Rolling technology of a new type of Q235B patterned plate

Abstract

The present application relates to the technical field of rolling process, and specifically to a new type of Q235B patterned plate rolling process. The process includes: selecting Q235B patterned plate billet as the material; the heating furnace is discharged from the furnace through three-stage heating and soaking section insulation; the surface of the patterned plate after discharge is dephosphorized, and the temperature of the patterned plate billet is controlled for rough rolling and finish rolling after dephosphorization; then the temperature of the patterned plate billet is adjusted for cooling; after cooling, it is placed in a straightening machine for straightening, and the straightened patterned plate is sheared; in the soaking section of the heating furnace, the temperature at different positions at different times is uniformly collected, and the heating uniformity coefficient is obtained by comparing the temperature and temperature change rate between all sampling points, and the temperature disturbance is obtained by the temperature difference between all sampling points and the sampling point and the adjacent sampling point at the even temperature point, thereby obtaining the temperature uniformity, and completing the insulation based on this. The present application improves the uniformity of the temperature of the patterned plate billet discharged from the furnace.

Description

Technical Field

[0001] The present application relates to the technical field of rolling technology, and in particular to a rolling technology for a new type of Q235B patterned plate. Background Art

[0002] In the context of the steel industry advocating low-carbon and high-efficiency development, the requirements for improving the efficiency of the rolling process are becoming increasingly higher. How to improve efficiency while ensuring the quality of rolling has become one of the important research contents of the current rolling process.

[0003] In the prior art, the rolling process mainly includes heating, descaling, rough rolling, finishing rolling, cooling, straightening, shearing and other links. In order to ensure the continuity of production and processing and production efficiency, the heating temperature and heating time are usually set as needed during the heating process. However, the initial state of the Q235B checkered plate billet is different. The use of fixed heating parameter settings may cause uneven heating of the Q235B checkered plate billet when it is out of the furnace. The initial state of the environment in the heating furnace is different, which may lead to different temperature changes of the Q235B checkered plate billet. Therefore, it is difficult for the manufacturer to distinguish the actual state of the checkered plate billet when monitoring the Q235B checkered plate billet, and then the judgment of the uniform heating of the Q235B checkered plate billet is biased, which ultimately leads to uneven temperature of the checkered plate billet out of the furnace, affecting the subsequent rolling quality. Summary of the invention

[0004] In order to solve the technical problem of uneven furnace temperature, the present application provides a new rolling process for Q235B patterned plate, and the technical solution adopted is as follows:

[0005] This application proposes a new rolling process for Q235B patterned plate, which includes the following steps:

[0006] Material selection, Q235B patterned plate billet is selected as the material for subsequent processing;

[0007] The heating furnace is used to heat the patterned plate billet using three-stage heating and a soaking section. The soaking section has the following steps:

[0008] (1) Setting multiple evenly distributed sampling points on the patterned plate billet, collecting the temperature values ​​at each sampling point at each moment, and forming a temperature sequence;

[0009] (2) Obtain the similarity of temperature change based on the difference in the mean temperature between the sampling points and the temperature change rate at all the sampling points; divide each moment into a uniform temperature point and a variable temperature point according to the temperature sequence; obtain the temperature constancy coefficient based on the number of uniform temperature points and the number of variable temperature points between the uniform temperature points; obtain the heating uniformity coefficient based on the temperature constancy coefficient and the similarity of temperature change;

[0010] (3) The temperature change influence coefficient is obtained based on the difference in the corresponding temperature values ​​of the average temperature points between the sampling points and the difference in the time between the sampling points at the first average temperature point; the local influence coefficient is obtained based on the difference in the corresponding temperature values ​​of the average temperature points between the sampling point and the adjacent sampling points and the similarity of the temperature series between the sampling point and the adjacent sampling points; the temperature disturbance is obtained based on the temperature change influence coefficient and the local influence coefficient;

[0011] (4) Obtaining temperature uniformity based on the ratio of the heat uniformity coefficient to the temperature disturbance; using the temperature uniformity before the current moment as input to obtain the segmentation threshold, and comparing the temperature uniformity at the current moment with the segmentation threshold to complete the heat preservation, so that the patterned plate billet can be taken out of the furnace;

[0012] High-pressure water dephosphorization: after the patterned plate billet comes out of the furnace, the surface of the patterned plate billet is dephosphorized;

[0013] Rolling-rough rolling, rough rolling of the patterned plate billet after dephosphorization;

[0014] Rolling-finishing rolling, adjusting the temperature of the patterned plate billet after rough rolling for finishing rolling;

[0015] Cooling, adjusting the temperature of the patterned plate billet after finish rolling for cooling;

[0016] Straightening: the cooled pattern plate billet is straightened by a straightening machine;

[0017] Shearing: the straightened patterned plate billet is sheared by a disc shear.

