A method and system for adjusting annealing strip properties online

Abstract

The invention relates to the technical field of strip steel manufacturing, and discloses a system for online adjustment of annealing strip steel performance, comprising a primary control system, a secondary control system, a tertiary control system, and a quaternary control system, wherein the primary control system, the secondary control system, the tertiary control system, and the quaternary control system cooperate to complete control; two sets of online mechanical property detectors and one set of plate shape meters are equipped in an annealing unit to realize comprehensive closed-loop control of annealing temperature, flattening elongation, and flattening plate shape; the invention can realize online adjustment of the mechanical properties of the strip steel; can obtain a strip steel with uniform mechanical properties throughout a roll; can improve work efficiency, shorten the adjustment reaction cycle; can reduce the workload of manual intervention, and is conducive to realizing automated production.

Description

Technical Field

[0001] The invention relates to the technical field of strip steel manufacturing, and in particular to a method and a system for online adjusting the performance of annealed strip steel. Background Art

[0002] As users' requirements for the quality of cold-rolled strip steel continue to increase, including requirements for strip steel surface quality, plate shape, dimensional accuracy, mechanical properties and other aspects, the tensile strength and yield strength in mechanical properties are important indicators for measuring the quality of strip steel products, and are the main basis for downstream product design and material selection. Testing the mechanical properties parameters of strip steel is an important means to ensure its product quality. There are many factors that affect the mechanical properties of cold-rolled strip steel, including the influence of steelmaking chemical composition, hot rolling process, cold rolling mill process and cold rolling annealing process. Among them, the cold rolling annealing unit is the last process facing users. The annealing process in the annealing unit is the final guarantee of mechanical properties. Adjusting the annealing temperature and the leveling elongation is an effective means to improve mechanical properties.

[0003] For ultra-high strength steel, which is mainly used for structural parts and safety parts, mechanical properties are the first priority. Traditionally, the detection of mechanical properties of cold-rolled strip is still mainly obtained through offline tensile testing, which is time-consuming and laborious. At the same time, due to the non-continuity of laboratory testing, it cannot reflect the overall quality of cold-rolled strip. Therefore, the conclusions obtained from offline testing can only be used to guide process adjustments and stabilize product quality. After the strip comes off the unit, the mechanical properties are tested by manually sending samples to the inspection and testing. It takes at least one hour for the performance to come out after the whole process. If the performance does not match within this hour, it means that the performance of multiple consecutive rolls does not match. This is the first disadvantage of the traditional performance inspection, which is not timely enough. Secondly, after the performance results come out, the process needs to be adjusted. After the adjustment, the first sample test needs to be repeated. If it is still unqualified, it is necessary to wait for more than one hour before the result comes out. This is the disadvantage of untimely feedback of the results after adjustment. Thirdly, for a single roll, the conclusion obtained by offline detection can only obtain the performance data of the head, middle and tail, but cannot truly reflect the performance distribution of an entire roll. For example, if the yield strength of a certain section is too low / too high, it is impossible to achieve automatic online adjustment, which easily leads to insufficient uniformity of the yield strength of the entire roll. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In view of the deficiencies in the prior art, the present invention provides a method and system for online adjustment of annealing strip performance, which solves the problems existing in the above-mentioned background technology.

[0006] (II) Technical solution

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a method and system for online adjustment of annealing strip performance, comprising a primary control system, a secondary control system, a tertiary control system and a quaternary control system, wherein the primary control system, the secondary control system, the tertiary control system and the quaternary control system cooperate to complete control; two sets of online mechanical property detectors and one set of plate shape meter are equipped in the annealing unit to realize comprehensive closed-loop control of annealing temperature, flattening elongation and flattening plate shape, wherein the secondary control system includes, in addition to conventional process control systems such as annealing furnace temperature control system, a consistent annealing temperature pre-setting control system (1) for the annealing unit, an annealing temperature feedback automatic control system (2) for the annealing unit furnace, an elongation automatic control system for the flattening mill (3) and an automatic control system for the flattening plate shape (4); firstly, the consistent annealing temperature pre-setting control system (1) for the annealing unit sends a command to the annealing furnace temperature control system through the secondary control system according to the incoming material chemical composition and hot rolling process obtained from the quaternary system. The annealing temperature is pre-set and controlled, and the annealing process is dynamically adjusted to complete an online adjustment of the annealing process; then, the annealing temperature feedback automatic control system (2) of the annealing unit furnace controls the annealing temperature according to the measurement results of the online mechanical property detector (A) at the annealing furnace outlet to complete the real-time online adjustment of the annealing process; at the same time, the leveling machine elongation automatic control system (3) pre-sets the leveling machine elongation according to the measurement results of the online mechanical property detector (A) at the annealing furnace outlet to achieve online feedforward control of the leveling elongation; in addition, the leveling machine elongation automatic control system (3) also dynamically corrects and adjusts the leveling elongation according to the measurement results of the online mechanical property detector (B) at the leveling machine outlet to achieve online feedback control of the leveling elongation, and the leveling plate shape automatic control system (4) adjusts the leveling bending roller force according to the measurement results of the plate shape meter (C) at the leveling machine outlet, and corrects the leveling elongation for a second time in combination with the measurement results of the online mechanical property detector (B) at the leveling machine outlet to achieve comprehensive control of the plate shape and online mechanical properties.

