Cold continuous rolling method of high-strength steel and hot rolling maintenance device

Abstract

The application discloses a high-strength steel cold continuous rolling method and a hot rolling maintenance device. The rolling method comprises smelting and refining molten iron; continuously casting and heating the molten iron into a slab; sequentially hot continuous rolling the heated slab by dividing the slab into a head part, a middle part and a tail part; coiling the head part and the tail part at a first temperature based on a first set hot rolling coiling temperature range, and coiling the middle part at a second temperature based on a second set hot rolling coiling temperature range, the first temperature being higher than the second temperature; and cold continuous rolling the steel coil after the hot continuous rolling. The rolling method avoids the generation of martensite structure due to the excessively low hot rolling coiling temperature of the head and tail parts by making the hot rolling coiling temperature of the head and tail parts higher than that of the middle part, so that the rolling force of the head and tail parts is relatively small during the cold continuous rolling, the cold continuous rolling is stable and smooth, and the problem that the abnormal shutdown or the broken strip of the cold continuous rolling caused by the sharp increase of the rolling force of the head and tail parts is solved.

Description

Technical Field

[0001] This application relates to the field of steel rolling technology, and in particular to a cold continuous rolling method and a hot rolling maintenance device for high-strength steel. Background Technology

[0002] Cold rolling of high-strength steel is a common challenge in the steel industry. Especially in cold rolling processes, the ends of the strip, compared to the middle section, experience faster cooling and lower coiling temperatures after hot rolling, resulting in higher mechanical properties and making them prone to excessive rolling forces during cold rolling. For high-strength steel, the rolling force during cold rolling is already near its limit. The high mechanical properties of hot-rolled strip will cause the rolling force to exceed the capacity of the cold rolling equipment, leading to abnormal shutdowns or strip breakage of the cold rolling mill.

[0003] In the published papers and patent documents, the main methods to achieve stable rolling of high-strength steel are to optimize the setting of cold rolling mill roll process parameters, rolling load distribution, reduction of cold rolling mill reduction rate, unit tension of strip steel between stands, rolling lubrication process parameters, optimization of composition, and reduction of coiling temperature. Summary of the Invention

[0004] This application provides a cold continuous rolling method for high-strength steel, which can reduce the rolling force at the beginning and end of the cold continuous rolling mill when producing high-strength steel by about 1000KN to 1500KN, solving the problem of abnormal shutdown or strip breakage in cold continuous rolling caused by the surge in rolling force in existing high-strength steel production.

[0005] S1. Smelting and refining molten iron;

[0006] S2. Molten steel is continuously cast into slabs and heated;

[0007] S3. The heated steel strip is subjected to hot continuous rolling, wherein the steel strip is divided into three parts, the head, the middle and the tail, and hot rolling is performed sequentially. The head and the tail are coiled at a first temperature based on a first set hot rolling coiling temperature range, and the middle is coiled at a second temperature based on a second set hot rolling coiling temperature range to obtain a strip steel coil. The first temperature is higher than the second temperature.

[0008] S4. Perform cold continuous rolling on the hot-rolled strip steel coil.

[0009] Beneficial effects

[0010] The cold continuous rolling method for high-strength steel in this invention adjusts the hot rolling coiling temperatures at the beginning and end of the strip and in the middle of the hot rolling process. The hot rolling coiling temperatures at the beginning and end are higher than those in the middle, but the temperature difference is not significant. This results in higher hot rolling coiling temperatures at the beginning and end of the strip and lower mechanical properties at the beginning and end, preventing the formation of martensitic structures due to excessively low coiling temperatures at the beginning and end. Consequently, the rolling force at the beginning and end of the strip is relatively smaller during cold continuous rolling, achieving stable and smooth cold continuous rolling. When producing high-strength steel, the rolling force at the beginning and end of the cold continuous rolling mill can be reduced by 1000KN to 1500KN, solving the problem of a sharp increase in rolling force at the beginning and end of the strip during cold continuous rolling, which can easily lead to abnormal shutdowns or strip breakage. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a flowchart of a cold continuous rolling method for high-strength steel provided in an embodiment of the present invention;

[0013] Figure 2 This is a flowchart of the hot continuous rolling substandard determination process for high-strength steel provided by an embodiment of the present invention for a cold continuous rolling method;

[0014] Figure 3 This is a flowchart of the process parameter determination system in the hot continuous rolling process of the high-strength steel hot continuous rolling method provided in the embodiments of the present invention.