[0018] In the above scheme, the present application collects temperature data of the soaking section of the heating furnace before rolling the Q235B patterned plate, analyzes the temperature change characteristics of the patterned plate billet in the soaking section and the temperature difference of the billet caused by the temperature change when the soaking section is disturbed, constructs the heating uniformity coefficient and the temperature disturbance degree of the patterned plate billet, and further constructs the temperature uniformity to characterize the temperature uniformity of the patterned plate billet in the soaking section of the heating furnace before rolling, and controls the temperature of the soaking section of the heating furnace through the heating furnace automatic control system based on this, solves the problem of difficulty in monitoring the temperature during the current monitoring of the heating uniformity of the Q235B patterned plate billet due to the different initial states of the patterned plate billet and the environment in the heating furnace, improves the uniformity of the temperature of the patterned plate billet out of the furnace, avoids cracks, fractures, and unevenness in the patterned plate billet during subsequent rolling, and thus improves the production quality and efficiency of the Q235B patterned plate.

[0019] In one embodiment, the weight percentages of chemical components in the Q235B patterned plate steel billet are C=0.19%, Si=0.25%, Mn=0.42%, S=0.030%, P=0.035%, and the rest are Fe and impurities.

[0020] In one embodiment, the method for obtaining the temperature sequence is:

[0021] A preset number of sampling points are set on the patterned steel billet so that the sampling points are evenly distributed on the patterned steel billet, the temperature value of each sampling point at each moment is collected, and the temperature values ​​collected at each sampling point are sorted in chronological order to obtain a temperature sequence.

[0022] In one embodiment, the method for obtaining the thermal uniformity coefficient is:

[0023] The temperature sequence of each sampling point is first-order differentiated. The value of the first-order difference is the temperature change rate at the corresponding moment. The average of all temperature change rates of the first-order difference is taken as the overall temperature change rate of the sampling point.

[0024] Calculate the mean temperature of the sampling point at all times, and sum the difference between the mean temperature of each sampling point and the mean temperature of all other sampling points as the temperature similarity of each sampling point;

[0025] The temperature change similarity of the sampling points is obtained according to the temperature similarity of the sampling points and the overall temperature change rate of the sampling points;

[0026] The similarity of temperature change at the sampling points is negatively correlated with the temperature similarity of each sampling point and the overall temperature change rate of the sampling points;

[0027] The first-order difference of the temperature series is processed by the Otsu threshold method to obtain the division threshold. When the first-order difference is less than or equal to the division threshold, it is regarded as the average temperature point, otherwise it is regarded as the variable temperature point.

[0028] For any two adjacent average temperature points of the sampling points, the number of all the temperature changing points therein is counted and recorded as a first number; for each sampling point, the mean of the first number is calculated as the temperature fluctuation value of the sampling point;

[0029] The temperature constancy coefficient of each sampling point is calculated according to the number of average temperature points and the temperature fluctuation value of each sampling point. The temperature constancy coefficient of the sampling point is positively correlated with the number of average temperature points and negatively correlated with the temperature fluctuation value.

[0030] The expression of thermal uniformity coefficient is:

[0031] , is the temperature variation similarity of the i-th sampling point, is the temperature constant coefficient of the i-th sampling point, represents the number of sampling points, Indicates the heating uniformity coefficient of the patterned plate billet at the current moment, represents the linear normalization function.

[0032] In one embodiment, the method for obtaining the temperature disturbance is:

[0033] Calculate the average of the temperature values ​​of all the average temperature points of each sampling point and record it as the first temperature average of each sampling point. Subtract the first temperature average of each sampling point from the first temperature average of all other sampling points and then sum them up to obtain the uniform temperature difference of each sampling point. Subtract the time corresponding to the first average temperature point of each sampling point from the time corresponding to the first average temperature point of the other sampling points and then calculate the average value as the time offset of each sampling point.

[0034] The expression of temperature change influence coefficient is:

[0035] , represents the uniform temperature difference of the i-th sampling point, represents the time offset of the i-th sampling point, represents the temperature change influence coefficient of the i-th sampling point;

[0036] For each sampling point, the sampling points in its adjacent sampling area are the adjacent sampling points of the sampling point. The difference between the first temperature mean of each sampling point and the first temperature mean of its adjacent sampling points is calculated. The difference corresponding to each sampling point is summed as the local temperature influence of each sampling point. The average of the dtw distances of the temperature series of each sampling point and the remaining adjacent sampling points is calculated and recorded as the distance mean of each sampling point.

[0037] The expression of local influence coefficient is:

[0038] , represents the local temperature influence of the i-th sampling point, represents the mean distance of the i-th sampling point, represents the local influence coefficient of the i-th sampling point;

[0039] The expression of temperature disturbance is:

[0040] , represents the temperature change influence coefficient of the i-th sampling point, represents the local influence coefficient of the i-th sampling point, m represents the number of sampling points, Indicates the temperature disturbance at the current sampling moment, represents the linear normalization function.