[0008] The system also includes: an annealing furnace 1, a mechanical property detector ①4 at the outlet of the annealing furnace 1, a mechanical property detector ②10 at the outlet of the leveling machine 7, and the leveling machine 7.

[0009] Preferably, the annealing unit consistent annealing temperature presetting control system (1) is equipped with a complete set of comparison tables of target deviations of chemical composition of various steel grades (including: C, Si, Mn, P, S, N, Ti, Nb, Cr, Mo, V, B, Ni, Cu), hot rolling slab heating temperature, slab furnace time, hot rolling final rolling temperature and hot rolling coiling temperature and compensation amounts of annealing temperatures of various sections of the annealing furnace (heating temperature, soaking temperature, slow cooling temperature, rapid cooling intermediate temperature, rapid cooling outlet temperature and over-aging temperature), which are used for presetting the temperatures of various sections of the annealing furnace (heating temperature, soaking temperature, slow cooling temperature, rapid cooling intermediate temperature, rapid cooling outlet temperature and over-aging temperature) to realize feedforward control of the mechanical properties of the steel strip.

[0010] Preferably, the measurement results of the online mechanical property detector (A) at the annealing furnace outlet include yield strength, tensile strength and elongation at break, and the annealing temperature feedback automatic control system (2) of the annealing unit furnace adjusts the temperature of each section of the annealing furnace (heating temperature, soaking temperature, slow cooling temperature, rapid cooling intermediate temperature, rapid cooling outlet temperature and over-aging temperature) online according to the deviation between the measurement results of the online mechanical property detector (A) at the annealing furnace outlet of each steel grade and the user's required mechanical properties (including yield strength, tensile strength and elongation at break) obtained from the four-level control system to achieve real-time feedback control of the annealing temperature.

[0011] Preferably, the leveling machine elongation automatic control system (3) includes a leveling machine elongation preset control and a leveling machine elongation feedback control, wherein the leveling machine elongation preset control adjusts the leveling elongation preset value of the strip according to the yield strength measurement result of the online mechanical property detector (A) at the annealing furnace outlet and the yield strength deviation required by the user obtained from the four-level control system for preset control, and the leveling machine elongation feedback control controls the leveling elongation of the strip according to the yield strength measurement result of the online mechanical property detector (B) at the leveling machine outlet and the yield strength deviation required by the user obtained from the four-level control system for real-time feedback.

[0012] Preferably, the flat plate shape automatic control system (4) adjusts the flattening bending roller force according to the deviation between the plate shape curve measured by the flattening machine outlet shape meter (C) and the target plate shape curve, and corrects the flattening elongation secondary by comparing the yield strength measured by the online mechanical property detector (B) at the flattening machine outlet with the maximum and minimum allowable yield strength values ​​required by the user obtained from the four-level control system, thereby achieving comprehensive control of the plate shape and online mechanical properties, and achieving online mechanical property control when the flattening machine plate shape is acceptable.

[0013] Preferably, a comparison table of target deviations of the chemical composition of each steel grade, hot-rolled slab heating temperature, slab furnace time, hot-rolled final rolling temperature and hot-rolled coiling temperature and annealing temperature compensation of each section of the annealing furnace is maintained in a database system and equipped with a self-learning function. When the corresponding deviation value of the steel grade appears later, the self-learned data in the database can be automatically called for adjustment.

