mill process water comprises: in the finishing process, the anti-peeling water is stopped to be inputted in the 5 m area of the strip head and the strip tail; the adoption of the hot head and hot tail process in the laminar cooling process comprises: in the laminar cooling process, by adopting the hot head and hot tail process of the strip, the temperature of the strip head and the strip tail is greater than the temperature of the middle part of the strip; the adoption of the hot head and hot tail process of the strip, the temperature of the strip head and the strip tail is greater than the temperature of the middle part of the strip comprises: by adopting the hot head and hot tail process of the strip, the temperature of the strip head and the strip tail is greater than the temperature of the middle part of the strip, wherein the difference between the temperature of the strip head and the temperature of the middle part of the strip is greater than 50 DEG C, and the difference between the temperature of the strip tail and the temperature of the middle part of the strip is greater than 50 DEG C; the controlling of the coiling tension of the strip tail comprises: in the coiling process, the coiling tension of the strip tail is controlled to be less than 9 MPa.

2. The method of claim 1, wherein, in the process of adopting the hot head and hot tail process of the strip for the strip head and the strip tail, the method further comprises: respectively adopting the hot head and hot tail process of the strip for the 80 m area of the strip head and the strip tail.

3. The method of claim 1, wherein, the closing of the water spraying function of the front side of the coiler by selecting the appropriate range of the strip comprises: in the coiling process, the water spraying of the front side of the coiler is closed in the 50 m area of the strip head.

4. The method of claim 1, wherein, the increasing of the number of the coiling assisting rollers comprises: in the coiling process, the number of the coiling assisting rollers in the coiler is increased to 3, so as to realize the tail fixing of the strip tail.

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