265 results about "Strip steel" patented technology

This invention provides a thickness control method for a single-stand reversible cold rolling mill. The single-stand reversible cold rolling mill unit includes an inlet coiler, an outlet coiler, a mill body, a mill hydraulic system, an inlet thickness gauge, an outlet thickness gauge, an inlet speed gauge, an outlet speed gauge, an inlet tension gauge, and an outlet tension gauge. The single-stand reversible cold rolling mill unit also includes an S-roll, with S-rolls at both the inlet and outlet of the unit. The S-roll can rotate 180°, with the upper roll of the S-roll able to rotate to the lower roll position and the lower roll of the S-roll able to rotate to the upper roll position. The 180° rotation causes the strip steel to wind in an S-shape on the S-roll. The thickness difference of the strip steel is eliminated by adjusting the speed of the inlet S-roll to control the metal flow rate entering the roll gap.

This invention relates to an automatic control method for the second-by-second flow rate correction of hot-rolled strip steel. The method includes the following steps: Step 1: Acquisition and preparation of some physical quantities; Step 2: Automatic judgment of the narrowing state; Step 3: Automatic locking of the strip looper and the mill number; Step 4: Automatic judgment and automatic correction of the second-by-second flow rate. This scheme automatically determines the looper and mill requiring correction based on the looper angle state during strip head threading, the rolling force correction coefficient state, and the duration of strip head width narrowing. Instead of relying on traditional speed correction for control, it automatically adjusts the rolling force prediction parameters of the corresponding mill that affect thickness to control the looper flow rate. This fundamentally optimizes the factors affecting abnormal second-by-second flow rate between finishing mill stands, thereby achieving automatic control and correction of the second-by-second flow rate of hot-rolled strip steel.

This invention discloses an improved YOLOv8 strip steel burr detection model based on a fusion of a dynamic working condition perception module, belonging to the field of machine vision image processing technology. The specific steps are as follows: A feature extraction fusion network is constructed with CSPDarknet-53 as the backbone, combined with C2f and SPPF modules, employing multi-scale feature fusion and a decoupled detection head; a dynamic working condition perception module is constructed to collect real-time working condition parameters during strip steel production, which are then processed by Z-score standardization and dynamic weight allocation before being input into a dual-branch lightweight sub-network to generate adjustment signals for the detection threshold and anchor frame size; these adjustment signals are dynamically injected into the forward inference process of the YOLOv8 detection head through a hook function to achieve real-time adaptation of detection parameters to working conditions; the final model is obtained through multi-stage collaborative training. This invention significantly improves the robustness and generalization ability of burr detection under complex working conditions, achieving a detection accuracy of over 95% and a false negative rate of 3.1%, meeting the real-time detection needs of industry.

The present application relates to the technical field of thermal process, and especially relates to a method for optimizing edge searching precision of a surface inspection system, which divides a gray scale distribution into two regions of light and dark based on a gray scale reference value; sets a fixed edge threshold parameter or a variable edge threshold parameter for the surface inspection system; resets a periodic parameter; collects defect data in a way of training, modifying and adding; and optimizes a detection region. The present application has the following advantages: the gray scale range is expanded from 0-255 to 0-280, the reference value is increased from 128 to 140, and the light and dark regions are redivided, so that the defect pixel distribution is more balanced; for the working condition that the dark strip steel is close to the worn roller surface, the edge searching accuracy is improved, the positioning error is reduced, and the edge searching drift caused by the change of steel type and the wear of roller surface is solved; and the fixed and adaptive double-mode edge threshold strategy is adopted, the threshold value in the region within 30mm from the edge is narrowed by 20%-30%, and the fixed mode reduces the false positive rate.

The application discloses a kind of 800 MPa level cold-rolled martensitic steel hot-rolled substrate laser welding method, belongs to the technical field of welding.The application adopts laser butt welding process, the tail of front coil strip steel and the head of rear coil strip steel is formed loop respectively by welding machine pinch roll before and after welding machine, positioning and centering after being carried out to strip head and tail, using double cutting shear is cut to head and tail to ensure the quality of welding machine end surface.The application moves laser from operating side to transmission side by protection gas purging, cooperates with the front and rear heat devices that advance with laser and carries out butt welding, avoids the shortcomings of traditional laser welding high energy consumption and flash welding, reduces production cost and process complexity, improves production speed and weld quality, reaches the purpose that 800 MPa level cold-rolled martensitic steel hot-rolled substrate is welded.