[0014] Preferably, the automatic control system (3) for elongation of the flattening machine regularly compares the online mechanical property test results with the actual test results of the inspection and laboratory test, and corrects the online mechanical property test results according to the actual test results of the inspection and laboratory test, so as to ensure that the online mechanical property test results are basically consistent with the actual test results of the inspection and laboratory test.

[0015] Preferably, the system automatically obtains the actual test results and performs fitting correction on the online measurement results in real time.

[0016] Preferably, each temperature segment of the annealing furnace DCS screen is designed with ΔT, which is used to receive the annealing temperature compensation value issued by the cold rolling secondary system. The leveling mill HMI screen and the mechanical properties tester screen are designed with Δε, which are used to receive the elongation compensation value issued by the cold rolling secondary system.

[0017] (III) Beneficial effects

[0018] The present invention provides a method and system for online adjustment of annealing strip properties, which has the following beneficial effects:

[0019] The present invention can realize online adjustment of the mechanical properties of the steel strip; can obtain a steel strip with uniform mechanical properties throughout the roll; can improve work efficiency and shorten the adjustment reaction cycle; can reduce the workload of manual intervention, and is conducive to realizing automated production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the automatic control system related to the present invention;

[0021] Figure 2 The present invention is a schematic diagram of the implementation position of the present invention in a strip steel continuous annealing unit or a hot dip galvanizing unit.

[0022] In the figure: 1. Annealing furnace; 2. 6# tension roller; 3. Strip steel; 4. Mechanical property tester (A); 5. Intermediate looper; 6. 7# tension roller; 7. Leveling machine; 8. Flatness meter; 9. 8# tension roller; 10. Mechanical property tester (B). DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] like Figure 1-2 As shown, the present invention provides a technical solution: the strip steel 3 leaves the annealing furnace 1, passes through the 6# tension roller 2, and passes through the mechanical property detector (A) 4 to measure the mechanical properties of the strip steel, and then enters the intermediate looper 5, and after coming out, passes through the pre-leveling tension roller 6 to reach the leveling machine 7, and after leveling, comes out to the post-leveling tension roller 9 of the leveling machine, and then passes through the flatness meter 8 and the mechanical property detector (B) 10. In this example, the annealing furnace 1 has a separate control computer for temperature adjustment during the production process, and the temperature design of each section in the corresponding annealing furnace model has ΔT, which is used to receive the annealing temperature compensation value issued by the cold rolling secondary system. The mechanical property tester (A) 4 and the mechanical property tester (B) 10 are equipped with separate computers, which can be used to display performance and adjust the flattening elongation. In the cold rolling secondary system, a special comparison table 1 of the target deviation of chemical composition of each steel grade and the annealing temperature compensation of each section of the annealing furnace, a comparison table 2 of the target deviation of hot rolling process of each steel grade and the annealing temperature compensation of each section of the annealing furnace, a comparison table 3 of the mechanical property deviation of each steel grade and the annealing temperature compensation of each section of the annealing furnace, and a comparison table 4 of the mechanical property deviation and elongation compensation of each steel grade are prepared. This table is used to send the annealing temperature compensation corresponding to the chemical composition target deviation and hot rolling process target deviation issued by the cold rolling third-level system to the annealing furnace primary system; it is also used to send the annealing temperature compensation corresponding to the mechanical property deviation value uploaded by the mechanical property tester to the annealing furnace primary system; it is also used to send the elongation compensation corresponding to the performance deviation value uploaded by the mechanical property tester to the flattening mill primary system for execution and send it to the mechanical property tester at the same time, so as to realize online mechanical property adjustment.

