A method for reducing edge flaking of cold-rolled steel strip and the resulting cold-rolled steel strip

Abstract

The application provides a method for reducing the edge peeling of a cold-rolled strip and a resultant cold-rolled strip, and comprises the following steps: sequentially performing rough rolling, finish rolling and coiling on a continuous casting billet to obtain a cold-rolled strip; the rough rolling comprises multiple passes; the tapping temperature of the continuous casting billet is 1180-1230 DEG C; the time for the continuous casting billet to enter the rough rolling is less than or equal to 90s; in the step of rough rolling, only the phosphorus removal water is started in the last N even passes; N is an integer and N is greater than or equal to 1; and the passes in which the phosphorus removal water is started are all even passes. The edge peeling defect of the cold-rolled strip prepared by the method is radically improved, the edge peeling occurrence rate is stably controlled to be less than or equal to 0.8%, the quality of the strip is upgraded, the economic benefits and production efficiency are simultaneously improved, and the technical problems of high edge peeling rate and high production cost of the cold-rolled strip produced by the existing hot rolling process are solved.

Description

Technical Field

[0001] This invention relates to the field of iron and steel smelting technology, and in particular to a method for reducing edge peeling of cold-rolled strip steel and the resulting cold-rolled strip steel. Background Technology

[0002] The hot rolling process of cold-rolled strip steel is the core step determining the surface quality of the substrate. However, existing hot rolling processes have significant shortcomings in controlling edge peeling defects in cold-rolled strip steel. Production practice shows that this defect is concentrated at the beginning and end of the strip steel and on both sides, especially in the range of 1-5 meters from the beginning and end, and there is no obvious periodic distribution pattern. Its microscopic morphology presents as discontinuous black and white dot-like chains, with a certain depth and obvious skin-lifting characteristics, belonging to irreversible surface damage defects. Mechanism analysis shows that peeling defects under existing processes are mainly induced by low-temperature rolling conditions in roughing. When the single-pass reduction in roughing is too large, the strip steel deviates severely during the rolling process, the slab exhibits buckling / curving phenomena, and the sharp corner defects of the continuously cast slab are severe, the generation of peeling defects will be greatly aggravated. The edge peeling defect of cold-rolled strip steel not only seriously damages the appearance flatness of the strip steel, but also makes the peeling area prone to stress concentration and cracking during subsequent cold rolling deep processing. Moreover, the repair of this defect is extremely difficult, the rework process is complex, and the rework cycle is long, which will greatly increase the production rework cost, cause batch products to be scrapped, and bring significant economic losses to enterprises.

[0003] In existing technologies, methods for controlling edge defects in strip steel mostly focus on adjusting single process parameters, such as adjusting the reduction rate, controlling temperature, or regulating cooling water. However, the lack of strict time control during roughing, the large temperature gradient of the strip steel, and the uneven temperature between the edge and core generate thermal stress that induces edge peeling. Excessive reduction in a single pass during roughing leads to surface cracking and peeling. The widespread use of continuous water cooling causes sudden cooling of the strip steel edges in the early stages of roughing, and the alternating hot and cold temperatures trigger surface metal peeling, making it difficult to fundamentally solve the edge peeling problem. Therefore, this invention provides a method for reducing edge peeling in cold-rolled strip steel and the resulting cold-rolled strip steel, addressing the problems of high edge peeling defect rates and high production costs in the production of cold-rolled strip steel using existing hot-rolling processes. Summary of the Invention

[0004] This invention provides a method for reducing edge peeling of cold-rolled strip and the resulting cold-rolled strip, aiming to solve the technical problems of high edge peeling defect rate and high production cost when producing cold-rolled strip using existing hot rolling processes.

[0005] To achieve the above objectives, the present invention provides a method for reducing edge peeling of cold-rolled strip steel, comprising: sequentially performing rough rolling, finish rolling and coiling on a continuously cast billet to obtain cold-rolled strip steel.

[0006] The roughing process includes multiple rolling passes.

[0007] The tapping temperature of the continuously cast billet is 1180~1230℃.

