A production method for high carbon tool steel hot rolling small crown control

Abstract

The application provides a production method for high-carbon tool steel hot-rolled small-crown control, comprising the following steps: S1, slab heating: entering a heating furnace in a hot charging mode, with an entering temperature greater than or equal to 300 DEG C; after entering the furnace, a slow temperature rising heating system is adopted, and the slab sequentially passes through a preheating section, a first heating section, a second heating section, a solid solution section and a furnace outlet; S2, rough rolling: after the furnace outlet, the slab sequentially passes through a four-roller rough rolling mill with large vertical rollers for width reduction, and rough rolling is performed in 7 passes; S3, finish rolling: four-roller seven-stand finish rolling mill is adopted for rolling, and high-speed steel rollers are adopted for the F2, F3 and F4 stands; S4, coiling; S5, flattening: convex roller flattening is adopted. The application adopts a slow temperature rising heating mode, can ensure that the temperature of the slab head and tail has small fluctuation, the austenite structure is uniform and complete, the rolling force fluctuation of rough rolling and finish rolling is small, and the crown control is more stable.

Description

Technical Field

[0001] This invention relates to the field of steel manufacturing, and specifically to a production method for controlling the small crown of hot-rolled high-carbon tool steel. Background Technology

[0002] High-carbon tool steel mainly refers to steel grades with a carbon content of 0.65% to 1.35%. High-carbon tool steel has high hardenability and wear resistance, and is widely used in the manufacture of high-precision hardware tools. Hot-rolled high-carbon tool steel usually requires annealing and cold rolling. Cold-rolled finished products require high thickness accuracy. Since the cold rolling process has limited ability to improve transverse thickness differences, the hot-rolled base material must have a good cross-sectional shape profile.

[0003] The crown of hot-rolled coils generally refers to the difference between the thickness H at the middle of the strip width and the representative thickness Hx near the edge, after removing the edge dorp of the strip. It is an important indicator reflecting the cross-sectional shape and profile of the steel plate. Excessive crown can easily lead to thinner edges, resulting in excessive transverse thickness variation after cold rolling. Figure 1 The schematic diagram of the strip cross-section shown shows the formula for calculating the crown: Cx = H - (H x1 +H x2 ) / 2, where H is the thickness at the center, H x1 H represents the operating side thickness. x2 This refers to the thickness on the transmission side. Most hot-rolled sheet crown control is expressed as C40, which is the average thickness difference between the center thickness and the two 40mm edges. According to feedback from downstream cold-rolling mills, when the crown C40 of the hot-rolled steel sheet is controlled within 50μm, it can better meet the requirements of subsequent cold-rolling processes.

[0004] Currently, crown control in hot rolling is mainly achieved through the shifting and bending of the work rolls on the front stand. However, high-carbon tool steel has high strength, is extremely sensitive to temperature changes, has a large rolling load, and poor rolling stability, making crown control difficult and frequently resulting in uncontrolled crown, which greatly hinders subsequent cold rolling processes.

[0005] In the existing technology, the crown control during hot rolling of high-carbon tool steel has the following problems:

[0006] 1. In the early stage of producing high carbon tool steel, the roll temperature is uneven due to the small amount of steel passing through, resulting in different thermal expansion of the roll at different positions. The actual thermal crown of the roll is too large when passing through the steel, and the crown of the steel coil rolled in the early stage is not under control.

[0007] 2. When producing high-carbon tool steel in the later stages of rolling mill production, the middle part of the rolls is severely worn. Adjustments by shifting and bending the rolls are ineffective, and the crown of the rolled workpiece will remain high.

[0008] 3. Fluctuations in rolling force caused by temperature changes, or unreasonable control or distribution of rolling force in the front stand when changing specifications, resulting in uncontrolled crown.

[0009] Therefore, there is an urgent need for a production method that can effectively control the small crown of hot-rolled high-carbon tool steel to meet the requirements of downstream cold-rolling processing. Summary of the Invention

[0010] The purpose of this invention is to provide a production method for controlling the small crown of hot-rolled high-carbon tool steel. By optimizing the rolling schedule, heating regime, rolling process parameters, etc., the crown of hot-rolled high-carbon tool steel can be effectively controlled, the thickness difference of the strip cross section can be improved, and the application requirements of downstream users can be met.