[0025] For example, the target chemical composition of the substrate is 0.14% C-0.10% Si-1.3% Mn. After steelmaking, the actual measured smelting composition of the strip is 0.135%-0.08% Si-1.27% Mn. The comparison table 1 of the annealing temperature compensation of each section of the annealing furnace is a comparison table of the substrate C content and the annealing slow cooling annealing temperature. It can be seen from Table 1 that during annealing, the ΔT of the slow cooling section is 5°C, that is, during annealing, the slow cooling temperature will increase by 5°C. After the hot rolling process, the hot rolling coiling temperature is 520°C, which is 20°C higher than the target coiling temperature of 500°C. The comparison table 2 of the hot rolling process target deviation and the annealing temperature compensation of each section of the annealing furnace is a comparison table of the coiling temperature, the annealing heating temperature and the soaking temperature. It can be seen from Table 2 that during annealing, the ΔT of the heating section and the soaking section is -10°C, that is, during annealing, the heating temperature and the soaking temperature will be reduced by 5°C. During actual annealing, the mechanical property detector (A) 4 measured the strip steel mechanical property and the actual measured strip steel yield strength was 680MPa, which was 20MPa lower than the target value of 700MPa or more. At this time, the feedback control increased the strip steel slow cooling temperature by another 3°C. After the strip steel was flattened, the mechanical property detector (B) 10 measured the strip steel yield strength of 732MPa, which was close to the strip steel yield strength target value of 730MPa. Table 4 of the mechanical property deviation and elongation compensation of this steel grade is the yield strength deviation and flattening elongation compensation comparison table. As can be seen from Table 4, at this time, the yield strength is qualified (this embodiment considers that the yield is qualified within the target value ±5MPa), and the flattening maintains the original control without adjustment.

[0026] Table 1 Comparison table of chemical composition of steel substrate and annealing slow cooling temperature

[0027] Substrate C content Annealing slow cooling temperature correction C＜0.135％ +10℃ 0.135％≤C＜0.138％ +5℃ 0.138≤C＜0.142％ 0℃ 0.142％≤C＜0.145％ -5℃ C＞0.145％ -10℃

[0028] Table 2 Comparison table of hot rolling coiling temperature, annealing heating temperature and soaking temperature of example steel grades

[0029]

[0030]

[0031] Table 3 Comparison table of yield strength deviation after annealing and annealing slow cooling temperature of example steel grades

[0032] Yield strength deviation Δσs Annealing slow cooling temperature correction Δσs<-20MPa +5℃ -20MPa≤Δσs<-10MPa +3℃ -10MPa≤Δσs≤+10MPa 0℃ +10MPa<Δσs≤+20MPa -3℃ Δσs>20MPa -5℃

[0033] Table 4 Comparison table of yield strength deviation and flattening elongation of example steel grades after flattening

[0034] Yield strength deviation Δσs Annealing slow cooling temperature correction Δσs<-30MPa +0.2％ -30MPa≤Δσs<-20MPa +0.1％ -20MPa≤Δσs≤+20MPa 0℃ +20MPa<Δσs≤+30MPa -0.1％ Δσs>30MPa -0.2％

[0035] In the actual production process, the C content of the substrate, the hot rolling coiling temperature, the yield strength deviation after annealing and the yield strength deviation after flattening are not exactly the values ​​in the table. In actual applications, they are calculated through interpolation to obtain the correction adjustment amount.

[0036] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A system for adjusting the properties of annealed strip steel online, comprising a primary control system, a secondary control system, a tertiary control system, and a quaternary control system, characterized in that: The system is controlled by the cooperation among the primary control system, the secondary control system, the tertiary control system and the quaternary control system; two sets of online mechanical property detectors and one set of flatness meter are equipped in the annealing unit to realize the comprehensive closed-loop control of annealing temperature, flattening elongation and flattening plate shape; the secondary control system includes, in addition to the conventional process control system, a consistent annealing temperature presetting control system (1) of the annealing unit, an annealing temperature feedback automatic control system (2) of the annealing unit furnace, an elongation automatic control system of the flattening mill (3) and an automatic control system of the flattening plate shape (4); two sets of online mechanical property detectors, one set is equipped after the annealing furnace outlet and before the flattening mill, and the other set is equipped after the flattening mill, and the flatness meter is equipped at the flattening mill outlet; firstly, the consistent annealing temperature presetting control system (1) of the annealing unit sends a command to the annealing furnace temperature control system through the secondary control system to perform annealing temperature presetting control according to the incoming material chemical composition and hot rolling process obtained from the quaternary control system, dynamically adjusts the annealing process, and completes one-time online adjustment of the annealing process; Then, the annealing temperature feedback automatic control system (2) of the annealing unit furnace controls the annealing temperature according to the measurement result of the online mechanical property detector (A) at the annealing furnace outlet to complete the real-time online adjustment of the annealing process; at the same time, the leveling machine elongation automatic control system (3) pre-sets the leveling machine elongation according to the measurement result of the online mechanical property detector (A) at the annealing furnace outlet, so as to realize the online feedforward control of the leveling elongation; in addition, the leveling machine elongation automatic control system (3) also dynamically corrects and adjusts the leveling elongation in real time according to the measurement result of the online mechanical property detector (B) at the leveling machine outlet, so as to realize the online feedback control of the leveling elongation, and the leveling plate shape automatic control system (4) adjusts the leveling bending roller force according to the plate shape meter, and corrects the leveling elongation for a second time in combination with the measurement result of the online mechanical property detector (B) at the leveling machine outlet to realize the comprehensive control of the plate shape and online mechanical properties.

