A method for automatically controlling the feeding of heat treatment furnace replaced heating process steel plates into the furnace

Abstract

The present invention discloses a method for automatically controlling the feeding of steel plates with changed heating processes into a heat treatment furnace, belonging to the technical field of metallurgical automation. The method generates a production mark for process change by program judgment when the set furnace temperature of the last steel plate in the furnace is different from that of the steel plate to be loaded. Steel plates with the production mark for process change are not allowed to be automatically fed into the furnace. At the same time, according to the real-time position of the steel plate in the furnace in the heating zone, the function of automatically setting the temperature of each heating zone is realized, and the time required for the heat preservation zone of the heat treatment furnace to reach the set temperature is calculated based on the heating and cooling rates of the heat treatment furnace. By comparing the heating and cooling time with the time for the steel plate to be loaded to reach the heat preservation zone, the feeding time of the steel plate with the changed heating process is automatically judged, and the automatic control of the feeding of the steel plate with the changed heating process is realized. This method can effectively avoid the situations of slow production rhythm and energy waste caused by untimely manual furnace temperature setting, misjudgment of the manual loading time, delay, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of metallurgical automation, and particularly relates to a method for automatically controlling the charging of steel plates with a changed heating process into a heat treatment furnace. Background Art

[0002] Currently, in the production of heat treatment furnaces, for a steel plate to be charged to be allowed to enter the heat treatment furnace for heating, the following two conditions need to be met: 1. The available space in the furnace is allowed, that is, the remaining production space in the furnace should be greater than the length of the steel plate to be charged; 2. The actual furnace temperature and the set furnace temperature are within the process deviation range. Generally, the heating processes for steel plates of different materials are different. After each change of the heating process, the furnace temperature needs to be changed accordingly. For the steel plates after the heating process is changed, they need to wait until the actual furnace temperature reaches within the process range before being allowed to enter the furnace for production.

[0003] A heat treatment furnace is generally divided into multiple heating zones. In the actual production mode of changing the heating process, in order not to affect the temperature of the steel plates being produced in the furnace and to ensure that the steel plates to be charged can enter the furnace for production earlier under the process requirements, the operators usually wait for the steel plates being produced to move a certain distance and then perform the temperature increase and decrease operations on the front heating zones. The distance interval between the heating zone to be temperature-adjusted and the tail position of the steel plates in the furnace is generally 1 - 3 heating zones. This production process requires the operators to observe the furnace temperature situation and judge the appropriate charging time. The last heating zone in the furnace is also called the heat preservation zone. Since the furnace temperature setting in the heat preservation zone is generally set after the last steel plate in the furnace is discharged, as long as the temperature in the heat preservation zone reaches the set temperature and is within the process deviation range when the steel plate to be charged reaches the heat preservation zone, it is considered at this time that the steel plate to be charged can enter the furnace. In actual production, situations such as untimely manual furnace temperature setting, misjudgment of the manual charging time, and delay are likely to occur, resulting in a slow production rhythm and energy waste.

[0004] Based on this, the present invention designs a method for automatically controlling the charging of steel plates with a changed heating process in a heat treatment furnace to solve the above problems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is the problems of untimely furnace temperature setting and inaccurate grasp of the manual charging time when changing the heating process of the current heat treatment furnace, and a method for automatically controlling the charging of steel plates with a changed heating process in a heat treatment furnace is provided.

[0006] To solve the above technical problems, the present invention provides the following technical solutions:

[0007] The method first compares the process-set temperature of the steel plate to be charged with the process-set temperature of the last steel plate produced in the furnace. When the two are not equal, a mark for changing the production process is generated. The steel plate to be charged with the mark for changing the production process is not allowed to automatically enter the furnace (where the process-set temperature is sent by the superior system before the steel plate enters the furnace or is input manually). At the same time, according to the position of the last steel plate produced in the furnace, the heating zones passed through are calculated in real time, and the first to (K - a) heating zones are automatically set to the process temperature of the steel plate to be charged. At the same time, according to the heating or cooling rate of the heat treatment furnace, the time Ti required for the temperature of the holding zone (the last heating zone in the furnace) to reach the set temperature of the steel plate to be charged is calculated. According to the length of the steel plate to be charged, the distance between the steel plate to be charged and the furnace door, the furnace door protection distance, the distance of the steel plate after entering the furnace to the holding zone, the charging speed of the steel plate to be charged, and the process speed of the steel plate, the time Ta required for the steel plate to be charged to reach the holding zone in the furnace is calculated. When Ta >= Ti, the mark for changing the production process is cancelled, and the steel plate to be charged is allowed to automatically enter the furnace.