[0015] Explanation of reference numerals in the attached figures:

[0016] 1. Hot rolling L2 system, corresponding to the hot rolling parameter setting unit; 2. Process parameter determination system, corresponding to the process parameter determination unit; 3. Hot rolling L3 system, corresponding to the hot rolling interception unit. Detailed Implementation

[0017] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely intended to explain the present invention and not to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present invention by illustrating examples of the invention.

[0018] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0019] To address the problems of the prior art, this invention provides a cold continuous rolling method for high-strength steel. The cold continuous rolling method for high-strength steel provided by this invention will be described below.

[0020] like Figure 1 As shown, an embodiment of this application provides a cold continuous rolling method for high-strength steel, comprising:

[0021] S1. Use a blast furnace to smelt molten iron to obtain molten steel, use a converter to smelt molten steel, and then use an LF furnace or RH furnace to refine the molten steel to obtain refined molten steel.

[0022] S2. Refined molten steel is continuously cast into slabs to obtain steel slabs, which are then heated to facilitate rapid hot rolling.

[0023] S3. The heated steel slab is subjected to hot continuous rolling, wherein the steel strip is divided into three parts: head, middle and tail. The head and tail are coiled at a first temperature within a first set hot rolling coiling temperature range, and the middle is coiled at a second temperature within a second set hot rolling coiling temperature range to obtain strip steel coil. The first temperature is higher than the second temperature. The steel strip is the steel slab in the hot continuous rolling process.

[0024] S4. The hot-rolled strip steel coil is then cold-rolled to produce high-strength steel.

[0025] The cold continuous rolling method for high-strength steel in this embodiment of the invention adjusts the hot rolling coiling temperature at the beginning and end of the hot rolling process and the hot rolling coiling temperature in the middle of the strip. The hot rolling coiling temperature at the beginning and end of the strip is higher than that in the middle, but the temperature difference is not significant. This results in a higher hot rolling coiling temperature at the beginning and end of the hot-rolled coil and lower mechanical properties at the beginning and end, avoiding the formation of martensitic structures due to excessively low hot rolling coiling temperatures at the beginning and end. Consequently, the rolling force at the beginning and end of the high-strength steel is relatively small during the cold continuous rolling process, achieving stable and smooth cold continuous rolling. When producing high-strength steel, the rolling force at the beginning and end of the cold continuous rolling mill can be reduced by 1000KN to 1500KN, solving the problem that a sharp increase in rolling force at the beginning and end of the cold continuous rolling process can easily lead to abnormal shutdowns or strip breakage.

[0026] According to an embodiment of this application, step S3 includes continuously acquiring the single-point value T1 of the head coiling temperature during the hot strip rolling process.

[0027] Determine whether the obtained head winding temperature single-point value T1 meets the first set hot rolling winding temperature range: first set hot rolling winding temperature -50℃ ≤ T1 ≤ first set hot rolling winding temperature +30℃.

[0028] If the single-point value T1 of the head coiling temperature meets the first set hot-rolling coiling temperature range, the coiling temperature is determined to be normal, and hot rolling continues. If the single-point value T1 of the head coiling temperature does not meet the first set hot-rolling coiling temperature range, the coiling temperature is determined to be abnormal, and the coil with the abnormal coiling temperature is intercepted to prevent it from entering the subsequent cold rolling process. At the same time, the location and length of the excess are recorded so that after hot rolling is completed, the hot-rolled plate can be reworked and the head coil exceeding the first set hot-rolling coiling temperature range can be cut off to obtain a head coil that meets the first set hot-rolling coiling temperature range.

[0029] In one embodiment, step S3 further includes

[0030] The single-point value T2 of the coiling temperature in the middle of the hot strip mill is continuously obtained.

