A method for high-efficiency and low-cost quenching control of medium plate

Abstract

The application discloses a kind of for medium plate high-efficiency low-cost quenching control method, it is related to heat treatment technical field, comprising: establishing quenching machine water volume-water pressure double closed-loop control system;In quenching machine pass mode, corresponding nozzle is controlled to open in advance before steel plate passes, and corresponding nozzle is controlled to close after steel plate passes;In quenching machine swing mode, steel plate swing region is moved to quenching machine end;Control multiple steel plates quenching simultaneously, and control two steel plates swing cooling in low pressure section simultaneously.The application reduces the water consumption when quenching, improves quenching efficiency, realizes the high-efficiency low-cost quenching control method of medium plate.

Description

Technical Field

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

[0002] Currently, roller hardening machines are divided into a high-pressure section and a low-pressure section, and use a variable frequency pump for water supply. The design principle of the hardening machine is to rapidly reduce the surface temperature of the steel plate to below 500℃ in the high-pressure section, and then continue cooling with a large amount of low-pressure water to remove the heat from the core of the steel plate until the temperature of the steel plate drops to an acceptable temperature for the product or room temperature. However, due to the limitation of the length of the hardening machine, when the steel plate reaches a certain thickness, it needs to be oscillated and cooled in the low-pressure section until the temperature of the steel plate drops to an acceptable temperature for the product or room temperature before leaving the hardening machine.

[0003] Problems with the thick and extra-thick plate quenching mode include: low quenching roller speed, quenching only one steel plate at a time, and allowing the next steel plate to be quenched only after the steel plate has completely exited the quenching machine. If the steel output rhythm is faster than the quenching rhythm, the steel plate output efficiency will be reduced; the steel plate will oscillate under low pressure for a long time; the existing quenching machine will have a long water adjustment time, and unnecessary water spraying will be prominent, resulting in serious waste of cooling water and high water consumption per ton of steel. Summary of the Invention

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

[0005] To solve the above technical problems, the technical solution of the present invention is as follows: A high-efficiency, low-cost quenching control method for medium-thick plates, comprising: Establish a dual closed-loop control system for water volume and water pressure in the quenching machine; In the quenching machine through mode, the corresponding nozzles are controlled to open in advance before the steel plate passes through, and the corresponding nozzles are controlled to close after the steel plate passes through. In the oscillation mode of the quenching machine, the oscillation area of ​​the steel plate is moved to the end of the quenching machine; Multiple steel plates are quenched simultaneously, and two steel plates are simultaneously oscillated and cooled in the low-pressure section.

[0006] As a preferred embodiment of the efficient and low-cost quenching control method for medium and heavy plates described in this invention, the method further includes, after controlling the corresponding nozzles to open in advance before the steel plate passes through in the quenching machine's through-pass mode and controlling the corresponding nozzles to close after the steel plate passes through, the method also includes: The nozzles in the cooling section of the quenching machine that do not pass through the steel plate are closed.

[0007] As a preferred embodiment of the efficient and low-cost quenching control method for medium-thick plates described in this invention, the method of controlling the simultaneous quenching of multiple steel plates includes: The steel plate position tracking system inside the quenching machine tracks the position of the steel plate in real time and controls the moving speed of the steel plate, so that multiple steel plates can be quenched at the same time.

[0008] As a preferred embodiment of the efficient and low-cost quenching control method for medium and heavy plates described in this invention, the method of using a steel plate position tracking system inside the quenching machine to track the position of the steel plates in real time and control the moving speed of the steel plates to enable simultaneous quenching of multiple steel plates includes: When the steel loading rhythm is greater than the quenching rhythm, and the first steel plate exits the high-pressure section and swings in the low-pressure section, the second steel plate exits the furnace for quenching. When the first steel plate finishes swinging, the second steel plate has not reached the tail of the first steel plate and the diameter position of the quenching machine roller.

[0009] As a preferred embodiment of the efficient and low-cost quenching control method for medium-thick plates described in this invention, wherein controlling the simultaneous oscillating cooling of two steel plates in the low-pressure section includes: The length of the low-pressure section of the quenching machine should be greater than the length of the previous steel plate + the length of the next steel plate + the diameter of the quenching machine roller conveyor * 4.