The utility model relates to a kind of high-precision self-adapting cold-rolled strip steel uncoiling and threading device hydraulic system, including swing oil cylinder, proportional reversing valve and proportional pressure reducing valve, interface one and interface two on proportional reversing valve are communicated and interface three and interface four are communicated, or interface one and interface three are communicated and interface two and interface four are communicated, proportional pressure reducing valve is equipped with interface five and interface six;Interface one is communicated with the one end of oil supply pipeline, interface two is communicated with the rodless cavity of swing oil cylinder by pipeline, interface three is communicated with the rod cavity of swing oil cylinder by pipeline, and the pipeline communicated between interface three and swing oil cylinder is equipped with plug-in check valve;Interface four is communicated with the one end of oil return pipeline, interface five and interface six are communicated with the pipeline communicated between interface three and swing oil cylinder by pipeline respectively.The high-precision hydraulic system provided by the utility model can avoid fatigue damage of equipment fittings caused by inertia and impact force when equipment suddenly stops, and can reduce labor cost and safety hazard.

The utility model provides a device for controlling the uniformity of strip steel width belongs to the strip steel production technical field. Including the base for installing in the strip steel export position, the top of base is provided with the workbench of liftable adjustment, the side of workbench is slidably installed with two adjustable interval's fixed base, two fixed base all are fixed with vertical guide roller, and the upper end face both ends of workbench are fixed with two support columns, and the top of two support columns is installed with infrared range finder. The utility model, not only can control the adjustment strip steel width, moreover can real -time monitoring adjusted data, and according to real -time data to ensure that the strip steel width is always uniform, and the use effect is good.

The utility model provides a kind of leveling device for cold-rolled strip steel processing includes: shell;Feeding unit, the feeding unit is arranged in the inner bottom of the shell;Limiting component, the limiting component is connected with the feeding unit, for the cold-rolled strip steel limiting;The feeding unit includes multiple rotation arrangement in the shell inside feeding roller;The limiting component includes two limit plates, the limit plate is set in multiple the both ends of feeding roller, and with the feeding roller bearing sliding connection.After cold-rolled strip steel is put into feeding roller, start second motor and drive bidirectional screw rod to rotate, two limit plates are relatively moved by bidirectional screw rod, and then the both sides of cold-rolled strip steel are clamped and limited by two limit plates, the contact area of limit plate and cold-rolled strip steel is larger, can effectively prevent the deviation and inclination of cold-rolled strip steel in conveying, and the rotation axle auxiliary conveying cold-rolled strip steel is set.

The utility model relates to patching machine automation production feed equipment technical field, and disclose a kind of with HOME function precision feeder, the precision feeder with HOME function, including bottom plate, the side wall of bottom plate is provided with feeding assembly.The precision feeder with HOME function, through the feeding assembly of setting, gear set is rotated by stepper motor, compared with traditional belt drive, more have the characteristics of response fast, rotating angle accurate, while HOME inductor detects paper strip steel tooth piece rotation, compensating value is calculated by software, further improve feeding accuracy, meet the normal suction of small component material, eliminate or reduce gear error, the data needed to compensate for each tooth compared with standard value is saved on the register of electronic board, so that the steel tooth piece of paper strip is driven to walk distance accurately, compensation value is saved locally, without re-calculation each time, avoid each time to start recalibration, keep runtime data consistency.

This invention discloses a strip descaling and straightening device. The upper straightening roller group includes at least two upper straightening rollers spaced apart in the front-to-back direction, and the lower straightening roller group includes at least two lower straightening rollers spaced apart in the front-to-back direction. The upper straightening roller group is located above the lower straightening roller group. Both the upper and lower straightening rollers can rotate relative to the machine base. The rotation axes of the upper and lower straightening rollers are both set in the left-to-right direction. A strip straightening zone is formed between the upper and lower straightening roller groups. The straightening mechanism also includes a lower straightening frame and an exit angle adjustment driver. The lower straightening rollers of the lower straightening roller group are respectively configured as a first lower straightening roller and a second lower straightening roller. The first lower straightening roller is rotatably mounted on the machine base, and the second lower straightening roller is rotatably mounted on the lower straightening frame. The lower straightening frame is movably mounted on the machine base in the up-down direction. The exit angle adjustment driver is mounted on the machine base and is used to drive the lower straightening frame to move up and down. The second lower straightening roller is located at the foremost side of the lower straightening roller group.