[0041] In one embodiment, the method of using the temperature uniformity before the current moment as input to obtain the segmentation threshold, and comparing the temperature uniformity at the current moment with the segmentation threshold to complete the heat preservation is:

[0042] All temperature uniformity at the moment before the current moment is taken as input, and the segmentation threshold is obtained through the cross-validation algorithm; if the temperature uniformity at the current moment is greater than or equal to the segmentation threshold, there is no need to adjust the temperature, otherwise the temperature needs to be adjusted until the temperature uniformity at the next moment is greater than the segmentation threshold.

[0043] In one embodiment, during the rough rolling process, the rough rolling outlet temperature is 1100°C.

[0044] In one embodiment, during the finishing rolling process, the finishing rolling inlet temperature is 1040°C, and the finishing rolling outlet target temperature is 870°C.

[0045] In one embodiment, during the cooling process, the final cooling temperature is 840°C.

[0046] In one embodiment, during the straightening process, the gap between the rollers is controlled at -0.2 to -5 mm, and the straightening force is controlled at 35 to 45 tons.

[0047] The beneficial effects of this application are:

[0048] The present application collects temperature data of the soaking section of a heating furnace before rolling the Q235B patterned plate, analyzes the temperature change characteristics of the patterned plate billet in the soaking section and the temperature difference of the billet caused by the temperature change when the soaking section is disturbed, constructs a heat uniformity coefficient and a temperature disturbance degree of the patterned plate billet, and further constructs a temperature uniformity to characterize the temperature uniformity of the patterned plate billet in the soaking section of the heating furnace before rolling. Based on this, the temperature of the soaking section of the heating furnace is controlled by an automatic control system of the heating furnace, thereby solving the problem of difficulty in monitoring the temperature during the current monitoring of the heating uniformity of the Q235B patterned plate billet due to the different initial states of the patterned plate billet and the environment in the heating furnace, improving the uniformity of the temperature of the patterned plate billet out of the furnace, avoiding cracks, fractures, and unevenness in the patterned plate billet during subsequent rolling, and thereby improving the production quality and efficiency of the Q235B patterned plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0050] Figure 1 A rolling process flow chart of a new type of Q235B patterned plate provided in one embodiment of the present application;

[0051] Figure 2This is a schematic diagram of the setting method of the sampling points;

[0052] Figure 3 Schematic diagram of the temperature variation over time of patterned plate steel at different sampling points in the soaking section. DETAILED DESCRIPTION

[0053] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of the rolling process of a new Q235B patterned plate proposed in the present application, its specific implementation method, structure, characteristics and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0054] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0055] A new rolling process example of Q235B patterned plate:

[0056] The specific scheme of the rolling process of a new type of Q235B patterned plate provided by the present application is described in detail below with reference to the accompanying drawings.

[0057] See also Figure 1 , which shows a rolling process flow chart of a new type of Q235B patterned plate provided by an embodiment of the present application, the process includes the following steps:

[0058] Material selection, Q235B checkered plate billet is selected for subsequent processing. In this embodiment, the size of Q235B checkered plate billet is 250mm*1600mm*3230mm, and 14mm medium and thick plate is rolled. The main chemical components of Q235B checkered plate billet are C=0.19%, Si=0.25%, Mn=0.42%, S=0.030%, P=0.035% by weight, and the rest are Fe and unavoidable impurity elements.

[0059] The heating furnace is used for heating, and the heating temperature of the first section is controlled at 950°C, the heating temperature of the second section is 1170°C, the heating temperature of the third section is 1240°C, the equalizing temperature of the equalizing section is 1300°C, and the total heating time is 175min; the slab out-of-furnace temperature is 1300°C.

[0060] S1, set a plurality of evenly distributed sampling points on the patterned plate billet, collect the temperature value of each sampling point at each moment, and form a temperature sequence.

[0061] For the patterned plate billet, m sampling points are set, wherein the sampling points are evenly distributed on the patterned plate billet, and multiple high-temperature resistant infrared probes are set in the air valve of the soaking section of the heating furnace, and multiple optical fibers are used to connect to the computer, and the computer controls the background suppression sensor through the multi-probe software to collect data from each sampling point of the patterned plate billet. Each background suppression sensor collects the temperature of the patterned plate billet at the position corresponding to the sensor once every interval T, and the collected temperature is obtained according to the sampling time sequence to obtain the temperature sequence of each sampling point at the current moment, and finally obtains the temperature sequence at different positions of multiple patterned plate billets.

[0062] In this embodiment, T is 1min and m is 50. The patterned half steel billet is divided into rectangular sampling areas of equal area. The center point of each sampling area is the sampling point of the patterned steel billet area. The implementer can evenly set it according to the size of the patterned steel billet. The specific setting method is as follows: Figure 2 shown.

[0063] At this point, the temperature sequence corresponding to each sampling point has been obtained.