[0031] Determine whether the obtained head winding temperature single-point value T2 meets the second set hot rolling winding temperature range: second set hot rolling winding temperature -30℃ ≤ T2 ≤ second set hot rolling winding temperature +30℃;

[0032] If the single-point value T2 of the central coiling temperature meets the second set hot-rolling coiling temperature range, the coiling temperature is determined to be normal, and hot rolling continues. If the single-point value T2 of the central coiling temperature does not meet the second set hot-rolling coiling temperature range, the coiling temperature is determined to be abnormal, and the coil with the abnormal coiling temperature is intercepted to prevent it from entering the subsequent cold rolling process. At the same time, the location and length of the excess are recorded so that after hot rolling is completed, the hot-rolled plate can be reworked and the portion of the central coil exceeding the second set hot-rolling coiling temperature range can be cut off to obtain a central coil that meets the second set hot-rolling coiling temperature range.

[0033] For steel coils with excessive winding temperature in the middle section, especially if the excess length is long, the entire coil may need to be re-evaluated. Re-evaluation means downgrading the entire coil that does not meet the minimum winding temperature and has a long excess length, so that it meets the requirements of a lower grade product.

[0034] In one embodiment, step S3 includes

[0035] The single-point value T3 of the tail coiling temperature during the hot strip rolling process is continuously obtained.

[0036] Determine whether the obtained tail winding temperature single-point value T3 meets the first set hot rolling winding temperature range: first set hot rolling winding temperature -50℃ ≤ T3 ≤ first set hot rolling winding temperature +30℃.

[0037] If the single-point value T3 of the tail coiling temperature meets the first set hot-rolling coiling temperature range, the coiling temperature is determined to be normal, and hot continuous rolling continues. If the single-point value T3 of the tail coiling temperature does not meet the first set hot-rolling coiling temperature range, the coiling temperature is determined to be abnormal, and the coil with the abnormal coiling temperature is intercepted to prevent it from entering the subsequent cold continuous rolling process. At the same time, the location and length of the excess are recorded so that after hot continuous rolling, the hot-rolled plate can be reworked and the tail coil exceeding the first set hot-rolling coiling temperature range can be cut off to obtain a tail coil that meets the first set hot-rolling coiling temperature range.

[0038] In one embodiment, step S3 includes

[0039] Continuously acquire single-point coiling temperature values ​​at the head, middle, and tail sections during the hot strip rolling process, and calculate the average value T of all single-point coiling temperature values ​​during the hot strip rolling process. A ;

[0040] Determine the average value T of the acquired single-point winding temperature. A Does it meet the third temperature range: Second set hot rolling coiling temperature -20℃ ≤ T A ≤Second set hot rolling coiling temperature +20℃;

[0041] If the average value T of the single-point temperature is takenA If the third temperature range is met, the coiling temperature is determined to be normal, and hot rolling continues; if the average value T of the single-point coiling temperature is... A If the third temperature range is not met, the coiling temperature is determined to be abnormal, and the coil with the abnormal coiling temperature is intercepted. At the same time, the location and length of the excess are recorded so that the portion of the coil exceeding the first temperature range can be reworked after hot continuous rolling and cut off.

[0042] For steel coils whose average hot-rolled coiling temperature does not meet the third temperature range for judgment, the following handling methods are available:

[0043] 1) If the temperature curve of the whole coil fluctuates too much, the resulting strip steel coil will be processed at a lower grade and treated as a strip steel coil product with lower requirements.

[0044] 2) If the average hot rolling temperature of the entire coil does not meet the standard due to temperature fluctuations at the beginning and end, cut off the beginning and end and continue cold rolling.

[0045] 3) If the temperature curve of the whole coil is off to the lower or upper limit, it shall be reclassified as a steel strip coil of other grades that meet the requirements based on its performance data.

[0046] According to an embodiment of the present invention, the first temperature is 18°C ​​to 22°C higher than the second temperature, so that the difference between the hot rolling coiling temperature at the tail end and the hot rolling coiling temperature in the middle of the hot strip does not exceed 22°C. This avoids the formation of martensite due to excessively low hot rolling coiling temperature at the tail end of the strip, which would lead to excessively high rolling force in the subsequent cold rolling process. This, in turn, avoids shutdown or strip breakage caused by a sharp increase in rolling force during the cold rolling process.

[0047] In one embodiment, the first temperature is 20°C higher than the second temperature.

[0048] In the above embodiments, the first set hot rolling coiling temperature is set to a predetermined temperature of 578°C to 632°C; the second set hot rolling coiling temperature is set to a predetermined temperature of 560°C to 610°C. The predetermined temperature is a point value, that is, the temperature at which each part is suitable for processing hot-rolled steel strip.