[0008] The time for all the continuously cast billets to enter the roughing mill is ≤90s.

[0009] In the rough rolling step, dephosphorization water is only turned on during the last N even-numbered rolling passes.

[0010] Wherein, 1≤N≤3, N is an integer, and the number of times the dephosphorization water is turned on is an even number of times.

[0011] According to an embodiment of this application, the flow rate of the phosphorus removal water is 450~480m³. 3 / h.

[0012] According to an embodiment of this application, the thickness of the intermediate billet obtained after rough rolling is 45~55mm.

[0013] In the roughing rolling step, when the head of the continuously cast billet bends downward, the roughing roll speed ratio is 1 to 1.1, and when the head of the continuously cast billet bends upward, the roughing roll speed ratio is 1.1 to 1; and the symmetrical center line of the large vertical roll and the width center line of the continuously cast billet are both aligned with the rolling center line of the roughing mill.

[0014] According to an embodiment of this application, the exit temperature of the roughing mill is 1080~1110℃.

[0015] According to an embodiment of this application, the inlet temperature of the finishing mill is 980~1040℃.

[0016] The exit temperature of the finishing mill is 850~890℃.

[0017] According to an embodiment of this application, the winding temperature is 580~600°C.

[0018] According to an embodiment of this application, the composition of the continuously cast billet, by mass percentage, includes: C 0.15~0.24wt%, Mn 0.8~1.3wt%, Si 0.18~0.3wt%, P ≤0.015wt%, Al 0.01~0.06wt%, S ≤0.003wt%, Ti 0.002~0.045wt%, B 0.0015~0.004wt%, V ≤0.006wt%, Nb 0.002~0.005wt%, Cr 0.10~0.25wt%, As 0.001~0.01wt%, N ≤0.008wt%, balance being iron and unavoidable impurities.

[0019] According to the embodiments of this application, the number of rolling passes is 5 to 8.

[0020] The time for all the continuously cast billets to enter the roughing mill is 60-90 seconds.

[0021] According to an embodiment of this application, the exit temperature of the roughing mill is 1080~1100℃.

[0022] The inlet temperature of the finishing mill is 980~990℃.

[0023] The exit temperature of the finishing mill is 850~860℃.

[0024] This invention provides a cold-rolled strip steel, which is prepared by the method described above.

[0025] Compared with the prior art, the beneficial effects of the present invention are: The aforementioned method for reducing edge peeling in cold-rolled strip steel suppresses the defect at its source by synergistically optimizing key process parameters such as roughing mill feed time, rolling passes, and descaling water activation mode. Specifically, controlling the time for the entire continuously cast billet to enter the roughing mill to ≤90s significantly reduces the billet's residence time in air, lowers the temperature drop during roughing, and prevents edge peeling caused by decreased fluidity at low temperatures. Employing a multi-pass roughing process effectively disperses the reduction in a single pass, preventing excessive edge deformation that hinders effective rolling. Using an even-numbered pass activation mode for descaling slows the cooling process, avoiding peeling caused by sudden cooling of the edges in the preceding roughing passes. Through the control of each step and process parameter, the edge peeling rate can be stably controlled at ≤0.8%.

[0026] The cold-rolled strip steel prepared using the method of this invention exhibits a fundamental improvement in edge peeling defects, significantly enhancing the surface smoothness and integrity of the strip steel and effectively reducing the risk of edge cracking during subsequent cold rolling processes. Simultaneously, the substantial reduction in defect incidence directly decreases strip steel rework and scrapping, significantly lowering production costs and improving yield and production efficiency. The optimized process parameters demonstrate strong synergistic adaptability, requiring no additional equipment investment. While ensuring production continuity, it achieves simultaneous improvements in strip steel quality, economic benefits, and production efficiency, solving the technical problems of high edge peeling rates and high production costs in the production of cold-rolled strip steel using existing hot rolling processes. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0028] Figure 1 This is a photograph of the cold-rolled strip prepared by the method for reducing edge peeling in Example 1.