The application provides an electric heating device for a strip steel heat treatment furnace, which comprises an electric heating radiation tube mechanism and an atmosphere protection cover mechanism, the electric heating radiation tube mechanism is horizontally suspended in the strip steel heat treatment furnace, one end of the electric heating radiation tube mechanism is fixed on a side wall of the strip steel heat treatment furnace, the end of the electric heating radiation tube mechanism is exposed to the strip steel heat treatment furnace, and the other end of the electric heating radiation tube mechanism extends into the strip steel heat treatment furnace, and the atmosphere protection cover mechanism covers the end of the electric heating radiation tube mechanism connected with the strip steel heat treatment furnace and is fixed on the wall of the strip steel heat treatment furnace, the electric heating device has the advantages of low cost, high temperature control precision, good energy-saving effect, long service life and low maintenance cost.

This invention belongs to the field of non-oriented silicon steel technology and discloses a method for improving the edge quality of hot-rolled strip steel of high-grade non-oriented silicon steel, including the following steps: 1) setting vertical rolls at the entrance of each stand of the finishing mill and giving a single-sided reference side pressure P. 基 ;2) Detect F i The real-time temperature of the strip at the frame inlet is used to obtain the lateral pressure coefficient L in the length direction. i And the lateral pressure coefficient W in the width direction i ;3) According to F i The thickness H of the strip at the frame entrance is used to obtain the thickness lateral compression coefficient H. i ;4) Select the compositional lateral pressure coefficient X based on the sum of the percentage contents X of Si and Als in the steel. i ;5) Calculate F i Real-time single-sided side pressure P of the vertical roller at the frame entrance i =P 基 ×L i ×W i ×H i ×X i The side pressure is dynamically adjusted based on the calculation results. This invention dynamically adjusts the side pressure of the vertical rolls at the entrance of each stand in the finishing mill to correct strip deviation and improve edge cracks, thereby achieving optimal edge quality.

The application discloses a disc shear process parameter multi-objective optimization method based on machine learning and NSGA-II, acquires existing disc shear cutting related data of a factory, and constructs a disc shear cutting quality evaluation data set; a multi-model prediction system containing ANN, XGBoost, LightGBM and CatBoost is established, combined with Bayesian optimization to realize automatic optimization of hyperparameters, and the optimal prediction model combination suitable for different defects is screened; based on the optimal model combination, an NSGA-II multi-objective optimization model is constructed, and under the constraint of industrial operation parameters, a Pareto process parameter solution set is obtained, and the optimal solution is screened. The method combining industrial measured data, multi-model prediction and multi-objective optimization algorithm is adopted to mine the internal coupling correlation between process parameters and cutting quality, realize the collaborative improvement of multiple defects, and has important guiding significance for improving the cutting quality of the strip steel and enhancing the production benefit.

This application provides a method for preparing hot-rolled wide coils of 60Si2Mn spring steel with anti-strip breakage properties, and the hot-rolled wide coils thereof. The method includes: heating a 60Si2Mn spring steel slab to obtain a heated slab; hot-rolling the heated slab to obtain a hot-rolled wide strip steel with a width of 900-1500 mm; subjecting the hot-rolled wide strip steel to laminar flow cooling to obtain laminar flow cooled hot-rolled wide strip steel, wherein the laminar flow cooling consists of a pre-stage non-water cooling treatment and a post-stage rapid cooling treatment, with a target temperature of 760-800℃ for the pre-stage non-water cooling treatment and a cooling rate of 10-20℃ / s for the rapid cooling treatment; and coiling and cooling the laminar flow cooled hot-rolled wide strip steel to obtain hot-rolled wide coils of 60Si2Mn spring steel with anti-strip breakage properties. Using the embodiments of this application, hot-rolled wide coils of 60Si2Mn spring steel with anti-strip breakage properties can be produced, and they will not break during subsequent processing steps.

