High-efficiency and low-cost quenching control method for medium plate

Abstract

The invention discloses a high-efficiency and low-cost quenching control method for a medium plate, and relates to the technical field of heat treatment, and the method comprises the following steps: establishing a water quantity-water pressure double closed-loop control system of a quenching machine; in the quenching machine passing mode, the corresponding nozzles are controlled to be opened in advance before the steel plate passes, and the corresponding nozzles are controlled to be closed after the steel plate passes; in the quenching machine swing mode, the steel plate swing area is moved backwards to the tail end of the quenching machine; the multiple steel plates are controlled to be quenched at the same time, and the two steel plates are controlled to swing and cool in the low-pressure section at the same time. According to the quenching control method, the water consumption during quenching is reduced, the quenching efficiency is improved, and the efficient and low-cost quenching control method for the medium-thickness plate is realized.

Description

Technical Field

[0001] The invention relates to the technical field of heat treatment, and in particular to a high-efficiency and low-cost quenching control method for medium and thick plates. Background Art

[0002] At present, the roller quenching machine is divided into a high-pressure section and a low-pressure section, and a variable-frequency pump is used for water supply. The design principle of the quenching machine is to quickly reduce the surface temperature of the steel plate to below 500°C through the high-pressure section, and then continue to cool the core of the steel plate with a large amount of low-pressure water until the temperature of the steel plate drops to an acceptable temperature for the variety or room temperature. However, due to the length limitation of the quenching machine, when the steel plate reaches a certain thickness, it needs to be swing-cooled at low pressure until the temperature of the steel plate drops to an acceptable temperature for the variety or room temperature before leaving the quenching machine.

[0003] For thick plates and extra-thick plates, this mode has the following problems: the quenching roller speed is low, only one steel plate is quenched during quenching, and the next steel plate is allowed to be quenched only after the steel plate is completely out of the quenching machine. If the steel-out rhythm is faster than the quenching rhythm, the steel-out efficiency is reduced; the low-pressure swing time of the steel plate is long; the existing quenching machine has a long water adjustment time, and the phenomenon of unnecessary water spraying is prominent, resulting in serious waste of cooling water and high consumption of water per ton of steel. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the disadvantages of the prior art and provide a high-efficiency and low-cost quenching control method for medium and thick plates.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows: A high-efficiency and low-cost quenching control method for medium and thick plates, comprising: Establish a double closed-loop control system of water volume and water pressure for the quenching machine; In the quenching machine passing mode, the corresponding nozzles are controlled to open in advance before the steel plate passes, and the corresponding nozzles are controlled to close after the steel plate passes; In the quenching machine swing mode, move the steel plate swing area back to the end of the quenching machine; Control multiple steel plates to be quenched simultaneously, and control two steel plates to be swung and cooled simultaneously in the low-pressure section.

[0006] As a preferred solution of the high-efficiency and low-cost quenching control method for medium and thick plates of the present invention, wherein: in the quenching machine passing mode, after controlling the corresponding nozzle to open in advance before the steel plate passes, and controlling the corresponding nozzle to close after the steel plate passes, it also includes: Control the nozzles in the cooling section of the quenching machine where no steel plate passes to close.

[0007] As a preferred solution of the high-efficiency and low-cost quenching control method for medium and thick plates of the present invention, the controlling of simultaneous quenching of multiple steel plates comprises: Based on the steel plate position tracking system in the quenching machine, the steel plate position is tracked in real time and the moving speed of the steel plate is controlled so that multiple steel plates can be quenched at the same time.

[0008] As a preferred solution of the high-efficiency and low-cost quenching control method for medium and thick plates of the present invention, the method of real-time tracking of the position of the steel plate based on the steel plate position tracking system in the quenching machine and controlling the moving speed of the steel plate so that multiple steel plates are quenched simultaneously includes: When the steel loading rhythm is greater than the quenching rhythm, and the first steel plate comes out of the high-pressure section and swings in the low-pressure section, the second steel plate is taken out of the furnace for quenching, and when the first steel plate finishes swinging, the quenching of the second steel plate has not reached the position between the tail of the first steel plate and the diameter of the quenching machine roller.

[0009] As a preferred solution of the high-efficiency and low-cost quenching control method for medium and thick plates of the present invention, the control of the simultaneous swing cooling of two steel plates in the low-pressure section includes: Control the length of the low-pressure section of the quenching machine to be greater than the length of the previous steel plate + the length of the next steel plate + the diameter of the quenching machine roller * 4.