[0008] Specifically, it includes the following steps:

[0009] S1: Compare the process-set temperature of the last steel plate produced in the furnace with the process-set temperature of the steel plate to be charged in front of the furnace. When the two are not equal, a mark for changing the production process is generated. The steel plate to be charged with the mark for changing the production process is not allowed to automatically enter the furnace;

[0010] S2: Calculate that the tail position of the last steel plate in the furnace is in the Kth heating zone, and automatically set the temperature of the first to (K - a) heating zones to the process-set temperature of the steel plate to be charged, where a is the interval zone;

[0011] S3: Calculate the time Ti required for the temperature of the holding zone to reach the process-set temperature of the steel plate to be charged;

[0012] S4: Calculate the time Ta required for the steel plate to be charged to reach the temperature of the holding zone in the furnace;

[0013] S5: Judge whether Ta is greater than Ti. If it is greater, clear the mark for changing the production process. At this time, the steel plate to be charged with the changed heating process is allowed to enter the furnace. If Ta is less than Ti, the steel plate to be charged is not allowed to enter the furnace until Ta is greater than or equal to Ti.

[0014] Among them, the value range of a in S2 is 1 - 3.

[0015] In S3, the holding zone is the last heating zone in the furnace.

[0016] In S3, Ti = Ts + Td / Dt, where Ts is the remaining time of the last steel plate in the furnace, Td is the temperature difference between the process-set temperature of the steel plate to be charged and the set temperature of the last steel plate in the furnace, Dt is the heating or cooling rate of the heat treatment furnace, the units of Ti and Ts are minutes, the unit of Td is degree Celsius, and the unit of Dt is degree Celsius per minute.

[0017] In S4, Ta = (L + da + db) / Vs + dc / Vt, where L is the length of the steel plate to be charged, da is the distance from the steel plate to be charged to the furnace door, db is the furnace door protection distance, dc is the distance from the steel plate to reach the heat preservation area after the steel plate to be charged enters the furnace, Vs is the feeding speed of the steel plate to be charged into the furnace, and Vt is the process speed of the steel plate to be charged; where the unit of Ta is minutes, the units of L, da, db, and dc are meters, and the units of Vs and Vt are meters per minute.

[0018] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0019] The above technical solution solves the problems of slow production rhythm and energy waste caused by the situation that in actual production, it is easy to occur that the artificial furnace temperature setting is not timely, or the judgment of the artificial charging timing is incorrect or delayed. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 It is the process flow chart of the method for automatically charging the heat treatment furnace to change the heating process steel plate in Embodiment 1 of the present invention;

[0022] Figure 2 It is the schematic plan view involved in the embodiment of the present invention.

[0023] Among them: 1 - steel plate to be charged; 2 - side of the charging furnace door; 3 - heating area; 4 - position after the steel plate to be charged enters the furnace; 5 - the last steel plate in the furnace. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the drawings and specific embodiments.

[0025] The present invention provides a method for automatically controlling the charging of a heat treatment furnace to change the heating process steel plate.

[0026] As Figure 1 shown, the method includes the following steps:

[0027] S1: Compare the process set temperature of the last steel plate produced in the furnace with the process set temperature of the steel plate to be charged in front of the furnace (where the process set temperature is sent by the superior system before the steel plate enters the furnace or is manually input). When the two are not equal, a production mark for changing the process is generated, and the steel plate to be charged with the production mark for changing the process is not allowed to be automatically charged into the furnace;

[0028] S2: Calculate the number of heating zones that the last steel plate in the furnace passes through as K, and automatically set the temperatures of the first to (K - a) heating zones in front of the K-th heating zone to the process-set temperature of the steel plate to be loaded, where a is the interval zone.

[0029] S3: Calculate the time Ti required for the temperature in the holding zone to reach the process-set temperature of the steel plate to be loaded.

[0030] S4: Calculate the time Ta required for the steel plate to be loaded to reach the temperature in the holding zone of the furnace.

[0031] S5: Determine whether Ta is greater than or equal to Ti. If it is greater, clear the production mark for process change. At this time, the steel plate to be loaded that allows process change is allowed to enter the furnace. If Ta is less than Ti, the steel plate to be loaded is not allowed to enter the furnace until Ta is greater than or equal to Ti.

[0032] As Figure 2 shown, the whole furnace is divided into N heating zones. The heating zone 3 where the tail of the last steel plate 5 in the furnace is located is the K-th heating zone (K < N). The length of the steel plate 1 to be loaded is L. The steel plate 1 to be loaded enters from the side of the charging furnace door 2. The distance of the steel plate to be loaded from the furnace door is da, the furnace door protection distance is db. After the steel plate to be loaded enters the furnace, the distance from the position 4 after the steel plate to be loaded enters the furnace to the holding zone is dc.

[0033] In the specific implementation process, the operations are carried out according to the following steps:

[0034] (1) Compare the process-set temperature of the last steel plate produced in the furnace with the process-set temperature of the steel plate to be loaded in front of the furnace. When the two are not equal, a production mark for process change is generated on this steel plate. The steel plate to be loaded with the production mark for process change is not allowed to automatically enter the furnace.

