A slab heating furnace discharged slab upper and lower surface temperature difference adjusting system and method

Abstract

The application discloses a slab heating furnace discharged slab upper and lower surface temperature difference adjusting system, which is provided with a first temperature detector and a second temperature detector. The first temperature detector is installed below the gap of two transmission rollers of the roller table after the rough descaling machine, detects the bottom temperature of the slab from bottom to top, and the second temperature detector is installed above the roller table after the rough descaling machine and detects the surface temperature of the slab downward. The application can collect the actual temperature of the discharged slab in real time, calculate the upper and lower surface temperature difference, feed back to the combustion control mathematical model, supplement and correct the upper and lower layer furnace temperature of the soaking section and the second adding section according to the temperature difference range classification, and automatically adjust and eliminate the upper and lower surface temperature difference of the heated slab after being discharged, so that the influence of the heating temperature on the rolling process on the upward bending or downward buckling of the rolled piece is reduced, and the equipment operation safety is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the slab production technical field. BACKGROUND

[0002] In the slab heating furnace design, each section is divided into upper and lower parts by the water beam in the furnace, and the burners (nozzles) are arranged to heat the billets. In daily operation, the operating personnel can only adjust the furnace temperature according to the temperature detected by the upper and lower layer furnace hearth thermocouples, but the furnace gas temperature cannot directly reflect the actual billet temperature, especially the depth of the thermocouple is different, and the measured temperature will also be different.

[0003] The temperature feedback by the thermocouple is the furnace atmosphere temperature, which cannot truly feedback the actual temperature in the billet heating process due to the influence of various factors, and the operation model lacks the upper and lower surface temperature balance parameters as target values for adjustment, and can only adjust the process temperature parameters according to the furnace gas temperature measured by the upper and lower layer thermocouples.

[0004] The above monitoring and adjustment method will cause large fluctuations in the temperature difference between the upper and lower surfaces of the billet, and the slab shape will be easily upwarping or down-drawing in the rolling process, which will impact the equipment and cause damage to the equipment, and even lead to accidents. SUMMARY

[0005] The technical problem to be solved by the present application is to realize a system and method for reliably monitoring the temperature difference between the upper and lower surfaces of the billet in the slab heating furnace, adjusting the production parameters and improving the quality of the slab.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: a slab heating furnace billet upper and lower surface temperature difference adjustment system, the system is provided with a first temperature detector and a second temperature detector, the first temperature detector is installed below the gap between the two transmission rollers of the roller table after the rough descaling machine, and detects the temperature of the bottom of the billet from bottom to top, and the second temperature detector is installed above the roller table after the rough descaling machine, and detects the surface temperature of the billet downward.

[0007] The detection ports of the first temperature detector and the second temperature detector are respectively provided with a sleeve extending towards the slab, each sleeve is in communication with a gas pipe, and the gas pipe is connected with an air source to introduce compressed air into the sleeve.

[0008] The first temperature detector and the second temperature detector are connected and output the collected detection temperature signal to the PLC, and the PLC controls the working condition of the heating furnace according to the detection temperature signal.

[0009] The PLC feeds back the detection temperature signal to the combustion control model, and the combustion control model compensates and corrects the temperature of the soaking section and the second heating section according to the temperature difference value.

[0010] The first temperature detector is arranged in the negative layer pit, and the first temperature detector and the second temperature detector are both fixed through a support.

[0011] The first temperature detector and the second temperature detector are above and below the same area of the roller.

[0012] The first temperature detector measures the lower surface temperature of the center position of the billet after descaling from bottom to top, and the second temperature detector measures the upper surface temperature of the center position of the billet after descaling from top to bottom.

[0013] A slab heating furnace discharged billet upper and lower surface temperature difference adjustment method comprises the following two adjustment methods:

[0014] 1) When the upper and lower surface temperature difference value is less than or equal to a set value temperature value, the combustion control model corrects and compensates the soaking section;

[0015] 2) When the upper and lower surface temperature difference value is greater than the set value temperature value, the combustion control model corrects and compensates the second heating section.

[0016] In the 1), the combustion control model increases the upper and lower surface temperature difference value of the thermocouple measured temperature of the side with high temperature in the soaking section participating in the temperature process control, so as to adjust the combustion control model to the target value after compensation and correction;

[0017] In the 2), the combustion control model increases the upper and lower surface temperature difference value of the thermocouple measured temperature of the side with high temperature in the second heating section participating in the temperature process control, so as to adjust the combustion control model to the target value after compensation and correction;

[0018] Through the adjustment of the 2), when the upper and lower surface temperature difference value is less than or equal to the set value temperature value, the adjustment method of the 1) is used for adjustment again;

[0019] The set value temperature value is 20℃.

[0020] The system has a collection cycle every 30 minutes;

[0021] The first group of data in each collection cycle satisfies that any data of the upper and lower surfaces is greater than 1000℃, and the data in the collection cycle is defined as valid data;

[0022] When the temperature of each section of the heating furnace is lower than the lower limit of the process, the slab heating furnace discharged billet upper and lower surface temperature difference adjustment method is not executed.