[0010] The beneficial effects of the present invention are: The present invention establishes a quenching machine flow-pressure dual closed-loop control system to shorten the water volume and water pressure adjustment time of each nozzle and reduce the water consumption in the lifting stage; a water spraying strategy is adopted to open the water in advance when the steel plate passes through the front nozzle and close the water in time when the steel plate passes through the rear nozzle, and the swing area of ​​the steel plate is moved back to the end of the quenching machine and the swing range is shortened to reduce the water consumption during quenching; the cooling process of simultaneous quenching of multiple steel plates and simultaneous swinging of two short steel plates in the low-pressure section is controlled to improve the quenching efficiency, thereby realizing a high-efficiency and low-cost quenching control method for medium and thick plates. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0012] Figure 1 A basic principle diagram of dual control of water volume and water pressure in the high-efficiency and low-cost quenching control method for medium and thick plates provided by the present invention; Figure 2 A schematic diagram of a water spraying strategy of a quenching machine in a high-efficiency and low-cost quenching control method for medium and thick plates provided by the present invention; Figure 3 A schematic diagram of an optimized swing strategy for a quenching machine in a high-efficiency and low-cost quenching control method for medium and thick plates provided by the present invention; Figure 4It is a schematic diagram of two steel plates being quenched simultaneously in the high and low pressure sections; Figure 5 Schematic diagram of two steel plates being quenched simultaneously in the low-pressure section. DETAILED DESCRIPTION

[0013] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific implementation modes and in combination with the accompanying drawings.

[0014] The present application provides a method for controlling quenching of medium and thick plates with high efficiency and low cost, and the method specifically comprises the following steps: Step S101: Establish a quenching machine water volume-water pressure double closed-loop control system.

[0015] For details, see Figure 1 , analyze the response-regulation characteristics of the quenching machine control valve group, study the influence of the flow in the pipe on the flow and pressure of each branch water supply pipe, establish a quenching machine flow-pressure dual closed-loop control system, and shorten the water volume and water pressure adjustment time of each nozzle.

[0016] Step S102: In the quenching machine passing mode, the corresponding nozzles are controlled to open in advance before the steel plate passes, and the corresponding nozzles are controlled to close after the steel plate passes, and the nozzles of the cooling section in the quenching machine where no steel plate passes are controlled to close.

[0017] For details, see Figure 2 In the passing mode, according to the quenching process of steel plates of different steel grades and thicknesses, based on the micro-tracking of the steel plate position in the quenching machine, a water spraying strategy is implemented to open the water in advance when the steel plate passes through the front nozzle and close the water in time when the steel plate passes through the rear nozzle. In addition, the cooling section without steel plates in the quenching machine is controlled not to spray water, thereby reducing the consumption of cooling water.

[0018] Step S103: In the quenching machine swing mode, the steel plate swing area is moved back to the end of the quenching machine.

[0019] For details, see Figure 3 In the swing mode, according to the quenching process of steel plates of different steel grades and thicknesses, a water spraying strategy is developed based on micro-tracking of the steel plate position in the quenching machine, moving the steel plate swing area back to the end of the quenching machine and shortening the swing range, thereby reducing the number of nozzles opened in the low-pressure section and reducing the consumption of cooling water.

[0020] Step S104: controlling the simultaneous quenching of multiple steel plates, and controlling the simultaneous swing cooling of two steel plates in the low-pressure section.

[0021] See also Figure 4 and Figure 5 In order to realize the simultaneous quenching of multiple steel plates, it is necessary to optimize the quenching machine tracking system, improve the tracking accuracy of multiple steel plates in the quenching machine, realize the process control of simultaneous quenching of multiple steel plates, and improve the quenching efficiency.

[0022] Specifically, when the steel loading rhythm is greater than the quenching rhythm, when the first steel plate comes out of the high-pressure section and swings in the low-pressure section, the second steel plate comes out of the furnace for quenching, and it must be ensured that when the first steel plate finishes swinging, the quenching of the second steel plate has not reached the diameter position between the tail of the first steel plate and the quenching machine roller.

[0023] In order to achieve simultaneous swing cooling of two steel plates in the low-pressure section, it is necessary to improve the utilization rate of the cooling zone of the low-pressure section based on micro-tracking information transmission and interlocking control of multiple steel plates in the quenching machine, achieve simultaneous swing cooling of two short steel plates in the low-pressure section, and improve quenching efficiency.

[0024] Specifically, to achieve the simultaneous swinging of two steel plates in the low-pressure section, the length of the low-pressure section of the quenching machine must be greater than the length of the previous steel plate + the length of the next steel plate + 4*the diameter of the quenching machine roller.

[0025] The following is further described by means of specific examples.

[0026] Case 1: Taking the quenching production of Q690D with a specification of 120mm*3000mm*10000mm as an example, the quenching machine is 24m long, of which the high-pressure section is 6m long and the low-pressure section is 18m long. The quenching roller speed is 0.025m / s. The specific steps of the efficient quenching control method for Q690D are as follows, including: When increasing the frequency: by establishing a quenching machine flow-pressure dual closed-loop control system, the frequency conversion pump frequency increase time is shortened from 150s to 60s.

[0027] During quenching: when the furnace door of the steel plate is opened, open 2 groups of spray groups first. When the head of the steel plate contacts the 1st group of nozzles, open 2 more groups in sequence based on the existing 2 groups of nozzles. When the steel plate contacts the 3rd group of nozzles, open 2 more groups in sequence... until the last 2 groups / 1 group of nozzles. When the tail of the steel plate passes through 2 groups of spray groups, close the 1st group. When the tail of the steel plate passes through 3 groups of spray groups, close the 1st and 2nd groups... until the steel plate is in the low-pressure swing area.