[0011] In the technical solution adopted in this invention, the high-carbon tool steel composition includes: C: 0.65-1.35%, Si: 0-0.35%, Mn: 0-1.0%, Cr: 0-1.0%, P≤0.030%, S≤0.030%, with the remainder being iron and unavoidable impurities.

[0012] A production method for controlling the small crown of hot-rolled high-carbon tool steel according to the present invention includes the following steps:

[0013] S1. Rolling Schedule: The rolling production of high-carbon tool steel needs to be scheduled into the early to mid-stages of the roll cycle. The steel throughput of the roughing work rolls should not exceed 100,000 tons, and the steel throughput of the finishing F7 rolls should not exceed 80 km. For the initial rolling, steel grades with a width greater than 200 mm and a thickness greater than 4.0 mm should be used as transition material for hot rolling, ensuring that the hot rolling area covers the contact position between the strip and the rolls when the rolls reach their limit. During production scheduling, the quantity of transition material (transition material is generally a steel coil transitioning from a thicker specification to a thinner specification, so it is often called thickness transition material) should be controlled. Simultaneously, the quantity of transition material should be ≥10 coils or the F7 steel throughput should be greater than 8 km before rolling thin specifications, to ensure uniform roll temperature and normal roll thermal crown.

[0014] S2. Slab Heating: The thickness of the continuously cast slab is 220-240mm. It is charged into the heating furnace with a furnace temperature ≥300℃. After entering the furnace, a segmented and slow heating regime is adopted, passing through the preheating section, heating section one, heating section two, soaking section, and exiting the furnace. The temperature of the preheating section is 400-700℃, the temperature of heating section one is 700-900℃, the temperature of heating section two is 900-1100℃, the temperature of soaking section is 1000-1200℃, the soaking time is ≥50 minutes, the exit temperature is 1100-1200℃, and the total time in the furnace is 200-300 minutes.

[0015] S3. Roughing: After exiting the furnace, the slab passes sequentially through a four-high roughing mill with descaling and widening using large vertical rolls. Roughing is performed in seven passes, with descaling occurring in passes 1, 3, and 5. The flat roll reduction ratios for the seven passes are: 15%–25%, 15%–25%, 18%–28%, 20%–30%, 23%–33%, 25%–35%, and 28%–38%. The intermediate slab thickness is set at 30–56 mm, and the final roughing temperature is 1000–1150℃. For thinner specifications, a hot coiler is used after roughing to reduce the intermediate slab thickness and decrease the finishing rolling force.

[0016] S4. Finishing: The finishing mill adopts a four-roll, seven-stand finishing mill unit. The finishing mill stands F2, F3, and F4 use high-speed steel rolls. The finishing mill rolls are all CVC rolls. The finishing mill work roll shifting range is -150 to 150 mm. The bending roll force is preset from 0 to 2000 KN. The finishing mill thickness control adopts the absolute value AGC mode, and the rolling crown is set to 20-40 μm. A multi-function instrument monitors parameters such as thickness and C40 crown. The interstand water supply (ISC) for F1 and F2 is closed, while the rear stand is opened normally. The final rolling temperature is 800-950℃. Finishing mill reduction rates: F1: 40%-55%, F2: 40%-55%, F3: 30%-45%, F4: 25%-40%, F5: 20%-30%, F6: 15%-25%, F7: 8%-20%. Roll cooling water flow rate: 900-1200 m³ / h for the front stand. 3 / h, the cooling water level of the working rollers on the rear frame should be appropriately reduced to 500-1000m³ / h. 3 / h, reduce rolling force; optimize rolling speed. When the temperature drop at the tail end is large, resulting in excessive rolling force and crown at the tail end, speed-up rolling can be adopted to reduce the rolling force at the tail end; control the width of the guide side at the entry of the finishing mill by +30 to 50 mm of the rolling width to effectively prevent strip deviation, improve rolling stability and centering, and avoid long-term wear of the rolls on the same side.