[0029] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The technical solutions of the various embodiments of the present invention can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0032] To achieve the above objectives, the present invention provides a method for reducing edge peeling of cold-rolled strip steel, comprising: sequentially performing rough rolling, finish rolling and coiling on a continuously cast billet to obtain cold-rolled strip steel.

[0033] The roughing process includes multiple rolling passes.

[0034] The tapping temperature of the continuously cast billet is 1180~1230℃.

[0035] The time for all the continuously cast billets to enter the roughing mill is ≤90s.

[0036] In the rough rolling step, dephosphorization water is only turned on during the last N even-numbered rolling passes.

[0037] Wherein, 1≤N≤3, N is an integer, and the number of times the dephosphorization water is turned on is an even number of times.

[0038] In some embodiments, controlling the tapping temperature of the continuously cast billet serves two purposes. First, it ensures the billet remains in the fully austenitic single-phase region, preventing partial ferrite precipitation and resulting in uneven microstructure, thus guaranteeing the uniformity of microstructure transformation during subsequent rolling. Second, compared to traditional high-temperature heating processes above 1250°C, moderately lowering the tapping temperature effectively reduces the temperature gradient between the edge and core of the billet, minimizing thermal stress caused by the temperature gradient. Simultaneously, it suppresses the formation rate of iron oxide scale at high temperatures, reducing surface iron oxide scale thickness and subsequent iron oxide scale indentation defects from the source. Furthermore, this temperature range also prevents excessive austenite grain growth, facilitating sufficient dynamic recrystallization and grain refinement during subsequent rolling, and directly reducing furnace fuel consumption, achieving energy conservation and emission reduction.

[0039] In some embodiments, strictly controlling the time from when the continuously cast billet exits the furnace to when it enters the roughing mill can minimize heat radiation loss from the edges of the billet in the air, suppress edge temperature drop, and make the edge temperature more consistent with the core temperature, thereby avoiding a decrease in plastic deformation capacity due to excessively low edge temperature. Simultaneously, shortening the exposure time of the high-temperature billet in air can effectively reduce the degree of secondary oxidation and reduce the regeneration of surface iron oxide scale. Furthermore, this method can shorten the production cycle; improved temperature uniformity also makes the deformation of the edges more uniform during the roughing process, reducing stress concentration and microcrack initiation at the edges caused by uneven temperature.

[0040] In some embodiments, descaling water is only turned on during the last N even-numbered passes of roughing. This significantly reduces the number of edge water cooling cycles and the cooling intensity, avoiding the repeated rapid cooling of the edges caused by turning on descaling water in every pass. This allows the edge temperature to be maintained during roughing, preventing the edges from entering the two-phase or ferrite region due to overcooling, and ensuring that the edges remain in the austenitic single-phase region for plastic deformation. Furthermore, precisely turning on the descaling water in the later stages of roughing effectively removes surface iron oxide scale and prevents it from being pressed into the strip surface, without overcooling the edges. In addition, reducing the number of descaling water cycles also reduces water consumption and wastewater treatment costs.

[0041] In some embodiments, turning on the descaling water in even-numbered passes can better match the rolling force distribution, further reduce the adverse effects of edge temperature drop on deformation behavior, enhance the edge plastic deformation capacity, and thus suppress edge peeling defects.

[0042] The aforementioned method for reducing edge peeling in cold-rolled strip steel suppresses the defect at its source by synergistically optimizing key process parameters such as roughing mill feed time, rolling passes, and descaling water activation mode. Specifically, controlling the time for the entire continuously cast billet to enter the roughing mill to ≤90s significantly reduces the billet's residence time in air, lowers the temperature drop during roughing, and prevents edge peeling caused by decreased fluidity at low temperatures. Employing a multi-pass roughing process effectively disperses the reduction in a single pass, preventing excessive edge deformation that hinders effective rolling. Using an even-numbered pass activation mode for descaling slows the cooling process, avoiding peeling caused by sudden cooling of the edges in the preceding roughing passes. Through the control of each step and process parameter, the edge peeling rate can be stably controlled at ≤0.8%.

[0043] In some embodiments, the tapping temperature of the continuously cast billet is 1180~1200℃.