[0049] In one embodiment, the first set hot rolling temperature is set to a temperature between 580°C and 630°C.

[0050] In one embodiment, the rolling length of the head and tail of the hot rolling step is 16-32m, preferably 30m, to reduce the cold rolling cut-off length of the head and tail.

[0051] In another embodiment, the rolling method further includes step S5:

[0052] S5. Anneal the cold-rolled strip steel coil to obtain high-strength steel.

[0053] In one embodiment of this application, the rolling method further includes step S6:

[0054] The high-strength steel that has completed the annealing in step S5 is leveled by a leveling machine and then finished by coiling or cutting to obtain the desired high-strength steel.

[0055] A second aspect of the embodiments of this application provides a hot-rolled maintenance device, comprising:

[0056] The hot rolling parameter setting unit is used to set the hot rolling length of the head and tail of the steel strip, as well as the hot rolling coiling temperature of the head, middle, and tail of the steel strip during the hot continuous rolling process; it is also used to obtain and upload the single-point value and average value of the hot rolling coiling temperature of the head, middle, and tail of the steel strip during the hot continuous rolling process. The average value of the hot rolling coiling temperature refers to the average value calculated from the single-point values ​​of all hot rolling coiling temperatures, including the head, middle, and tail, i.e., the average value of the single-point values ​​of the hot rolling coiling temperature of the entire steel coil.

[0057] The process parameter determination unit is used to set the first set hot rolling coiling temperature range for the head and tail of the hot rolling process, the second set hot rolling coiling temperature range for the middle section, and the third temperature range of the average hot rolling coiling temperature. The unit then determines whether the single-point values ​​of the hot rolling coiling temperature for the head and tail and the average hot rolling coiling temperature for the middle section, uploaded by the hot rolling parameter setting unit, meet the corresponding first set hot rolling coiling temperature range, second set hot rolling coiling temperature range for the middle section, and third temperature range of the average hot rolling coiling temperature according to the determination rules, and obtains and uploads the corresponding determination results.

[0058] The hot rolling interception unit is used to intercept strip steel coils that exceed the temperature range of each part during the hot continuous rolling process of the steel slab based on the judgment result uploaded by the process parameter judgment unit, so as to obtain strip steel coils that meet the temperature range of each part.

[0059] The technical solution and its advantages of this application will be described in detail below through specific embodiments.

[0060] Embodiments of this application provide a cold continuous rolling method for high-strength steel, comprising:

[0061] S1. Use a blast furnace to smelt molten iron to obtain molten steel, use a converter to smelt molten steel, and then use an LF furnace or RH furnace to refine the molten steel to obtain refined molten steel.

[0062] S2. Refined molten steel is continuously cast into slabs to obtain steel slabs, which are then heated to facilitate rapid hot rolling.

[0063] S3. The heated steel slab is hot-rolled continuously, wherein the steel strip is divided into three parts: head, middle, and tail. The hot rolling length of the head and tail is 30 meters each. The head and tail are coiled at a first temperature within a first set hot rolling coiling temperature range, and the middle is coiled at a second temperature within a second set hot rolling coiling temperature range to obtain a strip steel coil. The first temperature is higher than the second temperature. The first set hot rolling coiling temperature range is 580℃~630℃, and the second set hot rolling coiling temperature range is 560℃~610℃. The first temperature is 20℃ higher than the second temperature, so that the hot rolling coiling temperature of the head and tail is higher than that of the middle, thus obtaining a strip steel coil.

[0064] The present invention will be described below. Figure 3 The hot rolling maintenance device shown identifies and intercepts substandard steel coils during the hot continuous rolling process. The specific process is as follows:

[0065] 1) First, set the hot rolling parameters for high-strength steel in hot rolling parameter unit 1. The rules for setting the head and tail temperatures and lengths of high-strength steel are shown in Table 1 below:

[0066] Table 1 Rules for Setting the Head and Tail Temperatures and Lengths of High-Strength Steel

[0067]

