Method for controlling the step-by-step operation of a steel billet in a walking beam furnace

Abstract

The application discloses a kind of step-by-step heating furnace in billet step-by-step operation control method.The method includes: setting heating weight value for billet;Determine the billet with maximum heating weight value in step-by-step heating furnace, and the billet with maximum heating weight value in step-by-step heating furnace is regarded as heating reference billet;Determine the heating grade of heating reference billet;If heating reference billet is judged as first heating grade, then according to first step control strategy to determine a target step cycle length;If heating reference billet is judged as second heating grade, then according to second step control strategy to determine a target step cycle length;Target step cycle length is used to adjust the step cycle length of step-by-step heating furnace.The method of the application can give priority to meet the heating requirement of high-grade steel billet, and the step-by-step heating process of step-by-step heating furnace is reasonable and orderly, which overcomes the problem of different varieties of billet heating rhythm incoordination.

Description

Technical Field

[0001] This invention relates to a walking beam furnace operation control technology, and more particularly to a method for controlling the walking beam movement of steel billets within a walking beam furnace. Background Technology

[0002] A walking beam furnace is a continuous heating furnace that uses the rising, advancing, descending, and retracting motion of the furnace bottom or water-cooled metal beams to move the billet step by step. A walking beam furnace contains fixed beams and walking beams. In steel rolling furnaces, the walking beams are typically composed of water-cooled pipes. Walking beam furnaces can heat the billet from both the top and bottom. The walking mechanism transports the steel billet being heated inside the furnace from the charging end to the discharging end through the reciprocating motion of the walking beams. According to the billet transport direction, the walking beam frame performs rising → advancing → descending → retracting movements. The lifting of the walking beam is detected using two linear displacement sensors, and the translation is detected using one linear displacement sensor. Its advantages are: flexible material handling, allowing all the furnace charge to be discharged when necessary; and the billet is spaced out on the walking beams at intervals, enabling faster and more uniform heating.

[0003] Currently, the control methods for walking beam furnaces are relatively simple. As long as there is space on the conveyor rollers at the furnace opening, the billet will be continuously moved forward. If the temperature of the billet when it exits the furnace does not meet the process requirements, the set temperature of the furnace will be continuously increased or the temperature and steel extraction cycle will be manually set.

[0004] However, the billet tapping temperature is crucial for subsequent hot rolling processes, especially for some high-grade billet varieties, which have high requirements for tapping temperature. Currently, the control method of walking beam furnaces makes it difficult to ensure that the billet tapping temperature meets the process requirements. Summary of the Invention

[0005] The purpose of this invention is to provide a method for controlling the step-by-step operation of steel billets in a walking beam furnace. This method can prioritize the heating requirements of high-grade steel billets, and the step-by-step heating process of the steel billets in the walking beam furnace is reasonable and orderly, overcoming the problem of inconsistent heating rhythms for different types of steel billets.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0007] A method for controlling the stepping movement of steel billets in a walking beam furnace, the method comprising:

[0008] S1, set heating weight values ​​for each type and specification of steel billet; set grade classification weight values;

[0009] S2, When the billet is heated by the walking beam furnace, the billet with the largest heating weight value in the walking beam furnace is periodically determined according to the preset judgment cycle time, and the billet with the largest heating weight value in the walking beam furnace is used as the heating reference billet.

[0010] S3, determine the heating level of the heating reference steel billet. If the heating weight value of the heating reference steel billet is not lower than the grade division weight value, the heating reference steel billet is determined to be the first heating level; if the heating weight value of the heating reference steel billet is lower than the grade division weight value, the heating reference steel billet is determined to be the second heating level.

[0011] S4. If the heating reference billet is determined to be of the first heating level, a target step cycle duration is determined according to the first step control strategy.

[0012] S5, the stepping cycle time of the stepping furnace is adjusted by using the target stepping cycle time;

[0013] S6. Repeat steps S2 to S5 until the walking beam furnace stops heating all the billets.