This utility model relates to a cleaning device for the surface contamination of hot-rolled strip steel. The inlet guide includes an operating side and a transmission side; the operating side and the transmission side surround and form a conduction zone for the hot-rolled strip steel. A first nozzle and a second nozzle are respectively located at the tail ends of the operating side and the transmission side, with their openings facing the conduction zone. The spray angles of the first nozzle and the second nozzle relative to the transmission direction are a first included angle and a second included angle, respectively, with a difference of 10°. The ends of the first nozzle and the second nozzle each have a first nozzle head and a second nozzle head; the first nozzle head and the second nozzle head are respectively located close to the tail ends of the operating side and the transmission side. The height difference between the plane where the center of the first nozzle head and the second nozzle head is located and the conduction zone is 60-75mm. Through mutual cooperation, the water curtain can completely cover the surface of the hot-rolled strip steel, achieving the cleaning of surface contamination. This design simplifies installation, facilitates operation, improves product quality, and reduces production costs.

This invention relates to a method for improving transverse temperature uniformity and suppressing residual stress in hot-rolled strip steel, belonging to the field of hot-rolled strip shape control technology in the metallurgical industry. The technical solution is as follows: During the post-rolling cooling stage of hot-rolled strip steel, the cooling in the strip width direction is divided into three zones: the middle of the strip steel is the normal cooling zone, the edge of the strip steel is the zone sensitive to strip temperature and residual stress, and the outer side of the strip steel is the unsprayed zone. The ultra-fast cooling manifold cooling nozzles in the normal cooling zone in the middle of the strip steel and the outer side of the strip steel are perpendicular to the strip surface. The ultra-fast cooling manifold cooling nozzles in the edge zone sensitive to strip temperature and residual stress are deflected towards the center of the strip steel at a certain angle α. The formula for calculating the number of nozzles is: [Formula omitted]. The beneficial effects of this invention are: it improves the transverse temperature uniformity of the strip steel, which is lower at the edges and higher in the middle, reduces the timing difference in the strip entering the phase transformation process, enhances the uniformity of the microstructure, and thus reduces the residual stress in the hot-rolled strip steel.

This application relates to a hot-rolled pickled strip steel for compressor housings and its preparation method, belonging to the field of steel manufacturing technology. The chemical composition of the hot-rolled pickled strip steel, by mass fraction, is: C: 0.05%~0.09%, Si≤0.05%, Mn: 0.20%~0.40%, P≤0.02%, S≤0.02%, Al: 0.015%~0.050%, N≤0.004%, with the remainder being Fe and unavoidable impurities. By optimizing the composition system design and key control points of the hot rolling process, a hot-rolled pickled strip steel with both excellent strength and high elongation has been successfully developed while achieving low-cost production. During the production process, the surface quality of the hot-rolled pickled strip steel is significantly improved by precisely controlling the hot rolling temperature, applying high-speed steel rolls, and precision descaling. Ultimately, hot-rolled pickled strip steel has outstanding advantages in terms of excellent surface quality and balanced strength and plasticity. It is particularly suitable for parts such as compressor housings that have strict requirements for material properties and surface quality, thereby effectively improving the overall quality, stability and sealing reliability of the housing structure.

This invention discloses an online electric edge-rolling machine for continuous acid rolling. The edge-rolling machine includes a split frame, a double-cone adaptive rolling shaft, a permanent magnet synchronous drive module, a waste edge centering device, a tension adaptive module, and a PLC linkage control unit. Through permanent magnet synchronous drive and linkage with the production line, the synchronization error is ≤1m / min, and the speed reaches 350m / min. The double-cone rolling shaft is suitable for waste edges of 10-50mm, and the tension is adjustable from 80-250N. This significantly improves wear resistance, centering accuracy, tension stability, and equipment lifespan. This invention solves the problems of loose edge winding, poor synchronization, and severe wear in high-speed thick strip steel production lines and is suitable for continuous acid rolling production lines.

The utility model relates to oiling device technical field, concretely is a kind of cold-rolled strip steel oiling device, including oil sump, the front and rear both ends of the right side of oil sump are fixedly connected with guide plate, the inner surface of guide plate is equipped with guide slot, the inboard of guide slot is fixedly connected with guide sliding block, one side of guide sliding block is fixedly connected with L type connecting plate, one end of L type connecting plate is fixedly installed with cleaning brush plate, the upper end of the inner chamber of oil sump is fixedly connected with taking material roller, the right end of the top of oil sump is provided with transfer roller, the upper end of the right side of transfer roller is fixedly connected with coating roller, the lower end of the right side of oil sump and the left side between cleaning brush plate are fixedly connected with spring.The utility model can clean cold-rolled strip steel surface before oiling, avoid the iron filings, scale, dust and other pollutants generated in strip steel rolling process, the adverse effect of oiling, guarantee the oiling effect of the device.