[0068] According to the set values ​​of the hot rolling coiling temperature for the head, middle, and tail sections in Table 1, as well as the lengths of the head and tail sections, the set parameters are maintained in the hot rolling L2 system, i.e., hot rolling parameter unit 1, to carry out the production and control of the hot continuous rolling process; the single-point values ​​of the hot rolling coiling temperature for the head, middle, and tail sections and the average value of the hot rolling coiling temperature during the hot continuous rolling process are obtained through the hot rolling L2 system and uploaded to the process parameter judgment system;

[0069] 2) According to the hot rolling temperature judgment rules for the head, middle, and tail sections of high-strength steel in the hot continuous rolling process in Table 2, the single-point and average values ​​of the hot rolling temperature at the head, middle, and tail sections of the hot continuous rolling process are judged in the process parameter judgment system, i.e., process parameter judgment unit 2. The process parameter judgment system judges whether the single-point and average values ​​are within the specification range according to the maintenance rules, and then judges whether the produced steel coil is qualified. Specifically, the hot rolling temperature judgment rules for high-strength steel are shown in Table 2.

[0070] Table 2 Rules for Determining the Hot Rolling Coiling Temperature of High-Strength Steel

[0071]

[0072] The single-point value determination range of the head and tail hot rolling coiling temperature in Table 2 is the first hot rolling coiling temperature range, the single-point value determination range of the middle hot rolling coiling temperature is the second hot rolling coiling temperature range, and the determination range of the average hot rolling coiling temperature is the third temperature range.

[0073] like Figure 2 As shown, step S3 specifically includes:

[0074] S301. Determine if the head hot rolling coil temperature exceeds the standard:

[0075] Continuously acquire the single-point value T1 of the head coiling temperature during the hot strip mill head rolling process;

[0076] Determine whether the obtained head winding temperature single-point value T1 meets the first set hot rolling winding temperature range: first set hot rolling winding temperature -50℃ ≤ T1 ≤ first set hot rolling winding temperature +30℃.

[0077] If the single-point value T1 of the head coiling temperature meets the first set hot-rolling coiling temperature range, the coiling temperature is determined to be normal, and hot continuous rolling continues. If the single-point value T1 of the head coiling temperature does not meet the first set hot-rolling coiling temperature range, the coiling temperature is determined to be abnormal, and the coil with the abnormal coiling temperature is intercepted to prevent it from entering the subsequent cold continuous rolling process. At the same time, the location and length of the excess are recorded so that after hot continuous rolling, the hot-rolled plate can be reworked and the head coil exceeding the first set hot-rolling coiling temperature range can be cut off to obtain a head coil that meets the first set hot-rolling coiling temperature range.

[0078] S302. Determine if the temperature of the hot-rolled coil in the middle section exceeds the standard:

[0079] The single-point value T2 of the coiling temperature in the middle of the hot strip mill is continuously obtained.

[0080] Determine whether the obtained head winding temperature single-point value T2 meets the second set hot rolling winding temperature range: second set hot rolling winding temperature -30℃ ≤ T2 ≤ second set hot rolling winding temperature +30℃;

[0081] If the single-point value T2 of the mid-coiling temperature meets the second set hot-rolling coiling temperature range, the coiling temperature is determined to be normal, and hot rolling continues. If the single-point value T2 of the mid-coiling temperature does not meet the second set hot-rolling coiling temperature range, the coiling temperature is determined to be abnormal, and the coil with the abnormal coiling temperature is intercepted to prevent it from entering the subsequent cold rolling process. At the same time, the location and length of the excess are recorded so that after hot rolling is completed, the hot-rolled plate can be reworked and the portion of the mid-coil exceeding the second set hot-rolling coiling temperature range can be cut off to obtain a mid-coil that meets the second set hot-rolling coiling temperature range.

[0082] For steel coils with excessive winding temperature in the middle section, especially if the excess length is long, the entire coil may need to be re-evaluated. Re-evaluation means downgrading the entire steel coil that does not meet the winding temperature requirement in the middle section and has a long excess length, so that it meets the requirements of a lower grade product.

[0083] S303. Determine if the tail-end hot-rolling coiling temperature exceeds the standard:

[0084] The single-point value T3 of the tail coiling temperature during the hot strip rolling process is continuously obtained.