[0014] Furthermore, the first step-by-step control strategy includes: tracking the temperature of the reference billet in real time according to the real-time billet temperature tracking model of the walking beam furnace; recording the time point when the temperature of the reference billet reaches the target temperature in the furnace; calculating the remaining furnace time of the billet based on the remaining furnace travel distance of the reference billet, and comparing the remaining furnace time of the reference billet with the target residence time of the reference billet; if the deviation between the remaining furnace time of the reference billet and the target residence time of the reference billet is within a preset deviation range, then the current walking beam furnace... The furnace's walking cycle duration is used as the target walking cycle duration. If the deviation between the remaining furnace time of the heated reference billet and the target dwell time of the heated reference billet exceeds the preset deviation range, the target walking cycle duration is calculated and determined according to the formula S=(T1-T2) / (L1 / L2), where S is the target walking cycle duration, T1 is the target dwell time after the target furnace temperature of the heated reference billet is reached, T2 is the duration after the target furnace temperature of the heated reference billet is reached, L1 is the remaining furnace travel distance of the heated reference billet, and L2 is the single-step walking distance of the walking beam of the walking beam furnace.

[0015] Furthermore, S4 also includes:

[0016] If the heating reference billet is determined to be of the second heating level, a target step cycle duration is determined according to the second step control strategy.

[0017] The second step control strategy includes: determining the furnace section of the walking beam furnace where the heating reference billet is currently located; calculating the target step cycle duration according to the formula S=(T3-T4) / (L3 / L4), where S is the target step cycle duration, T3 is the target dwell time of the current furnace section of the heating reference billet, T4 is the duration of the current furnace section of the heating reference billet, L3 is the remaining travel distance of the current furnace section of the heating reference billet, and L4 is the single step distance of the walking beam of the walking beam furnace.

[0018] Furthermore, the weight value for the grade division is set to 90.

[0019] Furthermore, the judgment period is preset to 1 minute.

[0020] Furthermore, the walking beam furnace is a two-stage furnace, with one stage being the heating stage and the other stage being the soaking stage.

[0021] In the billet step-by-step operation control method of the present invention, a heating weight value is set for each type and specification of billet; when the billet is step-by-step heated by the walking beam furnace, the billet with the largest heating weight value in the walking beam furnace is determined and used as the heating reference billet. Then, the target step-by-step cycle length is determined according to the heating requirements of the heating reference billet. The step-by-step cycle length of the walking beam furnace is adjusted and set according to the target step-by-step cycle length. The walking beam furnace performs step-by-step heating of the billet according to the adjusted step-by-step cycle length. At the same time, automatic step-by-step operation control of the walking beam furnace when heating different types of billets is realized.

[0022] Compared with the prior art, the billet step-by-step operation control method of the present invention has the following advantages: the billet step-by-step operation control method of the present invention prioritizes meeting the heating requirements of high-grade billets, and then meets the heating requirements of low-grade billets. The step-by-step heating process of the billet in the walking beam furnace is optimized and adjusted, and the step-by-step heating process is more reasonable and orderly. At the same time, it overcomes the problem of uncoordinated heating rhythm of different types of billets and improves production efficiency. Attached Figure Description

[0023] Figure 1 This is a schematic flowchart of the billet step-by-step operation control method in the walking beam furnace of the present invention. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0025] This embodiment provides a method for controlling the step-by-step operation of steel billets in a walking beam furnace. This method can prioritize the heating requirements of high-grade steel billets, and the step-by-step heating process of the steel billets in the walking beam furnace is reasonable and orderly.

[0026] Those skilled in the art will understand that a walking beam furnace is a prior art heating furnace device with a walking beam underneath. The walking beam can move the material in the furnace from the inlet to the outlet at a set rate. During the material movement, the furnace heats the material.

[0027] The billet walking beam operation control method of this embodiment involves a two-stage walking beam furnace, meaning it consists of two consecutive furnace sections: a heating section and a soaking section. Both ends of the walking beam furnace have furnace openings. The opening at the heating section is the furnace inlet, and the opening at the soaking section is the furnace outlet. Conveying rollers for transporting the billets are installed at both the furnace inlet and outlet. When the walking beam furnace heats the billets, the billets first enter the heating section through the furnace inlet, then enter the soaking section, and finally exit the furnace through the outlet. A steel drawing machine transfers the billets from inside the walking beam furnace to the outer conveying rollers, which then transport the billets to the subsequent hot rolling operation station.

[0028] See Figure 1 The billet step-by-step operation control method of this embodiment includes the following steps S1 to S6.

[0029] S1. For all types and specifications of steel billets, a corresponding weight value is pre-set for each type and specification of steel billet. This weight value is called the heating weight value. At the same time, a grade division weight value is pre-set. All types of steel billets are divided into heating grades. Steel billets with a heating weight value not lower than the grade division weight value (heating weight value ≥ grade division weight value) are classified as steel billets of the first heating grade. Steel billets with a heating weight value lower than the grade division weight value (heating weight value < grade division weight value) are classified as steel billets of the second heating grade.