[0064] S2, obtain the temperature change similarity based on the difference in temperature means between sampling points and the temperature change rate of all sampling points at all times; divide each moment into average temperature points and variable temperature points according to the temperature sequence; obtain the temperature constancy coefficient based on the number of average temperature points and the number of variable temperature points between average temperature points; obtain the heating uniformity coefficient based on the temperature constancy coefficient and the temperature change similarity.

[0065] In this application, the patterned plate billet will be heated in three stages to raise its overall temperature to a certain level, and then enter the soaking stage for heat preservation; in the soaking stage, under normal circumstances, the temperature of each part of the patterned plate billet will gradually increase, and the heating rate of each part is relatively similar. When the temperature is raised to the soaking temperature, the temperature will remain unchanged for a long time. That is, the temperature of each sampling point increases slowly, the temperature change rate is similar, the overall temperature gradient gradually decreases, and the temperature tends to be stable after a period of time.

[0066] Based on the above analysis of the temperature variation characteristics of the patterned plate billet in the soaking section, a temperature variation similarity characterizing the temperature variation is constructed for each sampling point.

[0067] First, the temperature change rate of each sampling point at different times is obtained. In this embodiment, a first-order difference is performed on the temperature sequence of each sampling point. The value of the first-order difference is the temperature change rate at the corresponding moment. The average of all temperature change rates of the first-order difference is taken as the overall temperature change rate of the sampling point.

[0068] Furthermore, for each sampling point, the temperature mean of the sampling point at all times is calculated, and the temperature mean of each sampling point is subtracted from the temperature mean of all other sampling points and then summed up as the temperature similarity of each sampling point.

[0069] The temperature change similarity of the sampling points is obtained according to the temperature similarity of the sampling points and the overall temperature change rate of the sampling points.

[0070] The similarity of temperature change at the sampling points is negatively correlated with the temperature similarity of each sampling point and the overall temperature change rate of the sampling points.

[0071] It should be noted that negative correlation means that when one variable increases, the other variable decreases accordingly, and the two variables change in opposite directions. When one variable changes from large to small or from small to large, the other variable also changes from small to large or from large to small. The specific relationship is determined by actual application and this application does not impose any special restrictions.

[0072] Preferably, in this embodiment, the expression of temperature change similarity is:

[0073] , is the temperature variation similarity of the i-th sampling point, is the overall temperature change rate of the i-th sampling point, represents the temperature similarity of the i-th sampling point, To adjust the parameters, in this embodiment, the role is to prevent the denominator from being 0, and the value is 0.001.

[0074] Preferably, in another embodiment, the expression of temperature variation similarity is:

[0075] , is the temperature variation similarity of the i-th sampling point, is the overall temperature change rate of the i-th sampling point, Represents the temperature similarity of the i-th sampling point.

[0076] If the patterned plate billet is normally kept warm in the soaking section, the temperature rise conditions at various locations of the patterned plate billet are relatively similar, which is specifically manifested in that the average values ​​of the temperature change rates of each sampling point of the patterned plate billet are closer, and the temperature change between each sampling point is smaller. At this time, the similarity of temperature change is greater, indicating that the temperature of the patterned plate billet at the corresponding position of the sampling point in the soaking section is steadily rising, and gradually becoming consistent with the temperature of the patterned plate billet at other positions. At this time, the temperature of the patterned plate billet in the soaking section is more uniform. The smaller it is, the smaller the difference in temperature change rate between the sampling points is, and the more similar the temperature changes are. The smaller it is, the smaller the temperature difference between the sampling points is and the more similar the temperature changes are.

[0077] As the heat-averaging and heat-insulating process proceeds, the temperature of the patterned plate billet will tend to be stable. When the temperature of the patterned plate billet is in a uniform state, the temperature difference of each sampling point is very small. In order to be able to judge the continuous situation when the temperature is relatively uniform, the first-order difference data of the temperature sequence of a single sampling point is used as input in this application, and the Otsu threshold method is used to output the division threshold of the first-order difference data. When a certain first-order difference data is less than or equal to the threshold, it is considered that the change in temperature data between the two sampling moments is very small, and the more likely it is a very small change when the temperature is uniform, and the temperature data at the sampling moment corresponding to the first-order difference data is used as the average temperature point, and the rest are variable temperature points. The average temperature points and variable temperature points in all sampling points can be obtained in the above manner. Among them, the Otsu threshold method and the first-order difference are both well-known technologies, and this application does not repeat their processes.

[0078] For any two adjacent average temperature points of the sampling points, the number of all temperature changing points is counted as the first number. For each sampling point, the average of the first number is calculated as the temperature fluctuation value of the sampling point, which is used to characterize the temperature fluctuation change. In the present application, the adjacent only means that the average temperature points are adjacent, that is, the average temperature point is adjacent to the previous average temperature point and adjacent to the next average temperature point.

[0079] The temperature constancy coefficient of each sampling point is calculated according to the number of average temperature points and the temperature fluctuation value of each sampling point. The temperature constancy coefficient of the sampling point is positively correlated with the number of average temperature points and negatively correlated with the temperature fluctuation value.