[0017] S5. Winding: After laminar flow cooling, the coil is wound into a roll at a temperature of 550–700℃.

[0018] S6. Leveling: Leveling is performed using convex rollers with a roll crown of -0.4 to +0.4 mm, a leveling rolling force of 2000 KN to 10000 KN, and a tension of 50 to 300 KN. Using convex rollers reduces the stress on the edges during leveling, greatly improving the double-sided waviness of the strip edges, while also reducing the thickness drop at the edges, resulting in a more uniform transverse thickness of the strip.

[0019] Technical effects of the present invention:

[0020] This invention starts with the rolling schedule and sets clear requirements for the roll service life, hot roll material requirements, and roll hot crown formation system. This ensures that the actual crown is within a controllable range during hot rolling production, while also improving uneven wear and service life of the rolls and reducing roll consumption.

[0021] The present invention adopts a segmented and slow heating method, which can ensure that the temperature fluctuation at the beginning and end of the slab is small, the microstructure is uniform and complete in austenitization, the rolling force fluctuation between roughing and finishing rolling is small, and the crown control is more stable.

[0022] By reducing the water level between the stands in the finishing mill, optimizing the rolling load distribution and rolling speed, and increasing the cooling water flow rate of the work rolls in the front stand, the deformation of the front stand rolls is minimized, and better thermal crown is easily achieved. Combining the crown control functions of the CVC work rolls (roll shifting and bending) enables stable, mass production of high-carbon tool steel with small crown.

[0023] This invention innovatively proposes the use of convex rollers for the production of high-carbon tool steel, which can better control edge waviness while improving the transverse thickness difference of the strip.

[0024] Compared with other technologies, this invention requires no equipment improvement, has good operability, and can significantly improve the crown pass rate of high carbon tool steel, reducing the average crown of hot-rolled high carbon tool steel by more than 10μm, and reducing the failure rate from the original 15.9% to less than 5%. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the cross-section of the strip steel;

[0026] Figure 2 The curve showing the effect of rolling force variation on crown;

[0027] Figure 3 The curves show the effect of slab temperature changes on rolling force and crown.

[0028] Figure 4 The SK4 convexity curve obtained before applying the method of the present invention;

[0029] Figure 5 The SK4 convexity curve is obtained by applying the method of the present invention. Detailed Implementation

[0030] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with specific embodiments.

[0031] Example 1: Control of small crown in 75CR1 hot-rolled strip

[0032] 75CR1 is an alloy tool steel with good hardenability, widely used in various sawing tools such as circular saw blades, band saw blades, and cutting tools. Its chemical composition is: C: 0.76%, Si: 0.24%, Mn: 0.82%, Cr: 0.49%, P: 0.012%, S: 0.010%, with the remainder being iron and unavoidable impurities. The production steps for 75CR1 steel with a planned specification of 2.5*1200mm are as follows:

[0033] 1) Rolling schedule: Hot rolling production will commence when the roughing mill work roll throughput reaches approximately 60,000 tons. During finishing mill roll changes, the throughput of the F7 rolls will be controlled to not exceed 80 km. The initial transition material is 4.5*1500mm cross-section Q355B. After rolling 10 Q355B rolls, 3.0*1200mm 75CR1 will be produced, and then transitioned to a 2.5mm thickness based on the rolling conditions. During production scheduling, to ensure uniform roll temperature and normal roll crown, as directly rolling high-carbon steel in the first few coils can cause unstable crown control (sometimes resulting in very high crown), transition material must be rolled first. The quantity of transition material should be ≥10 coils or the F7 throughput should be greater than 8 km.

[0034] 2) Slab heating: The continuous casting slab thickness is 230mm. It is charged into the furnace hot at a temperature of 580℃. After entering the furnace, a segmented, slow heating regime is adopted, passing through the preheating section, heating section 1, heating section 2, soaking section, and then exiting the furnace. The preheating section temperature is 660℃, heating section 1 temperature is 850℃, heating section 2 temperature is 950℃, soaking section temperature is 1150℃, soaking time is 50 minutes, and the exit temperature is 1190℃, with a total furnace time of 230 minutes.