[0085] Determine whether the obtained head winding temperature single-point value T3 meets the first set hot rolling winding temperature range: first set hot rolling winding temperature -50℃ ≤ T3 ≤ first set hot rolling winding temperature +30℃;

[0086] If the single-point value T3 of the tail coiling temperature meets the first set hot-rolling coiling temperature range, the coiling temperature is determined to be normal, and hot continuous rolling continues. If the single-point value T3 of the tail coiling temperature does not meet the first set hot-rolling coiling temperature range, the coiling temperature is determined to be abnormal, and the coil with the abnormal coiling temperature is intercepted to prevent it from entering the subsequent cold continuous rolling process. At the same time, the location and length of the excess are recorded so that after hot continuous rolling, the hot-rolled plate can be reworked and the tail coil exceeding the first set hot-rolling coiling temperature range can be cut off to obtain a tail coil that meets the first set hot-rolling coiling temperature range.

[0087] For steel coils with excessive winding temperatures at the beginning and end, the excessive portions should be removed during subsequent cold continuous rolling.

[0088] S304. Determine whether the average hot-rolled coiling temperature exceeds the standard:

[0089] Continuously acquire single-point values ​​of coiling temperature at the head, middle, and tail sections during the hot strip rolling process, and calculate the average value T of all single-point coiling temperature values ​​during the hot strip rolling process. A ;

[0090] Determine the average value T of the acquired single-point winding temperature. A Does it meet the third temperature range: Second set hot rolling coiling temperature -20℃ ≤ T A ≤Second set hot rolling coiling temperature +20℃;

[0091] If the average value T of the single-point temperature is taken A If the third temperature range is met, the coiling temperature is determined to be normal, and hot rolling continues; if the average value T of the single-point coiling temperature is... A If the third temperature range is not met, the coiling temperature is determined to be abnormal, and the coil with the abnormal coiling temperature is intercepted. At the same time, the location and length of the excess are recorded to complete the rework after hot continuous rolling and cut off the portion of the coil that exceeds the first temperature range;

[0092] 3) The judgment results of the process parameter judgment system are transmitted from the process parameter judgment system to the hot rolling L3 system; the hot rolling L3 system intercepts the steel coils that fail the hot rolling coiling temperature judgment according to the judgment results, so that the unqualified parts can be cut off after hot continuous rolling, so as not to affect the performance of subsequent finished products and avoid phenomena such as excessive rolling force and strip breakage in the cold continuous rolling mill.

[0093] S4. Perform cold continuous rolling on the hot-rolled strip steel coil;

[0094] S5. Anneal the cold-rolled strip steel coil to obtain high-strength steel.

[0095] S6. The annealed high-strength steel is leveled by a leveling machine and then finished by coiling or cutting to obtain the desired high-strength steel.

[0096] The following examples illustrate the use of the aforementioned cold continuous rolling method for high-strength steel to roll steel slabs.

[0097] Example 1: For grade A cold-rolled carbon-manganese high-strength steel, the code correspondence in each process is shown in Table 3 below.

[0098] Table 3. Slab Materials and Their Numbers

[0099] slab number Hot-rolled coil number Cold hard roll number 22340032000030 22Y00021500 A200176300

[0100] The high-strength steel is rolled according to the cold continuous rolling method of the embodiments of this application.

[0101] The main purpose of the hot rolling step is to roll thicker slabs into hot-rolled coils that meet product standards in terms of specifications, surface quality, and performance. The hot rolling coiling temperature primarily affects the performance of the hot-rolled coils. For Grade A, the hot rolling coiling temperature in the middle section is set at 590℃, and the head and tail hot rolling coiling temperatures are set at 610℃, with a head and tail length of 30m. The single-point value judgment range for the head and tail hot rolling coiling temperatures is 560℃~640℃, the single-point judgment range for the middle hot rolling coiling temperatures is 560℃~620℃, and the judgment range for the average hot rolling coiling temperature is 570℃~610℃.

[0102] The actual single-point value of the hot-rolled coil temperature at the last 25 meters of the hot-rolled coil with coil number 22Y00021500 is 551℃, which does not meet the judgment range of 560℃~640℃ for single-point values ​​of hot-rolled coil temperature at both ends. The actual average value of the hot-rolled coil temperature is 595℃, which meets the judgment range of 570℃~610℃ for the average value of hot-rolled coil temperature. Because the single-point value of the hot-rolled coil temperature at the last 25 meters of the hot-rolled coil with coil number 22Y00021500 is unqualified, the system intercepts the coil, cuts off the last 25 meters, and then continues to send it for cold rolling production.