[0080] It should be noted that positive correlation means that when one variable increases, the other variable also increases, and the two variables change in the same direction. When one variable changes from large to small or from small to large, the other variable also changes from large to small or from small to large. The specific relationship is determined by actual application and this application does not impose any special restrictions.

[0081] Preferably, in this embodiment, the expression of the temperature constancy coefficient of the sampling point is:

[0082] , is the temperature constant coefficient of the i-th sampling point; is the number of average temperature points corresponding to the i-th sampling point; is the temperature fluctuation value of the i-th sampling point.

[0083] Preferably, in another embodiment of the present application, the expression of the temperature constancy coefficient of the sampling point is:

[0084]

[0085] is the temperature constant coefficient of the i-th sampling point; is the number of average temperature points corresponding to the i-th sampling point; is the temperature fluctuation value of the i-th sampling point.

[0086] It should be noted that positive correlation means that when one variable increases, the other variable also increases, and the two variables change in the same direction. When one variable changes from large to small or from small to large, the other variable also changes from large to small or from small to large. The specific relationship can be a multiplication relationship, an addition relationship, or the idempotence of an exponential function, which is determined by actual application and is not specifically limited in this application.

[0087] If the patterned plate billet heats up normally in the equalizing section and the temperature tends to be stable after a period of time, the total number of equalizing points in each sampling point is large, and the total number of temperature change points between two adjacent equalizing points is small, which means that the continuity of the equalizing points corresponding to the sampling moments is greater, and the possibility of large temperature changes is lower, that is, the temperature constancy coefficient is larger, which means that the temperature of the patterned plate billet at the corresponding position of the sampling point in the equalizing section is relatively constant.

[0088] According to the temperature variation characteristics of each sampling point of the patterned plate billet in the soaking section and the temperature constancy, the heating uniformity coefficient of the patterned plate billet at the current sampling moment is constructed.

[0089] Preferably, in this embodiment, the expression of the thermal uniformity coefficient is:

[0090] , is the temperature variation similarity of the i-th sampling point, is the temperature constant coefficient of the i-th sampling point, represents the number of sampling points, Indicates the heating uniformity coefficient of the patterned plate billet at the current moment, represents the linear normalization function.

[0091] When the patterned plate steel billet is kept warm normally in the equalizing section, the temperature changes at various parts of the patterned plate steel billet are more similar, and the longer the temperature remains constant, the more stable it tends to be, that is, the greater the heating uniformity coefficient, which means that the temperature change of the patterned plate steel billet in the equalizing section is more uniform, the greater the overall temperature uniformity, and the better the equalizing effect.

[0092] At this point, the heating uniformity coefficient of the patterned plate billet at the current moment is obtained.

[0093] S3, obtain the temperature change influence coefficient according to the difference in the corresponding temperature values ​​of the average temperature points between the sampling points and the difference in the time between the sampling points at the first average temperature point; obtain the local influence coefficient according to the difference in the corresponding temperature values ​​of the average temperature points between the sampling point and the adjacent sampling points and the similarity of the temperature series between the sampling point and the adjacent sampling points; obtain the temperature disturbance degree according to the temperature change influence coefficient and the local influence coefficient.

[0094] However, since the heating conditions at different locations in the equalizing section may be inconsistent, such as uneven distribution of hot air in the furnace, resulting in heat accumulation in local areas, or aging of the heating furnace, etc., there are certain differences in the temperature at different locations in the equalizing section of the heating furnace, which in turn leads to certain differences in the heating of the patterned plate billet in the equalizing section. When the heat received by a local area of ​​the patterned plate billet is low, the temperature of the patterned plate billet in this local area cannot reach the specified furnace outlet temperature, but the temperature change is similar to the normal heating change of the patterned plate billet in the equalizing section, that is, it slowly heats up to a certain temperature and then changes steadily. At this time, the heating uniformity coefficient of the patterned plate billet calculated only by the above method is still large, which leads to a misjudgment of the heating uniformity of the patterned plate billet. Therefore, further analysis is needed, wherein the schematic diagram of the temperature change over time of different sampling points of the patterned plate steel in the equalizing section is shown in the figure. Figure 3 shown.

[0095] When there is a temperature difference in the equalizing section, there is a certain temperature difference between the temperature of the affected patterned plate billet area after heating and the other unaffected areas. Since there is a certain temperature difference in the affected patterned plate billet area, the time for the patterned plate billet in the affected area to heat up to a constant temperature is also greatly different from that of the other unaffected areas.

[0096] Thus, the average temperature value of all the average temperature points of each sampling point is calculated and recorded as the first temperature average of each sampling point. The difference between the first temperature average of each sampling point and all other sampling points is summed up as the temperature uniformity difference of each sampling point. Then, the time corresponding to the first average temperature point of each sampling point is counted, and the time corresponding to the first average temperature point of each sampling point and the other sampling points is subtracted and averaged as the time offset of each sampling point.