[0010] The beneficial effects of this invention are: This invention establishes a flow-pressure dual closed-loop control system for the quenching machine, shortening the water volume and pressure adjustment time of each nozzle and reducing water consumption during the lifting and lowering stages; employs a water spraying strategy that opens the nozzle before the steel plate passes and closes the nozzle promptly after the steel plate passes; and moves the swinging area of ​​the steel plate to the end of the quenching machine and shortens the swinging range, further reducing water consumption during quenching; and controls the simultaneous quenching of multiple steel plates and the simultaneous swinging and cooling process of two short steel plates in the low-pressure section, thereby improving quenching efficiency and realizing a high-efficiency and low-cost quenching control method for medium and heavy plates. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

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

[0013] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0014] This application provides a method for efficient and low-cost quenching control of medium-thick plates, which specifically includes the following steps: Step S101: Establish a dual closed-loop control system for water volume and water pressure of the quenching machine.

[0015] For details, see Figure 1 The response-regulation characteristics of the control valve group of the quenching machine were analyzed, the influence of the flow in the pipe on the flow and pressure of each branch water supply pipe was studied, and a dual closed-loop control system for flow and pressure of the quenching machine was established to shorten the adjustment time of water volume and pressure of each nozzle.

[0016] Step S102: In the quenching machine through mode, control the corresponding nozzles to open in advance before the steel plate passes through, and control the corresponding nozzles to close after the steel plate passes through, and control the nozzles in the cooling section of the quenching machine that have not passed through the steel plate to close.

[0017] For details, see Figure 2 In the pass mode, based on the quenching process of different steel grades and thicknesses of steel plates, and based on the micro-tracking of the position of the steel plate in the quenching machine, a water spraying strategy is implemented to open the nozzle in advance before the steel plate passes and close the nozzle in time after the steel plate passes. In addition, the cooling section in the quenching machine without steel plates is not sprayed with water to reduce the amount of cooling water used.

[0018] Step S103: In the oscillation mode of the quenching machine, move the oscillation area of ​​the steel plate to the end of the quenching machine.

[0019] For details, see Figure 3 In the swing mode, based on the quenching process of different steel grades and thicknesses, a water spraying strategy was developed that is based on micro-tracking of the steel plate position inside the quenching machine, moving the swing area of ​​the steel plate 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 amount of cooling water used.

[0020] Step S104: Control multiple steel plates to be quenched simultaneously, and control two steel plates to swing and cool simultaneously in the low-pressure section.

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

[0022] Specifically, when the steel loading rhythm is greater than the quenching rhythm, the second steel plate is quenched while the first steel plate is swinging in the low-pressure section after exiting the high-pressure section. It is also necessary to ensure that the quenching of the second steel plate has not reached the tail of the first steel plate and the diameter position of the quenching machine roller when the swinging of the first steel plate ends.

[0023] To achieve simultaneous oscillating cooling of two steel plates in the low-pressure section, it is necessary to improve the utilization rate of the low-pressure section cooling zone by using multi-plate micro-tracking information transmission and interlocking control based on the quenching machine, thereby enabling simultaneous oscillating cooling of two short steel plates in the low-pressure section and improving quenching efficiency.

[0024] Specifically, to achieve simultaneous oscillation 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 first steel plate plus the length of the second steel plate plus 4 * the diameter of the quenching machine roller.

[0025] The following specific examples will provide further details.

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

[0027] During quenching: When the furnace door is opened, first open 2 sets of spray nozzles. When the head of the steel plate contacts the first set of nozzles, open 2 more sets in sequence based on the existing 2 sets of nozzles. When the steel plate contacts the third set of nozzles, open 2 more sets in sequence... until the last 2 sets / 1 set of nozzles. When the tail of the steel plate passes through 2 sets of spray nozzles, close the first set. When the tail of the steel plate passes through 3 sets of spray nozzles, close the first and second sets... until the steel plate is in the low-pressure oscillation zone.

[0028] When the first steel plate exits the high-pressure section, and the second steel plate travels a distance of 1m (approximately the distance between two sets of nozzles) from the end of the first steel plate's quenching process, it is allowed to exit the furnace for quenching. The spray group switching method repeats step (2).

[0029] After the steel plate enters the low-pressure section, it oscillates between 6-18m in the low-pressure section of the quenching machine at a roller speed of 0.02m / s. After the oscillation time ends, the steel plate exits the quenching machine at a roller speed of 0.25 m / s.