[0035] 3) Rough rolling: After exiting the furnace, the slab passes sequentially through a four-high roughing mill with large vertical rolls for descaling and width reduction. Rough rolling is performed in 7 passes, with descaling occurring in passes 1, 3, and 5. The flat roll reduction ratios for the 7 passes are: 18%, 20%, 22%, 22%, 23%, 26%, and 31%. The intermediate slab thickness is 34 mm, and the final roughing temperature is 1100℃.

[0036] 4) Finishing Rolling: A four-high, seven-stand finishing mill is used. High-speed steel rolls are used in stands F2, F3, and F4. All finishing rolls are CVC rolls. The work roll shifting positions for F1 to F7 are -45mm, -34mm, -6mm, -2mm, 76mm, 55mm, and 34mm, respectively. The bending roll forces for F1 to F7 are set to 897.6KN, 803.6KN, 1068.2KN, 919.9KN, 1227.5KN, and 1079.8KN, respectively. 722.7KN; Finishing thickness control adopts absolute value AGC mode, rolling crown is set at 20μm, and parameters such as average thickness and C40 crown are monitored by a multi-function instrument; Interstand water (ISC) between F1 and F2 is closed, and the rear stand is opened normally; Finishing temperature is 920℃; Finishing reduction rate: F1: 46%, F2: 44%, F3: 35%, F4: 31%, F5: 26%, F6: 16%, F7: 10%; Roll cooling water flow rate: Front stand working water flow rate is 993m³ / h. 3 / h, Cooling water for the rear frame work rollers 630m³ 3 / h; adopt speed-increasing rolling to reduce tail rolling force and crown; set the width of the guide at the entry of the finishing mill to 1250mm to prevent strip deviation, improve rolling stability and centering, and avoid long-term wear of the rolls on the same side.

[0037] 5) Winding: After laminar flow cooling, the product is wound into a roll at a temperature of 650℃.

[0038] 6) Leveling: The convex roller is used for leveling, with a leveling rolling force of 6810KN and a tension of 180KN.

[0039] The produced 75CR1 strip has a convexity within 45μm, and the convexity difference between the head, middle and tail of the strip is within 18μm, which meets the requirements of subsequent users.

[0040] In addition, according to statistics from the production line, the defect rate has decreased from 15.9% to 4.25%.

[0041] Example 2: SK4 Hot-Rolled Strip Steel Small Crown Control Process

[0042] SK4 is a carbon tool steel with high toughness and hardness, widely used in various tools such as lathe tools, planer tools, drill bits, paper cutters, and measuring tools. Its chemical composition is: C: 0.98%, Si: 0.25%, Mn: 0.36%, Cr: 0.19%, P: 0.015%, S: 0.009%, with the remainder being iron and unavoidable impurities. The production steps for SK4 steel with a planned specification of 2.0*1250mm are as follows:

[0043] 1) Rolling schedule: Hot rolling production begins when the roughing mill work roll throughput reaches approximately 60,000 tons. During finishing mill roll changes, the throughput of the F7 rolls is controlled to not exceed 80 km. First, a 4.5*1500mm cross-section Q235B transition material is rolled for roll warming. After rolling 6-10 rolls, 3.0*1250mm SK4 is produced. Two coils of 3.0mm thickness and two coils of 2.5mm thickness are produced from the transition material, followed by the production of 2.0mm SK4 thin-gauge rolls. During production scheduling, to ensure uniform roll temperature and normal roll crown, the quantity of transition material needs to be controlled. Directly rolling high-carbon steel in the first few coils can cause unstable crown control, sometimes resulting in very high crown. Therefore, it is necessary to roll transition material first for roll warming. The quantity of transition material should be ≥10 coils or the F7 throughput should be greater than 8 km.

[0044] 2) Slab Heating: The continuous casting slab thickness is 230mm. It is charged into the furnace hot at 650℃. After entering the furnace, a segmented, slow heating regime is adopted, passing through the preheating section, heating section one, heating section two, solution treatment section, and then exiting the furnace. The preheating section temperature is 660℃, heating section one temperature is 800℃, heating section two temperature is 900℃, soaking section temperature is 1100℃, soaking time is 60 minutes, and the exit temperature is 1200℃, with a total furnace time of 250 minutes.