[0023] The present application can collect the actual temperature of the discharged slab in real time, calculate the upper and lower surface temperature difference, feed back to the combustion control mathematical model, supplement and correct the upper and lower layer furnace temperature of the soaking section and the second section according to the temperature difference range classification, automatically adjust, eliminate the upper and lower surface temperature difference of the heated slab after discharging, reduce the influence of the heating temperature on the rolling process on the rolling piece, and ensure the safety of equipment operation. BRIEF DESCRIPTION OF DRAWINGS

[0024] The following is a brief description of the content expressed in each of the drawings in the specification of the present application and the labels in the drawings:

[0025] Figure 1 Principle diagram of slab heating furnace slab surface temperature difference adjusting system;

[0026] Figure 2 Schematic diagram of slab heating furnace slab surface temperature difference adjusting system monitoring part;

[0027] The labels in the above drawings are as follows: 1, first temperature detector; 2, second temperature detector; 3, negative layer pit; 4, PLC; 5, rough descaling machine; 6, roller; 7, second heating section; 8, soaking section; 9, billet; 10, sleeve; 11, air pipe; 12, support. DETAILED DESCRIPTION

[0028] The specific embodiments of the present application will be further described in detail below with reference to the drawings, through the description of the embodiments, the shape, structure, mutual position and connection relationship between the parts, the action and working principle of each part, the manufacturing process and the operation and use method of each component involved, etc. are described in further detail, to help the skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present application.

[0029] The slab heating furnace slab surface temperature difference adjusting system is provided with two temperature detectors on the non-driving side of the roller 6 after the rough descaling machine 5, wherein the first temperature detector 1 is installed below the gap of the two driving rollers of the roller 6 after the rough descaling machine 5, detects the temperature of the bottom of the billet 9 from bottom to top, and the second temperature detector 2 is installed above the roller 6 after the rough descaling machine 5, detects the surface temperature of the billet 9 downward. The first temperature detector 1 and the second temperature detector 2 are arranged adjacently, that is, the first temperature detector 1 and the second temperature detector 2 are above and below the same area of the roller 6.

[0030] During installation, the first temperature detector 1 and the second temperature detector 2 are fixed on the top and bottom of the roller 6 through the support 12, the first temperature detector 1 is placed in the negative layer pit 3, both temperature detectors are connected to the PLC 4 and the detected temperature signals are collected to the PLC 4, the PLC 4 controls the working condition of the heating furnace according to the detected temperature signal, the PLC 4 feeds back the detected temperature signal to the combustion control model, and the combustion control model performs temperature compensation correction on the soaking section 8 and the second heating section 7 according to the upper and lower temperature difference value.

[0031] In order to protect the temperature detector, and also to make the temperature collection more accurate, the detection ports of the first temperature detector 1 and the second temperature detector 2 are respectively provided with a sleeve 10 extending to the slab direction, and a ventilation pipe 11 is obliquely inserted at the connection between the sleeve 10 and the temperature detector, the ventilation pipe 11 is connected with an air source to introduce compressed air into the sleeve 10, and the compressed air is blown from the sleeve 10 to the slab to avoid dust falling into the temperature measuring lens to affect the temperature measuring effect, the first temperature detector 1 measures the lower surface temperature of the center position of the descaled slab 9 from bottom to top, and the second temperature detector 2 measures the upper surface temperature of the center position of the descaled slab 9 from top to bottom, so that the upper and lower surface temperatures of the center position of the descaled slab 9 can be measured from top to bottom and from bottom to top.

[0032] After the slab 9 is heated and discharged, the surface scale is removed through rough descaling, and when the slab 9 runs to the positions of the first temperature detector 1 and the second temperature detector 2 along the roller 6 to the rolling mill, the temperature detector measures the upper and lower surface temperature data of the slab 9, the collected data is fed back to the combustion control model through the PLC 4, the model analyzes the collected upper and lower surface temperature difference data of the slab 9, calculates the upper and lower temperature difference value, and performs temperature compensation correction through the soaking section 8 and the second heating section 7, and through periodic repeated tracking correction, the upper and lower surface temperature of the discharged slab is balanced.

[0033] In order to ensure the temperature adjustment time, the temperature measuring instrument data is collected every 30 minutes as a collection cycle, after 30 minutes, the first group collects any data of the upper and lower surfaces >1000℃ (in order to ensure that the collected data is the discharged steel slab, the temperature >1000℃ at any position of the upper and lower surfaces is set as valid data to prevent the environment temperature data from being collected as valid data when there is no steel slab, and this temperature setting value is set according to the minimum temperature of the discharged steel slab according to the rolling process) and sends the combustion model for data analysis, and calculates the upper and lower surface temperature difference value;

[0034] Adjustment method 1: when the upper and lower surface temperature difference value is ≤20℃, the combustion control model only positively corrects and compensates the temperature measured by the high thermocouple of the upper and lower surfaces of the soaking section 8, for example, if the upper surface temperature is 15℃ higher than the lower surface temperature, the model analyzes and displays the measured temperature of the thermocouple participating in the temperature process control of the upper soaking section 8 as +15℃, so that the model control adjusts to the target value after compensation and correction. When the lower surface temperature is higher than the upper surface temperature, the adjustment is also the same way;