[0097] The temperature change influence coefficient of each sampling point is obtained according to the time offset of each sampling point and the temperature uniformity difference of each sampling point.

[0098] Preferably, in this embodiment, the expression of the temperature change influence coefficient is:

[0099] , represents the uniform temperature difference of the i-th sampling point, represents the time offset of the i-th sampling point, Represents the temperature change influence coefficient of the i-th sampling point.

[0100] When the temperature in the equalizing section is disturbed and causes differences in the temperature change of the patterned plate billet, the greater the difference between the temperature average of the sampling point corresponding to the affected patterned plate billet area after the heating is completed and the temperature average of the other sampling points, and the greater the difference between the time for heating to a constant temperature and the time of the other sampling points, that is, the greater the temperature change influence coefficient, indicating that the temperature change of the patterned plate billet in the equalizing section is more affected at this time, and the greater the possibility of temperature differences in the equalizing section.

[0101] Since there may be a certain range of influence when the temperature of a local area in the soaking section is affected, the sampling points corresponding to the affected patterned plate billet area are closer in position and the degree of influence is more similar.

[0102] Based on the temperature influence of the local area of ​​the above-mentioned soaking section, the local influence coefficient of each sampling point is constructed.

[0103] For each sampling point, the sampling points in its adjacent sampling area are the neighboring sampling points of the sampling point. The difference between the first temperature mean of each sampling point and the first temperature mean of its neighboring sampling points is calculated. The difference corresponding to each sampling point is summed as the local temperature influence of each sampling point. The mean of the dtw distances of the temperature series between each sampling point and the remaining neighboring sampling points is calculated and recorded as the distance mean of each sampling point.

[0104] The local influence coefficient of each sampling point is calculated based on the local temperature influence and distance mean of each sampling point. The expression is:

[0105] , represents the local temperature influence of the i-th sampling point, represents the mean distance of the i-th sampling point, Represents the local influence coefficient of the i-th sampling point.

[0106] If the temperature of the patterned plate billet is affected by the temperature interference in the local area in the equalizing section, the temperature change trends of each sampling point in the local area are more similar, and the temperature data when the temperature is constant after heating is higher in approximation, that is, the larger the local influence coefficient, the more the temperature of the patterned plate billet at the sampling point is affected to a certain extent in the equalizing section.

[0107] The temperature variation characteristics of the patterned plate billet due to the interference of the temperature in the local area of ​​the soaking section, and the billet temperature disturbance at the current sampling moment are constructed. The patterned plate billet temperature disturbance can be determined by the temperature variation influence coefficient and the local influence coefficient.

[0108] Preferably, in this embodiment, the expression of temperature disturbance is:

[0109] , represents the temperature change influence coefficient of the i-th sampling point, represents the local influence coefficient of the i-th sampling point, m represents the number of sampling points, Indicates the temperature disturbance at the current sampling moment, represents the linear normalization function.

[0110] If the temperature in the soaking section is disturbed, there will be certain differences in the temperature changes of the patterned plate billet at various locations in the soaking section. The greater the difference in temperature change between a single sampling point and the other sampling points, and the more similar the changes in the local range, that is, the greater the temperature change influence coefficient and the local influence coefficient, the greater the temperature disturbance of the patterned plate billet, which means that the temperature change of the patterned plate billet in the soaking section is disturbed more obviously, and the temperature may be more uneven.

[0111] At this point, the temperature disturbance of the patterned plate billet at the current sampling moment is obtained.

[0112] S4, obtaining temperature uniformity according to the ratio of the heating uniformity coefficient and the temperature disturbance; using the temperature uniformity before the current moment as input to obtain the segmentation threshold, and comparing the temperature uniformity at the current moment with the segmentation threshold to complete the heat preservation, so that the patterned plate billet can be taken out of the furnace.

[0113] The temperature uniformity at the current acquisition moment is obtained according to the heat uniformity coefficient and temperature disturbance of the patterned plate billet at the current moment obtained as described above, wherein the temperature uniformity is obtained by the ratio of the heat uniformity coefficient to the temperature disturbance.

[0114] If the patterned plate billet is heated evenly in the equalizing section and the insulation is carried out normally, the patterned plate billet is heated more evenly, the greater the heating uniformity coefficient, and the temperature in the equalizing section is not disturbed, the temperature is uniform everywhere, and the possibility of the temperature of the patterned plate billet being affected is smaller; the smaller the temperature disturbance of the patterned plate billet, that is, the greater the temperature uniformity of the patterned plate billet, the better the heating condition of the patterned plate billet in the equalizing section, and the less need to adjust the equalizing section.

[0115] The acquired temperature uniformity is normalized. In this embodiment, the normalization method used is a linear normalization method. The normalized temperature uniformity at all times before the current acquisition time is used as input, and a segmentation threshold is obtained through a cross-validation algorithm. The cross-validation algorithm is a well-known technology and will not be described in detail here.