[0028] When the first steel plate comes out of the high pressure section, the second steel plate is allowed to come out of the furnace for quenching only after the running distance of the second steel plate reaches the end of the first steel plate + 1m (about the distance between two groups of nozzles) and the quenching of the first steel plate is completed. The switching mode of the nozzle group repeats step (2).

[0029] After the steel plate enters the low pressure, it swings between 6-18m at a roller speed of 0.02m / s in the low pressure section of the quenching machine; After the swing time is over, the steel plate quickly leaves the quenching machine at a roller speed of 0.25m / s.

[0030] Case 2: Take the continuous quenching production of two pieces of Q690D with the same specifications of 150mm*3000mm*6000mm as an example. The length of the quenching machine is 24m, of which the high-pressure section is 6m long and the low-pressure section is 18m long. The quenching roller speed is 0.02m / s. The specific steps of the efficient quenching control method for quenching Q690D are as follows, including: When increasing the frequency: by establishing a quenching machine flow-pressure dual closed-loop control system, the frequency conversion pump frequency increase time is shortened from 150s to 60s.

[0031] During quenching: when the furnace door of the steel plate is opened, open two groups of spray groups first. When the head of the steel plate contacts the first group of nozzles, open two more groups in sequence based on the existing two groups of nozzles. When the steel plate contacts the third group of nozzles, open two more groups in sequence... until the last 2 groups / 1 group of nozzles; when the tail of the steel plate passes through the second group of spray groups, close the first group. When the tail of the steel plate passes through the third group of spray groups, close the first and second groups... until the steel plate is in the low-pressure swing area.

[0032] When the first steel plate comes out of the high pressure section, the second steel plate begins to come out of the furnace for quenching, and the spray group switching mode repeats step (2).

[0033] After the first steel plate enters the low pressure section, it swings between 10-18m at a roller speed of 0.02m / s in the low pressure section of the quenching machine; after the second steel plate enters the low pressure section, it swings between 2-10m at the same roller speed of 0.02m / s.

[0034] After the swinging time is over, the first block quickly exits the quenching machine at a roller speed of 0.25m / s, and the second block runs to the tail end for swinging; after the swinging is over, it quickly exits the quenching machine at a roller speed of 0.25m / s again.

[0035] Therefore, when the technical solution of the present application is upgraded, a quenching machine flow-pressure dual closed-loop control system is established, and the water volume and water pressure adjustment time of each nozzle are shortened by 60%; a water spraying strategy is implemented in which water is turned on in advance when the steel plate passes through the front nozzle and closed in time when the steel plate passes through the rear nozzle, and the steel plate swinging area is moved back to the end of the quenching machine and the swing range is shortened, thereby reducing the energy consumption for quenching a ton of steel by 40%; multiple steel plates are quenched simultaneously and two short steel plates are swung and cooled simultaneously in the low-pressure section, and the quenching efficiency of extra-thick plates is increased by 20%.

[0036] In addition to the above embodiments, the present invention may also have other implementation modes; any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present invention.

Claims

1. A high-efficiency and low-cost quenching control method for medium and thick plates, characterized by: include: Establish a double closed-loop control system of water volume and water pressure for the quenching machine; In the quenching machine passing mode, the corresponding nozzles are controlled to open in advance before the steel plate passes, and the corresponding nozzles are controlled to close after the steel plate passes; In the quenching machine swing mode, move the steel plate swing area back to the end of the quenching machine; Control multiple steel plates to be quenched simultaneously, and control two steel plates to be swung and cooled simultaneously in the low-pressure section.

2. The high-efficiency and low-cost quenching control method for medium and thick plates according to claim 1 is characterized in that: After the corresponding nozzles are controlled to open in advance before the steel plate passes through the quenching machine in the passing mode and the corresponding nozzles are controlled to close after the steel plate passes through, the method further includes: Control the nozzles in the cooling section of the quenching machine where no steel plate passes to close.

3. The high-efficiency and low-cost quenching control method for medium and thick plates according to claim 1 is characterized in that: The controlling of simultaneous quenching of multiple steel plates comprises: Based on the steel plate position tracking system in the quenching machine, the steel plate position is tracked in real time and the moving speed of the steel plate is controlled so that multiple steel plates can be quenched at the same time.

4. The high-efficiency and low-cost quenching control method for medium and thick plates according to claim 3 is characterized in that: The method of tracking the position of the steel plates in real time based on the steel plate position tracking system in the quenching machine and controlling the moving speed of the steel plates so as to quench multiple steel plates simultaneously includes: When the steel loading rhythm is greater than the quenching rhythm, and the first steel plate comes out of the high-pressure section and swings in the low-pressure section, the second steel plate is taken out of the furnace for quenching, and when the first steel plate finishes swinging, the quenching of the second steel plate has not reached the position between the tail of the first steel plate and the diameter of the quenching machine roller.

5. The high-efficiency and low-cost quenching control method for medium and thick plates according to claim 1 is characterized in that: The controlling of the two steel plates to swing and cool simultaneously in the low-pressure section comprises: Control the length of the low-pressure section of the quenching machine to be greater than the length of the previous steel plate + the length of the next steel plate + the diameter of the quenching machine roller * 4.

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