[0044] In some embodiments, the time for the entire continuous casting billet to enter the roughing mill is controlled within 10 to 90 seconds, which shortens the residence time of the high-temperature continuous casting billet in the air, effectively reduces the temperature drop during the roughing milling process, and avoids edge peeling defects caused by the poor low-temperature fluidity of the edge metal.

[0045] In some embodiments, roughing is performed in 5 to 8 passes. Compared with low-pass rolling, the amount of flat roll reduction per pass can be reduced, avoiding excessive edge deformation that prevents effective rolling and reducing edge peeling from the deformation control level.

[0046] In some embodiments, roughing is performed in 6 to 8 passes.

[0047] In some embodiments, the dephosphorization water used for cooling is opened in an intermittent manner, which delays the cooling process until the later stage of rough rolling, slows down the overall cooling process, and avoids the peeling problem induced by sudden cooling at the edges of the previous pass.

[0048] In some embodiments, the roughing process is performed in 7 passes, and the dephosphorization water is turned on during the 2nd, 4th and 6th passes of the roughing process.

[0049] In some embodiments, the flow rate of the dephosphorization water is 450~480 m³ / h. 3 / h.

[0050] In some embodiments, the flow rate of the dephosphorization water is 450~460 m³ / h. 3 / h.

[0051] In some embodiments, the cooling water flow rate is finely controlled and maintained at a low level to reduce the risk of overcooling at the edges and further suppress the formation of peeling defects.

[0052] In some embodiments, the thickness of the intermediate billet obtained after rough rolling is 45~55mm.

[0053] In some embodiments, the thickness of the intermediate billet obtained after rough rolling is 50-55 mm.

[0054] In the roughing rolling step, when the head of the continuously cast billet bends downward, the roughing roll speed ratio is 1 to 1.1, and when the head of the continuously cast billet bends upward, the roughing roll speed ratio is 1.1 to 1; and the symmetrical center line of the large vertical roll and the width center line of the continuously cast billet are both aligned with the rolling center line of the roughing mill.

[0055] In some embodiments, the roughing roll speed ratio is set differently. When the head of the continuously cast billet bends downward, the roughing roll speed ratio is 1 to 1.1. When the head of the continuously cast billet bends upward, the roughing roll speed ratio is 1.1 to 1. This reduces the edge peeling caused by scraping against the equipment when the head of the continuously cast billet bends downward or upward.

[0056] In some embodiments, the centering accuracy of the rolling process is precisely controlled, and the center line of the vertical roll, the center line of the strip, and the center line of the rolling mill are simultaneously adjusted during the rolling process. This avoids peeling caused by the vertical roll and the strip not being able to wrap around each other, and also eliminates peeling defects caused by the strip scraping against the equipment.

[0057] In some embodiments, the exit temperature of the roughing mill is 1080~1110°C.

[0058] In some embodiments, the exit temperature of the roughing mill is 1080~1100℃.

[0059] In some embodiments, the inlet temperature of the finishing mill is 980~1040°C.

[0060] The exit temperature of the finishing mill is 850~890℃.

[0061] In some embodiments, the inlet temperature of the finishing mill is 980~1010℃.

[0062] In some embodiments, the exit temperature of the finishing mill is 850~870°C.

[0063] In some embodiments, the winding temperature is 580~600°C.

[0064] In some embodiments, the winding temperature is 580~590°C.

[0065] In some embodiments, the composition of the continuously cast billet, by mass percentage, includes: C 0.15~0.24wt%, Mn 0.8~1.3wt%, Si 0.18~0.3wt%, P ≤0.01wt%, Al 0.02~0.05wt%, S ≤0.003wt%, Ti 0.002~0.045wt%, B 0.0015~0.004wt%, V ≤0.006wt%, Nb 0.002~0.005wt%, Cr 0.10~0.25wt%, As 0.001~0.01wt%, N ≤0.008wt%, with the balance being iron and unavoidable impurities.