[0030] Case 2: Taking the continuous quenching production of two Q690D steel sheets of the same specifications (150mm*3000mm*6000mm) as an example, the quenching machine is 24m long, with a 6m high-pressure section and an 18m low-pressure section. The quenching roller speed is 0.02m / s. The specific steps of the efficient quenching control method for Q690D are as follows: During frequency ramp-up: By establishing a dual closed-loop control system for flow and pressure in the quenching machine, the frequency ramp-up time of the variable frequency pump is shortened from 150s to 60s.

[0031] During quenching: When the furnace door of the steel plate is opened, first open two sets of spray groups. When the head of the steel plate contacts the first set of nozzles, open two more sets in sequence based on the existing two sets of nozzles. When the steel plate reaches the third set of nozzles, open two more sets in sequence... until the last two sets / one set of nozzles. When the tail of the steel plate passes through two sets of spray groups, close the first set. When the tail of the steel plate passes through three sets of spray groups, close the first and second sets... until the steel plate is in the low-pressure swing zone.

[0032] When the first steel plate exits the high-pressure section, the second steel plate begins to exit 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 oscillates at a roller speed of 0.02 m / s between 10 and 18 m in the low-pressure section of the quenching machine; after the second steel plate enters the low-pressure section, it also oscillates at a roller speed of 0.02 m / s between 2 and 10 m in the low-pressure section.

[0034] After the oscillation time ends, the first piece exits the quenching machine at a roller speed of 0.25 m / s, while the second piece runs to the tail end for oscillation; after the oscillation ends, it exits the quenching machine at a roller speed of 0.25 m / s again.

[0035] Therefore, the technical solution of this application utilizes the establishment of a dual closed-loop control system for flow and pressure of the quenching machine during frequency increase, which shortens the water volume and water pressure adjustment time of each nozzle by 60%; implements a water spraying strategy of opening the nozzle in advance before the steel plate passes through and closing the nozzle in time after the steel plate passes through, and moves the swing area of ​​the steel plate to the end of the quenching machine and shortens the swing range, which reduces the quenching energy consumption per ton of steel by 40%; and improves the quenching efficiency of extra-thick plates by 20% by quenching multiple steel plates at the same time and swinging and cooling two short steel plates at the same time in the low-pressure section.

[0036] In addition to the above embodiments, the present invention may have other implementation methods; all technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A high-efficiency and low-cost quenching control method for medium-thick plates, characterized in that: include: Establish a dual closed-loop control system for water volume and water pressure in the quenching machine; In the quenching machine through mode, the corresponding nozzles are controlled to open in advance before the steel plate passes through, and the corresponding nozzles are controlled to close after the steel plate passes through. In the oscillation mode of the quenching machine, the oscillation area of ​​the steel plate is moved to the end of the quenching machine; Multiple steel plates are quenched simultaneously, and two steel plates are simultaneously oscillated and cooled in the low-pressure section. The method of controlling the simultaneous quenching of multiple steel plates includes: tracking the position of the steel plates in real time based on the steel plate position tracking system inside the quenching machine, and controlling the moving speed of the steel plates to enable the simultaneous quenching of multiple steel plates. The system based on the steel plate position tracking system inside the quenching machine tracks the position of the steel plate in real time and controls the moving speed of the steel plate so that multiple steel plates can be quenched at the same time. This includes: when the steel loading rhythm is greater than the quenching rhythm, and the first steel plate exits the high-pressure section and swings in the low-pressure section, the second steel plate exits the furnace for quenching, and when the swing of the first steel plate ends, the quenching of the second steel plate has not reached the tail of the first steel plate and the diameter position of the quenching machine roller. The control of the two steel plates to swing and cool simultaneously in the low-pressure section includes: controlling the length of the low-pressure section of the quenching machine to be greater than the length of the first steel plate + the length of the second steel plate + the diameter of the quenching machine roller conveyor * 4.

2. The efficient and low-cost quenching control method for medium and heavy plates according to claim 1, characterized in that: In the quenching machine passing mode, after controlling the corresponding nozzles to open in advance before the steel plate passes through and controlling the corresponding nozzles to close after the steel plate passes through, the method further includes: The nozzles in the cooling section of the quenching machine that do not pass through the steel plate are closed.

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