[0030] The significance of setting the heating weight value for steel billets is that the higher the heating weight value, the higher the heating level of the steel billet. When heating in a walking beam furnace, the heating requirements of steel billets with higher heating weight values ​​need to be prioritized. Dividing steel billets into heating levels is to strengthen the priority of meeting the heating requirements of steel billets in the first heating level. In this embodiment, the weight value for level division is set to 90.

[0031] S2, When the steel billet is heated by the walking beam furnace, the steel billet with the largest heating weight value in the walking beam furnace is periodically determined according to the preset judgment cycle time, and the steel billet with the largest heating weight value in the walking beam furnace is used as the heating reference steel billet.

[0032] In this embodiment, the judgment period is preset to 1 minute.

[0033] S3. Determine the heating grade of the reference steel billet. If the heating weight value of the reference steel billet is not lower than the grade classification weight value, the reference steel billet is determined to be a steel billet of the first heating grade. If the heating weight value of the reference steel billet is lower than the grade classification weight value, the reference steel billet is determined to be a steel billet of the second heating grade.

[0034] S4. If the heating reference billet is determined to be a billet of the first heating level, a target step cycle duration is determined according to the first step control strategy; if the heating reference billet is determined to be a billet of the second heating level, a target step cycle duration is determined according to the second step control strategy.

[0035] The first step of the advance control strategy includes:

[0036] Based on the real-time temperature tracking model of the billet in the walking beam furnace, the temperature of the heating reference billet is tracked in real time.

[0037] Those skilled in the art will understand that the real-time billet temperature tracking model for walking beam furnaces is prior art. Existing walking beam furnace control systems typically include a real-time billet temperature tracking model. This model calculates the real-time temperature of each billet in the walking beam furnace based on various parameters, facilitating real-time temperature tracking of each billet. The model calculates the billet temperature in real time and predicts the temperature at the end of the furnace section based on the remaining furnace time and current furnace temperature. It should be noted that the specific implementation algorithms of the real-time billet temperature tracking models vary between different manufacturers' walking beam furnaces; however, regardless of the algorithm, the function is the same: real-time temperature tracking of each billet in the walking beam furnace. Furthermore, while the specific names of the real-time billet temperature tracking models may differ between manufacturers, their functions are similar.

[0038] When the temperature of the heated reference steel billet reaches the target temperature in the furnace, the position of the heated reference steel billet in the furnace at that time is recorded as the "starting position of achieving the target" and the time at that time is recorded as the "starting moment of achieving the target".

[0039] The remaining furnace time of the heating reference steel billet is determined by calculating the remaining furnace travel distance of the heating reference steel billet.

[0040] The "remaining furnace time" of the billet mentioned in this article refers to the time from the current moment until the billet is removed from the furnace.

[0041] It should be noted that calculating the remaining furnace time of the billet based on the remaining travel distance of the billet in the heating furnace is a conventional calculation in the existing technology. It can be obtained by dividing the remaining travel distance of the billet in the heating furnace by the walking beam speed of the walking beam furnace.

[0042] The remaining time of the heated reference billet in the furnace is compared with the target duration of the heated reference billet.

[0043] If the deviation between "remaining time in the furnace for heating reference billet" and "target duration of heating reference billet" is within the preset deviation range, then the original walking beam cycle time of the walking beam furnace will be maintained, that is, the current walking beam cycle time of the walking beam furnace will be used as the target walking beam cycle time.

[0044] Those skilled in the art will understand that the walking cycle time of the walking beam furnace mentioned herein refers to the walking cycle time of the walking beam furnace, specifically the interval between two adjacent walking beam movements.

[0045] The "target dwell time for heating the reference billet" is the difference between "target dwell time after the target temperature of the heating reference billet in the furnace is reached" and "duration after the target temperature of the heating reference billet in the furnace is reached".

[0046] If the deviation between "remaining time in the furnace for the heating reference billet" and "target dwell time for the heating reference billet" exceeds the preset deviation range, the target stepping cycle time is calculated and determined according to the formula S = (T1 - T2) / (L1 / L2), where S is the target stepping cycle time, T1 is the target dwell time after the target temperature of the heating reference billet in the furnace is reached, T2 is the elapsed time after the target temperature of the heating reference billet in the furnace is reached, L1 is the remaining travel distance of the heating furnace for the heating reference billet, and L2 is the single-step walking beam distance of the walking beam in the walking beam furnace. It should be noted that the target dwell time after the target temperature of the heating reference billet in the furnace is reached, the elapsed time after the target temperature is reached, the remaining travel distance of the heating furnace, and the single-step walking beam distance of the walking beam in the walking beam furnace can all be obtained by the production process control computer in the operating area where the walking beam furnace is located.