[0066] In some embodiments, the composition of the continuously cast billet, by mass percentage, includes: C 0.18~0.24wt%, Mn 1.0~1.3wt%, Si 0.2~0.3wt%, P ≤0.015wt%, Al 0.01~0.06wt%, S ≤0.002wt%, Ti 0.002~0.01wt%, B 0.0015~0.003wt%, V ≤0.003wt%, Nb 0.002~0.004wt%, Cr 0.10~0.25wt%, As 0.003~0.008wt%, N ≤0.005wt%, with the balance being iron and unavoidable impurities.

[0067] In some embodiments, the composition of the continuously cast billet, by mass percentage, includes: C 0.18~0.22wt%, Mn 1.0~1.2wt%, Si 0.2~0.25wt%, P ≤0.008wt%, Al 0.04~0.04wt%, S ≤0.002wt%, Ti 0.002~0.006wt%, B 0.0015~0.003wt%, V ≤0.003wt%, Nb 0.002~0.003wt%, Cr 0.15~0.25wt%, As 0.004~0.006wt%, N ≤0.004wt%, with the balance being iron and unavoidable impurities.

[0068] In some embodiments, the number of rolling passes is 5 to 8.

[0069] The time for all the continuously cast billets to enter the roughing mill is 60-90 seconds.

[0070] In some embodiments, the time for all the continuously cast billets to enter the roughing mill is controlled to be 60-80 seconds.

[0071] In some embodiments, the exit temperature of the roughing mill is 1080~1100℃.

[0072] The inlet temperature of the finishing mill is 980~990℃.

[0073] The exit temperature of the finishing mill is 850~860℃.

[0074] This invention provides a cold-rolled strip steel, which is prepared by the method described above.

[0075] The cold-rolled strip steel prepared using the method of this invention exhibits a fundamental improvement in edge peeling defects, significantly enhancing the surface smoothness and integrity of the strip steel and effectively reducing the risk of edge cracking during subsequent cold rolling processes. Simultaneously, the substantial reduction in defect incidence directly decreases strip steel rework and scrapping, significantly lowering production costs and improving yield and production efficiency. The optimized process parameters demonstrate strong synergistic adaptability, requiring no additional equipment investment. While ensuring production continuity, it achieves simultaneous improvements in strip steel quality, economic benefits, and production efficiency, solving the technical problems of high edge peeling rates and high production costs in the production of cold-rolled strip steel using existing hot rolling processes.

[0076] To further illustrate the present invention, the following examples are provided: Example 1 A method for reducing edge peeling of cold-rolled strip steel is as follows: The continuously cast billet is sequentially subjected to rough rolling, finish rolling, and coiling to obtain cold-rolled strip steel. The furnace exit temperature of the continuously cast billet is 1180℃, the time for all the billets to enter the rough rolling mill is 60s, the rough rolling process consists of 7 passes, the exit temperature of the rough rolling mill is 1080℃, the entry temperature of the finish rolling mill is 980℃, the exit temperature of the finish rolling mill is 850℃, and the coiling temperature is 580℃. In the rough rolling process, descaling water is only turned on for cooling in the 2nd, 4th, and 6th passes, and the flow rate of the descaling water is 450m³. 3 / h.

[0077] The composition of the continuously cast billet, by mass percentage, is: C 0.20wt%, Mn 1.1wt%, Si 0.24wt%, P 0.0075wt%, Al 0.03wt%, S 0.0015wt%, Ti 0.004wt%, B 0.002wt%, V 0.003wt%, Nb 0.0025wt%, Cr 0.2wt%, As 0.005wt%, N 0.004wt%, with the balance being iron and unavoidable impurities.

[0078] The thickness of the intermediate billet obtained after rough rolling is 55 mm. In the rough rolling step, when the head of the continuously cast billet bends downward, the speed ratio of the rough rolling rolls is 1.1, and when the head of the continuously cast billet bends upward, the speed ratio of the rough rolling rolls is 1. The symmetrical center line of the large vertical roll and the width center line of the continuously cast billet are aligned with the rolling center line of the rough rolling mill.