[0103] Example 1 uses pickling and cold continuous rolling. The main purpose of pickling and rolling is to remove the iron oxide scale on the surface of the steel plate while rolling the thicker hot-rolled coil into a thinner cold-rolled coil. The 22Y00021500 hot-rolled coil obtained from hot continuous rolling is then subjected to cold continuous rolling. The rolling force at the beginning and end is 15000KN, and the rolling force in the middle is 16000KN, resulting in stable rolling.

[0104] Example 2: For grade B cold-rolled dual-phase high-strength steel, the code correspondence in each process is shown in Table 4 below. Table 4: Slab materials and their numbers.

[0105] slab number Hot-rolled coil number Cold hard roll number 1513459101040 2A00114400 A200153400

[0106] The high-strength steel is rolled according to the cold continuous rolling method of the embodiments of this application.

[0107] The main purpose of the hot rolling step is to roll thicker slabs into hot-rolled coils that meet product standards in terms of specifications, surface quality, and performance. The hot rolling coiling temperature mainly affects the performance of the hot-rolled coils. For grade B, the hot rolling coiling temperature in the middle is set at 600℃, the head and tail hot rolling coiling temperature is set at 620℃, and the head and tail length is set at 30m. The single-point value judgment range for the head and tail hot rolling coiling temperature is 570℃~650℃, the single-point value judgment range for the middle hot rolling coiling temperature is 570℃~630℃, and the judgment range for the average hot rolling coiling temperature is 580℃~620℃.

[0108] The actual single-point value of the hot-rolled coil temperature at the last 20 meters of the hot-rolled coil with coil number 2A00114400 is 551℃, which does not meet the judgment range of 570℃~650℃ for the single-point value of the hot-rolled coil temperature at the beginning and end. The actual average value of the hot-rolled coil temperature is 602℃, which meets the judgment range of 580℃~620℃ for the average value of the hot-rolled coil temperature. Because the single-point value of the hot-rolled coil temperature at the last 20 meters of the hot-rolled coil with coil number 2A00114400 is unqualified, the system intercepts the coil, cuts off the last 20 meters, and continues to send it to cold rolling production. In this example 2, pickling and cold continuous rolling are used. The main purpose of pickling is to remove the iron oxide scale on the surface of the steel plate while rolling the thicker hot-rolled coil into a thinner cold-rolled coil. The 2A00114400 hot-rolled coil obtained from hot continuous rolling is subjected to cold continuous rolling. The rolling force at the beginning and end is 13000KN, and the rolling force in the middle part is 14000KN, with stable rolling.

[0109] It should be clarified that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of the present invention.

[0110] It should also be noted that the exemplary embodiments mentioned in this invention describe methods or systems based on a series of steps or apparatus. However, this invention is not limited to the order of the steps described above; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0111] The above description is merely a specific embodiment of the present invention. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A method for cold continuous rolling of high-strength steel, characterized in that, Including the following steps: S1. Smelting and refining molten iron; S2. Molten steel is continuously cast into slabs and heated; S3. The heated steel slab is subjected to hot continuous rolling, wherein the steel strip is divided into three parts—head, middle, and tail—and coiled sequentially. The head and tail parts are coiled at a first temperature within a first set hot rolling temperature range, and the middle part is coiled at a second temperature within a second set hot rolling temperature range to obtain a strip steel coil. The first temperature is 18°C ​​to 22°C higher than the second temperature. The process of dividing the steel strip into three parts—head, middle, and tail—and coiling sequentially includes: The single-point value T1 of the head coiling temperature during the hot rolling process is continuously acquired; it is determined whether the acquired single-point value T1 of the head coiling temperature meets the first set hot rolling coiling temperature range: first set hot rolling coiling temperature - 50℃ ≤ T1 ≤ first set hot rolling coiling temperature + 30℃; if the single-point value T1 of the head coiling temperature meets the first set hot rolling coiling temperature range, the coiling temperature is determined to be normal and the hot rolling continues; if the single-point value T1 of the head coiling temperature does not meet the first set hot rolling coiling temperature range, the coiling temperature is determined to be abnormal, and the steel coil with the abnormal coiling temperature is intercepted. The single-point value T2 of the coiling temperature in the middle of the hot rolling process is continuously acquired; it is determined whether the acquired single-point value T2 of the middle coiling temperature meets the second set hot rolling coiling temperature range: second set hot rolling coiling temperature - 30℃ ≤ T2 ≤ second set hot rolling coiling temperature + 30℃; if the single-point value T2 of the middle coiling temperature meets the second set hot rolling coiling temperature range, the coiling temperature is determined to be normal and the hot rolling continues; if the single-point value T2 of the middle coiling temperature does not meet the second set hot rolling coiling temperature range, the coiling temperature is determined to be abnormal and the steel coil with the abnormal coiling temperature is intercepted. The single-point value T3 of the tail coiling temperature during the hot continuous rolling process is continuously acquired; it is determined whether the acquired single-point value T3 of the tail coiling temperature meets the first set hot rolling coiling temperature range: first set hot rolling coiling temperature - 50℃ ≤ T3 ≤ first set hot rolling coiling temperature + 30℃; if the single-point value T3 of the tail coiling temperature meets the first set hot rolling coiling temperature range, the coiling temperature is determined to be normal and the hot continuous rolling continues; if the single-point value T3 of the tail coiling temperature does not meet the first set hot rolling coiling temperature range, the coiling temperature is determined to be abnormal, and the steel coil with the abnormal coiling temperature is intercepted. S4. Perform cold continuous rolling on the hot-rolled strip steel coil.