[0116] If the temperature uniformity at the current moment is greater than or equal to the segmentation threshold, it is considered that the insulation temperature of the soaking section is normal and does not need to be adjusted. Otherwise, it is considered that the temperature in the soaking section may be disturbed, resulting in uneven temperature, which in turn leads to a decrease in temperature uniformity. At this time, the heating furnace automatic control system outputs a control signal to the heating furnace regulator. The heating furnace regulator outputs a heating power signal according to the control signal of the heating furnace automatic control system and transmits it to the heating element. The heating element adjusts the temperature change of the heating furnace according to the heating power signal output by the heating furnace regulator, and then adjusts the temperature in the soaking section of the heating furnace until the normalized billet temperature uniformity is greater than or equal to the segmentation threshold. Finally, the insulation of the patterned plate billet is completed, so that the furnace discharge temperature of the patterned plate billet is uniform at all locations.

[0117] At this point, the heat preservation of the patterned plate billet is completed, so that the temperature of the patterned plate billet is uniform at all locations and it is ready to be taken out of the furnace.

[0118] High-pressure water dephosphorization, after the Q235B patterned plate billet comes out of the furnace, it is transferred through the roller and enters the high-pressure water descaling box. The descaling pressure is controlled at 21MPa, and the upper and lower surfaces of the patterned plate billet are roughly descaled to ensure that the oxidized iron scale on the surface of the descaled thick steel plate is cleanly descaled.

[0119] Rolling - rough rolling, 7 rough rolling passes, rough rolling outlet temperature is 1100℃, and descaling operation is performed in odd passes.

[0120] Rolling-finishing rolling, 7 passes of finishing rolling, the finishing entrance temperature is 1040℃, and the finishing exit target temperature is 870℃; after fine-tuning in the finishing rolling stage, 3 passes of reduction are performed, the first pass reduction rate is 23%, the second pass reduction rate is 22%, and the third pass reduction rate is 13%. Descaling is performed once in the odd passes during the finishing rolling process, and descaling is performed twice during the finishing rolling process.

[0121] Cooling, the final cooling temperature is 840℃.

[0122] Straightening: Three passes of the head and one pass of overall low-speed straightening are adopted. The guide rollers at the entrance and exit of the straightening machine are adjusted in time according to the steel plate shape. The specific gap between the rollers is controlled at -0.2~-5mm, and the straightening force is controlled at 35-45 tons.

[0123] Shearing: After straightening, the rolled piece is transferred to the cooling bed and sheared by a disc shear according to the actual size requirements of the patterned plate.

[0124] It should be noted that the above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