[0035] (2) The program calculates the number of heating zones that the tail of the last steel plate in the furnace passes through, denoted as K. Automatically set the temperatures of the first to (K - a) heating zones in front of this heating zone to the process temperature of the steel plate to be loaded, where a is the interval zone. To ensure that the temperature of the steel plate produced in the furnace is not affected by temperature rise and fall, the value range of a is 1 - 3. In this embodiment, a takes 2.

[0036] (3) The program calculates the time Ti required for the temperature in the holding zone to reach the set temperature of the steel plate to be loaded. Ti = Ts + Td / Dt, where Ts is the remaining time of the last steel plate in the furnace, Td is the temperature difference between the set temperature of the steel plate to be loaded and the set temperature of the last steel plate in the furnace, and Dt is the heating or cooling rate of the heat treatment furnace. Dt is based on the actual heating efficiency of the furnace and is generally input by the operator on the HMI screen. Among them, the units of Ti and Ts are minutes, the unit of Td is degrees Celsius, and the unit of Dt is degrees Celsius per minute.

[0037] (4) The program calculates the time Ta required for the steel plate to be charged to reach the heat preservation zone in the furnace, Ta = (L + da + db) / Vs + dc / Vt, where L is the length of the steel plate to be charged, da is the distance between the steel plate to be charged and the furnace door, db is the protection distance of the furnace door, dc is the distance from the head position of the steel plate in the furnace to the heat preservation zone, Vs is the charging speed of the steel plate to be charged, and Vt is the process speed of the steel plate to be charged. The unit of Ta is minutes, the units of L, da, db, and dc are meters, and the units of Vs and Vt are meters per minute;

[0038] (5) Determine whether Ta is greater than or equal to Ti. If it is greater, clear the production mark for process change. At this time, the steel plate to be charged for process change is allowed to enter the furnace. If Ta is less than Ti, the steel plate to be charged is not allowed to enter the furnace until Ta is greater than or equal to Ti.

[0039] This method has been successfully applied to the automatic furnace charging control of a steel plant's heat treatment furnace. While reducing the labor intensity of operators, it has also improved production efficiency and control accuracy, and reduced energy waste, receiving favorable comments from users.

[0040] The above is the preferred implementation mode of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle described in the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for automatically controlling the feeding of steel plates with changed heating processes into a heat treatment furnace, characterized in that, it includes the following steps: S1: Compare the process set temperature of the last steel plate produced in the furnace with the process set temperature of the steel plate to be loaded in front of the furnace. When the two are not equal, a production mark for process change is generated, and the steel plate to be loaded with the production mark for process change is not allowed to be automatically fed into the furnace; S2: Calculate that the tail position of the last steel plate produced in the furnace is in the Kth heating zone, and automatically set the temperatures of the 1st to (K - a) heating zones to the process set temperature of the steel plate to be loaded, where a is the interval zone; S3: Calculate the time Ti required for the temperature in the heat preservation zone to reach the process set temperature of the steel plate to be loaded; S4: Calculate the time Ta required for the steel plate to be loaded to reach the temperature in the heat preservation zone in the furnace; S5: Judge whether Ta is greater than or equal to Ti. If Ta ≥ Ti, clear the production mark for process change. At this time, the steel plate to be loaded with the changed heating process is allowed to enter the furnace. If Ta is less than Ti, the steel plate to be loaded is not allowed to enter the furnace until Ta is greater than or equal to Ti; In the above S3, Ti = Ts + Td / Dt, where Ts is the remaining time of the last steel plate in the furnace, Td is the temperature difference between the process set temperature of the steel plate to be loaded and the set temperature of the last steel plate in the furnace, Dt is the heating or cooling rate of the heat treatment furnace, the units of Ti and Ts are minutes, the unit of Td is degree Celsius, and the unit of Dt is degree Celsius per minute; In the above S4, Ta = (L + da + db) / Vs + dc / Vt, where L is the length of the steel plate to be loaded, da is the distance of the steel plate to be loaded from the furnace door, db is the furnace door protection distance, dc is the distance for the steel plate to reach the heat preservation zone after being fed into the furnace, Vs is the feeding speed of the steel plate to be loaded, and Vt is the process speed of the steel plate to be loaded; the unit of Ta is minutes, the units of L, da, db, and dc are meters, and the units of Vs and Vt are meters per minute.

2. The method for automatically controlling the feeding of steel plates with changed heating processes into a heat treatment furnace according to claim 1, characterized in that, the value range of a in the above S2 is 1 - 3.

3. The method for automatically controlling the feeding of steel plates with changed heating processes into a heat treatment furnace according to claim 1, characterized in that, the heat preservation zone in the above S3 is the last heating zone in the furnace.

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