2. The rolling method according to claim 1, characterized in that, Step S3 includes The coiling temperature at the head, middle, and tail of the hot strip rolling process is continuously acquired, and the average value of all coiling temperature values ​​at each point during the hot strip rolling process is calculated. Determine the average value T of the acquired single-point winding temperature. A Does it meet the third temperature range: Second set hot rolling coiling temperature - 20℃ ≤ T A ≤Second set hot rolling coiling temperature +20℃; If the average value T of the single-point temperature is taken A If the third temperature range is met, the coiling temperature is determined to be normal, and hot rolling continues; if the average value T of the single-point coiling temperature... A If the third temperature range is not met, the coiling temperature is determined to be abnormal, and the coil with the abnormal coiling temperature is intercepted.

3. The rolling method according to any one of claims 1-2, characterized in that, The first set hot rolling coiling temperature is set to a predetermined temperature of 578°C to 632°C, and the second set hot rolling coiling temperature is set to a predetermined temperature of 560°C to 610°C.

4. The rolling method according to claim 3, characterized in that, The first set hot rolling coiling temperature is set to a temperature between 580°C and 630°C.

5. The rolling method according to claim 3, characterized in that, It also includes step S5: annealing the cold-rolled strip steel coil to obtain high-strength steel.

6. The rolling method according to claim 1, characterized in that, It also includes step S6: High-strength steel is flattened and finished by coiling or cutting to obtain the desired form of high-strength steel.

7. The rolling method according to any one of claims 1-2 and 4-6, characterized in that, In step S3, the rolling length of the head and tail of the steel strip is 16 m to 32 m.

8. A hot-rolling maintenance device, characterized in that, include The hot rolling parameter setting unit is used to set the hot rolling length of the head and tail of the steel strip, as well as the hot rolling coiling temperature of the head, middle and tail of the steel strip during the hot continuous rolling process; and to obtain and upload the single-point value and the average value of the hot rolling coiling temperature of the head, middle and tail of the steel strip during the hot continuous rolling process. The process parameter determination unit is used to set the first set hot rolling coiling temperature range for the head and tail of the hot rolling process, the second set hot rolling coiling temperature range for the middle section, and the third temperature range of the average hot rolling coiling temperature. The unit then determines whether the single-point values ​​of the hot rolling coiling temperature for the head and tail and the average hot rolling coiling temperature for the middle section, uploaded by the hot rolling parameter setting unit, meet the corresponding first set hot rolling coiling temperature range, second set hot rolling coiling temperature range for the middle section, and third temperature range of the average hot rolling coiling temperature according to the determination rules, and obtains and uploads the corresponding determination results. The hot rolling interception unit is used to intercept strip steel coils that exceed the temperature range of each part during the hot continuous rolling process of steel slabs, based on the judgment results uploaded by the process parameter judgment unit.

Images