[0125] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A new rolling process for Q235B patterned plate, characterized in that: The process includes the following steps: Material selection, Q235B patterned plate billet is selected as the material for subsequent processing; The heating furnace is used to heat the patterned plate billet using three-stage heating and a soaking section. The soaking section has the following steps: (1) Setting multiple evenly distributed sampling points on the patterned plate billet, collecting the temperature values ​​at each sampling point at each moment, and forming a temperature sequence; (2) Obtain the similarity of temperature change based on the difference in the mean temperature between the sampling points and the temperature change rate at all the sampling points; divide each moment into a uniform temperature point and a variable temperature point according to the temperature sequence; obtain the temperature constancy coefficient based on the number of uniform temperature points and the number of variable temperature points between the uniform temperature points; obtain the heating uniformity coefficient based on the temperature constancy coefficient and the similarity of temperature change; (3) The temperature change influence coefficient is obtained based on the difference in the corresponding temperature values ​​of the average temperature points between the sampling points and the difference in the time between the sampling points at the first average temperature point; the local influence coefficient is obtained based on the difference in the corresponding temperature values ​​of the average temperature points between the sampling point and the adjacent sampling points and the similarity of the temperature series between the sampling point and the adjacent sampling points; the temperature disturbance is obtained based on the temperature change influence coefficient and the local influence coefficient; (4) Obtaining temperature uniformity based on the ratio of the heat uniformity coefficient to the temperature disturbance; using the temperature uniformity before the current moment as input to obtain the segmentation threshold, and comparing the temperature uniformity at the current moment with the segmentation threshold to complete the heat preservation, so that the patterned plate billet can be taken out of the furnace; High-pressure water dephosphorization: after the patterned plate billet comes out of the furnace, the surface of the patterned plate billet is dephosphorized; Rolling-rough rolling, rough rolling of the patterned plate billet after dephosphorization; Rolling-finishing rolling, adjusting the temperature of the patterned plate billet after rough rolling for finishing rolling; Cooling, adjusting the temperature of the patterned plate billet after finish rolling for cooling; Straightening: the cooled pattern plate billet is straightened by a straightening machine; Shearing: the straightened pattern plate billet is sheared by a disc shear; The method for obtaining the thermal uniformity coefficient is: The temperature sequence of each sampling point is first-order differentiated. The value of the first-order difference is the temperature change rate at the corresponding moment. The average of all temperature change rates of the first-order difference is taken as the overall temperature change rate of the sampling point. Calculate the mean temperature of the sampling point at all times, and sum the difference between the mean temperature of each sampling point and the mean temperature of all other sampling points as the temperature similarity of each sampling point; The temperature change similarity of the sampling points is obtained according to the temperature similarity of the sampling points and the overall temperature change rate of the sampling points; The similarity of temperature change at the sampling points is negatively correlated with the temperature similarity of each sampling point and the overall temperature change rate of the sampling points; The first-order difference of the temperature series is processed by the Otsu threshold method to obtain the division threshold. When the first-order difference is less than or equal to the division threshold, it is regarded as the average temperature point, otherwise it is regarded as the variable temperature point. For any two adjacent average temperature points of the sampling points, the number of all the temperature changing points therein is counted and recorded as a first number; for each sampling point, the mean of the first number is calculated as the temperature fluctuation value of the sampling point; The temperature constancy coefficient of each sampling point is calculated according to the number of average temperature points and the temperature fluctuation value of each sampling point. The temperature constancy coefficient of the sampling point is positively correlated with the number of average temperature points and negatively correlated with the temperature fluctuation value. The expression of thermal uniformity coefficient is: , is the temperature variation similarity of the i-th sampling point, is the temperature constant coefficient of the i-th sampling point, represents the number of sampling points, Indicates the heating uniformity coefficient of the patterned plate billet at the current moment, represents the linear normalization function; The method for obtaining the temperature disturbance is: Calculate the average of the temperature values ​​of all the average temperature points of each sampling point and record it as the first temperature average of each sampling point. Subtract the first temperature average of each sampling point from the first temperature average of all other sampling points and then sum them up to obtain the uniform temperature difference of each sampling point. Subtract the time corresponding to the first average temperature point of each sampling point from the time corresponding to the first average temperature point of the other sampling points and then calculate the average value as the time offset of each sampling point. The expression of temperature change influence coefficient is: , represents the uniform temperature difference of the i-th sampling point, represents the time offset of the i-th sampling point, represents the temperature change influence coefficient of the i-th sampling point; For each sampling point, the sampling points in its adjacent sampling area are the neighboring sampling points of the sampling point. The difference between the first temperature mean of each sampling point and the first temperature mean of its neighboring sampling points is calculated. The difference corresponding to each sampling point is summed as the local temperature influence of each sampling point. The average of the dtw distances of the temperature series of each sampling point and the remaining neighboring sampling points is calculated and recorded as the distance mean of each sampling point. The expression of the local influence coefficient is: , represents the local temperature influence of the i-th sampling point, represents the mean distance of the i-th sampling point, represents the local influence coefficient of the i-th sampling point; The expression of temperature disturbance is: , represents the temperature change influence coefficient of the i-th sampling point, represents the local influence coefficient of the i-th sampling point, m represents the number of sampling points, Indicates the temperature disturbance at the current sampling moment, represents the linear normalization function.

2. The rolling process of a new type of Q235B patterned plate as claimed in claim 1, characterized in that: The weight percentages of the chemical components in the Q235B patterned plate steel billet are C=0.19%, Si=0.25%, Mn=0.42%, S=0.030%, P=0.035%, and the rest are Fe and impurities.

3. The rolling process of a new type of Q235B patterned plate as claimed in claim 1, characterized in that: The method for obtaining the temperature sequence is: A preset number of sampling points are set on the patterned steel billet so that the sampling points are evenly distributed on the patterned steel billet, the temperature value of each sampling point at each moment is collected, and the temperature values ​​collected at each sampling point are sorted in chronological order to obtain a temperature sequence.

4. The rolling process of a new type of Q235B patterned plate as claimed in claim 1, characterized in that: The method of taking the temperature uniformity before the current moment as input to obtain the segmentation threshold, and comparing the temperature uniformity at the current moment with the segmentation threshold to complete the heat preservation is: All temperature uniformities before the current moment are taken as input, and the segmentation threshold is obtained through the cross-validation algorithm; if the temperature uniformity at the current moment is greater than or equal to the segmentation threshold, there is no need to adjust the temperature, otherwise the temperature needs to be adjusted until the temperature uniformity at the next moment is greater than the segmentation threshold.

5. The rolling process of a new type of Q235B patterned plate as claimed in claim 1, characterized in that: During the rough rolling process, the rough rolling outlet temperature is 1100°C.

6. The rolling process of a new type of Q235B patterned plate as claimed in claim 1, characterized in that: During the finishing rolling process, the finishing rolling inlet temperature is 1040°C and the finishing rolling outlet target temperature is 870°C.

7. The rolling process of a new type of Q235B patterned plate as claimed in claim 1, characterized in that: During the cooling process, the final cooling temperature is 840°C.

8. The rolling process of a new type of Q235B patterned plate as claimed in claim 1, characterized in that: During the straightening process, the gap between the rollers is controlled at -0.2~-5mm, and the straightening force is controlled at 35-45 tons.

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