[0035] Adjustment method 2: considering the limited temperature adjustment range of the soaking section 8, when the upper and lower surface temperature difference is >20℃, the same as adjustment method 1, but only the temperature of the second heating section 7 is adjusted, and the soaking section 8 is not involved in the correction and adjustment. That is, the combustion control model corrects and compensates the second heating section 7, and the combustion control model increases the temperature difference value of the high side participating in the temperature process control of the thermocouple of the second heating section 7, so that the combustion control model adjusts to the target value after compensation and correction;

[0036] When the temperature difference between the upper and lower surfaces is less than or equal to 20℃, the control model is converted into the adjustment method 1, and the second heating section 7 does not participate in the correction compensation, and the above-mentioned process is repeated.

[0037] When the temperature of each section of the heating furnace is lower than the lower limit of the process, the temperature difference between the inside and outside of the steel billet is large, the overall heating is uneven, and the measured temperature data of the upper and lower surfaces have no reference value. At this time, the temperature difference adjustment model between the upper and lower surfaces does not participate in the temperature correction compensation control, the load of each section is distributed, the temperature is raised according to the normal combustion control model, and the temperature difference correction compensation between the upper and lower surfaces is automatically put into until the temperature of each section reaches the lower limit of the process.

[0038] The temperature difference range of the soaking section 8 and the second heating section of the heating furnace can be adjusted according to different conditions and processes in the model, and the model participates in the model control according to the set temperature difference target value.

[0039] The above describes the present application with reference to the drawings, and it is obvious that the specific implementation of the present application is not limited to the above-mentioned manner. Any non-essential improvement or direct application of the concept and technical solution of the present application to other occasions without improvement is within the protection scope of the present application.

Claims

1. A system for adjusting the temperature difference between the upper and lower surfaces of a steel billet exiting a slab heating furnace, characterized in that: The system is equipped with a first temperature detector and a second temperature detector. The first temperature detector is installed below the gap between the two drive rollers of the roller conveyor after the coarse descaling machine and detects the bottom temperature of the billet from bottom to top. The second temperature detector is installed above the roller conveyor after the coarse descaling machine and detects the surface temperature of the billet from bottom to top. The first temperature detector measures the temperature of the lower surface of the billet at the center after descaling from bottom to top, and the second temperature detector measures the temperature of the upper surface of the billet at the center after descaling from top to bottom; The PLC feeds back the detected temperature signal to the combustion control model, which performs temperature compensation and correction on the homogenization zone and the secondary heating zone based on the temperature difference between the upper and lower sections. Methods for adjusting the temperature difference between the upper and lower surfaces of the billet exiting the slab heating furnace include the following two methods: 1) When the temperature difference between the upper and lower gauges is less than or equal to the set temperature, the combustion control model corrects and compensates for the heat spread zone. 2) When the temperature difference between the upper and lower gauges exceeds the set temperature, the combustion control model corrects and compensates for the second heating section. In method 1), the combustion control model increases the temperature difference between the upper and lower gauges of the thermocouples used for temperature process control on the side with higher temperature in the heat spreader, thereby adjusting the combustion control model toward the compensated and corrected target value. In method 2), the combustion control model increases the temperature difference between the upper and lower gauges of the thermocouples used for temperature process control on the side with higher temperature in the two heating sections, so that the combustion control model is adjusted toward the target value after compensation and correction. When the temperature difference between the upper and lower gauges is less than or equal to the set temperature value after adjusting using method 2), then adjust using method 1). The set temperature value is 20℃.

2. The temperature difference adjustment system for the upper and lower surfaces of the billet exiting the slab heating furnace according to claim 1, characterized in that: The first and second temperature detectors are respectively provided with sleeves extending towards the slab. Each sleeve is connected to a vent pipe, which is connected to an air source to introduce compressed air into the sleeve.

3. The temperature difference adjustment system for the upper and lower surfaces of the billet exiting the slab heating furnace according to claim 2, characterized in that: The first temperature detector and the second temperature detector are connected and output the collected temperature signals to the PLC. The PLC controls the operating conditions of the heating furnace according to the temperature signals.

4. The temperature difference adjustment system for the upper and lower surfaces of the billet exiting the slab heating furnace according to any one of claims 1-3, characterized in that: The first temperature detector is placed in the negative layer pit, and both the first and second temperature detectors are fixed by brackets.

5. The temperature difference adjustment system for the upper and lower surfaces of the billet exiting the slab heating furnace according to claim 4, characterized in that: The first temperature detector and the second temperature detector are located above and below the same area of ​​the roller conveyor.

6. The temperature difference adjustment system for the upper and lower surfaces of the billet exiting the slab heating furnace according to claim 1, characterized in that: The system completes a data collection cycle every 30 minutes. The data in the first set of data in each acquisition cycle is defined as valid data if either data in the upper or lower table is greater than 1000°C. When the temperature of each section of the heating furnace is lower than the lower limit of the process, the method of adjusting the temperature difference between the upper and lower surfaces of the billet exiting the slab heating furnace shall not be implemented.

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