[0045] 3) Roughing: After exiting the furnace, the slab passes sequentially through a four-high roughing mill with rough descaling and widening using large vertical rolls. Roughing is performed in 7 passes, with descaling occurring in passes 1, 3, and 5. The flat roll reduction ratios for the 7 passes are: 16%, 20%, 23%, 25%, 26%, 28%, and 31%. The intermediate slab thickness is 32 mm, and the final roughing temperature is 1080℃. Hot-rolled coiling is used to reduce the intermediate slab thickness and decrease the finishing rolling force.

[0046] 4) Finishing Rolling: A four-high, seven-stand finishing mill is used. High-speed steel rolls are used in stands F2, F3, and F4. All finishing rolls are CVC rolls. The work roll shifting positions for F1 to F7 are 107mm, 130mm, 147mm, 73mm, 55mm, 53mm, and 15mm, respectively, with bending forces of 898.9KN, 921.5KN, 810.4KN, 812.2KN, 882.9KN, 800.6KN, and 789.6KN, respectively. KN; Finishing thickness control adopts absolute value AGC mode, rolling crown target set at 20μm, and average thickness and C40 crown parameters are monitored using a multi-function instrument; Interstand water (ISC) for F1 and F2 is closed, and the rear stand is opened normally; Finishing temperature 920℃; Finishing reduction rate: F1: 49%, F2: 45%, F3: 36%, F4: 34%, F5: 28%, F6: 16%, F7: 11%; Roll cooling water flow rate: front stand working water flow rate 980m³ / h 3 / h, Cooling water for the rear frame work rollers 660m³ 3 / h; adopt speed-increasing rolling to reduce tail rolling force and crown; set the width of the guide at the entry of the finishing mill to 1300mm to prevent strip deviation, improve rolling stability and centering, and avoid long-term wear of the rolls on the same side.

[0047] 5) Winding: After laminar flow cooling, the product is wound into a roll at a temperature of 620℃.

[0048] 6) Leveling: The cam roller is used for leveling, with a leveling rolling force of 4650KN and a tension of 120KN.

[0049] The average crown of the produced SK4 strip was reduced from 47.7μm to 20μm, and the crown difference between the head, middle and tail of the strip was within 15μm, which met the small crown requirements of subsequent cold rolling.

[0050] In addition, according to statistics from the production line, the defect rate has been reduced to 4.20%.

[0051] Example 3

[0052] The difference between this embodiment and Embodiment 1 is that in the slab heating step, the preheating section temperature is 400℃, the first heating section temperature is 700℃, the second heating section temperature is 900℃, the soaking section temperature is 1000℃, the soaking time is 70 minutes, the furnace exit temperature is 1000℃, and the total furnace time is 300 minutes.

[0053] The crown of the produced 75CR1 strip was reduced to 45.3μm, and the crown difference between the head, middle and tail of the strip was within 16μm, which met the small crown requirements of subsequent cold rolling.

[0054] Example 4

[0055] The difference between this embodiment and Embodiment 1 is that in the slab heating step, the preheating section temperature is 700℃, the first heating section temperature is 900℃, the second heating section temperature is 1100℃, the soaking section temperature is 1200℃, the soaking time is 50 minutes, the furnace exit temperature is 1200℃, and the total furnace time is 200 minutes.

[0056] The crown of the produced 75CR1 strip was reduced to 20.8μm, and the crown difference between the head, middle and tail of the strip was within 11μm, which met the small crown requirements of subsequent cold rolling.

[0057] Example 5

[0058] The difference between this embodiment and Embodiment 1 is that, in the roughing step, the distribution ratio of the reduction rate of the 7 passes of flat rolls is: 15%, 15%, 18%, 20%, 30%, 35%, and 38%.

[0059] The crown of the produced 75CR1 strip was reduced to 42.7μm, and the crown difference between the head, middle and tail of the strip was within 17μm, which met the small crown requirements of subsequent cold rolling.