[0047] Those skilled in the art will understand that the single-step walking beam distance of the walking beam in the walking beam furnace mentioned herein refers to the distance the material can move in one step of the walking beam movement, which is a fixed value.

[0048] The "target furnace temperature" and "target residence time after reaching the target furnace temperature" mentioned in this article are two process parameters that every billet of the first heating grade has. The significance of these two parameters is that, in a walking beam furnace, after the billet reaches the target furnace temperature, it must remain in the furnace for the specified duration ("target residence time after reaching the target furnace temperature") before being removed from the furnace. The target furnace temperature is not necessarily the final target temperature at which the billet exits the furnace. The target furnace temperature is usually the final target exit temperature of the billet as required by the quality design minus 30°C or 50°C. The target furnace temperature is determined based on the solution treatment temperature requirements of different billet grades and specifications.

[0049] The "time elapsed after the target temperature in the furnace is reached" mentioned in this article refers to the time elapsed from the moment the billet reaches the target temperature in the furnace to the current moment in the walking beam furnace. Furthermore, by subtracting the previously recorded start time of reaching the target temperature from the current time, the time elapsed after the target temperature in the furnace is obtained.

[0050] The "remaining furnace travel distance" of the billet mentioned in this article refers to the travel distance from the current position of the billet in the walking beam furnace to the outlet at the end of the walking beam furnace.

[0051] This concludes the first step of the progressive control strategy.

[0052] The second step control strategy includes:

[0053] Determine the furnace section of the walking beam furnace where the reference steel billet was located at that time.

[0054] The target stepping cycle time is calculated using the formula S = (T3 - T4) / (L3 / L4), where S is the target stepping cycle time, T3 is the target dwell time of the current furnace section of the heating reference billet, T4 is the elapsed time of the current furnace section of the heating reference billet, L3 is the remaining travel distance of the current furnace section of the heating reference billet, and L4 is the single-step walking beam distance of the walking beam in the walking beam furnace. It should be noted that the target dwell time of the current furnace section of the heating reference billet, the elapsed time of the current furnace section, the remaining travel distance of the current furnace section, and the single-step walking beam distance of the walking beam in the walking beam furnace can all be obtained by the production process control computer in the operating area where the walking beam furnace is located.

[0055] The "target dwell time in the current furnace section" mentioned in this article refers to the duration that the billet must remain in the current section of the walking beam furnace according to the requirements of the heating process. Specifically, the dwell time of the billet in each furnace section during heating in a walking beam furnace is specified by the process. For example, each billet has a process parameter "target dwell time in the heating section" for the heating section. According to the process requirements, the billet must remain in the heating section for the "target dwell time in the heating section" before leaving the heating section. Similarly, each billet has a process parameter "target dwell time in the soaking section" for the soaking section. According to the process requirements, the billet must remain in the soaking section for the "target dwell time in the soaking section" before leaving the soaking section.

[0056] The "duration of the current furnace section" mentioned in this article refers to the time elapsed from the moment the billet enters the current furnace section to the present moment.

[0057] The "remaining furnace travel distance" of the billet mentioned in this article refers to the travel distance from the current position of the billet in the walking beam furnace to the outlet at the end of the walking beam furnace.

[0058] The "remaining travel distance of the current furnace section" of the billet mentioned in this article refers to the travel distance from the current position of the billet to the end of the current furnace section.

[0059] The second step control strategy ends here.

[0060] S5, the stepping cycle time of the walking beam furnace is adjusted by using the determined target stepping cycle time, and the walking beam furnace heats the billet in a stepping manner according to the adjusted stepping cycle time.

[0061] S6. Repeat steps S2 to S5 until the walking beam furnace stops heating all the billets.

[0062] It should be noted that the billet step-by-step operation control method in the walking beam furnace of this embodiment is set in the production process control computer of the working area where the walking beam furnace is located in the form of a program. During the heating process of the walking beam furnace, the billet step-by-step operation control method in the walking beam furnace of this embodiment is realized by the production process control computer executing the program.

[0063] It should be noted that in this embodiment, there is no absolute temporal order among the steps.