This invention relates to the field of hot-dip galvanizing technology for steel plates, and particularly to a method for optimizing the microstructure of 780MPa grade reinforced formable hot-dip galvanized multiphase steel. The process route includes a three-stage heating process, pre-oxidation, reduction, a two-stage cooling process, hot-dip galvanizing, and a three-stage variable-temperature cooling process. Through microstructure regulation and pre-oxidation control, the enrichment of Si and Mn elements in high-strength automotive steel to the surface of the strip steel is suppressed, the formation of silicon and manganese oxides is reduced, the oxidation capacity of the pre-oxidation stage is strengthened, and the wettability of the zinc bath is enhanced. This results in a continuous and dense inhibition layer structure in the coating substrate, with uniform grain size and a single-layer inhibition layer grain morphology, reducing the thickening of brittle phases and reducing strip steel loss, thereby avoiding the production of bottom slag in the zinc pot. This invention solves the problem of insufficient zinc layer adhesion in traditional hot-dip galvanized high-strength steel, and the produced 780MPa grade hot-dip galvanized multiphase steel can simultaneously meet the requirements of ultra-high strength, excellent formability, and good coating quality.

This invention belongs to the field of steel rolling automation technology, and particularly relates to a method for quality diagnosis of cold-rolled strip steel products based on graph structure modeling. The method includes: acquiring production data, which includes process parameters and quality indicators; preprocessing and quality category encoding the production data to obtain encoded production data; dividing the encoded production data into training, validation, and test sets; constructing a graph neural network model based on an attention mechanism, the graph neural network model including a first graph attention network layer connected to the graph neural network, and a third graph attention layer generating modulation parameters; performing feature linear modulation on the graph neural network using the ProGAT framework based on the modulation parameters; training the graph neural network model using the training and validation sets; and inputting the test set into the trained graph neural network model to achieve quality diagnosis of cold-rolled strip steel products. This invention improves the ability to identify a few abnormal states.

Provided are a production line for the rapid hot galvanization of a strip steel, a production line for the rapid annealing of a strip steel, an ultra-short-process production line of an ultrahigh-strength strip steel, a flexible production line suitable for various high-strength strip steels and a dual use production line for the continuous annealing or hot galvanization of a high-strength strip steel. An injection straight fire preheating device, an injection radiant tube preheating device and / or a jet radiation composite heating / soaking device of the present invention are used in the production lines, such that rapid heating can be realized.

The application provides a coiling method of a strip steel. Firstly, the height of a coiling position of the strip steel is judged. When the height of the coiling position is greater than a preset height limit value, different positions of the coiling position of the strip steel are lifted, and the forward rotation of a conveying roller is controlled at the same time, so that the coiling position is loosened, the height of the coiling position is lowered, and then the strip steel is cold-coiled. The application uses the inherent equipment and tools in the production site, and cooperates with the operation, so that the production accident of the coiling of the strip steel can be quickly handled, the time of the production accident is greatly shortened, the flame gas cutting is avoided, the fire operation is not needed, and the application is safe, convenient, fast and easy to implement.

The utility model discloses a kind of two bending devices of steel plate, it includes platform, pressing mechanism, first bending mechanism and second bending mechanism, the platform has a bearing surface to carry the first section of steel plate, and make the second section and third section of steel plate suspended;The pressing mechanism has the pressing end of arrangement towards the bearing surface, for pressing the first section of steel plate;The first bending mechanism includes first bending piece and first drive assembly, and the first drive assembly is connected with the first bending piece.The beneficial effects of the utility model are: when this component is processed using the two bending devices of steel plate, the whole bending procedure period, no longer need worker to hold the other end of long strip steel plate, ensure the personal safety of worker, and after the first bending procedure, second bending procedure can be directly carried out to steel plate, save the time of worker to take out and re-adjust bending position steel plate, can improve processing efficiency.