[0060] Example 6

[0061] The difference between this embodiment and Embodiment 1 is that, in the roughing step, the distribution ratio of the reduction rate of the 7 passes of flat rolls is: 25%, 25%, 28%, 30%, 33%, 25%, and 28%.

[0062] The crown of the produced 75CR1 strip was reduced to 40.2μm, and the crown difference between the head, middle and tail of the strip was within 18μm, which met the small crown requirements of subsequent cold rolling.

[0063] Example 7

[0064] The difference between this embodiment and Embodiment 1 is that, in the finishing rolling step, the finishing rolling reduction ratios are: F1: 40%, F2: 40%, F3: 45%, F4: 25%, F5: 30%, F6: 25%, and F7: 8%.

[0065] The 75CR1 strip produced has a reduced crown of 49.1μm, and the crown difference between the head, middle and tail of the strip is within 15μm, which meets the small crown requirements of subsequent cold rolling.

[0066] Example 8

[0067] The difference between this embodiment and Embodiment 1 is that, in the finishing rolling step, the finishing rolling reduction ratios are: F1: 55%, F2: 55%, F3: 30%, F4: 40%, F5: 20%, F6: 15%, and F7: 20%.

[0068] The crown of the produced 75CR1 strip was reduced to 47.2μm, and the crown difference between the head, middle and tail of the strip was within 16μm, which met the small crown requirements of subsequent cold rolling.

[0069] Analysis of factors affecting the production of strip steel with small crown:

[0070] like Figure 2 As shown, the relationship between the changing trends of rolling force and crown during the production of the same coil of steel was examined. Figure 2 As can be seen from the curves shown, the trend of crown variation is basically consistent with the trend of rolling force variation. Therefore, to produce strip with small crown, it is necessary to minimize the rolling force in order to obtain strip with even smaller crown.

[0071] like Figure 3 As shown, the relationship between the variation trend of crown and the variation trend of rolling temperature during the production of the same coil of steel was examined. Figure 3As can be seen from the curves shown, the trend of crown change is opposite to that of temperature change. Therefore, it is useful to appropriately increase the temperature to produce strip with small crown.

[0072] like Figure 4 and Figure 5 As shown, the convexity curves of the strip before and after using the production method of the present invention are displayed respectively. The results show that the overall convexity of the strip is larger before using the production method of the present invention, which is above 40 μm. Taking Example 2 as an example, the overall convexity of the strip is reduced to about 20 μm after using this method.

[0073] Comparative Example 1

[0074] The difference between this comparative embodiment and Embodiment 1 is that the preheating temperature is 450°C, the first heating temperature is 600°C, the second heating temperature is 800°C, the soaking temperature is 1100°C, the soaking time is 60 minutes, the furnace exit temperature is 1200°C, and the total furnace time is 250 minutes.

[0075] The final 75CR1 strip produced had a crown exceeding 60μm, which could not meet the requirements for subsequent cold rolling.

[0076] Comparative Example 2

[0077] The difference between this comparative example and Example 1 is that the roughing process uses a 5-pass reduction process with reduction rates of 23%, 27%, 26%, 28%, and 30% for each pass. The 5-pass roughing process results in a thicker intermediate billet and a larger rolling force in the finishing process.

[0078] The final 75CR1 strip produced had a crown greater than 60μm, which was insufficient to meet the crown requirements for subsequent cold rolling.

[0079] Comparative Example 3

[0080] The difference between this comparative example and Example 1 is that the finishing rolling reduction rates F1-F7 are F1: 38%, F2: 35%, F3: 25%, F4: 42%, F5: 32%, F6: 14%, and F7: 13%, respectively.

[0081] The final 75CR1 strip had a crown greater than 60μm, which was insufficient to meet the crown requirements for subsequent cold rolling.

[0082] Comparative Example 4

[0083] The difference between this comparative example and Example 1 is that when producing high-carbon tool steel, the rolling schedule was scheduled to the end of the rolling mill, and the steel throughput of the finishing F7 work roll exceeded 80KM and production was still ongoing. The resulting 75CR1 strip had a plate crown greater than 60μm, which was difficult to meet the crown requirements of subsequent cold rolling.