[0079] See Figure 1 The cold-rolled strip prepared using the method for reducing edge peeling in Example 1 did not peel. Production testing showed that the peeling rate of the cold-rolled strip prepared using this method was 0.3%.

[0080] Example 2 A method for reducing edge peeling of cold-rolled strip steel is as follows: The continuously cast billet is sequentially subjected to rough rolling, finish rolling, and coiling to obtain cold-rolled strip steel. The furnace exit temperature of the continuously cast billet is 1230℃, the time for all the billets to enter the rough rolling mill is 90s, the rough rolling process consists of 7 passes, the exit temperature of the rough rolling mill is 1110℃, the entry temperature of the finish rolling mill is 1040℃, the exit temperature of the finish rolling mill is 890℃, and the coiling temperature is 600℃. In the rough rolling process, descaling water is only turned on for cooling in the 2nd, 4th, and 6th passes, and the flow rate of the descaling water is 480m³. 3 / h.

[0081] The composition of the continuously cast billet, by mass percentage, is: C 0.20wt%, Mn 1.1wt%, Si 0.24wt%, P 0.0075wt%, Al 0.03wt%, S 0.0015wt%, Ti 0.004wt%, B 0.002wt%, V 0.003wt%, Nb 0.0025wt%, Cr 0.2wt%, As 0.005wt%, N 0.004wt%, with the balance being iron and unavoidable impurities.

[0082] The thickness of the intermediate billet obtained after rough rolling is 45 mm. In the rough rolling step, when the head of the continuously cast billet bends downward, the speed ratio of the rough rolling rolls is 1, and when the head of the continuously cast billet bends upward, the speed ratio of the rough rolling rolls is 1.05. The symmetrical center line of the large vertical roll and the width center line of the continuously cast billet are aligned with the rolling center line of the rough rolling mill.

[0083] Production testing showed that the peeling rate of cold-rolled strip produced by using the method of reducing edge peeling was 0.8%.

[0084] Example 3 A method for reducing edge peeling of cold-rolled strip steel is as follows: The continuously cast billet is sequentially subjected to rough rolling, finish rolling, and coiling to obtain cold-rolled strip steel. The furnace exit temperature of the continuously cast billet is 1200℃, the time for all the billets to enter the rough rolling mill is 80s, the rough rolling process consists of 7 passes, the exit temperature of the rough rolling mill is 1100℃, the entry temperature of the finish rolling mill is 1010℃, the exit temperature of the finish rolling mill is 870℃, and the coiling temperature is 590℃. In the rough rolling process, descaling water is only turned on for cooling in the 2nd, 4th, and 6th passes, and the water flow rate of the descaling water is 460m³. 3 / h.

[0085] The composition of the continuously cast billet, by mass percentage, is: C 0.20wt%, Mn 1.1wt%, Si 0.24wt%, P 0.0075wt%, Al 0.03wt%, S 0.0015wt%, Ti 0.004wt%, B 0.002wt%, V 0.003wt%, Nb 0.0025wt%, Cr 0.2wt%, As 0.005wt%, N 0.004wt%, with the balance being iron and unavoidable impurities.

[0086] The thickness of the intermediate billet obtained after rough rolling is 50 mm. In the rough rolling step, when the head of the continuous casting billet bends downward, the speed ratio of the rough rolling rolls is 1, and when the head of the continuous casting billet bends upward, the speed ratio of the rough rolling rolls is 1. Furthermore, the symmetrical center line of the large vertical roll and the width center line of the continuous casting billet are aligned with the rolling center line of the rough rolling mill.

[0087] Production testing showed that the peeling rate of cold-rolled strip produced by using the method of reducing edge peeling was 0.5%.

[0088] The aforementioned method for reducing edge peeling in cold-rolled strip steel suppresses the defect at its source by synergistically optimizing key process parameters such as roughing mill feed time, rolling passes, and descaling water activation mode. Specifically, controlling the time for the entire continuously cast billet to enter the roughing mill to ≤90s significantly reduces the billet's residence time in air, lowers the temperature drop during roughing, and prevents edge peeling caused by decreased fluidity at low temperatures. Employing a multi-pass roughing process effectively disperses the reduction in a single pass, preventing excessive edge deformation that hinders effective rolling. Using an even-numbered pass activation mode for descaling slows the cooling process, avoiding peeling caused by sudden cooling of the edges in the preceding roughing passes. Through the control of each step and process parameter, the edge peeling rate can be stably controlled at ≤0.8%.