This invention discloses a method and apparatus for sorting and grading cold-rolled strip steel based on a gray-level co-occurrence matrix and a decision tree, relating to the fields of metallurgical machinery and automation technology. It includes: acquiring image data and text data of the surface of the cold-rolled strip steel to be graded; inputting the image data and text data into a pre-constructed surface quality sorting and grading model for cold-rolled strip steel; and obtaining the surface quality sorting and grading result of the cold-rolled strip steel based on the image data, text data, and the surface quality sorting and grading model. This invention enables better intelligent judgment of the surface quality of cold-rolled strip steel, improves the accuracy of surface quality judgment, and makes the judgment system results more relevant to quality inspectors.

This invention discloses a method for detecting strip steel misalignment. The method involves acquiring the tension difference across a connecting port on a cold-rolled galvanizing line, where the cold-rolled galvanizing line is installed, and the connecting port is either the inlet or outlet of the cold-rolled galvanizing line. The method also involves acquiring the total tension across the connecting port and determining whether to output a warning message indicating strip steel misalignment based on the tension difference and the total tension. This invention discloses a method and apparatus for detecting strip steel misalignment, which can detect whether strip steel misalignment exists within the cold-rolled galvanizing line, reducing the probability of strip steel scraping and breakage, and improving the output and quality of the galvanizing production line.

The utility model relates to a horizontal-vertical mixed annealing furnace, which comprises a horizontal furnace section, a vertical furnace section and a transition connecting section, the horizontal furnace section is connected with the vertical furnace section through the transition connecting section, the side of the horizontal furnace section away from the vertical furnace section is the entrance side of products, and the side of the vertical furnace section away from the horizontal furnace section is the exit side of products. The utility model has the advantages that compared with the traditional horizontal annealing furnace, the length is greatly shortened, the plant investment is saved, the strip steel distance in the furnace is long, more products can be produced, and the applicability of the utility model is improved; compared with the traditional vertical annealing furnace, the single heating power is high, and the heating time is short.

This invention discloses a method, apparatus, electronic device, and medium for analyzing strip tension. The method includes: collecting tension information of strip steel on a target production line within each preset scanning cycle; calculating the tension fluctuation rate based on the collected tension information; determining whether the tension fluctuation rate is within a target range, where the target range is one of multiple preset fluctuation rate ranges; if so, incrementing the tension fluctuation count in the target range by 1; and determining the strip tension fluctuation status based on the tension fluctuation counts for each of the multiple fluctuation rate ranges. This method enables online analysis of strip tension fluctuation, automatically analyzing strip tension fluctuation data according to a unified standard, which helps improve the accuracy of the tension fluctuation analysis results.

The utility model relates to cold-rolled strip steel pickling technical field, concretely relates to a cold-rolled strip steel surface pickling device, including the body, the body is installed with prewash pool and a plurality of pickling pool according to the strip steel material conveying direction in proper order, and the side of pickling pool close to prewash pool is provided with pressure roller spare, and pressure roller spare includes two pressure roller rods set up in up and down, and the first through -hole for the strip steel to pass through is arranged between two pressure roller rods set up in up and down, and the side of pickling pool far from prewash pool is provided with squeeze dry roller spare, and squeeze dry roller spare includes two squeeze dry roller rods set up in up and down, and the second through -hole for the strip steel to pass through is arranged between two squeeze dry roller rods set up in up and down, and the setting of pressure roller spare thereby realized to the strip steel first carries out a physical derusting, and the strip steel that passes through the first through -hole is extruded to two pressure roller rods set up in up and down face each other, and the surface oxide layer of strip steel is destroyed, improves the efficiency of strip steel derusting, and the subsequent pickling is convenient, and the pickling efficiency is improved.

The application discloses a kind of control method, device, electronic equipment and medium of hot-rolled strip thickness, the method includes: obtaining the steel grade information of strip steel and the rolling speed of finishing mill group to strip steel;Determine the speed of steel throwing of the tail section of strip steel based on the steel grade information by finishing mill group;Based on the rolling speed, the speed of steel throwing and the preset conversion time, the speed of steel throwing rate of finishing mill group is determined, to reduce the rolling speed to the speed of steel throwing based on the speed of steel throwing rate;When tail section enters finishing mill group, the tail section of strip steel is thrown based on the speed of steel throwing, so that the temperature of tail section is within the preset temperature threshold value.The method can make the thickness of strip steel tail close to the target value of finished product, improve tail thickness hit rate.