2. The system for online adjusting the properties of annealed strip according to claim 1, characterized in that: The annealing unit consistent annealing temperature presetting control system (1) is equipped with a complete set of chemical compositions of various steel types including: C, Si, Mn, P, S, N, Ti, Nb, Cr, Mo, V, B, Ni, Cu, hot rolling slab heating temperature, slab furnace time, hot rolling final rolling temperature and hot rolling coiling temperature target deviation and annealing furnace each section temperature including heating temperature, soaking temperature, slow cooling temperature, rapid cooling intermediate temperature, rapid cooling outlet temperature and over-aging temperature compensation amount comparison table, used for presetting each section temperature of the annealing furnace including heating temperature, soaking temperature, slow cooling temperature, rapid cooling intermediate temperature, rapid cooling outlet temperature and over-aging temperature, so as to realize feedforward control of strip steel mechanical properties.

3. The system for online adjusting annealing strip properties according to claim 1, characterized in that: The measurement results of the online mechanical property detector (A) at the outlet of the annealing furnace include yield strength, tensile strength and elongation at break. The annealing temperature feedback automatic control system (2) of the annealing unit furnace adjusts the temperature of each section of the annealing furnace online, including the heating temperature, soaking temperature, slow cooling temperature, rapid cooling intermediate temperature, rapid cooling outlet temperature and over-aging temperature, according to the measurement results of the online mechanical property detector (A) at the outlet of the annealing furnace of each steel grade and the deviation of the mechanical properties required by the user obtained from the four-level control system, including yield strength, tensile strength and elongation at break, to achieve real-time feedback control of the annealing temperature.

4. The system for adjusting the properties of annealed steel strip online according to claim 1, characterized in that: The leveling machine elongation automatic control system (3) includes a leveling machine elongation preset control and a leveling machine elongation feedback control. The leveling machine elongation preset control adjusts the leveling elongation preset value of the steel strip according to the yield strength measurement result of the online mechanical property detector (A) at the annealing furnace outlet and the yield strength deviation required by the user obtained from the four-level control system for preset control. The leveling machine elongation feedback control controls the leveling elongation of the steel strip according to the yield strength measurement result of the online mechanical property detector (B) at the leveling machine outlet and the yield strength deviation required by the user obtained from the four-level control system for real-time feedback control.

5. The system for online adjusting annealing strip properties according to claim 1, characterized in that: The flattening plate shape automatic control system (4) adjusts the flattening bending roller force according to the deviation between the plate shape curve measured by the plate shape meter and the target plate shape curve, and corrects the flattening elongation rate by comparing the yield strength measured by the online mechanical property detector (B) at the outlet of the flattening machine with the maximum and minimum allowable yield strength values ​​required by the user obtained from the four-level control system, thereby achieving comprehensive control of the plate shape and online mechanical properties, and achieving online mechanical property control when the plate shape of the flattening machine is acceptable.

6. The system for online adjusting annealing strip properties according to claim 2, characterized in that: A comparison table of target deviations of the chemical composition of each steel grade, hot-rolled slab heating temperature, slab furnace time, hot-rolled final rolling temperature and hot-rolled coiling temperature and annealing temperature compensation of each section of the annealing furnace is maintained in the database system and equipped with a self-learning function. When the corresponding deviation value appears in the subsequent steel grade, the self-learned data in the database can be automatically called for adjustment.

7. The system for online adjusting annealing strip properties according to claim 1, characterized in that: The automatic control system (3) for elongation of the flattening machine regularly compares the online mechanical property test results with the actual test results of the inspection and testing, and corrects the online mechanical property test results according to the actual test results, so as to ensure that the online mechanical property test results are basically consistent with the actual test results of the inspection and testing.

8. The system for online adjusting the properties of annealed steel strip according to claim 7, characterized in that: The system automatically obtains the actual test results and performs fitting correction on the online measurement results in real time.

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