[0089] The cold-rolled strip steel prepared using the method of this invention exhibits a fundamental improvement in edge peeling defects, significantly enhancing the surface smoothness and integrity of the strip steel and effectively reducing the risk of edge cracking during subsequent cold rolling processes. Simultaneously, the substantial reduction in defect incidence directly decreases strip steel rework and scrapping, significantly lowering production costs and improving yield and production efficiency. The optimized process parameters demonstrate strong synergistic adaptability, requiring no additional equipment investment. While ensuring production continuity, it achieves simultaneous improvements in strip steel quality, economic benefits, and production efficiency, solving the technical problems of high edge peeling rates and high production costs in the production of cold-rolled strip steel using existing hot rolling processes.

[0090] In summary, the above-described technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for reducing edge peeling of cold-rolled strip steel, characterized in that, include: The continuously cast billet is subjected to rough rolling, finish rolling and coiling in sequence to obtain cold-rolled strip steel; The roughing process includes multiple rolling passes; The tapping temperature of the continuously cast billet is 1180~1230℃; The time for all the continuously cast billets to enter the roughing mill is ≤90s; In the rough rolling step, the dephosphorization water is only turned on in the last N even-numbered rolling passes; Wherein, 1≤N≤3, N is an integer, and the number of times the dephosphorization water is turned on is an even number of times.

2. The method for reducing edge peeling of cold-rolled strip steel according to claim 1, characterized in that, The flow rate of the phosphorus removal water is 450~480 m³ / h. 3 / h.

3. The method for reducing edge peeling of cold-rolled strip steel according to claim 1, characterized in that, The thickness of the intermediate billet obtained after rough rolling is 45~55mm; In the roughing rolling step, when the head of the continuously cast billet bends downward, the roughing roll speed ratio is 1 to 1.1, and when the head of the continuously cast billet bends upward, the roughing roll speed ratio is 1.1 to 1; and the symmetrical center line of the large vertical roll and the width center line of the continuously cast billet are both aligned with the rolling center line of the roughing mill.

4. The method for reducing edge peeling of cold-rolled strip steel according to claim 1, characterized in that, The exit temperature of the roughing mill is 1080~1110℃.

5. The method for reducing edge peeling of cold-rolled strip steel according to claim 1, characterized in that, The inlet temperature of the finishing mill is 980~1040℃; The exit temperature of the finishing mill is 850~890℃.

6. The method for reducing edge peeling of cold-rolled strip steel according to claim 1, characterized in that, The winding temperature is 580~600℃.

7. The method for reducing edge peeling of cold-rolled strip steel according to claim 1, characterized in that, The components of the continuously cast billet, by mass percentage, include: C 0.15~0.24wt%, Mn 0.8~1.3wt%, Si 0.18~0.3wt%, P ≤0.015wt%, Al 0.01~0.06wt%, S ≤0.003wt%, Ti 0.002~0.045wt%, B 0.0015~0.004wt%, V ≤0.006wt%, Nb 0.002~0.005wt%, Cr 0.10~0.25wt%, As 0.001~0.01wt%, N ≤0.008wt%, balance being iron and unavoidable impurities.

8. The method for reducing edge peeling of cold-rolled strip steel according to claim 1, characterized in that, The number of rolling passes is 5 to 8. The time for all the continuously cast billets to enter the roughing mill is 60-90 seconds.

9. The method for reducing edge peeling of cold-rolled strip steel according to claim 1, characterized in that, The exit temperature of the roughing mill is 1080~1100℃; The inlet temperature of the finishing mill is 980~990℃; The exit temperature of the finishing mill is 850~860℃.

10. A cold-rolled strip steel, characterized in that, It is prepared by the method described in any one of claims 1 to 9.

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