[0064] In the billet step-by-step heating control method of this embodiment, a heating weight value is assigned to each type and specification of billet. When the billet is step-by-step heated in a walking beam furnace, the billet with the largest heating weight value in the furnace is identified and used as the heating reference billet. Then, the target step-by-step cycle length is determined based on the heating requirements of the reference billet. The step-by-step cycle length of the walking beam furnace is adjusted using the target step-by-step cycle length, and the furnace performs step-by-step heating of the billet according to the adjusted cycle length. In other words, the billet step-by-step heating control method of this embodiment prioritizes meeting the heating requirements of high-grade billets (billets with larger heating weight values) before meeting the heating requirements of low-grade billets (billets with smaller heating weight values). This optimizes the step-by-step heating process of the billet, making the heating process more rational and orderly.

[0065] Furthermore, the billet step-by-step operation control method of this embodiment realizes automatic control of the step-by-step operation of the step-by-step heating furnace when heating different types of billets, overcomes the problem of uncoordinated heating rhythm of different types of billets, improves production efficiency, reduces the operating load of operators, and ensures the flexibility of billet operation in the step-by-step heating furnace.

[0066] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for controlling the stepping movement of steel billets in a walking beam furnace, characterized in that: The billet step-by-step movement control method includes: S1, set heating weight values ​​for each type and specification of steel billet; set grade classification weight values; S2, When the billet is heated by the walking beam furnace, the billet with the largest heating weight value in the walking beam furnace is periodically determined according to the preset judgment cycle time, and the billet with the largest heating weight value in the walking beam furnace is used as the heating reference billet. S3, determine the heating level of the heating reference steel billet. If the heating weight value of the heating reference steel billet is not lower than the grade division weight value, the heating reference steel billet is determined to be the first heating level; if the heating weight value of the heating reference steel billet is lower than the grade division weight value, the heating reference steel billet is determined to be the second heating level. S4. If the heating reference billet is determined to be of the first heating level, a target step cycle duration is determined according to the first step control strategy; if the heating reference billet is determined to be of the second heating level, a target step cycle duration is determined according to the second step control strategy. S5, the stepping cycle time of the stepping furnace is adjusted by using the target stepping cycle time; S6. Repeat steps S2 to S5 until the walking beam furnace stops heating all the billets. The first step of the walking beam control strategy includes: tracking the temperature of the reference billet in real time according to the billet temperature real-time tracking model of the walking beam furnace; recording the time point when the temperature of the reference billet reaches the target temperature in the furnace; calculating the remaining furnace time of the billet based on the remaining furnace travel distance of the reference billet, and comparing the remaining furnace time of the reference billet with the target residence time of the reference billet; if the deviation between the remaining furnace time of the reference billet and the target residence time of the reference billet is within a preset deviation range, then adjusting the step of the walking beam furnace at that time. The cycle duration is used as the target stepping cycle duration. If the deviation between the remaining time of the heated reference billet in the furnace and the target dwell time of the heated reference billet exceeds the preset deviation range, the target stepping cycle duration is calculated and determined according to the formula S=(T1-T2) / (L1 / L2), where S is the target stepping cycle duration, T1 is the target dwell time after the target temperature of the heated reference billet in the furnace is reached, T2 is the time elapsed after the target temperature of the heated reference billet in the furnace is reached, L1 is the remaining travel distance of the heated reference billet in the furnace, and L2 is the single stepping distance of the walking beam of the walking beam furnace. The second step control strategy includes: determining the furnace section of the walking beam furnace where the heating reference billet is currently located; calculating the target step cycle duration according to the formula S=(T3-T4) / (L3 / L4), where S is the target step cycle duration, T3 is the target dwell time of the current furnace section of the heating reference billet, T4 is the duration of the current furnace section of the heating reference billet, L3 is the remaining travel distance of the current furnace section of the heating reference billet, and L4 is the single step distance of the walking beam of the walking beam furnace.

2. The method for controlling the stepping movement of steel billets in a walking beam furnace according to claim 1, characterized in that: The weight value for the grading system is set to 90.

3. The method for controlling the stepping movement of steel billets in a walking beam furnace according to claim 1, characterized in that: The judgment period is preset to 1 minute.

4. The method for controlling the stepping movement of steel billets in a walking beam furnace according to claim 1, characterized in that: The walking beam furnace is a two-stage furnace, with one stage being the heating stage and the other stage being the soaking stage.

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