[0084] As can be seen from the above comparative examples, in the production method of the present invention, by controlling the parameters of factors such as rolling schedule arrangement, slab heating, roughing passes, roughing and reduction rates, and finishing reduction rates, the hot rolling crown can be perfectly controlled to below 50μm.

[0085] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A production method for controlling the small crown of hot-rolled high-carbon tool steel, characterized in that, Includes the following steps: S1. Rolling schedule arrangement steps: Schedule the rolling production of high carbon tool steel to the early to mid-stage of the roll cycle, with the steel throughput of roughing work rolls within 100,000 tons and the steel throughput of finishing F7 rolls within 80 km. S2. Slab heating: The thickness of the continuously cast slab is 220-240mm. It is charged into the heating furnace by hot charging and the furnace temperature is ≥300℃. After entering the furnace, a segmented and slow heating system is adopted, passing through the preheating section, heating section one, heating section two, soaking section, and exiting the furnace in sequence. S3. Rough rolling: After exiting the furnace, the slab passes through a four-high roughing mill with rough descaling and widening with large vertical rolls. The roughing process is carried out in 7 passes. The thickness of the intermediate slab is set to 30-56 mm, and the final rolling temperature is 1000-1150℃. S4. Finishing Rolling: A four-roll, seven-stand finishing mill is used. High-speed steel rolls are used in stands F2, F3, and F4. All finishing rolls are CVC rolls. The roll shifting range is -150 to 150 mm, and the bending force is preset from 0 to 2000 kN. Finishing thickness control uses absolute value AGC mode, with rolling crown set at 20 to 40 μm. A multi-function instrument monitors the thickness and C40 crown parameters. Water between stands F1 and F2 is shut off, while the rear stands are opened normally. The final rolling temperature is 800–950℃. During finishing operation, the finishing reduction rate is: F1: 40%–55%, F2: 40%–55%, F3: 30%–45%, F4: 25%–40%, F5: 20%–30%, F6: 15%–25%, F7: 8%–20%. Roll cooling water flow rate: 900–1200 m³ / h for the front stand. 3 / h, the cooling water level of the working rollers on the rear frame is reduced to 500-1000m³. 3 / h; S5. Winding: After laminar flow cooling, the coil is wound into a roll at a temperature of 550-700℃. S6. Leveling: Using convex rollers for leveling reduces the stress on the edges during leveling, improves the double-sided waviness of the strip edges, and reduces the thickness drop at the edges, making the transverse thickness of the strip more uniform.

2. The production method according to claim 1, characterized in that, High-carbon tool steel contains the following elements by weight percentage: carbon: 0.65-1.35%, silicon: 0-0.35%, manganese: 0-1.0%, chromium: 0-1.0%, phosphorus ≤0.030%, sulfur ≤0.030%, with the remainder being iron and unavoidable impurities.

3. The production method according to claim 1, characterized in that, During the slab heating operation, the preheating zone temperature is 400-700℃, the first heating zone temperature is 700-900℃, the second heating zone temperature is 900-1100℃, the soaking zone temperature is 1000-1200℃, the soaking time is ≥50 minutes, the furnace exit temperature is 1100-1200℃, and the total furnace time is 200-300 minutes.

4. The production method according to claim 1, characterized in that, During the roughing operation, descaling is performed in passes 1, 3, and 5. The flat roll reduction ratios for the seven passes are: 15%–25%, 15%–25%, 18%–28%, 20%–30%, 23%–33%, 25%–35%, and 28%–38%.

5. The production method according to claim 1, characterized in that, During finishing rolling operations, the width of the side guide at the finishing rolling inlet is controlled at +30 to 50 mm of the rolling width.

6. The production method according to claim 1, characterized in that, During the leveling operation, the roll crown is -0.4 to +0.4 mm, the leveling rolling force is 2000 KN to 10000 KN, and the tension is 50 to 300 KN.

7. The high-carbon tool steel product prepared by the production method according to claim 1.

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